Patent ID: 12188328

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

A BPV is a well tool that is installed in a tubing hanger to isolate production tubing. The BPV is designed to hold pressure from below to isolate well pressure downhole of a location at which the BPV is installed. The BPV is also designed to pump fluid, at a low flowrate, from uphole of the location at which the BPV is installed. As described below, the BPV is designed to set at a tubing hanger. The BPV is usually below ground level (i.e., a surface of the Earth at which the wellbore is formed) and is part of a wellhead barrier. The BPV is configured to minimize potential leak from the well with the benefit of being located inside (i.e., too far deep within) the wellbore. Consequently, the BPV is easier to retrieve compared with other well tools that are installed deeper within the wellbore and may require complex retrieval operations. The BPV can be used for either short term shut-ins of the wellbore or for longer term suspensions of wellbore operations. If an incident occurs at the wellhead tree valves, the BPV can still hold pressure from below and prevent leakage from the wellbore.

A pressure gauge is a well tool that is used to monitor wellbore pressure, in particular, at locations at which a seal or a fluidic isolation is created. Pressure measured by the pressure gauge can be used by well operators in different phases of wellbore operations including production, injection, shut-in conditions, and the like. Thus, the pressure gauge allows wellbore operators to evaluate subsurface well data. Pressure gauges can include built-in memories (e.g., computer-readable processors and memory), and can be run into the wellbore to record measured pressure and to store the measured pressure in the built-in memories. Examples of other gauges that can be used in place of pressure gauges include temperature gauges that can measure wellbore temperatures and combination gauges that can measure wellbore pressures and temperatures.

This disclosure describes a sub-assembly that includes a BPV to which a pressure gauge (or a temperature gauge or a pressure and temperature gauge) is mounted. The sub-assembly can be used to seal and fluidically isolate a wellbore production string. While sealing and fluidically isolating the wellbore production string, the sub-assembly can simultaneously and continuously measure wellbore properties (pressure or temperature or both) in the fluidically isolated portion of the wellbore production string. The measured wellbore properties can either be stored in memories onboard the gauge or can be wirelessly transmitted to a surface of the wellbore.

The BPV-pressure gauge sub-assembly described in this disclosure can be implemented to perform wellbore monitoring operations that are an important aspect of oil and gas wellbore operations. For example, when performing a diagnostic injection test for evaluation of subsurface reservoir behavior of the subterranean zone, small volume (e.g., 10-30 barrels) of water-based fluid can be pumped or injected at low rate into the wellbore. The pumping can then be stopped and the pressure response over time monitored (e.g., for 1-10 days) to evaluate reservoir properties and behavior or tightness (e.g., frac gradient, minimal in-situ stress, fracture closure pressure, reservoir permeability, etc.). The sub-assembly described in this disclosure can be implemented to monitor the pressure response over time. Because the sub-assembly is installed within the wellbore (or the wellhead), as opposed to outside the wellbore (or the wellhead), negative impact on pressure measurements due to day and night temperature changes can be minimized or avoided. The need to install production trees on top of the wellbore to record the pressure from surface-installed pressure gauges can also be avoided by using the sub-assembly described here. The risk of leaks associated with surface-installed equipment can also be reduced by implementing the sub-assembly described here, which is installed inside the wellbore. In addition, the sub-assembly described here can simultaneously and continuously perform the dual function of sealing the wellbore production string and measuring pressure (or other well properties) in the location downhole of the sub-assembly.

FIG.1is a schematic diagram of a sub-assembly100including a back pressure valve (BPV)102and pressure gauge104. The sub-assembly100can be a component sub-assembly of a wellbore tool assembly described later. The BPV102is configured to be installed at a location in a wellbore production tubing, which, in turn, is configured to be installed in a wellbore. The BPV is configured to fluidically isolate a portion of the wellbore production tubing downhole of the location from a portion of the wellbore production tubing uphole of the location. When installed within a wellbore production tubing, the BPV has an uphole end106and a downhole end108.

A threaded connection110is attached to the downhole end108of the BPV102. The threaded connection110can be a tubular cylindrical member that includes threads (e.g., metal threads) formed on an outer surface or an inner surface or both of the threaded connection110to be coupled to the BPV102and to the pressure gauge104, as described later. To couple to the downhole end108of the BPV102, a universal thread profile can be formed on the downhole end108of the BPV102. Metal-to-metal thread connection can be formed between an uphole end112the thread profile formed on the downhole end108of the BPV102and the thread profile formed on the threaded connection110. The thread profile can extend along an entire length of the threaded connection110to connect a downhole end114of the threaded connection110to other wellbore tools as described below. In some implementations, the thread profile formed at the uphole end112can be different from that formed at the downhole end114of the threaded connection110. The threaded connection110can be made of a material that can withstand downhole conditions including high temperatures and pressure, and that can maintain a seal formed by the BPV102with the wellbore production tubing to fluidically isolate the portion of the wellbore production tubing downhole of the sub-assembly100from the portion of the wellbore production tubing uphole of the sub-assembly100. The threaded connection110can help easily and practically connect the BPV102and the pressure gauge104. The threaded connection110can be rated to support the weight of the pressure gauge104. The pressure gauge104, which includes memory for storing the data, can weight between 500 g and 1000 g. The threaded connection110can also reduce vibration during production or installation.

The pressure gauge104is fluidically coupled to the BPV102through the threaded connection110. To do so, a thread profile can be formed on or attached to an uphole end of the pressure gauge104. The thread profile on the pressure gauge104can be configured to be received by and mate with the thread profile of the threaded connection110. In some implementations, the thread profile on the pressure gauge104can be formed on an outer surface, and the thread profile of the threaded connection110can be formed on an inner surface. In some implementations, the thread profile on the pressure gauge104can be formed on an inner surface, and the thread profile of the threaded connection110can be formed on an outer surface. The thread profiles can be constructed such that, when engaged, the interface between the threaded connection110and the pressure gauge104maintains a fluidic isolation of the portion of the wellbore tubing string downhole of the sub-assembly100. For example, the thread profiles can be metal-to-metal threads.

The pressure gauge104is configured to measure a pressure in the portion of the wellbore downhole of the location at which the sub-assembly100is installed in the wellbore production string. In some implementations, the pressure gauge104can be replaced with a temperature or a combined pressure/temperature gauge or another gauge or sensor that can measure other wellbore properties. The pressure gauge104can be an electronic pressure gauge with an onboard memory116that is configured to store the pressure sensed by the pressure gauge104. The pressure values stored on the onboard memory116can be transferred to a computer system when the sub-assembly100is retrieved after use.

The sub-assembly100permits fluid flow in one direction (specifically, the uphole direction) and prevents fluid flow in the opposite direction (specifically, the downhole direction). The downhole end118of the pressure gauge104is open to fluid flow through the sub-assembly100in the uphole direction. However, because the BPV102prevents fluid flow in the uphole direction, fluid downhole of the location at which the sub-assembly100is installed cannot flow to the surface of the wellbore. In contrast, fluid can be flowed from a surface of the wellbore in the downhole direction through the BPV102and the pressure gauge104.

FIG.2is a schematic diagram of a tubing hanger landing joint200in which the sub-assembly100is installed. The joint200is a device in the wellbore to support the wellbore production string (described later). The joint200can include a hollow portion with thread profiles near an uphole end of the joint200and near a downhole end of the joint200, each to receive corresponding threads. In particular, the threads near the downhole end of the joint200can couple to threads formed on the wellbore production string to hang the string from the joint200. In some implementations, the sub-assembly100is installed within the joint200at a pre-determined location. The sub-assembly100fluidically isolates the portion of the wellbore production string below the pre-determined location. In some implementations, a BPV profile202is formed on an inner surface of the joint200to receive the BPV102(FIG.1) of the sub-assembly100. The BPV profile202forms the fluidic seal that creates the fluidic isolation described above. The BPV profile202includes an elastomeric O-ring. The tubing hanger BPV housing area has tapered shoulders. During installation of the BPV, the elastomeric O-ring sails between tubing hanger and BPV to generate pressure seal which creates the fluidic isolation.

FIG.3is a schematic diagram of a well system300including the sub-assembly of100. The well system100includes a wellbore302formed from a surface304of the Earth to a subsurface reservoir306through a subterranean zone308(e.g., a formation, a portion of a formation, multiple formations) to raise (i.e., produce) hydrocarbons entrapped in the subsurface reservoir306. After forming the wellbore302through the subterranean zone308using a wellbore drilling assembly, multiple strings (e.g., casing strings310a,310b) can be lowered into the wellbore302and installed in place using cement312. A wellbore production string314can be lowered through the multiple strings to span a length from the wellbore surface304to the subsurface reservoir306. Perforations316formed at a downhole end of the wellbore production string314can allow the hydrocarbons to enter into the wellbore production string314from the subsurface reservoir306.

Different wellbore completions can be installed in the wellbore production string314to produce the hydrocarbons. For ease of illustration, only the sub-assembly100and a production tree318are schematically shown inFIG.3. The production tree318can include additional components, e.g., valves, etc., using which fluid flow through the wellbore302can be operated and controlled. The pre-determined location at which the sub-assembly100is installed can be at or as close to the wellbore surface304as possible while still being within the wellbore302. Such a pre-determined location allows easy installation and retrieval of the sub-assembly100without the need to perform complex retrieval operations. By installing the sub-assembly100at the pre-determined location, fluidic isolation of the portion of the wellbore production string314downhole of the pre-determined location can be implemented and simultaneously, pressure in the isolated portion of the wellbore production string314can be continuously measured.

FIG.4is a schematic diagram of the tubing hanger landing joint200in which the sub-assembly100is installed. A wellbore production string402is installed downhole of the sub-assembly100. For example, a downhole end of the joint200can include a threaded profile on an inner surface that can complement a threaded profile on an outer surface of an uphole end of the wellbore production string402. When the uphole end of the wellbore production string202is coupled to the downhole end of the joint200, a metal-to-metal seal is formed between the threads causing the outer surface of the wellbore production tubing402to be fluidically sealed to the inner surface of the joint200. Uphole of the wellbore production tubing402, the BPV profile202(FIG.2) formed on an inner surface of the joint200forms a similar metal-to-metal seal with the sub-assembly100. In this manner, the joint200enables the sub-assembly100to fluidically isolate the wellbore production string402downhole of the sub-assembly100.

FIG.5is a flowchart of an example of a method500of forming and using the sub-assembly100(FIG.1). Some of the method steps can be performed by a human operator. Some of the method steps can be performed by the sub-assembly100(FIG.1). At502, a threaded connection is attached to a downhole end of a BPV. At504, a pressure gauge is fluidically coupled to the threaded connection. For example, the method steps502and504can be performed at a surface of a wellbore. At506, the BPV, fluidically coupled to the pressure gauge, is installed in a wellbore production tubing. At508, an uphole portion of the wellbore production string is fluidically isolated from a downhole portion using the BPV. Simultaneously and continuously, at510, the pressure in the downhole portion is measured using the pressure gauge.

Implementations of the sub-assembly100can be implemented using standard Cameron type H BPV outer thread to install the sub-assembly100in the tubing hanger joint200. The sub-assembly100described here can record well properties including temperature, pressure, combinations of them, or other well properties using appropriate gauges/sensors while the wellbore production tubing is fluidically isolated with the BPV. The sub-assembly100can work when all wellhead valves including those in the production tree are in closed positions. The sub-assembly100can allow grease and integrity test for wellhead gate valves during fluidic isolation and pressure monitoring. Implementing the sub-assembly100does not require any changes to the tubing hanger. The tubing hanger can be installed with the same BPV profile. Deploying the sub-assembly100does not require any kind of slickline or wireline operation for installation or removal from the wellbore. The sub-assembly100can be installed with any industry standard BPV lubricator, and can be installed or removed under pressure using the BPV lubricator.

Thus, particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims.