This invention relates to a measurement while drilling tool. More specifically, but without limitation, this invention relates to an apparatus and method for telemetering a down hole parameter from a well.
Operators drill wells many thousands of feet in the search for hydrocarbons. The wells are expensive and take a significant amount of time to plan. Operators find it important to obtain data about the various subterranean reservoirs once the actual drilling begins. Thus, measurement while drilling (MWD) tools have been developed that gather information about the subterranean reservoirs and telemetry the data to the surface. Engineers and geologist can then use this data in an effort to understand the formations and make plans on completion, sidetracking, abandoning, further drilling etc.
MWD tools are expensive tools due to their complexity. The tools are designed for a lifetime of 5-7 years, and the tools are routinely made of expensive materials and electronics which require a lot of maintenance by highly trained personnel. Typically, service companies have geographically positioned regional maintenance facilities that perform these tasks. As the use of MWD and LWD tools expanded, several problems have become evident. One problem is that maintenance requires very high levels of training. Mean time between failures (MTBF) has become the standard measurement for evaluating the reliability of the MWD technology, and a central question is when will the tool fail. Another problem is that the maintenance facilities require large spaces and expensive testing equipment. It is not uncommon for a MWD tool to spend as much time traveling to and from these maintenance facilities as it does at the wellsite. In one study, it was found that a MWD tool string spends less than 90 days a year in a well, and the maintenance and logistics cost of a MWD tool can amount to 50% of the annual expense of the system.
Therefore, it is an object of the present invention to reduce the maintenance and repair time of MWD tools. It is also an object of the present invention to reduce the maintenance and repair cost. It is also an object to manufacture a tool that is less expensive to build, less complex and have higher reliability. These objects, and many others, will be met by the following disclosure.
An apparatus for telemetering a down hole parameter from a well is disclosed. The apparatus comprises a cylindrical housing having a bore there through. The apparatus further comprises an annular main valve positioned within the bore, with the main valve having a center of axis, and wherein the main valve is in a funnel shape having a tubular inlet and tubular outlet, and a restrictor member concentrically disposed within the bore of the cylindrical housing, wherein the restrictor member is aligned with the center of axis, the restrictor member configured to define an annular passage with the main valve. The apparatus also includes: a hydraulic circuit control pressure passage means for supplying hydraulic pressure to the main valve; control means, operatively associated with the restrictor member, for controlling pressure to the main valve; and a solenoid control valve assembly for activating the control means. It should be noted that the solenoid control valve assembly may also be referred to as the magnetic control valve assembly.
In one preferred embodiment, the solenoid control valve assembly comprises a controller for emitting an electrical signal, a coil receiving the electrical signal in order to energize the coil and generating a magnetic field, a solenoid static pole receptive to the generated magnetic field, and a solenoid moving pole responsive to the magnetic field so that the solenoid moving pole moves in a direction towards the solenoid static pole. Also, the control means may comprise a shaft operatively associated with the solenoid moving pole, a ball engageable with the shaft, and a ball seat configured to sealingly engage with the ball. The restrictor member may include a restrictor housing having a bolt that is selectively movable within the restrictor housing to vary the size of the annular passage. The restrictor housing further includes an annular screen for allowing passage of a fluid into an annular cavity.
The cylindrical housing is configured to have an annular flow area for the hydraulic circuit control passage means that communicates pressure from the pressure means to the main valve through the cylindrical housing. In one preferred embodiment, the hydraulic circuit control passage means includes a passage through said static pole and through the ball seat in order to act against the main valve. Additionally, as the coil de-energizes, the shaft, via the moving pole, returns and the ball is allowed to return to seal against the ball seat so that the main valve moves from a first position to a second position thereby enlarging the annular passage.
A method of communicating a down hole parameter is also disclosed. The method comprises providing a down hole apparatus, the down hole apparatus including: a cylindrical housing having a bore; an annular main valve positioned within the bore, the main valve having a center of axis, and wherein the main valve has a first end disposed within the bore and an enlarged second end, and wherein the main valve is movable from a first position to a second position; a restrictor member concentrically disposed within the bore of the enlarged second end of the main valve, wherein the restrictor member being aligned with the center of axis, and wherein the main valve has the first end disposed within the bore and the enlarged second end configured to form an annular passage about the restrictor member; hydraulic circuit control pressure passage means for supplying hydraulic pressure to the main valve.
The method further includes flowing the drilling fluid through the bore, emitting an electrical signal with a controller, and receiving the electrical signal with a coil. The method further includes generating a magnetic field, receiving the magnetic field at a solenoid static pole so that the solenoid static pole is magnetized, and moving a solenoid moving pole in response to the generated magnetic field in the direction of the solenoid static pole. The method further includes moving a shaft, the shaft being operatively attached to the solenoid moving pole. The method further comprises displacing a ball that is seated within a ball seat, allowing pressure from an annular cavity to pass through a hydraulic circuit control pressure passage means which includes through the ball seat and displace the main valve from the first position to the second position, and decreasing the annular passage between the main valve and the restrictor member thereby causing a pressure pulse to be created within the bore of the cylindrical housing indicative of the downhole parameter.
In one preferred embodiment, the step of flowing the drilling fluid through the bore includes channeling the turbulent flow of the drilling fluid through the enlarged second end of the main valve and into the annular passage. The method may further comprise emitting a second electrical impulse signal with the controller, terminating the second electrical signal to the coil so that the magnetic field is terminated, moving the ball onto the ball seat by the pressure within the annular cavity via the pressure within the cavity, terminating the flow through the hydraulic circuit control pressure passage means and moving the main valve from the second position to the first position via the pressure within the bore of the cylindrical housing.
An advantage of the present invention is that the design allows for fewer parts and a shorter tool length. Another advantage is that the components of the system are designed in modules, wherein the modules can be replaced with a new module. Another advantage is that no field service technicians are needed, eliminating maintenance problems. Because the tool is designed to go straight from manufacturing to the rig, much higher utilization rates will be achieved.
A feature of the present invention includes the annular main valve, wherein the funnel shape of the main valve contains all violent, turbulent flow caused by pulsers, and in doing so, it contains all the erosion within its surface that is made of very hard ceramic or tungsten carbide material. Another feature is the ball control valve that utilizes a poppet valve constructed of a separate ball and shaft that allows the ball to seat perfectly by eliminating concentricity issues. Another feature is that the present design is very well suited for fluids with high solid contents.
Yet another feature is the annular screen element that allows a large inlet area for a relatively small axial height, thus allowing the overall length to be significantly shorter than current designs. Still yet another feature is that the annular solenoid doughnut shape provides the geometry best suited to minimize overall valve length. Another feature is the annular control valve. Still yet another feature is the control valve ball seat, pilot driven main valve, and exit that are nearly aligned to minimize axial packaging requirements. Thus, the shortest (minimum axial length) possible valve is obtained.
Referring now to
Referring now to
Referring now to
The restrictor housing 24 holds the restrictor 37 and screen 26 and provides a passage for the drilling fluid from the center of the drill pipe to the annulus cavity between the restrictor 37 and the main valve 30. The restrictor 37 provides the restriction on the inner conical surface of the main valve for the flow of the drilling fluid. If the main valve 30 moves forward enough, the main valve 30 could contact the restrictor 37 and completely shut off the flow of the drilling fluid. In the embodiment shown, however, this could not happen because there is a physical stop upstream of the main valve that stops it from contacting the restrictor. As will be more fully explained later in the application, the solenoid control valve assembly opens and closes and causes flow or no flow through the hydraulic circuit control passage. The restrictor 37 will be attached to the annular control housing 28 as shown in
Returning to
It should be noted that as shown in
Referring now to
As seen in
It should be noted that
Referring back to
According to the teachings of the present invention, there are two (2) states for the pulser 16. In the first state, there is no flow through the hydraulic circuit control passage “BB”. The control valve ball 68 seals against the control valve ball seat 70 and prevents any flow through the hydraulic circuit control passage. The main valve 30 is pushed downstream against the mechanical stop 86 (seen expressly in
In the second state, there is flow through the hydraulic circuit control passage “BB”. The flow goes through the screen 26, then past the control valve ball 68 and ball seat 70 and finally, through a hole 88 in the main valve 30. The opening area of the control valve ball 68 and ball seat 70 of the solenoid control valve assembly is much larger than the hole 88 through the main valve 30. When flow begins in the hydraulic circuit control passage “BB, there is a pressure increase in the annular cavity AC2 of the main valve, that is, P3 increases to the value of P2. That is, the annular pressure of the main valve 30 now experiences the upstream inlet pressure of the pulser 16. This pressure increase causes the main valve 30 to move forward. As the main valve 30 moves forward, it closes the distance (space) between the main valve 30 and the restrictor 37 (i.e. the area of the annular passage decreases). This increases the pressure drop across the tool and more specifically through the restriction between the restrictor 37 and the main valve 30. This causes a pressure pulse that travels at the speed of sound upstream to the drilling rig. The main valve 30 then stops movement as it hits the upstream physical stop 90, which is the radial end of the annular control housing 28.
In operation, the solenoid control valve assembly starts operation in the closed position (i.e. the first state). The control flow through the hydraulic circuit control passage “BB” is shut-off. The net pressure on the main valve 30 is biased downward and so the main valve 30 rest on the downstream stop 86. As understood by those of ordinary skill in the art, the electronics encode sensor data into pressure pulses. Also as well understood by those of ordinary skill in the art, there are many algorithms to encode the sensor data. When it is time to send a pulse, the electronics (controller) send the necessary current and voltage to the solenoid coil 46, which pulls in the moving pole 56 to stop against the static pole 42.
The moving pole 56 pushes the poppet shaft 58, which pushes the ball 68 off the sealing seat 70. As mentioned earlier, this allows a free flow through the hydraulic circuit control passage BB, which is through the screen 26, through the annular space AC1, through the ball seat 70, and past the poppet shaft 58, into the annular cavity AC2 of the main valve in order for the hydraulic pressure to act against the radial surface “S” (on the outer diameter portion of the main valve 30). This control flow is restricted through the small exit hole 88 of the main valve 30 resulting in the system pressure drop being experienced in the AC2. This flow provides an increase in pressure in the annular cavity AC2 of the main valve 30, which creates an imbalance and starts moving the main valve 30 upstream. This movement continues until the main valve 30 hits the up-hole physical stop 90. When the movement stops, there is a tighter restriction in the annular passage “AP” i.e. the flow area between the main valve 30 and the restrictor 37. This restriction causes an increase in pressure above the tool, which can be seen at the surface. After a short time interval (anywhere from 1/10 of a second or greater, depending on the code format), the electronics shuts off the current to the solenoid, which allows the moving pole 56 to return to its un-energized state using the spring force 76. This action shuts-off flow through the hydraulic circuit control passage “BB”, since the ball 68 seats again on the seat 70. The system is again back to the original first state. The main valve 30 then returns to the original position due to the force of the drilling fluid moving down the drill string.
Referring now to
Although the present invention has been described in terms of specific embodiments, it is anticipated that alterations and modifications thereof will no doubt become apparent to those skilled in the art. It is therefore intended that the following claims be interpreted as covering all such alterations and modifications as fall within the true spirit and scope of the invention.