Patent Application
20070000697
The present invention relates generally to methods and apparatus for movement of equipment in passages, and more particularly, the present invention relates to drilling inclined and horizontally extending holes, such as an oil well.
The art of drilling vertical, inclined, and horizontal holes plays an important role in many industries such as the petroleum, mining, and communications industries. In the petroleum industry, for example, a typical oil well comprises a vertical borehole which is drilled by a rotary drill bit attached to the end of a drill string. The drill string is typically constructed of a series of connected links of drill pipe which extend between surface equipment and the drill bit. A drilling fluid, such as drilling mud, is pumped from the surface through the interior surface or flow channel of the drill string to the drill bit. The drilling fluid is used to cool and lubricate the drill bit, and remove debris and rock chips from the borehole created by the drilling process. The drilling fluid returns to the surface, carrying the cuttings and debris, through the space between the outer surface of the drill pipe and the inner surface of the borehole.
Conventional drilling often requires drilling numerous boreholes to recover oil, gas, and mineral deposits. For example, drilling for oil usually includes drilling a vertical borehole until the petroleum reservoir is reached. Oil is then pumped from the reservoir to the surface. As known in the industry, often a large number of vertical boreholes must be drilled within a small area to recover the oil within the reservoir. This requires a large investment of resources, equipment, and is very expensive. Additionally, the oil within the reservoir may be difficult to recover for several reasons. For instance, the size and shape of the oil formation, the depth at which the oil is located, and the location of the reservoir may make exploitation of the reservoir very difficult. Further, drilling for oil located under bodies of water, such as the North Sea, often presents greater difficulties.
In order to recover oil from these difficult to exploit reservoirs, it may be desirable to drill a borehole that is not vertically orientated. For example, the borehole may be initially drilled vertically downwardly to a predetermined depth and then drilled at an inclination to vertical to the desired target location. In other situations, it may be desirable to drill an inclined or horizontal borehole beginning at a selected depth. This allows the oil located in difficult-to-reach locations to be recovered. These boreholes with a horizontal component may also be used in a variety of circumstances such as coal exploration, the construction of pipelines, and the construction of communications lines.
While several methods of drilling are known in the art, two frequently used methods to drill vertical, inclined, and horizontal boreholes are generally known as rotary drilling and coiled tubing drilling. These types of drilling are frequently used in conjunction with drilling for oil. In rotary drilling, a drill string, consisting of a series of connected segments of drill pipe, is lowered from the surface using surface equipment such as a derrick and draw works. Attached to the lower end of the drill string is a bottom hole assembly. The bottom hole assembly typically includes a drill bit and may include other equipment known in the art such as drill collars, stabilizers, and heavy-weight pipe. The other end of the drill string is connected to a rotary table or top drive system located at the surface. The top drive system rotates the drill string, the bottom hole assembly, and the drill bit, allowing the rotating drill bit to penetrate into the formation. In a vertically drilled hole, the drill bit is forced into the formation by the weight of the drill string and the bottom hole assembly. The weight on the drill bit can be varied by controlling the amount of support provided by the derrick to the drill string. This allows, for example, drilling into different types of formations and controlling the rate at which the borehole is drilled.
The direction of the rotary drilled borehole can be gradually altered by using known equipment such as a downhole motor with an adjustable bent housing to create inclined and horizontal boreholes. Downhole motors with bent housings allow the surface operator to change drill bit orientation, for example, with pressure pulses from the surface pump. It will be understood that orientation includes inclination, asmuth, and depth components. Typical rates of change of orientation of the drill string are 1-3 degrees per 100 feet of vertical depth. Hence, over a distance of about 3,000 feet, the drill string orientation can change from vertical to horizontal relative to the surface. A gradual change in the direction of the rotary drilled hole is necessary so that the drill string can move within the borehole and the flow of drilling fluid to and from the drill bit is not disrupted.
Another type of known drilling is coiled tubing drilling. In coiled tubing drilling, the drill string tubing is fed into the borehole by an injector assembly. In this method the coiled tubing drill string has specially designed drill collars located proximate the drill bit that apply weight to the drill bit via gravity pull. In contrast to rotary drilling, the drill string is not rotated. Instead, a downhole motor provides rotation to the drill bit. Because the coiled tubing is not rotated or used to force the drill bit into the formation, the strength and stiffness of the coiled tubing is typically much less than that of the drill pipe used in comparable rotary drilling. Thus, the thickness of the coiled tubing is generally less than the drill pipe thickness used in rotary drilling, and the coiled tubing generally cannot withstand the same rotational and tension forces in comparison to the drill pipe used in rotary drilling.
A known method and apparatus for drilling laterally from a vertical well bore is disclosed in U.S. Pat. No. 4,365,676 issued to Boyadjieff, et al. The Boyadjieff patent discloses a pneumatically powered drilling unit which is housed in a specially designed carrier, and the carrier and drilling unit are lowered to a desired position within an existing vertical well bore. The carrier and drilling units are then pivoted into a horizontal position within the vertical well bore. This pivotal movement is triggered by a person located at the surface who pulls a string or cable that is attached to one end of the carrier unit. From this horizontal position, the drilling unit leaves the carrier unit and begins drilling laterally to create an abrupt switch from a vertical to a lateral hole. The carrier is removed from the well bore once the drilling unit exists the carrier unit.
The drilling unit disclosed in the Boyadjieff patent discharges air near the drill bit to push the cuttings and rock chips created by the drilling process around the drilling unit. These cuttings are supposed to fall into a sump located at the bottom of the vertical well bore. This causes the bottom end of the vertical well bore to be filled with debris and prevents the use of the vertical well bore. The debris ay also have a tendency to plug and fill the lateral hole. The drilling unit moves within the lateral hole by a series of teeth which are adapted to engage the sidewall of the lateral hole while the hole is being bored. These teeth transfer the drilling forces to the sidewalls of the hole to allow the drill bit to be pushed into the formation. The drilling unit is also connected to a cable guiding and withdrawal tool that is inserted into the vertical well bore to allow removal of the carrier and drilling unit from the lateral hole.
Another method and apparatus for forming lateral boreholes within an existing vertical shaft is disclosed in U.S. Pat. No. 5,425,429 issued to Thompson. The Thompson patent discloses a device that is lowered into a vertical shaft, braces itself against the sidewall of the vertical shaft, and applies a drilling force to penetrate the wall of the vertical shaft to form a laterally extending borehole. The device is generally cylindrical and includes a top section that is sealed to allow complete immersion in drilling mud. The top section also contains a turbine that is powered by the drilling mud. The bottom section of the device is open to the vertical shaft. The device is held in place within the vertical shaft by a series of anchor shoes that are forced by hydraulic pistons to engage the sidewall of the vertical shaft. These hydraulic pistons are powered by the turbine located in the top section of the device.
The device disclosed in the Thompson patent is anchored within the existing vertical shaft to provide support for the drilling unit as it drills laterally. The drilling unit uses an extendable insert ram to drill laterally into the surrounding formation. The insert ram consists of three concentric cylinders that are telescopically slidable relative to each other. The cylinders are hydraulically operated to extend and retract the insert ram within the lateral borehole. A supply of modular drill elements are cyclically inserted between the insert ram and the drill bit so that the insert ram can extend the drill bit into the surrounding formation. In operation, the drilling unit must be stopped and retracted each time the length of the insert ran is to be increased by inserting additional modular drill elements. The insert ram must then re-exlend to the end of the lateral borehole to begin drilling again.
A further method for creating lateral bores is described in U.S. Pat. No. 5,010,965 issued to Schmelzer. The Schmelzer patent discloses a self-propelled ram boring machine for making earth bores. The system is operated using compressed air and is driven by a piston which triggers periodic blows by a striking tip.
U.S. Pat. No. 3,827,512 issued to Edmond discloses an apparatus for applying a force to a drill bit. The apparatus drives a striking bit, under hydraulic pressure, against a formation which causes the striking bit to form a borehole. In particular, the body of the apparatus is a cylinder containing two hydraulically operated pistons. Connected to the pistons are two anchoring assemblies which are located around the exterior surface of the tool. The anchoring assemblies contain a plurality of serrations and are periodically actuated to engage the sidewall of the borehole. These anchors provide support for the apparatus within the borehole such that a drill bit can be forced into the formation. The drill bit, however, can only be pushed in one direction. Additionally, the drill bit can only be periodically pushed into the formation because the apparatus must repeatedly unanchor and repressurize the piston chambers to move within the borehole.
The present invention provides improved methods and apparatus for movement of equipment in passages. In a preferred embodiment, the present invention provides improved methods and apparatus for moving drilling equipment in passages. More preferably, the present invention allows drilling equipment to be moved within inclined or completely horizontal boreholes that extend for distances beyond those previously known in the art. The equipment utilized for this purpose is structurally simple and provides for easy in-the-field maintenance. The structural simplicity of the present invention increases the reliability of the tool. The equipment is also easy to operate with lower initial and long-term costs than equipment known in the art. Additionally, the present invention is readily adapted to operate in environments where known methods and apparatuses are unable to function.
The apparatus is able to move a wide variety of types of equipment within a borehole, and in a preferred embodiment the present invention can solve many of the problems presented by prior art methods of drilling inclined and horizontal boreholes. For example, conventional rotary drilling methods and coiled tubing drilling methods are often ineffective or incapable of producing a horizontally drilled borehole or a borehole with a horizontal component because sufficient weight cannot be maintained on the drill bit. Weight on the drill bit is required to force the drill bit into the formation and keep the drill bit moving in the desired direction. For example, in rotary drilling of long inclined holes, the maximum force that can be generated by prior art systems is often limited by the ability to deliver weight to the drill bit. Rotary drilling of long inclined holes is limited by the resisting friction forces of the drill string against the borehole wall. For these reasons, among others, current horizontal rotary drilling technology limits the length of the horizontal components of boreholes to approximately 4,500 to 5,500 feet because weight cannot be maintained on the drill bit at greater distances.
Coiled tubing drilling also presents difficulties when drilling or moving equipment within extended horizontal or inclined holes. For example, as described above, there is the problem of maintaining sufficient weight on the drill bit. Additionally, the coiled tubing often buckles or fails because frequently too much force is applied to the tubing. For instance, a rotational force on the coiled tubing may cause the tubing to shear, while a compression force may cause the tubing to collapse. These constraints limit the depth and length of holes that can be drilled with existing coiled tubing drilling technology. Current practices limit the drilling of horizontally extending boreholes to approximately 1,000 feet horizontally.
The methods and preferred apparatus of the present invention solve these prior art problems by generally maintaining the drill string in tension and providing a generally constant force on the drill bit. The problem of tubing buckling experienced in conventional drilling methods is no longer a problem with the present invention because the tubing is pulled down the borehole rather than being forced into the borehole. Additionally, the current invention allows horizontal and inclined holes to be drilled for greater distances than by methods known in the art. The 500 to 1,500 foot limit for horizontal coiled tubing drilled boreholes is no longer a problem because the preferred apparatus of the present invention can force the drill bit into the formation with the desired amount of force, even in horizontal or inclined boreholes. In addition, the preferred apparatus allows faster, more consistent drilling of diverse formations because force can be constantly applied to the drill bit.
A preferred aspect of the present invention provides a method for propelling a tool having a body within a passage. The method includes causing a gripper including at least a gripper portion to assume a first position that engages an inner surface of the passage and limits relative movement of the gripper portion relative to the inner surface. The method also includes causing the gripper portion to assume a second position that permits substantially free relative movement between the gripper portion and the inner surface of the passage. The method further includes a propulsion assembly for selectively continuously moving the body with respect to the gripper portion while the gripper portion is in the first position.
Another preferred aspect of the present invention provides a method for propelling a tool having a generally cylindrical body within a passage. The method includes causing a first gripper portion to assume a first position that engages an inner surface of the borehole passage and limits relative movement of the first gripper portion relative to the inner surface. Simultaneously, a second gripper portion assumes a position that permits substantially free relative movement between the second gripper portion and the inner surface of the borehole. The body of the tool, consisting of a central coaxial cylinder and a valve control pack, moves within the borehole with respect to the first gripper portion. The first gripper portion then assumes a second position that permits substantially free relative movement between the first gripper portion and the inner surface of the passage, while the second gripper portion engages the inner surface of the borehole and limits relative movement of the second gripper portion relative to the inner surface. At this time the body of the tool moves relative to the second gripper portion. This process can be repeated to allow the body of the tool to selectively continuously move with respect to at least one gripper portion. While prior art methods prevent continuous movement and drilling within a borehole, the present invention allows continuous operation, and a force can be constantly maintained on the drill bit.
Another aspect of the present invention provides a method for propelling a tool having a generally cylindrical body within a passage. The method includes causing a first gripper portion to assume a first position that engages the inner surface of the borehole and limits relative movement of the first gripper portion relative to the inner surface of the borehole. The body of the tool is then moved with respect to the first gripper portion. The first gripper portion then assumes a second position that permits substantially free relative movement between the first gripper portion and the inner surface of the borehole. At this time a second gripper portion assumes a first position that engages an inner surface of the borehole and limits relative movement of the second gripper portion relative to the inner surface of the passage. The body of the tool is then moved with respect to the second gripper portion. The second gripper portion then assumes a second position that permits substantially free relative movement between the second gripper portion and the inner surface of the borehole. By selectively continuously moving the body with respect to at least one gripper portion when it is in the position that allows substantially free relative movement between the gripper portion and the inner surface of the borehole, the present invention can continuously move within the borehole.
Still another preferred aspect of the present invention provides a method of propelling a tool having a generally cylindrical body within a passage using first and second engagement bladders. The first engagement bladder is inflated to assume a position that engages an inner surface of the passage and limits relative movement of the first engagement bladder relative to the inner surface of the passage. An element of the tool then moves with respect to the first engagement bladder. The second engagement bladder is in a position allowing free relative movement between the second engagement bladder and the inner surface of the passage. The first engagement bladder then deflates, allowing free relative movement between the first engagement bladder and the inner surface of the passage. The second engagement bladder is then inflated to assume a position that engages an inner surface of the passage and limits relative movement of the second engagement bladder relative to the inner surface. At this time an element of the tool is moved with respect to the second engagement bladder. This process can be cyclicly repeated to allow the tool to generally continuously move forward within the passage.
In a further preferred aspect of the present invention, an ambient fluid is used to inflate the first and second engagement bladders. Preferably, the ambient fluid is drilling fluid or, more preferably, drilling mud. In this aspect of the invention, the drilling mud used to inflate the bladder is from the central flow channel of the drill string. When the engagement bladders are deflated, the drilling mud is preferably returned to the central flow channel. This is referred to as an open system.
In another preferred embodiment of the present invention, a fluid such as hydraulic fluid is used to inflate the engagement bladders. The hydraulic fluid may be stored within a reservoir within the tool or it may be pumped from the surface to the engagement bladders through a flow line. This is referred to as closed system.
Equipment known in the art for drilling horizontally extending boreholes is relatively bulky and expensive both in initial and long-term operating costs. These known devices also require lengthy maintenance time as in-the-field service is generally not a viable option. In contrast, the apparatus of the present invention reduces the cost and maintenance constraints of the known drilling methods. For example, the present invention is easy to operate, with lower initial and long-term costs than those known in the art. The present invention also eases in-the-field maintenance for several reasons. First, in this preferred embodiment, the apparatus of the present invention is designed to operate with ambient fluid. Preferably the ambient fluid is drilling fluid or, more preferably, drilling mud. Advantageously, when a fluid such as drilling mud is used to power the present invention, problems of contamination are eliminated. This design eases problems associated with deterioration of the tool caused by the mixing of different fluids. Alternatively, when a fluid such as hydraulic fluid is used to power the invention, the hydraulic fluid may be either stored within the body of the tool or pumped from the surface to the tool. Second, many of the parts of the present invention are easily removed and disconnected for in-the-field changes of various elements. These elements can simply be removed and replaced in-the-field, allowing quicker changeovers and continued operation of the tool. Significantly, this eliminates much of the down time of conventional drilling equipment.
Another preferred aspect of the present invention provides a method for propelling a tool having a generally cylindrical body within a passage. The method includes causing a gripper portion to assume a first position in which the gripper portion engages an inner surface of the passage and limits relative movement of the gripper portion relative to the inner surface of the passage. The gripper portion is also caused to assume a second position that allows substantially free relative movement between the gripper portion and the inner surface of the passage. A propulsion assembly is provided for selectively moving the body with respect to the gripper portion in the first position. The power source includes a piston having a head reciprocally mounted within a cylinder so as to define a first chamber on one side of the head and a second chamber on the other side of the head. The body of the tool is selectively moved with respect to the gripper portion by forcing fluid into the first or second chamber.
Yet another preferred aspect of the present invention provides a method for propelling a tool having a generally cylindrical body within a passage in which the movement of the tool is controlled from the surface. The surface controls can preferably be manually or automatically operated. The tool may be in communication with the surface by a line which allows information to be communicated from the surface to the tool. This line, for example, may be an electrical line (generally known as an “E-line”), an umbilical line, or the like. In addition, the tool may have an electrical connection on the forward and aft ends of the tool to allow electrical connection between devices located on either end of the tool. This electrical connection, for example, may allow connection of an E-line to a Measurement While Drilling (MWD) system located between the tool and the drill bit. Alternatively, the tool and the surface may be in communication by down linking in which a pressure pulse from the surface is transmitted through the drilling fluid within the fluid channel to a transceiver. The transceiver converts the pressure pulse to electrical signals which are used to control the tool. This aspect of the invention allows the tool to be linked to the surface, and allows Measurement While Drilling systems, for example, to be controlled from the surface. Additional elements known in the art may be linked to the various embodiments of the present invention.
In another preferred aspect, the apparatus may be equipped with directional control to allow the tool to move in forward and backward directions within the passage. This allows equipment to be placed in desired locations within the borehole, and eliminates the removal problems associated with known apparatuses. It will be appreciated that the tool in each of the preferred aspects may also be placed in an idle or stationary position with the passage. Further, it will be appreciated that the speed of the tool within the passage may be controlled. Preferably, the speed is controlled by the power delivered to the tool.
These preferred aspects of the present invention can be used, for example, in combination with drilling tools to drill new boreholes which extend at vertical, horizontal, or inclined angles. The present invention also may be used with existing boreholes, and the present invention can be used to drill inclined or horizontal boreholes of greater length than those known in the art. Advantageously, the tool can be used with conventional rotary drilling apparatuses or coiled tubing drilling apparatuses. The tool is also compatible with various drill bits, motors, MWD systems, downhole assemblies, pulling tools, lines and the like. The tool is also preferably configured with connectors which allow the tool to be easily attached or disconnected to the drill string and other related equipment. Significantly, the tool allows selectively continuous force to be applied to the drill bit, which increases the life and promotes better wear of the drill bit because there are no shocks or abrupt forces on the drill bit. This continuous force on the drill bit also allows for faster, more consistent drilling. It will be understood that the present invention can also be used with multiple types of drill bits and motors, allowing it to drill through different kinds of materials.
It will also be appreciated that two or more tools, in each of the preferred embodiments, may be connected in series. This may be used, for example, to move a greater distance within a passage, move heavier equipment within a passage, or provide a greater force on a drill bit. Additionally, this could allow a plurality of pieces of equipment to be moved simultaneously within a passage.
Advantageously, the present invention can be used to pull the drill string down the borehole. This advantageously eliminates many of the compression and rotational forces on the drill string, which cause known systems to fail. The invention is also relatively simple and eliminates many of the multiple parts required by the prior art apparatuses. Significantly, in one preferred aspect the tool is self-contained and can fit entirely within the borehole. Further, the gripping structures of the present invention do not damage the borehole walls as do the anchoring structures known in the art. For these and other reasons described in more detail below, the present invention is an improvement over known systems.
The present invention also makes drilling in various locations possible because, for example, oil reserves that are currently unreachable or uneconomical to develop using known methods and apparatuses can be reached by using an apparatus of the present invention to drill horizontal or inclined boreholes of extended length. This allows economically marginal oil and gas fields to be productively exploited. In short, the preferred embodiments of the present invention present substantial advantages over the apparatuses and methods disclosed in the prior art.
These and other features of the invention will now be described with reference to the drawings of preferred embodiments, which are intended to illustrate and not to limit the invention.
FIGS. 17A1-4 are four cross sections of the valve control pack taken along the lines 17A1-4-17A1-4 of
As shown in
It will be understood that the apparatus and method for moving equipment within a passage may be used in many applications in addition to drilling. For example, these other applications include well completion and production work for producing oil from an oil well, pipeline work, and communication activities. It will be appreciated that these applications require the use of other equipment in conjunction with a preferred embodiment of the present device so that the device can move the equipment within the passage. It will be appreciated that this equipment, generally referred to as a working unit, is dependent upon the specific application undertaken.
For example, one of ordinary skill in the art will understand that well completion typically requires that the reservoir be logged using a variety of sensors. These sensors may operate using resistivity, radioactivity, acoustic, and the like. Other logging activities include measurement of formation dip and borehole geometry, formation sampling, and production logging. These completion activities can be accomplished in inclined and horizontal boreholes using a preferred embodiment of the device. For instance, the device can deliver these various types of logging sensors to regions of interest. The device can either place the sensors in the desired location, or the device may idle in a stationary position to allow the measurements to be taken at the desired locations. The device can also be used to retrieve the sensors from the well.
Examples of production work that can be performed with a preferred embodiment of the device include sands and solids washing and acidizing. It is known that wells sometimes become clogged with sand and other solids that prevent the free flow of oil into the borehole. To remove this debris, specially designed washing tools known in the industry are delivered to the region, and fluid is injected to wash the region. The fluid and debris then return to the surface. These washing tools can be delivered to the region of interest by a preferred embodiment of the device, the washing activity performed, and the tool returned to the surface. Similarly, wells can become clogged with hydrocarbon debris that is removed by acid washing. Again, the device can deliver the acid washing tools to the region of interest, the washing activity performed, and the acid washing tools returned to the surface.
In another example, a preferred embodiment of the device can be used to retrieve objects, such as damaged equipment and debris, from the borehole. For example, equipment may become separated from the drill string, or objects may fall into the borehole. These objects must be retrieved or the borehole must be abandoned and plugged. Because abandonment and plugging of a borehole is very expensive, retrieval of the object is usually attempted. A variety of retrieval tools known to the industry are available to capture these lost objects. This device can be used to transport retrieving tools to the appropriate location, retrieve the object, and return the retrieved tool to the surface.
In yet another example, a preferred embodiment of the device can also be used for coiled tubing completions. As known in the art, continuous-completion drill string deployment is becoming increasingly important in areas where it is undesirable to damage sensitive formations in order to run production tubing. These operations require the installation and retrieval of fully assembled completion drill string in borehole with surface pressure. This device can be used in conjunction with the deployment of conventional velocity string and simple primary production tubing installations. The device can also be used with the deployment of artificial lift installations. Additionally, the device can also be used with the deployment of artificial lift devices such as gas lift and downhole flow control devices.
In a further example, a preferred embodiment of the device can be used to service plugged pipelines or other similar passages. Frequently, pipelines are difficult to service due to physical constraints such as location in deep water or proximity to metropolitan areas. Various types of cleaning devices are currently available for cleaning pipelines. These various types of cleaning tools can be attached to the device so that the cleaning tools can be moved within the pipeline.
In still another example, a preferred embodiment of the device can be used to move communication lines or equipment within a passage. Frequently, it is desirable to run or move various types of cables or communication lines through various types of conduits. This device can move these cables to the desired location within a passage.
It will be understood that two or more of the preferred embodiments of the device may be connected in series. This may be used, for example, to allow the device to move a greater distance within a passage, move heavier equipment within a passage, or provide a greater force on a drill bit. Additionally, this could allow a plurality of pieces of equipment to be moved simultaneously within a passage.
As can be seen from the above examples, preferred embodiments of the device can provide transportation or movement to various types of equipment within a passage.
Basic System Components
As shown in
When operated, the tool 112 is configured to move within the borehole 132. This movement allows, for example, the tool 112 to maintain a preselected force on the drill bit 130 such that the rate of drilling can be controlled. The tool 112 can also be used to maintain a preselected force on the drill bit 130 such that the drill bit 130 is constantly being forced into the formation. Alternatively, the tool 112 may be used to move various types of equipment within the borehole 132. Advantageously, in coiled tubing drilling, for example, the tool 112 allows sufficient force to be maintained on the drill bit 130 to permit drilling of extended inclined or horizontal boreholes. Significantly, because the tool 112 pulls the coiled tubing 114 through the borehole 132, this eliminates many of the compression forces that cause coiled tubing in conventional systems to fail.
It will be understood that the apparatus of the preferred embodiment is used to produce extended horizontal or inclined boreholes in conjunction with this or similar coiled tubing drilling surface equipment, or with a rotary drilling system, as known in the art. The tool 112, however, may also be utilized with other types of drilling equipment, logging systems, or systems for moving equipment within a passage.
As seen in
Referring to
Fixed to the exterior surface of the outer cylindrical pipe 214 of the forward section 200 are two forward pistons 224. The forward pistons 224 are positioned within corresponding forward barrel assemblies 226. The forward barrel assemblies 226 reciprocate about the fixed forward pistons 224, and the forward gripper mechanism 222 is attached to the forward barrel assemblies 226 such that the forward gripper mechanism 222 moves with the forward barrel assemblies 226. The forward pistons 224, the forward barrel assemblies 226, and the outer surface of the outer cylindrical pipe 214 generally define forward reset chambers 230 and forward power chambers 232 in the forward section 200 of the tool 112.
Fixed to the exterior of the outer cylindrical pipe 214 of the aft section 202 of the tool 112 are two aft pistons 234. The aft pistons 234 are positioned within the corresponding aft barrel assemblies 236. The aft barrel assemblies 236 reciprocate about the fixed aft pistons 234, and the aft gripper mechanism 207 is attached to the aft barrel assemblies 236 such that the aft gripper mechanism 207 moves with the aft barrel assemblies 236. The aft pistons 234, the aft barrel assemblies 236, and the outer surface of the outer cylindrical pipe 214 generally define aft reset chambers 240 (
As shown in
Overview of System Flow Pattern and Operation
When the tool 112 is used in conjunction with rotary or coiled tubing drilling, the drill string provides drilling fluid to the central flow channel 206. Typically, the drilling fluid is drilling mud which is pumped from the surface, through the drill string and central flow channel 206, to the bottom hole assembly 120. The drilling fluid is returned to the surface in the area between the inner surface 246 of the borehole 132 and the outer surface of the tool 112. As shown in
In particular, as shown in
In an alternate configuration, the outer cylindrical pipe 214 and the inner mandrel 556 can have matching splines or grooves. This allows the transmission of rotational displacement from the coiled tubing 114 through the connector 116 to the aft barrel assemblies 236 through the aft expandable bladder 252 to the inner surface 246 of the borehole 132. This configuration advantageously prevents rotational displacement from the downhole motor 122 being delivered to the coiled tubing 114, thus assisting in the prevention of helical buckling.
As seen in
In
As fluid enters the aft power chambers 242, the aft pistons 234 begin to move forward relative to the aft barrel assemblies 236 and toward the forward ends of the aft barrel assemblies 236. This movement propels the aft pistons 234 and three concentric cylindrical pipes 201 of the tool 112 forward. This causes the tool 112 to move forwardly within the borehole 132 while simultaneously pulling the coiled tubing 114 behind it. The fluid in the forward reset chambers 240 of the aft section 202 is forced out into the return flow annulus 212A by the forward movement of the aft pistons 234, providing pressure in the return flow annulus 212A. Simultaneously, fluid is driven through the return flow annulus 212F into the forward reset chambers 230 of the forward section 200 of the tool 112 to reset the forward pistons 224 and forward barrel assemblies 226. In a similar manner to that described above, fluid forces the forward barrel assemblies 226 to move forward relative to the forward pistons 224 (note that the forward expandable bladder 250 is not inflated during the reset stage). The reset stage causes the forward pistons 224 to be located proximate the aft ends of the forward barrel assemblies 226, as shown in
At this point, the forward expandable bladder 250 begins to inflate, contacting and applying a force against the inner surface 246 of the borehole 132. The aft expandable bladder 252 then begins to deflate. As shown in
Flow Through the Valve Control Pack
The filters 302 are designed to remove particles and debris from the drilling fluid which increases the reliability and durability of the tool 112 because impurities that may wear and damage tool elements are removed. Filtering also allows greater tolerances of the various elements contained within tool 112. Preferably, the filters 302 are designed to remove particles greater than 73 microns in diameter. It will be appreciated that the size and number of filters 302 may be varied according to numerous factors, such as the type of drilling fluid utilized or the tolerances of the tool 112. Preferably, filters 302 are a wire mesh filter manufactured by Ejay Filtration, Inc. of Riverside, Calif.
The filtered drilling fluid then flows to the idler start/stop valve 304 which controls whether fluid flows through the valve control pack 220. Thus, the idler start/stop valve 304 preferably acts like an on/off switch to control whether the tool 112 is moving within the borehole 132. Preferably, the idler start/stop valve 304 is set at some predetermined pressure set-point, 500 psid, for example. This pressure set-point is based on differential pressure between the central flow channel 206 and the pressure in the idler start/stop valve 304 pilot line, which connects the central flow channel 206 and the exterior surface of the tool 112. When the pressure of the drilling fluid in the central flow channel 206 exceeds the predetermined pressure set-point, the idler start/stop valve 304 actuates allowing fluid to enter the idler start/stop valve 304. When the idler start/stop valve 304 opens, the filtered drilling mud flows from the idler start/stop valve 304 into the six-way valve 306. The six-way valve 306 can be actuated into one of three positions, two of which are shown in
As seen in
Simultaneously, flow exits the six-way valve 306 through opening C3, enters the return flow annulus 212A, proceeds into the aft section 202 of the tool, and flows into the aft section 202 aft reset chambers 240. The pressure of the fluid in the aft reset chambers 240 causes the aft barrel assemblies 236 to move forward relative to the aft pistons 234. The forward movement of the aft barrel assemblies 236 causes fluid in the aft power chambers 242 and the aft gripper mechanism 207 to flow into the power flow annulus 216A. This fluid then flows into the six-way valve 306 through passage Cl. Simultaneously, flow is driven out of the forward section 200 forward reset chambers 230, into the return flow annulus 212F, and into the six-way valve 306 through port C4.
These movements generally show the forward section 200 thrust stage or power stroke. During this power stroke the forward section 200 causes the three concentric cylindrical pipes 201 to move forward within the borehole 132. Advantageously, in a preferred embodiment, this movement can be used to force the drill bit 130 into a formation. At the end of the forward section 200 power stroke, the six-way valve 306 is actuated due to pressure differences between the aft reverser valve 310 and the forward reverser valve 312. This pressure differential is caused by the pressure difference between the flow leaving the aft section 202 aft power chambers 242 and the flow entering the forward section 200 forward power chambers 232. These flows enter the power flow annulus 216 and flow to the forward reverser valve 312 and the aft reverser valve 310, respectively. This pressure differential causes the six-way valve 306 to move into position to supply fluid to the aft section 202 aft power chambers 242, as shown in
In the position shown in
Simultaneously, fluid is directed from the six-way valve 306, through passage C4, and the return flow annulus 212F, and into the forward section 200 forward reset chambers 230. The fluid pressure in the forward reset chambers 230 causes the forward barrel assemblies 226 to move forward relative to the forward pistons 224. This also causes the fluid in the forward gripper mechanism 222 and the forward section 200 forward power chambers 232 to flow into the power flow annulus 216F. This fluid in the power flow annulus 216F then flows into the six-way valve 306 through passage C2. These movements comprise the aft section 202 power stroke. During this power stroke, the three concentric cylindrical pipes 201 move forward within the borehole 132. At the end of the aft section 202 power stroke, the forward reverser valve 312 actuates the six-way valve 306 due to pressure differences between the forward reverser valve 312 and the aft reverser valve 310. This activation forces the six-way valve 306 into the position illustrated in
Detailed Structure of the Forward and Aft Sections
As best seen in
The aft section 202 of the puller-thruster downhole tool 112 is linked to known equipment, such as the drill string, by a connector 510. As best seen in
As seen in
As best seen in
As shown in
A fourth cylindrical pipe or aft piston skin 570 surrounds a portion of the aft section of the outer cylindrical pipe 214 at a distance from the outer cylindrical pipe 214. Positioned between the aft piston skin 570 and the outer cylindrical pipe 214 are aft barrel ends 574. The aft barrel ends 574 are rigidly connected to the aft piston skin 570 by connectors 524. Seals 526 are placed between the inner surface of the aft piston skin 570 and the top surfaces of the aft barrel ends 574, and between the bottom surfaces of the aft barrel ends 574 and the outer surface of the outer cylindrical pipe 214 to prevent the escape of fluid from the aft fluid chamber 572. The aft barrel ends are preferably configured to slide along the outer surface of the outer cylindrical pipe 214.
An aft piston assembly 576 is also located between the skin 570 and the outer cylindrical pipe 214. Connectors 532 attach the aft piston assembly 576 to the outer cylindrical pipe 214 and the second cylindrical pipe 210. Thus, the aft piston assembly 576, which is rigidly fixed to the outer cylindrical pipe 214, is slidably movable relative to the aft piston skin 570. Seals 534 are located between the inner surface of the aft piston skin 570 and the top of the aft piston assembly 576 and between the bottom of the aft piston assembly 576 and the outer surface of the outer cylindrical pipe 214 to prevent fluid from passing around the outer surfaces of the aft piston assembly 576. The area between the aft piston skin 570, aft piston assemblies 576, outer cylindrical pipe 214, and aft barrel ends 574 defines an aft fluid chamber 572. The aft piston assembly 576 is located within the aft fluid chamber 572 so as to divide the aft fluid chamber 572 into a forward section 580 and an aft section 582. The forward section 580 is in fluid communication with the return flow annulus 212A. A port liner 505 links the return flow annulus 212A and the forward section 580 of the aft fluid chamber 572 to prevent the flow of fluid into the power flow annulus 216A. The aft section 582 is in fluid communication with the power flow annulus 216A. A spacer plate (not shown) may be used to prevent the pinching off of flow in the power flow annulus 216A and the return flow annulus 212A.
The aft end of the forward piston skin 516 attaches to a gripper mechanism. More specifically, the gripper mechanism includes an expandable bladder to grip the inner surface 246 of the borehole 132. In this, preferred embodiment the gripper mechanism is a packerfoot assembly 550 that includes an elastomeric body 552. As shown in
The packerfoot assembly 550 contains an elastomeric body 552 that inflates when filled with fluid. The elastomeric body 552 can be made of a variety of known elastomeric materials, the preferred material being reinforced graphite or Kevlar 49. The elastomeric body 552 attaches to the packerfoot assembly 550 by means of blind caps 554. The blind caps 554 are cylinders which fasten the ends of the elastomeric body 552 to an inner mandrel 556. The blind caps 554 are preferably made of 4130 Steel. The blind caps 554 are attached to the inner mandrel 556 by connectors such as set screws 560 and shear pins 562. While the preferred embodiment of the packerfoot assembly 550 uses set screws 560, shear pins 562, and chemical bonding, it is possible to fasten the blind caps 554 to the inner mandrel 556 using many fastener means known in the art. The aft end of the inner mandrel 556 preferably contains pads 564 located between the inner mandrel 556 and the outer cylindrical pipe 214. The pads 564 are constructed of graphite reinforced Teflon in the preferred embodiment, but any stable material with a low coefficient of friction could be utilized. A connector such as a retaining screw 566 bonds the inner mandrel 556 to the pad 564. The pad 564 enables the packerfoot assembly 550 to be slidably movable relative to the outer cylindrical pipe 214. This movability allows the packerfoot assembly 550 to slide relative to the outer cylindrical pipe 214 as the forward piston skin 516 slides relative to the forward piston assembly 530.
As shown in
As shown in
Detailed Structure of the Valve Control Pack
As best seen in
Four radially outward extending stabilizer blades 614 are preferably connected to the front section 200 and the aft section 202 of the puller-thruster downhole tool 112. These stabilizer blades 614 are used to properly position the valve control pack 220 within the borehole 132. Preferably, the valve control pack 220 is centered within the borehole 132 to facilitate the return of the drilling fluid to the surface. The stabilizer blades 614 are preferably constructed from high strength material such as steel. More preferably, the stabilizer blades are constructed of type 4130 steel with an amorphous titanium coating to lower the coefficient of friction between the blades 614 and the inner surface 246 of the borehole 132 and increase fluid flow around the stabilizer blades 614. The stabilizer blades 614 are connected to the coaxial cylinder assembly flanges 606 a plurality of fasteners, such as bolts (not shown in the accompanying figures). The stabilizer blades 614 are preferably spaced equidistantly around the valve control pack body 616. The stabilizer blades 614 are spaced from the valve control pack 220, allowing fluid to exit the valve control pack 220 and flow out around the stabilizer blades 614. This fluid then flows back to the surface with the return fluid flow through the passage between the inner surface 246 of the borehole 132 and the outer surface of the tool 112.
The valve control pack 220 also includes a valve control pack body 616. The valve control pack body 616 is preferably constructed of a high strength material. More preferably, the valve control pack body 616 is machined from a single cylinder of stainless steel, although other shapes and materials of construction are possible. Stainless steel prevents corrosion of the valve control pack body 616 while increasing the life and reliability of the tool 112. As shown in
Several other bores 620, for example, are also located within the valve control pack body 616, allowing fluid communication between the four bores 704, 706, 710, and 712; between the four bores 704, 706, 710, and 712 and the center bore 702; and between the four bores 704, 706, 710, and 712 and the exterior of the valve control pack body 616. These bores 620 are best seen in
As best seen in
Referring to
Part of the flow enters the tool 112 through the valve control pack 220.
As shown in
In the active position, fluid exits the aft reverser valve 310 through port P113 into exit channel 930 leading to the six-way valve 306. The aft reverser valve 310 also contains four exit ports P107 which allow fluid to escape from the valve control pack 220 to the exterior of the valve control pack 220 through the flapper valves 714. The exit ports P107 allow removal of fluids and reduces the tendency for plugging by contamination. When the aft reverser valve 310 shifts from an active to inactive position, the Bellevue spring 916 moves from a compressed position to an uncompressed position, forcing the piston 922 toward the aft end of the valve control pack 220. As the piston 922 moves toward the aft end of the valve control pack 220, the fluid in the fluid piston chamber 920 drains out of the chamber 920 through port P141, into a drain channel 932, and into the passage between the valve control pack 220 and the inner surface 246 of the borehole 132 through an orifice 934. The orifice 934 controls the rate of fluid exiting the fluid piston chamber 920 through the drain channel 932. Advantageously, the system is designed to continue to operate even if the drain channels should be partially or completely plugged. This increases the reliability and durability of the tool 112.
The six-way valve 306 contains fluid piston assemblies 914 at both the forward and aft ends which work in conjunction with each other to control the flow of fluid. As fluid from the aft reverser valve 310 enters the fluid chamber 920 at the aft end of the six-way valve 306 from channel 930 through port P115, the piston 922 pushes the valve body 903 forward relative to the fixed sleeve 901. As the valve body 903 moves forward the fluid chamber 920 at the aft end fills and fluid drains from the fluid chamber 920 at the forward end out port P117 through drain channel 936. This fluid flows through the drain channel 936, past the orifice 940, and into the passage between the valve control pack 220 and the inner surface 246 of the borehole 132. Conversely, as fluid from the forward reverser valve 312 enters the fluid chamber 920 at the forward end of the six-way valve 306 from a channel 942 through port P119, the piston 922 pushes the valve body 903 towards the aft end of valve control pack 220 relative to the fixed sleeve 901. As the valve body 903 moves toward the aft end, the fluid chamber 920 at the forward end fills, and fluid drains from the fluid chamber 920 at the aft end out port P121 through drain channel 944. This fluid flows through drain channel 944, past orifice 946, and into the passage between the valve control pack 220 and the inner surface 246 of the borehole 132.
In the various actuated positions, fluid from the idler start/stop valve 304 flows through exit channel 924 and enters the six-way valve 306 through ports P123 and P125. Fluid also enters and exits the six-way valve 306, depending on the position of the valve, from the forward section 200 power flow annulus 216F through flow channel 926, the forward section 200 return flow annulus 212F through flow channel 952, the aft section 202 power flow annulus 216A through flow channel 954, and the aft section 202 return flow annulus 212A through flow channel 956 through ports P127, P129, P131, and P133, respectively.
The six-way valve 306 contains five exit ports P107 which allow fluid to escape from the six-way valve 306 to the exterior of the valve control pack 220 through the flapper valves 714. These exit ports P107 prevent pressure build-up within the valve 306 and prevent clogging within the valve 306.
As shown in
In the active position, fluid exits the forward reverser valve 312 through port P139 into exit channel 942 leading to the six-way valve 306. The forward reverser valve 312 also contains four exit ports P107 which allow fluid to escape from the valve control pack 220 to the exterior of the valve control pack 220 through the flapper valves 714. When the forward reverser valve 312 shifts from an active to inactive position, the Bellevue spring 916 moves from a compressed position to an uncompressed position forcing the piston 922 toward the forward end of the valve control pack 220. As the piston 922 moves toward the forward end of the valve control pack 220, the fluid in the fluid piston chamber 920 drains out of the chamber 920 through port P143, into a drain channel 960, and into the passage between the valve control pack 220 and the inner surface 246 of the borehole 132 through an orifice 962. The orifice 962 helps maintain pressure within the fluid piston chamber 920.
The valve control pack 220 thus controls fluid distribution to the forward and aft sections 200 and 202 of the puller-thruster downhole tool 112.
Closed System Embodiment
Using drilling mud as the operating fluid for the system has several advantages. First, using drilling fluid prevents contamination of hydraulic fluid and the associated failures. While using hydraulic operating fluid may require supply lines and additional equipment to supply fluid to the tool 112, drilling mud requires no supply lines. Drilling mud use increases the reliability of the tool 112 as fewer elements are necessary and fluid contamination is not an issue.
The closed system shown in
Directionally Controlled System Embodiment
In another embodiment, the puller-thruster downhole tool 112 can be equipped with a directional control valve 2002 to allow the tool 112 to move in the forward and reverse directions within the borehole 132 as shown in
When the differential pressure exceeds the pressure set-point, the directional control valve 2002 actuates to the position shown in
For reversing services, where motion of the tool is desired to be toward the surface and away from the bottom of the borehole 132, the directional control valve 2002 and the bladder sensing valves 2004 are activated. This reverses the action of the pistons 224 and 234 and causes the gripper mechanisms 222, 207 to be activated in the proper sequence to permit the three cylindrical pipes 201 to move toward the surface; the reverse of the normal direction towards the bottom of the borehole 132.
Electrically Controlled Embodiment
While the standard tool 112 is pressure controlled and activated, it may be desirable to equip the tool 112 with electrical control lines. The standard tool 112 is pressure activated and has a lower cost than a tool 112 with electrical control. The standard tool has greater reliability and durability because it has fewer elements and no wires which can be cut as does the electrically controlled tool 112. To be compatible with existing systems or future system, electrical control may be required. As such,
The electrical lines 2402 would preferably be shielded within a protective coating or conduit to protect the electrical lines 2402 from the drilling fluid. The electrical lines 2402 may also be constructed of or sealed with a waterproof material, and other known materials. The electrical lines 2402 would preferably run from the control box at the surface to the idler start/stop valve 304 and the directional control valve 2002 through the central flow channel 206 and the center bore 702 of the valve control pack 220. One skilled in the art will recognize that these electrical lines 2402 may be located at various other places within the tool 112 as desired. These electrical lines 2402 then carry electrical signals from the control box at the surface to the idler start/stop valve 304 and the directional control valve 2002 where they trigger the solenoid to open or close the valve.
Alternatively, the electrical lines 2402 could lead to a mud pulse telepathy system rigged for down linking. Mud pulse telepathy systems are known in the art and are commercially available. In down linking, a pressure pulse is sent from the surface through the drilling mud to a downhole transceiver that converts the mud pressure pulse into electrical instructions. Electrical power for the transceiver can be supplied by batteries or an E-line. These electrical instructions actuate the idler start/stop valve 304 or the directional control valve 2002 depending on the desired operation. This system allows direct control of the tool 112 from the surface. This system could be utilized with a bottom hole assembly 120 that includes a Measurement While Drilling device 124 with down linking capability, as known in the art.
Electrical controls can also be used with bottom hole assemblies 120 that contain E-line (electrical line) controlled Measurement While Drilling devices 124. These electrical controls allow the tool 112 to be conveniently operated from the surface. Additional E-lines could be added to the E-line bundle to permit additional electrical connections without affecting the operation of the tool 112.
The tool 112 can also be equipped with electrical connections on the forward and aft ends of the tool 112 that communicate with each other. These electrical connections would allow equipment to operate off power supplied to the tool 112 from the surface or by internal battery. These connections could be used to power many elements known in the art, and to allow electrical communication between the forward and aft ends, 200 and 202, of the tool 112.
While the preferred embodiments of the puller-thruster downhole tool 112 are described, the tool 112 can be constructed on various size scales as necessary. The embodiment described is effective for drilling inclined and horizontal holes, especially oil wells.
Although this invention has been described in terms of certain preferred embodiments, other embodiments apparent to those of ordinary skill in the art are also within the scope of this invention. Accordingly, the descriptions above are intended merely to illustrate, rather than limit the scope of the invention.
This application is a continuation of co-pending Application Ser. No. 10/768,434, filed Jan. 30, 2004, which is a continuation of Application Ser. No. 10/624,249, filed Jul. 22, 2003, now U.S. Pat. No. 6,758,279, which is a continuation of application Ser. No. 09/919,669, filed Jul. 31, 2001, now U.S. Pat. No. 6,601,652, which is a continuation of application Ser. No. 09/213,952, filed Dec. 17, 1998, now U.S. Pat. No. 6,286,592, which is a continuation of application Ser. No. 08/694,910, filed Aug. 9, 1996, now U.S. Pat. No. 6,003,606, which claims priority from abandoned Provisional Application Ser. No. 60/003,555, filed Aug. 22, 1995, abandoned Provisional Application Ser. No. 60/003,970, filed Sept. 19, 1995 and abandoned Provisional Application Ser. No. 60/014,072, filed Mar. 26, 1996. Each of the above-referenced related applications is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60003555 | Aug 1995 | US | |
| 60003970 | Sep 1995 | US | |
| 60014072 | Mar 1996 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10768434 | Jan 2004 | US |
| Child | 11418451 | May 2006 | US |
| Parent | 10624249 | Jul 2003 | US |
| Child | 10768434 | Jan 2004 | US |
| Parent | 09919669 | Jul 2001 | US |
| Child | 10624249 | Jul 2003 | US |
| Parent | 09213952 | Dec 1998 | US |
| Child | 09919669 | Jul 2001 | US |
| Parent | 08694910 | Aug 1996 | US |
| Child | 09213952 | Dec 1998 | US |
