Patent Application
20230399908
The present disclosure is directed to a wireline pressure control string for performing wireline operations on hydrocarbon wells. More particularly, the present disclosure is directed to a wireline pressure control string which includes a pumpdown assembly for controlling the flow of fluid into the well bore during a wireline operation in order to, for example, propel a wireline tool through the well bore. The wireline pressure control string of the present disclosure therefore eliminates the need to provide the wellhead assembly (or assemblies, in a multi-well application) with separate pumpdown valves and associated pumpdown flowline assemblies. One embodiment of the present disclosure is also directed to a wireline pressure control string in which the pumpdown valve is connected to the pumpdown fluid source using a flexible flowline, thereby enabling the wireline pressure control string to be easily maneuvered around the well site.
Hydraulic fracturing, or “fracking”, is a common technique for enhancing the extraction of oil and gas from a hydrocarbon well. Fracking involves injecting a high pressure fracking fluid, or frac fluid, into the well bore in order to create fissures in the hydrocarbon formation through which the oil or gas may flow. Prior to this step, however, the production casing lining the well bore must be perforated. The perforation operation is performed using a perforating gun, which is often deployed on a wireline. The perforating gun is lowered into the well bore using a wireline pressure control string connected to the top of the frac tree. The wireline stack maintains pressure control of the well when the perforating gun is deployed in the well bore.
In many cases, the production casing must be perforated along a laterally extending branch of the well bore. However, gravity alone is typically not sufficient to move the perforating gun toward the perforating zones. In these cases, the perforating gun is typically propelled into the well bore using a pumpdown fluid, such as water. The pumpdown fluid is commonly conveyed to the well bore through a set of pumpdown valves on the frac tree. The pumpdown valves are connected to the pumpdown fluid source through a pumpdown flowline assembly, which normally includes numerous rigid pipes, valves and fittings.
Since each well on a multi-well frac pad must usually be fracked, this arrangement requires that each frac tree have its own set of pumpdown valves and that each set of pumpdown valves be connected to the pumpdown fluid source through a respective pumpdown flowline assembly. As a result, the complete pumpdown flowline assembly may be complicated and time consuming to assemble. In addition, each connection between the individual components of the pumpdown flowline assembly and between the pumpdown flowline assembly and the pumpdown valves represents a potential leak path.
In accordance with the present disclosure, these and other disadvantages are addressed by providing a wireline pressure control string for performing wireline operations on a hydrocarbon well having a well bore and a wellhead assembly positioned at the top of the well bore. The wireline pressure control string comprises a pumpdown assembly which includes a pumpdown sub having a body and a through bore which extends axially through the body and is fluidly connectable to the well bore, and at least one pumpdown valve having an inlet which is fluidly connectable to a pumpdown fluid source and an outlet which is fluidly connected to the through bore.
In certain embodiments, the wireline pressure control string may also include means for releasably securing the wireline pressure control string to the wellhead assembly. Such means may include, for example, a power-operated connector which is connected to the wireline pressure control string and is configured to operatively engage an adapter on the wellhead assembly. As an alternative, the means for releasably securing the wireline pressure control string to the wellhead assembly may comprise an adapter which is connected to the wireline pressure control string and is configured to be engaged by a power-operated connector on the wellhead assembly.
In certain embodiments, the wireline pressure control string may also include a flexible flowline for fluidly connecting said at least one pumpdown valve to the pumpdown fluid source. In embodiments in which the at least one pumpdown valve comprises a power-operated valve actuator which is operated through at least one valve control cable, the wireline pressure control string may further comprise an umbilical within which the flexible flowline and the at least one valve control cable are incorporated.
The present disclosure is also directed to a method for performing a wireline operation on a hydrocarbon well having a well bore and a wellhead assembly positioned at the top of the well bore. The method includes the steps of connecting a wireline pressure control string to a component of the a wellhead assembly, and pumping a fluid from a pumpdown fluid source through the wireline pressure control string to propel a wireline tool through the well bore. The step of pumping a fluid through the wireline pressure control string is performed using a pumpdown assembly which includes a pumpdown sub comprising a body and a through bore which extends axially through the body and is fluidly connected to the well bore, and at least one pumpdown valve comprising an inlet which is fluidly connectable to the pumpdown fluid source and an outlet which is fluidly connected to the through bore. In certain embodiments, the at least one pumpdown valve may be fluidly connected to the pumpdown fluid source with a flexible flowline.
Thus, by incorporating the pumpdown assembly into the wireline pressure control string, the need to provide the wellhead assemblies, such as frac trees, with separate pumpdown valves and associated pumpdown flowline assemblies is eliminated. Also, in embodiments in which the pumpdown valve is connected to the pumpdown fluid source using a flexible flowline, the wireline pressure control string can be easily installed on the wellhead assembly and moved from wellhead assembly to wellhead assembly with little or no need for manual intervention.
These and other objects and advantages of the present disclosure will be made apparent from the following detailed description, with reference to the accompanying drawings. In the drawings, the same reference numbers may be used to denote similar components in the various embodiments.
The present disclosure is directed to a wireline pressure control string for use in performing wireline operations on a hydrocarbon well. Such hydrocarbon wells can be defined by a well bore and a wellhead assembly which is positioned at the top of the well bore. In the context of the present application, a wellhead assembly may comprise any apparatus which is designed to control the flow of fluid into and out of the well bore, such as, e.g., a christmas tree, a frac tree, a frac stack, a frac head, a wellhead and a tubing spool, among others.
The wireline pressure control string includes a novel pumpdown assembly for controlling a flow of fluid into the well bore during a wireline operation in order to, for example, propel a wireline tool through the well bore. The fluid, which may be referred to herein as a pumpdown fluid, may comprise, e.g., water. In one embodiment of the disclosure, the pumpdown assembly includes a pumpdown sub having a body and a through bore. The through bore extends axially through the body and is fluidly connectable to the well bore. The pumpdown sub may also include at least one valve having an inlet which is fluidly connectable to a source of the pumpdown fluid (which may be referred to herein as a pumpdown fluid source) and an outlet which is fluidly connected to the through bore.
A connector is provided for releasably securing the wireline pressure control string to the wellhead assembly. In one embodiment, the connector is mounted directly to the wireline pressure control string below the pumpdown assembly and is configured to connect to a component of the wellhead assembly, such as, e.g., an adapter which is pre-installed on the top of the wellhead assembly. In another embodiment, the connector is mounted directly to the wellhead assembly and is configured to connect to a component of the wireline pressure control string, such as, e.g., an adapter which is pre-connected to the pressure control string below the pumpdown assembly. In certain embodiments, the connector is a power-operated connector which is operated via one or more power cables. For example, if the connector is a hydraulically operated connector, the power cable or cables may comprise hydraulic hoses. In other embodiments, the connector comprises a first connector half which is mounted to the pressure control string and a second connector half which is mounted to the wellhead assembly, and the first and second connector halves are secured together manually.
In one embodiment of the disclosure, the at least one pumpdown valve may comprise a power-operated valve actuator. The power-operated valve actuator may comprise, for example, a hydraulically operated valve actuator. In other embodiments, the power-operated valve actuator may comprise an electric or pneumatic actuator. Each power-operated valve actuator is activated via a corresponding power cable. In the case of a hydraulically operated valve actuator, the power cable may comprise a hydraulic hose. In the case of an electric or pneumatic actuator, the power cable may comprise an electric power cable or an air hose, respectively.
In accordance with another embodiment of the present disclosure, a flexible flowline is used to fluidly connect said at least one pumpdown valve to the pumpdown fluid source. In certain embodiments, the flexible flowline may be incorporated into an umbilical which also includes the power cable for the power-operated valve actuator and, optionally, the power cable for the connector.
In certain embodiments, the wireline pressure control string may also include a wireline pressure control head positioned above the pumpdown assembly. In the context of the present application, a wireline pressure control head may comprise any device which is designed to selectively retain pressure in the well bore during a wireline operation. For example, the wireline pressure control head may comprise a wireline valve or a wireline blowout preventer (BOP). The wireline pressure control head may, in certain embodiments, be of the type which is activated using a power cable, such as a hydraulic hose. In this case, the power cable for the wireline pressure control head may be incorporated into an umbilical with the flexible flowline and the power cable for the pumpdown valve actuator.
The wireline pressure control string and pumpdown assembly will be described hereafter in the context of a wellhead assembly in the form of a frac tree which is used in hydraulic fracturing, or fracking, operations. However, it should be understood that the wireline pressure control string and pumpdown assembly may be used in connection with other types of wellhead assemblies.
An example of a prior art frac tree is shown in
The frac tree 10 also includes a number of valves for controlling flow into and out of the tree bore through corresponding lateral ports in the flow cross 18, including a wing valve 24, a pair of flowback valves 26 and a pair of pumpdown valves 28. In this example, the wing valve 24 may be connected to a source of fracking fluid via a Tee fitting 30 and a suitable flowline (not shown). Also, the flowback valves 26 may be connected to a separate flowback apparatus, for instance a collecting tank or a fluid processing apparatus (such as a separation apparatus) via a corresponding fluid conduit (not shown), and the pumpdown valves 28 may be connected to a pumpdown fluid source via a corresponding fluid conduit (not shown).
The frac tree 10 is located on a frac pad, i.e., the place where the fracking equipment is located for fracking operations. Certain frac pads may contain more than one frac tree. Referring to
Bringing a well into production requires several operations. Generally, after the well has been drilled and cased and the frac tree has been installed, the production casing is perforated. Once the perforation operation is completed, the well can be fractured, or fracked. After the well has been fracked, the well is opened and the flowback phase of operation commences. During the flowback phase, the well produces a flowback well stream comprising mostly fracking water and sand, along with some formation fluids. Once the proportion of formation fluids in the well stream reaches a certain level, the well is put into the production phase of operation. If the frac pad contains two or more frac trees, these operations can take place simultaneously on separate wells. For example, if a frac pad contains three frac trees, a perforation operation can be performed on a first well while a fracturing operation is performed on a second well and flowback is taking place at a third well.
A perforation operation involves puncturing holes in the production casing at a number of locations, or zones, along the portion of the production casing which extends through the hydrocarbon formation. The perforation operation is performed using a perforating gun which is often deployed on a wireline. The perforating gun is lowered through the tree bore using a wireline pressure control string, which is sometimes called a wireline string or wireline stack. The wireline stack maintains pressure control of the well when the perforating gun is deployed in the well bore.
An example of a prior art wireline stack is shown connected to the left-most frac tree 10 in
The wireline stack 32 is typically made up on the frac pad and then lowered onto the frac tree 10 using a crane (not shown) connected to the lifting tool 46. In this simplified example, the free end of a wireline 48 is trained around the top sheave 44, inserted through the stuffing box 42 and pulled through the lubricator 40. The perforating gun (more typically, a bottom hole assembly comprising the perforating gun, a wireline setting tool and a frac plug) is then fastened to the wireline 48 and retracted into the lubricator 40. After the tool trap 38 is attached to the BOP 36 and the BOP is attached to the connector 34, the lubricator 40 is connected to the top of the tool trap to complete the assembly of the wireline stack 32. The wireline stack 32 can then be lifted and positioned over the frac tree 10 and then secured and sealed to the frac tree by engaging the connector 34 with an adapter 50 that has been pre-attached to the top of the frac tree.
Once the wireline stack 32 is connected to the top of the frac tree 10, the swab valve 20, upper master valve 16 and lower master valve 14 are opened and the perforating gun is lowered through the tree bore and into the well bore. In many cases, the perforating zones are located along a laterally extending branch of the well bore. Consequently, gravity alone is typically not sufficient to move the perforating gun to the perforating zones. In these cases, the perforating gun is propelled or “pumped” into the well bore using a pumpdown fluid, such as water.
The pumpdown fluid is commonly communicated to the well bore through the pumpdown valves 28 on the frac tree 10. The pumpdown fluid source is connected to the pumpdown valves 28 through a pumpdown flowline assembly 52, which typically includes numerous rigid pipes, valves and fittings. Since each well on a multi-well frac pad will need to be fracked, this arrangement requires that each frac tree 10 have its own set of pumpdown valves 28 and that each set of pumpdown valves be connected to the pumpdown fluid source through a respective pumpdown flowline assembly 52.
Referring also to
As shown in
In accordance with the present disclosure, the need to include individual pumpdown valves 28 on each frac tree 10 (or, more generally, each wellhead assembly) and the concomitant need for an extensive pumpdown flowline assembly to connect the pumpdown valves to the pumpdown fluid source 62 are eliminated by incorporating a unique pumpdown assembly into the wireline stack and connecting the pumpdown assembly to the pumpdown fluid source through a single flowline.
Referring to
In the particular example shown in
The valve assembly 80 may comprise a single valve or a combination of two or more valves suitable for controlling the flow of pumpdown fluid from the pumpdown fluid source to the pumpdown sub 78. In the illustrative embodiment of the disclosure shown in
In one embodiment of the disclosure, the valve assembly 80 may comprise any suitable single valve, such as, e.g., a plug valve, a gate valve or a ball valve. In yet another embodiment, the valve assembly 80 may comprise two (or more) suitable valves, such as, e.g., two plug valves, two gate valves or two ball valves, or any combination of suitable valves. Further, each valve of the valve assembly may comprise any appropriate actuator, such as, e.g., a manual, hydraulic, electric or pneumatic actuator 104, or any combination of such actuators.
As shown in
In an alternative embodiment, the valve assembly 80 may be connected directly to the body 82 of the pumpdown sub 78. In this embodiment, the first end connection 106 is configured to connect with a corresponding connection on the body 82. For example, the first end connection 106 may comprise a flanged end connection which is configured to connect to a studded end connection on the body 82. In another embodiment of the disclosure, the valve assembly 80 may be connected to the body 82 of the pumpdown sub 78 with a single pipe fitting, such as, e.g., a pipe spool, a clamp hub, the reducer 92, the Tee fitting 96 or any other suitable fitting. In yet another embodiment of the disclosure, the valve assembly 80 may be connected to the body 82 of the pumpdown sub 78 using any combination of suitable fittings.
The present disclosure is also directed to a novel wireline pressure control string which includes the pumpdown assembly 76. One embodiment of such a wireline pressure control string (which may also be referred to as a wireline string or a wireline stack) is shown in
In certain embodiments, the second component may comprise means by which the pressure control string 114 may be releasably secured to a frac tree or any other wellhead component positioned at the top of the well bore. In one embodiment, for example, the second component may comprise a power-operated connector, such as the connector 34 described above, which as shown in
The pumpdown assembly 76 may be connected to the first and second components by means of the top and bottom end connections 88, 90 described above. For example, the top end connection 88 may comprise a studded end connection which is configured to connect with a flanged end connection on the BOP 36. Likewise, the bottom end connection 90 may comprise a flanged end connection which is configured to be bolted to a flanged end connection on the connector 34. In an alternative, one or both of the end connections 88, 90 may comprise a threaded connection, such as a thread adapter. It should be noted, however, that the pumpdown assembly 76 need not be directly connected to the first and second components. Rather, the pumpdown assembly 76 may be connected to the first and second components through any number of fittings, connectors and components.
In the illustrative embodiment of the disclosure shown in
In accordance with one embodiment of the present disclosure, the pumpdown assembly 76 is connected to the pumpdown fluid source 62 using a fluid conduit 110 in the form of a flexible flowline, such as, e.g., the SAFlex™ flexible flowline sold by TechnipFMC PLC of Houston, Texas. As shown in
The flexible flowline 110 provides several advantages. For example, the flexible flowline 110 can be connected to the pumpdown assembly 76 at or near ground level before the wireline stack 114 is lifted and connected to the top of the frac tree 116. In addition, as shown in
Furthermore, when the wireline stack 114 includes a remotely operated connector, such as the Speedloc™-XT hydraulic connector described above, the flexible flowline 110 enables the wireline stack to be connected to a frac tree and moved from frac tree to frac tree without the need for any frac crewpersons to be present in the red zone, which is the area around the pressurized frac flowlines during a fracking operation. Thus, the connection of the wireline stack 114 to a frac tree 116 and the movement of the wireline stack from one frac tree to the next can be performed without having to wait until the completion of a fracking operation on another well.
Referring still to
In accordance with another embodiment of the disclosure, a frac tree 116 is provided which eliminates the need for pumpdown valves 28 on each frac tree and multiple pumpdown flowline assemblies 52 for connecting the pumpdown valves of each frac tree to the pumpdown fluid source 62. As shown in
Referring still to
It should be recognized that, while the present disclosure has been presented with reference to certain illustrative embodiments, those skilled in the art may develop a wide variation of structural and operational details without departing from the principles of the disclosure. For example, the various elements shown in the illustrative embodiments described above may be combined in a manner not specifically illustrated. Therefore, the following claims are to be construed to cover all equivalents falling within the true scope and spirit of the disclosure.
