This section is intended to introduce selected aspects of the art, which may be associated with various embodiments of the present disclosure. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present disclosure. Accordingly, it should be understood that this section should be read in this light and not necessarily as admissions of prior art.
The present disclosure relates to the field of hydrocarbon recovery operations. More specifically, the present invention relates to a wireline cutting tool used for releasing a downhole tool by severing the wireline within a wellbore. A novel electrical connection sub that releases the wireline from a downhole signal line is also provided.
In the drilling of an oil and gas well, a near-vertical wellbore is formed through the earth using a drill bit urged downwardly at a lower end of a drill string. After drilling to a predetermined depth, the drill string and bit are removed and the wellbore is lined with a string of casing. An annular region is thus formed between the string of casing and the formation penetrated by the wellbore.
A cementing operation is conducted in order to fill or “squeeze” the annular region with cement along part or all of the length of the wellbore. The combination of cement and casing strengthens the wellbore and facilitates the zonal isolation of aquitards and hydrocarbon-producing zones behind the casing.
In connection with the completion of the wellbore, several strings of casing having progressively smaller outer diameters will be cemented into the wellbore. These will include a string of surface casing, one or more strings of intermediate casing, and finally a production casing. The process of drilling and then cementing progressively smaller strings of casing is repeated until the well has reached total depth. In some instances, the final string of casing is a liner, that is, a string of casing that is not tied back to the surface.
Within the last two decades, advances in drilling technology have enabled oil and gas operators to “kick-off” and steer wellbore trajectories from a vertical orientation to a horizontal orientation. A horizontal “leg” of each of these wellbores now often exceeds a length of one mile, and sometimes two or even three miles. This significantly multiplies the wellbore exposure to a target hydrocarbon-bearing formation. The horizontal leg will typically include production casing.
During the completion of the well, it is common to run certain tools into the well at the end of a long wireline. In the case of wells that are completely horizontally, the tools will be pumped into the wellbore at the end of the wireline. Such tools may include perforating guns, casing collar locators, and well-logging equipment.
The wireline is typically an electric line. The electric line will include an inner conductive wire, which may be a collection of copper or other conductive wires. In one aspect, the inner copper wire represents two insulated wires and a ground wire. The insulated wires may be solid wires or strands that have been braided or otherwise wrapped together.
The electric line will also include an armor layer that resides around the conductive wire core. The armor layer may include a plurality of metal wires which may or may not be stranded or braided. Alternatively, a carbon fiber layer may be used as the armor layer. Those of ordinary skill in the art will understand that a variety of armors are known.
The electric line will also have an outer insulating layer. The outer insulating layer is typically fabricated from a polycarbonate material, designed to withstand the high pressures and high temperatures of the wellbore. The polycarbonate material is also resistant to corrosion from hydrocarbon fluids and wellbore chemicals residing downhole.
The electric wireline will have a defined tensile strength. The tensile strength must be higher than any anticipated tension that may be applied to the line from the surface during pumping and unspooling. In addition, the wireline is designed to have a point of weakness. The point of weakness resides just above the downhole tool, typically at a connection sub. The point of weakness allows the operator to pull the wireline out of the hole in the event the connected downhole tool becomes stuck. This typically occurs when the downhole tool is being pulled through a so-called “dog leg” of the wellbore. The dog leg is a location at which a direction of the wellbore changes sharply, commonly found at a point of inflection between the near-vertical wellbore and the horizontal “leg” of the wellbore.
Severing the wireline at the point of weakness allows the operator to spool the electric line back out of the hole and then run a fishing tool into the wellbore. The fishing tool may be run into the hole at an end of coiled tubing, or other line having a substantially higher tensile strength than the electric line. The fishing tool is designed to catch the wireline tool at the connection sub so that the tool may be removed from the wellbore. If the “fishing expedition” is not successful, the downhole tools are lost. More significantly, the well itself may be lost and will need to be re-drilled.
A problem arises in connection with fishing the downhole tool, that being the frayed electric line can interfere with the operator’s attempts to grab on to the head, or fishing neck, of the downhole tool. Those of ordinary skill in the art will understand that the frayed electric line will expose many wires, fragments, and loose ends. For this reason, a need exists for a way of severing the wireline in a clean and efficient manner without relying upon a point of weakness.
In lieu of a point of weakness, some wireline release mechanisms employ a so-called ballistic release tool. The ballistic release tool resides along the wireline below the casing collar locator (or CCL) and below the weight bars (sometimes referred to as sinker bars). If a perforating gun assembly becomes stuck, the operator can activate the ballistic release tool and bring out the CCL, the weight bars, and the wireline out of the wellbore and back to the surface. However, if the tool string is stuck above the ballistic release tool, or even on the weight bars, it does the operator no good to set off the ballistic release tool as that portion of the tool string below the ballistic release tool will disconnect and the tool string will remain stuck in the wellbore.
It is also observed that the ballistic release tool utilizes an explosive charge that severs the wireline in a violent and sometimes unpredictable manner. Ancillary damage can be done to the tools, or even the wellbore, while at the same time the wireline itself may not always separate.
Therefore, a need again exists for a method of severing an electric line from a downhole tool in a clean, predictable manner just above the casing collar locator or other downhole tools.
A wireline cutting tool is first provided herein. The wireline cutting tool is designed to be run into a wellbore on a wireline with a downhole tool. Examples of a downhole tool include a casing collar locator (CCL) and a perforating gun assembly. The wireline cutting tool is used to sever the wireline in the event that the downhole tool becomes stuck during pull-out. Preferably, the wellbore wireline is an electric wireline.
The cutting tool comprises an upper tubular sub and a lower tubular sub. Each of the subs has a first end and a second end, the second end being opposite the first end, and with a bore extending from the second end and through the first end. The first end of the lower sub is threadedly connected to the second end of the upper sub. Preferably, the second end of the upper sub comprises female threads, while the first end of the lower sub comprises male threads.
The cutting tool also includes a knife housing. The knife housing resides within the bore of the upper sub. The knife housing has a first end, a second end opposite the first end, and a bore extending from the second end up to and through the first end. Of interest, the bore of the knife housing tapers inwardly moving in a direction from the second end of the upper sub toward the first end of the upper sub.
The cutting tool additionally comprises a tubular plunger. The plunger resides within the bore of the lower sub. The plunger has a first end, and a second end opposite the first end. The plunger is configured to slide up the bore of the lower sub in response to a first shear load applied by a wellbore wireline.
The cutting tool also includes at least one knife. Preferably, two knives are provided, with the knives residing on opposing sides of the bore of the knife housing. The knives are configured to slide up the bore of the knife housing from the second end towards the first end in response to a second shear load. The second shear load is greater than the first shear load.
In operation, the sliding up of the plunger causes the first end of the plunger to engage a lower end of the at least one knife. In turn, the sliding up of the at least one knife causes the wellbore wireline to be pinched and ultimately severed.
The wireline cutting tool is designed so that the first shear load is applied by the wireline being spooled from a surface. Additionally, the second shear load is applied by the plunger acting against the at least one knife from below. At the same time, the force applied by the plunger is also by the spooling of the wireline from the surface at the second shear load.
In a preferred embodiment, the wireline cutting tool further comprises an electrical connection sub. The electrical connection sub defines a tubular body, with the tubular body having a shoulder along an outer diameter that abuts the second end of the plunger from below. A first end of the electrical connection sub is received within and is pinned to the plunger. The first end is an upstream end.
The electrical connection sub includes a bore which holds a pin connector. The bore is configured to receive a lower end of the wireline and places the wireline in electrical communication with the pin connector. The pin connector includes an elongated conductive pin that transmits signals from the electrical wireline down to a signal line for the downhole tools.
The bore of the upper sub, the bore of the knife housing, the bore of the plunger, and the bore of the electrical connection sub are aligned. Together, they pass signals from the surface to the downhole tools and back up to the surface.
The wireline cutting tool may include at least one shear pin that holds the plunger in place along the electrical connection sub. Preferably, the at least one shear pin holding the plunger in place comprises at least two shear pins, with the at least two shear pins being fabricated to break at the first shear load. More preferably, the shear pins releasably connect the second end of the plunger to the upper end of the electrical connection sub.
In addition, the wireline cutting tool may include at least one shear pin holding the at least one knife in place along the bore of the knife housing. Preferably, the at least one knife comprises a pair of knives disposed on opposing sides of the bore of the knife housing. In this instance, the at least one shear pin holding the at least one knife in place comprises at least one shear pin holding each of the two knives in place, respectively. The shear pins holding the two knives in place are fabricated to break at the second shear load.
A method of cutting a wireline within a wellbore is also provided herein. In one embodiment, the method first includes providing a wireline cutting tool. The wireline cutting tool may be configured in accordance with the tool disclosed above. In this respect, the wireline cutting tool will comprise:
The method also includes providing a downhole tool. The downhole tool may be, for example, a casing collar locator (including a CCL connector sub) or a perforating gun assembly. Preferably, the downhole tool includes a CCL connector sub, a casing collar locator, and then a perforating gun, all of which form a tool string.
The method further comprises connecting the downhole tool to the wireline cutting tool. Preferably, connecting the downhole tool to the cutting tool is accomplished by connecting the downhole tool to a lower end of an electrical connection sub. Connecting the downhole tool to the lower end of the electrical connection may be accomplished via a threaded connection. At the same time, the plunger is releasably connected to an upper end of the electrical connection sub.
The method then includes running an electric wireline through a bore of each of the knife housing and the plunger. An armor of the wireline is connected to the plunger. Preferably, this involves stripping away an outer insulating coating of the wireline, at least through the bore of the plunger. At the same time, conductive wires within the wireline are placed in communication with the electrical connection subby means of a banana clip or other substantially similar connect means. The electrical communication sub includes a novel pin connector assembly that transmits signals from the wireline down to the downhole tool.
The method also comprises pumping the electric wireline, the electrical connection sub, and the downhole tool into the wellbore. Typically, the wellbore will be completed to have a lengthy horizontal section. Many wells today are completed with horizontal sections that exceed one mile. The method then includes conducting a wellbore operation using the downhole tool. The wellbore operation may be, for example, a perforating operation, a plug setting operation, a well-logging operation, a formation fracturing operation, or combinations thereof.
The method may also comprise:
In connection with the method, the second shear load is greater than the first shear load. Preferably, the shear loads act on shear pins, with one set of shear pins releasably holding the plunger onto the electrical connection sub and another set of shear pins releasably holding the knives in place along the bore of the knife housing. Beneficially, an upper end of the lower sub may include a grease pocket. Viscous fluid residing inside the grease pocket slows the travel of the plunger up the lower sub en route to the knife housing after the first shear load has been applied.
In one embodiment, the method further comprises:
It is noted that the electrical connection sub will come out of the wellbore as part of the wireline downhole tool.
So that the manner in which the present inventions can be better understood, certain illustrations, charts, and/or flow charts are appended hereto. It is to be noted, however, that the drawings illustrate only selected embodiments of the inventions and are therefore not to be considered limiting of scope, for the inventions may admit to other equally effective embodiments and applications.
For purposes of the present application, it will be understood that the term “hydrocarbon” refers to an organic compound that includes primarily, if not exclusively, the elements hydrogen and carbon. Examples of hydrocarbon-containing materials include any form of oil, natural gas, coal, and bitumen that can be used as a fuel or upgraded into a fuel.
As used herein, the term “hydrocarbon fluids” refers to a hydrocarbon or mixtures of hydrocarbons that are gases or liquids. For example, hydrocarbon fluids may include a hydrocarbon or mixtures of hydrocarbons that are gases or liquids at formation conditions, at processing conditions, or at ambient conditions. Hydrocarbon fluids may include, for example, oil, natural gas, condensate, coal bed methane, shale oil, shale gas, and other hydrocarbons that are in a gaseous or liquid state. The term hydrocarbon fluids may include other elements, such as, but not limited to, halogens, metallic elements, nitrogen, oxygen, and/or sulfur.
As used herein, the terms “produced fluids,” “reservoir fluids,” and “production fluids” refer to liquids and/or gases removed from a subsurface formation, including, for example, a hydrocarbon reservoir, a shale formation, or an organic-rich rock formation. Produced fluids may include both hydrocarbon fluids and non-hydrocarbon fluids. Production fluids may include, but are not limited to, oil, natural gas, pyrolyzed shale oil, synthesis gas, a pyrolysis product of coal, carbon dioxide, hydrogen sulfide, and water (including steam).
As used herein, the term “wellbore fluids” means water, hydrocarbon fluids, formation fluids, or any other fluids that may be within a string of production tubing during a production operation.
The term “subsurface interval” refers to a formation or a portion of a formation wherein formation fluids may reside. The fluids may be, for example, hydrocarbon liquids, hydrocarbon gases, aqueous fluids, or combinations thereof.
The terms “zone” or “zone of interest” refer to a portion of a formation containing hydrocarbons. Sometimes, the terms “target zone,” “pay zone,” or “interval” may be used.
As used herein, the term “formation” refers to any definable subsurface region regardless of size. The formation may contain one or more hydrocarbon-containing layers, one or more non-hydrocarbon containing layers, an overburden, and/or an underburden of any geologic formation. A formation can refer to a single set of related geologic strata of a specific rock type or to a set of geologic strata of different rock types that contribute to or are encountered in, for example, without limitation, (i) the creation, generation, and/or entrapment of hydrocarbons or minerals, and (ii) the execution of processes used to extract hydrocarbons or minerals from the subsurface.
As used herein, the term “wellbore” refers to a hole in the subsurface made by drilling or insertion of a conduit into the subsurface. A wellbore may have a substantially circular cross section or other cross-sectional shape. As used herein, the term “well,” when referring to an opening in the formation, may be used interchangeably with the term “wellbore.”
The terms “tubular” or “tubular member” refer to any pipe, such as a joint of casing, a portion of a liner, a joint of tubing, a pup joint, or coiled tubing. The terms “production tubing” or “tubing joints” refer to any string of pipe through which reservoir fluids are produced.
The wireline cutting tool 100 may also be referred to as a mechanical release tool. The wireline cutting tool 100 is designed to go into a wellbore along with a downhole tool 800 and serves as a release mechanism in the event the downhole tool becomes stuck. It is understood that the downhole tool may be part of a longer tool string that includes, for example, weight bars, a logging tool and a perforating gun assembly. These tools can become stuck at the dog-leg of a horizontally completed well, or even in a cork-screw portion.
The wireline cutting tool 100 has a first end 102, and a second end 104 that is opposite the first end 102. In oil and gas parlance, the first end 102 is an upstream end while the second end 104 is a downstream end. The electric wireline 105 passes through the upstream end 102 and is connected internally to a plunger (shown at 150 in
In the view of
The upper sub 120 defines a generally tubular body 125 extending between the first end 122 and second end 124. In one embodiment, the tubular body 125 includes a series of equi-radially disposed flats 127. The flats 127 are useful for turning the tubular body 125 or otherwise tightening the tubular body 125 onto the lower sub 140. Stated another way, and as shown in
Also visible in
A hex nut 107 is used to screw the bushing 103 down onto the first end 122 of the upper sub 120. Specifically, outer threads of the hex nut 107 screw into inner threads 129 along the upper bore portion 123, which serve to hold the bushing 103 in place.
The tubular body 135 of the knife housing 130 include a series of through-openings 136. The series of through-openings 136 are dimensioned to receive pins (seen at 186 in
It is observed from the cross-sectional view of
The lower tubular sub 140 defines a generally tubular body 145 between the first 142 and second 144 ends. As shown in
The inner bore 141 of the lower sub 140 is dimensioned to hold a dart 150.
It can also be seen that a cap 170 has been placed over the upstream end 152 of the dart 150. The cap 170 is a dart cap and is screwed onto the threads at the upstream end 152.
Returning to
As noted earlier, the lower end 154 of the dart 150 is dimensioned to receive an upper end of the electrical connection sub 190. The dart 150 is pinned to the electrical connection sub 190 using the shear pins 959.
The connector sub 160 includes a first end 162, and a second end 164 opposite the first end 162. Each of the first end 162 and second end164 defines female threads. As noted above, first end 162 of the connector sub 160 connects to second end 144 of the lower tubular sub 140.
The connector sub 160 defines a generally tubular body 165 between the first 162 and second 164 ends. In one embodiment, the tubular body 165 includes a series of equi-radially disposed flats 167. The flats 167 are useful for turning the tubular body 165 or otherwise tightening the tubular body 165 onto the lower sub 140 above and the CCL 800 below.
Referring again to
An electrical connection sub 190 and an illustrative casing collar locator 800 are provided at the bottom of the view. The electrical connection sub 190 is shown in more detail in
The wireline cutting tool 100 described above is just one possible embodiment for providing a two-step mechanical release tool. The two steps represent the first shear load that separates the dart 150 from the electrical connection sub 190 followed by a second shear load that moves the knives 180 from a lower position within the knife housing 130 to an upper position. Moving the knives 180 up the upper sub 120 moves the blades 184 closer together, severing the electric wireline 105.
As with the wireline cutting tool 100 of
As with the wireline cutting tool 100 of
Residing within the lower tubular sub 940 is a plunger 950.
It can be seen that the first end 952 includes recessed portions 956. The recessed portions 956 are designed to receive O-rings 957 (seen in
The plunger 950 defines a generally tubular body 955 extending from the first end 952 to the second end 954. Movement of the plunger 950 through the surrounding bore 941 of the lower sub 940 and up the wireline cutting tool 900 is inhibited, or at least slowed, by the presence of grease in the bore 943.
The second end 954 of the plunger 950 is dimensioned to receive an upper end of the electrical connection sub (seen at 190 in
The shear pins 959 will shear when tension at the first shear load is applied to the electric wireline 105. This will cause the plunger 950 to become disconnected from the electrical connection sub 190 and move up the lower sub 940. As the elongated portion 953 of the plunger 950 advances towards the knife housing 130, it travels through the grease trap 943. The displaced grease enters a bore 951 of the plunger 950. However, due to the small inner diameter of the bore 951 along the elongated portion 953, displacement takes place very slowly. This significantly impedes the travel time of the plunger 950, protecting the knife housing 130 and knives 180 from violent contact with the plunger 950 when tension at the first shear load is applied to the wireline 150.
It is observed that, as a matter of designer’s choice, the rate of advance of the plunger 950 towards the knife housing 130 may be manipulated by (i) changing the viscosity of the grease (or other fluid medium) in the grease trap 943 or (ii) adjusting the inner diameter of the upper portion 953 of the plunger 950. The rate of advance may also be manipulated by the operator at the surface based on (iii) the amount of tension applied to the electrical wireline 150.
As shown in
The signal line connector 1250 has a stem 1255. The stem 1255 includes a durable outer layer that protects the electrically conductive pin 1220 as it passes through electrical connection sub 190. The signal line connector 1250 includes a wireline connection end 1252. The wireline connection end 1252 connects to a lowest end of the wireline 105 along the plunger 950. At the same time, the conductive pin 1220 connects to a signal line (not shown) associated with a downhole tool 800. This provides for a quick electrical connection such as by means of a banana clip. Together, the electrical connection sub 190 and the pin 1220 form an electrical connection assembly 1280.
The conductive pin 1220 is shown, in phantom, within the connector sub 160. The pin 1220 is then used to transmit signals up and down the wellbore, through the wireline cutting tool 900. Such signals may include:
It can be seen that the knife 180 includes an inner surface 185. The inner surface 185 faces the bore 131. The knife 180 also has an outer surface 188 which abuts an inner diameter of the knife housing 130. Openings 183 are provided along the knife 180. The openings 183 are dimensioned to align with openings 136 in the body 135 of the knife housing 130 and are configured to slidingly receive the pins 186.
It can be seen that novel wireline cutting tools 100 and 900 have been presented. Using the cutting tools 100 or 900, the present disclosure also provides for a method of cutting an electrical wireline within a wellbore is also provided herein.
The method 1600 first includes providing a wireline cutting tool. This is shown in Box 1605. The wireline cutting tool may be configured in accordance with the tool disclosed above in connection with
In essence, the wireline cutting tool will comprise:
The method 1600 also includes providing a downhole tool. This is provided in Box 1610. The downhole tool may be, for example, a casing collar locator (optionally including a CCL connector sub) or a perforating gun assembly.
The method 1600 further comprises connecting the downhole tool to the cutting tool. This is shown in Box 1615. Connecting the downhole tool to the cutting tool preferably is done by connecting the downhole tool to a lower end of an electrical connection sub, such as by means of a threaded connection. Alternatively, the downhole tool may be threadedly connected to a downstream end of the lower sub. At the same time, the plunger is releasably connected to an upper end of the electrical connection sub.
The method 1600 next includes running an electric wireline through a bore of each of the knife housing and the plunger. This is seen in Box 1620. Preferably, the step of Box 1620 involves stripping away the outer insulating coating of the wireline, exposing the wires, at least through the bore of the plunger. All of the armors of the wireline cable are tied into the plunger, providing the full strength of the wireline to the plunger. This enables the shear pins 959 residing in through-openings 957 and extending into the holes 196 of the electrical connection sub to serve as a point of weakness. Thus, when the wireline is pulled, the plunger is separated from the electrical connection sub.
The method 1600 also comprises pumping the electric wireline, the electrical connection sub, and the downhole tool into the wellbore. This is indicated at Box 1625. Typically, the wellbore will be completed to have a lengthy horizontal section. This is down by forming a dogleg using directional drilling technology as is known in the art. While the tools are moving downhole and across the dogleg, the wireline is unspooled from the surface.
The method 1600 further includes conducting a wellbore operation using the downhole tool. This is seen in Box 1630. The wellbore operation may be, for example, a perforating operation, a plug setting operation, a well logging operation, a formation fracturing operation, or combinations thereof.
The method 1600 also comprises spooling the electric line back up towards the surface. This is provided at Box 1635. As the electric line is spooled, it brings up the wireline cutting tool, the electrical connection sub, and the downhole tool together. As the electric line is spooled, it is not uncommon, or at least it is not rare, for a portion of the tool string to become stuck.
As shown in Box 1640, upon detecting that the downhole tool has become irretrievably stuck in the wellbore, the operator will further spool the wireline. The wireline operator will spool the line until a first shear load is reached. This will cause the plunger to separate from the electrical connection sub and travel up the bore of the lower tubular sub. Stated another way, shear pins 959 will together shear. Immediately thereafter, the plunger will pass through the grease pocket of the lower sub, elongating the conductor cable. This allows the winch operator time to shut down before the second set of pins, that is, the pins in the knife housing, become sheared and the electric wireline is cut.
The time delay afforded by the grease pocket can vary, depending on fluid viscosity, temperature, and the amount of tension applied by the winch operator. The grease prevents the plunger from slamming into the knives, preserving the integrity of the wireline cutting tool for a next job.
It is noted that in a preferred embodiment, a lower end of the wireline is in electrical communication with a pin associated with the electrical connection sub. This may be done, for example, through soldering, by means of a banana clip, or by means of other electrical connector. When the shear pins 959 in the electrical connection sub 190 are sheared in the step of Box 1640, the connection between the wireline 105 and the pin 1220 is also easily broken. This, of course, results in a loss of electrical communication between the surface and the downhole tool(s).
The method 1600 also includes still further spooling the wireline up to a second shear load. This is seen in Box 1645. The second shear load will cause pins 186 holding the knives 180 in place along the knife housing 130 to shear. Because of the angled inner diameter within the knife housing 130, the knives 180 will travel up the bore of the knife housing 130 and squeeze together. The knife blades 184 will pinch the electric wireline 105 to the point of cutting.
The shear pins 959 and the grease pocket/time delay work together with the cutting action to create a more predictable tool. In this way, the wireline 105 may be severed in a clean and efficient manner and the wireline 105 removed, leaving the downhole tool in place within the wellbore. This is provided in Box 1650 and shown in
Note that in connection with the method 1600, the second shear load is greater than the first shear load.
In one embodiment, the method 1600 further comprises running a fishing tool into the wellbore. This is indicated at Box 1655. The fishing tool is sometimes referred to as an overshot.
The method 1600 may also include landing the fishing tool onto an upper end 902 of the wireline cutting tool 900. This is presented in Box 1660. The method 1600 will then include pulling the wireline cutting tool 900 and connected downhole tool out of the wellbore. This is shown at Box 1665.
Further, variations of the wireline cutting tool and the method of severing an electrical wireline may fall within the spirit of the claims, below. It will be appreciated that the inventions are susceptible to modification, variation and change without departing from the spirit thereof.
This application claims the benefit of U.S. Serial No. 63/249,771 entitled “Mechanical Release Tool for Downhole Wireline.” That application was filed on Sep. 29, 2021, and is incorporated herein in its entirety by reference.
Not applicable. Not applicable.
Number | Date | Country | |
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63249771 | Sep 2021 | US | |
63249890 | Sep 2021 | US |