Patent Application
20240287878
This disclosure relates to wellbore operations and particularly to obtaining samples of hydrocarbons from within wellbores.
Hydrocarbons entrapped in subsurface reservoirs can be raised to the surface (i.e., produced) through wellbores formed from the surface to the subsurface reservoirs through a subterranean zone (e.g., a formation, a portion of a formation, multiple formations). Knowing the properties of the hydrocarbons (e.g., petroleum, natural gas, combinations of them) entrapped in the reservoirs can aid in well operations including hydrocarbon production. Consequently, sometimes, samples of hydrocarbons flowing into the wellbore are retrieved, and the retrieved samples are analyzed.
This disclosure describes technologies relating to a dual-pump assembly to sample downhole heavy hydrocarbons.
Certain aspects of the subject matter described here can be implemented as a well tool assembly. The assembly includes a tubing, a perforated shield, multiple packers and multiple pumps corresponding to the multiple packers. The tubing can be installed at a downhole location within a wellbore formed in a subterranean zone including a hydrocarbon zone from which hydrocarbons flow into the wellbore. The perforated shield is connected to the tubing. The perforated shield can be installed in the hydrocarbon zone surrounding the tubing. The perforated shield includes multiple perforations through which hydrocarbons from the hydrocarbon zone flow to the tubing. The multiple packers are connected to the perforated shield and can, when activated, isolate the hydrocarbon zone from the subterranean zone. The multiple pumps can activate the multiple packers and can draw a sample of the hydrocarbons that flow from the hydrocarbon zone through the perforated shield into the tubing.
An aspect combinable with any other aspect includes the following features. The multiple packers include a first packer and a second packer. The multiple pumps include a first pump and a second pump fluidically coupled to the first packer and the second packer, respectively. The first pump can draw the sample of the hydrocarbons. The assembly includes a sample container fluidically coupled to the first pump to receive the sample drawn by the first pump.
An aspect combinable with any other aspect includes the following features. The assembly includes a first flowline fluidically coupling the first pump to the sample container. The first pump flows the sample to the sample container through the flowline.
An aspect combinable with any other aspect includes the following features. The assembly includes a sensor fluidically coupled to the first flowline. The sensor can sense a property of the sample drawn by the first pump.
An aspect combinable with any other aspect includes the following features. The first flowline is fluidically coupled to the first packer. The first flowline can flow fluid to activate the first packer.
An aspect combinable with any other aspect includes the following features. The assembly includes a first flowline control valve fluidically coupled to the first flowline. The first flowline control valve is switchable between a state in which the first flowline control valve permits the first pump to activate the first packer and a different state in which the first flowline control valve permits the first pump to draw the sample.
An aspect combinable with any other aspect includes the following features. The first flowline is a heated flowline.
An aspect combinable with any other aspect includes the following features. The assembly includes a second flowline fluidically coupling the second pump to a viscosity reducer (VR) container configured to hold VR to reduce a viscosity of the hydrocarbons. The second pump flows a quantity of VR from the VR container into the hydrocarbon zone isolated by the multiple packers.
An aspect combinable with any other aspect includes the following features. The second flowline is fluidically coupled to the second packer. The second flowline can flow fluid to activate the second packer.
An aspect combinable with any other aspect includes the following features. The assembly includes the VR container. The VR container is installed at one end of the perforated shield. The first pump can be installed at an opposite end of the perforated shield. The perforated shield is narrower at the end at which the VR container is installed compared to the opposite end at which the first pump is installed.
An aspect combinable with any other aspect includes the following features. The assembly includes stabilizing members installed within the perforated shield. The stabilizing members include a blade installed near the end of the perforated shield at which the VR container is installed, and a collapsible cone installed near the opposite of the perforated shield at which the first pump is installed.
An aspect combinable with any other aspect includes the following features. The assembly includes a second flowline control valve fluidically coupled to the second flowline. The second flowline control valve is switchable between a state in which the second flowline control valve permits the second pump to activate the second packer and a different state in which the second flowline control valve permits the second pump to flow the quantity of VR from the VR container.
An aspect combinable with any other aspect includes the following features. The assembly includes a computer system including one or more processors and a computer-readable medium storing instructions executable by the one or more processors to perform operations including controlling the multiple pumps to switch between activating the multiple packers and drawing the sample of the hydrocarbons that flow from the hydrocarbon zone through the perforated shield into the tubing.
Certain aspects of the subject matter described here can be implemented as a method in a wellbore formed in a subterranean zone including a hydrocarbon zone from which hydrocarbons flow into the wellbore. A first pump and a second pump, each installed within the wellbore, activate a first packer and a second packer, respectively, to isolate the hydrocarbon zone from the subterranean zone. After isolating the hydrocarbon zone from the subterranean zone, VR from a VR container installed within the wellbore and fluidically connected to the second pump, is flowed to the isolated hydrocarbon zone. The VR reduces a viscosity of hydrocarbons that flowed into the wellbore from the hydrocarbon zone. After flowing the VR to the isolated hydrocarbon zone, the first pump draws a sample of the hydrocarbons from the isolated hydrocarbon zone.
An aspect combinable with any other aspect includes the following features. After activating the first packer and the second packer, and before flowing the VR to the isolated hydrocarbon zone, the second pump draws fluid in the isolated hydrocarbon zone.
An aspect combinable with any other aspect includes the following features. While drawing the fluid in the isolated hydrocarbon zone, a fluid pressure in the isolated hydrocarbon zone is monitored. In response to determining that the fluid pressure in the isolated hydrocarbon zone satisfies a threshold fluid pressure, the VR is flowed from the VR container to the isolated hydrocarbon zone.
An aspect combinable with any other aspect includes the following features. After flowing the VR to the isolated hydrocarbon zone and before drawing the sample of hydrocarbons from the isolated hydrocarbon zone, a pre-determined duration is allowed to pass for the VR to react with and reduce a viscosity of hydrocarbons in the isolated hydrocarbon zone.
An aspect combinable with any other aspect includes the following features. The sample of hydrocarbons drawn by the first pump is flowed to a sample container fluidically coupled to the first pump via a flowline. Before flowing the sample of hydrocarbons to the sample container, a sensor, fluidically coupled to the flowline, analyzes the sample of hydrocarbons.
An aspect combinable with any other aspect includes the following features. The flowline through which the sample of hydrocarbons is flowed to the sample container is heated.
Certain aspects of the subject matter described here can be implemented as a well tool assembly. The assembly includes a perforated shield that can be installed within a wellbore formed in a subterranean zone including a hydrocarbon zone from which hydrocarbons flow into the wellbore. The perforated shield is connected to a tubing installed at a downhole location within the wellbore. The perforated shield includes multiple perforations through which hydrocarbons from the hydrocarbon zone flow into an inner volume defined by the perforated shield. Multiple packers are connected to an outer surface of the perforated shield and configured, when activated, to isolate the hydrocarbon zone from the subterranean zone. Multiple pumps corresponding to the multiple packers are configured to activate the multiple packers and to draw a sample of the hydrocarbons that flow from the hydrocarbon zone through the perforated shield into the tubing. A computer system includes one or more processors and a computer-readable medium storing instructions executable by the one or more processors to perform operations including controlling the multiple pumps to switch between activating the multiple packers and drawing the sample of the hydrocarbons that flow from the hydrocarbon zone through the perforated shield into the tubing.
The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.
Like reference numbers and designations in the various drawings indicate like elements.
Hydrocarbons entrapped in subsurface reservoirs can include heavy hydrocarbons. Such hydrocarbons are a mixture of compounds consisting of alkylated cyclics, resins and asphaltenes. The high viscosity of heavy hydrocarbons can affect a rate at which such hydrocarbons flow into the wellbore from the subterranean zone and from the wellbore to the surface. The high viscosity can also affect operations performed to draw a sample of the heavy hydrocarbons from within a wellbore, for example, to analyze the sample and determine properties of the hydrocarbons. This disclosure describes a well tool assembly for sampling heavy hydrocarbons. As described below, the well tool assembly includes a dual pump arrangement that can be used to activate a dual packer arrangement to set the well tool assembly within the wellbore. The dual pump arrangement can also be used to reduce a viscosity of the heavy hydrocarbons that flow into the wellbore from a hydrocarbon producing zone of the subterranean zone and draw a sample of the reduced-viscosity hydrocarbons for analysis.
Implementing the techniques described here avoids or reduces complications and risks associated with heavy hydrocarbon sampling such as extended pumping hours, stuck pipe situations and inability to acquire samples. Implementing the techniques described here can optimize sampling duration, reduce operational risks and reduce or minimize human interference.
The assembly 100 can be installed at a downhole location within the wellbore 102 such that at least a portion of the assembly 100 extends across a depth of the hydrocarbon producing zone 106. In some implementations, the assembly 100 includes a tubing 108 that extends from the surface into the wellbore 102. The tubing 108 can include a wireline, slickline, coiled tubing or other types of tubing 108 that can be installed at and operate within the wellbore 102.
The assembly 100 includes a perforated shield 110 connected to (e.g., hanging from) the tubing 108. The perforated shield 110 can be installed in the hydrocarbon zone 106 surrounding the tubing 108. For example, the perforated shield 110 has a length such that, when installed within the wellbore 102, an upper end of the perforated shield 110 resides uphole of an uphole edge of the hydrocarbon producing zone 106, and a downhole end of the perforated shield 110 resides downhole of a downhole edge of the zone 106. The perforated shield 110 can be made of the same material as the tubing 108 or similar material that can be installed at and operated in the downhole location within the wellbore 102.
The perforated shield 110 can be formed as an elongate hollow tubing that is concentrically arranged with respect to the tubing 108. The perforated shield 110 can include multiple perforations (e.g., perforation 112a, perforation 112b), each of which is a through opening that connects an annular region between an outer surface of the perforated shield 110 and the inner wall of the wellbore 102 to an internal volume defined by the perforated shield 110. As described later, hydrocarbons from the hydrocarbon producing zone 106 can flow into the internal volume through the multiple perforations. In some implementations, the perforations are uniformly distributed along a cross-section and length of the perforated shield 110. Each perforation can be sized to be large enough to permit heavy hydrocarbons to flow through the perforations and into the internal volume.
In some implementations, the perforated shield 110 can have a one-way taper from the uphole end to the downhole end. That is, a diameter of the perforated shield 110 can decrease along an axial length of the perforated shield 110 from the uphole end to the downhole end. As described later, such construction allows installing components of the well tool assembly 100 in the narrow end of the perforated shield 110 and also increases stability of the assembly 100 once installed within the wellbore 102.
The assembly 100 includes multiple packers (e.g., two packers—a first packer (or uphole packer) 114a, a second packer (or downhole packer) 114b) connected to the perforated shield 110. Each packer can be retrievable seal bore hydraulic packer. When activated, the multiple packers isolate the hydrocarbon zone 106 from the rest of the subterranean zone 104. In some implementations, the uphole packer 114a is connected near the uphole end of the perforated shield 110, for example, at an intersection of the uphole edge of the hydrocarbon producing zone 106 and the portion of the subterranean zone 104 uphole of the zone 106. Similarly, the downhole packer 114b is connected near the downhole end of the perforated shield 110, for example, at an intersection of the downhole edge of the zone 106 and the portion of the subterranean zone 104 downhole of the zone 106. When activated, e.g., inflated, the packers seal against the inner wall of the wellbore 102, thereby fluidically isolating the portion of the wellbore 102 between the two packers. Once activated, the packers prevent hydrocarbons (or other well fluid) that flows from the zone 106 into the wellbore 102 from mingling with fluids in other portions of the wellbore 102. The activated packers also stabilize the well tool assembly 100 within the wellbore 102.
The assembly 100 includes multiple pumps corresponding to the multiple packers. For example, the assembly 100 includes a first pump (or uphole pump) 116a and a second pump (or downhole pump) 116b corresponding to the uphole packer 114a and the downhole packer 114b, respectively. Each pump can be a two-way pump that can both flow fluid in one direction and draw fluid in an opposite direction. The uphole pump 116a is fluidically coupled to the uphole packer 114a to activate/de-activate the uphole packer 114a. To activate the uphole packer 114a, the uphole pump 116a can pump fluid through the flowline 118a to the uphole packer 114a. To deactivate the uphole packer 114a, the uphole pump 116a can draw fluid through the flowline 118a away from the uphole packer 114a. For example, hydraulic fluid tanks are imbedded within the upper and lower two-way pump systems, which can be used to inflate and set the packers, and then restore the hydraulic fluids when deflating. The flowline control valve 120a is fluidically coupled to and controls the two-way flow of the fluid through the flowline 118a. Similarly to the flowline 118a and the flowline control valve 120a, the assembly 100 includes a flowline 118b and a flowline control valve 120b using which the downhole pump 116b controls activation and deactivation of the downhole packer 114b.
In some implementations, the same pumps that activate/deactivate the packers also draw samples of hydrocarbons that flow from the hydrocarbon zone 106 through the perforated shield 110 into the tubing 108. As described later, after activating the uphole packer 114a, the uphole pump 116a can be switched to draw a sample of hydrocarbons that have flowed into the isolated region between the two packers 114a and 114b. Also, after activating the downhole packer 114b, the downhole pump 116b can be switched to flow a viscosity reducer (VR) into the isolated region between the two packers 114a and 114b to reduce a viscosity of the heavy hydrocarbons, thereby assisting the uphole pump 116b to draw the sample of the hydrocarbons.
In some implementations, the assembly 100 includes a sample container 122 (for example, a reservoir) that is operatively coupled to the uphole pump 116a. A flowline 124 is fluidically coupled to the sample container 122 and to the uphole pump 116a. For example, the flowline 124 is installed within the tubing 108. One end of the flowline 124 opens to the internal volume within the perforated shield 110. In some implementations, one or more T-junctions can be formed at the end of the flowline 124, the ends of each T-junction passing through the wall of the tubing 108. Such an arrangement increases a number of inlets for fluids from the internal volume of the perforated shield 110 into the flowline 124. An opposite end of the flowline 124 terminates in the sample container 122. A flowline branch 126 branches off the flowline 124 with an outlet out of the tubing 108 into a portion of the wellbore 102 that is outside the isolated hydrocarbon zone 106.
One or more valves (e.g., valve 128, 130) can be fluidically coupled to the flowline 124 to control flow of the fluid through the flowline 124. By operating the valves and the uphole pump 116a, fluid drawn from the internal volume can be flowed either to the sample container 122 or through the flowline branch 126 to drain out of the flowline 124. For example, after isolating the hydrocarbon zone 106 as described above and before drawing the sample of hydrocarbon from the hydrocarbon zone 106, the valves 128 and 130 can be set such that the uphole pump 116a draws any fluid (e.g., drilling mud or other fluid) in the internal volume of the perforated shield 110 through the flowline 124 and discharges the fluid through the flowline branch 126 into the portion of the wellbore 102 that is outside the isolated hydrocarbon zone 106. Then, hydrocarbons can flow from the formation 106 into the internal volume through the multiple perforations on the perforated shield 110. Subsequently, the valves 128 and 130 can be switched such that the uphole pump 116a draws hydrocarbons from the internal volume through the flowline 124 to the sample container 122 for storage. In some implementations, the flowline 124 can be a heated flowline to heat the sample flowing through the flowline 124. Doing so can further decrease a viscosity of the sample and facilitate sample flow towards the sample container 122.
In some implementations, the assembly 100 includes a VR container 132 (for example, a reservoir) that is operatively coupled to the downhole pump 116b. The VR container 132 can be installed near a downhole end of the perforated shield 110, while the sample container 122 can be installed near an uphole end of the perforated shield 110. In some implementations, the arrangement of the VR container 132 and the sample container 122 can be reversed.
A flowline 134 is fluidically coupled to the sample container 132 and to the downhole pump 116b. For example, the flowline 134 is installed within the tubing 108. One end of the flowline 134 opens to the internal volume within the perforated shield 110. In some implementations, one or more T-junctions can be formed at the end of the flowline 134, the ends of each T-junction passing through the wall of the tubing 108. Such an arrangement increases a number of outlets for the VR flowed from the VR container 132 into the internal volume of the perforated shield 110 through the flowline 134. An opposite end of the flowline 134 terminates in the VR container 132.
One or more valves (e.g., valve 136) can be fluidically coupled to the flowline 134 to control flow of the VR through the flowline 134. By operating the valve 136 and the downhole pump 116b, VR from the VR container 132 can be flowed through the flowline 134 into the internal volume of the perforated shield 110. For example, after hydrocarbons flow from the formation 106 into the internal volume through the multiple perforations on the perforated shield 110, the downhole pump 116b can be operated to flow a pre-determined quantity of VR into the internal volume. A duration of time can be allowed to pass to allow the VR to react with and reduce a viscosity of the hydrocarbons. Subsequently, the uphole pump 116a can be operated as described above to draw a sample of the hydrocarbons from the internal volume through the flowline 124 to the sample container 122 for storage.
In some implementations, the assembly 100 includes a sensor module 138 fluidically coupled to the flowline 124 between the uphole pump 116a and the sample container 122. The sensor module 138 includes one or more sensors (e.g., a density sensor, a resistivity sensor, a capacitance sensor, other sensors) that can analyze properties of the sample flowed by the uphole pump 116a to the sample container 122. In some implementations, a flowline branch can fluidically couple to the sensor module 138 to the flowline 124 to divert a portion of the sample to the sensor module 138 for analysis. In some implementations, the sensors in the sensor module 138 can contact the sample that is flowing through the flowline 124 towards the sample container 124. The sensor module 138 can output one or more signals representative of the analyzed properties of the sample.
In some implementations, the assembly 100 can include stabilizing members installed within the perforated shield 110. The stabilizing members extend between the outer surface of the tubing 108 and the inner surface of the perforated shield 110. The stabilizing members are stiff to provide stability to the assembly 100. The stabilizing members can include a cone 140a to provide strength and stability while pumping. The cone 140a is installed near the uphole end of the perforated shield 110. The stabilizing members can also include a blade 140b (e.g., arms or hollow circular blade) installed near the downhole end of the perforated shield 110. In some implementations, the blade 140b can be installed at the narrower end of the perforated shield 110, abutting the VR container 132 on one edge of the blade 140b and the inner surface of perforated shield 110 on the other edge of the blade 140b. The stabilizing members are collapsible in that, in response to a control signal, the stabilizing members can retract away from the inner surface of the perforated shield 110. For example, each stabilizing member can include grooves along which the members can collapse in response to the control signal.
In some implementations, the assembly 100 can include a controller 142 implemented as a computer system that includes one or more processors and a computer-readable medium (e.g., non-transitory computer-readable medium) storing computer instructions executable by the one or more processors. The controller 142 can be operatively coupled to the two pumps 116a and 116b. For example, a power line 120 (e.g., a cable that can transmit power or both power and data) operatively couples the controller 142 to both pumps. The power line 120 can extend to the surface and be connected to a power source. Alternatively, the power source can be positioned downhole with the assembly 100. Power to the pumps to perform the operations described in this disclosure can be transmitted through the power line 120. The controller 142 can control both pumps to switch between activating the multiple packers 116a and 116b, and drawing the sample of the hydrocarbons that flow from the hydrocarbon zone 106 through the perforated shield 110 into the tubing 108.
The assembly 100 can include pressure gauges (e.g., pressure gauges 144a, 144b, 144c) installed above, within and below, respectively, the hydrocarbon zone 104. Each pressure gauge measures a wellbore pressure at the installed location. Each pressure gauge is operatively coupled to the controller 142 and transmits signals representative of the measured pressure. The controller 142 controls operations of both pumps as well as the valves described earlier using, in part, the pressure measured by the pressure gauges, as described below with reference to
At 202, the uphole pump 116a and the downhole pump 116b activate, respectively, the uphole packer 114a and the downhole packer 114b. For example, the controller 142 transmits signals to set the control valves in states in which the uphole pump 116a and the downhole pump 116b can flow fluids to activate the uphole packer 114a and the downhole packer 114b, respectively, through the flowlines 118a and 118b, respectively. The signals can cause the packers to be activated simultaneously or one after the other (e.g., first, the downhole packer 116b; then, the uphole packer 116a or vice versa). Once the packers have been set, the hydrocarbon zone 106 is isolated from a remainder of the subterranean zone 104 such that any hydrocarbons that flows into the wellbore 102 from the hydrocarbon zone 106 is retained in the isolated space between the two packers.
After the packers have been set, the controller 142 transmits signals to change the settings of the control valves to stop controlling flow of the packer-setting fluids, and to instead control flow of the VR from the VR container 132 and flow of the hydrocarbons to the sample container 122. The controller 142 transmits a signal to the uphole pump 116a to draw fluids in the internal volume defined by the perforated shield 110 through the flowline 124 and to flow the drawn fluids out of the tubing 108 into the space uphole of the isolated hydrocarbon zone 104. In such operations, the controller 142 can set the valve 130 to divert fluid drawn through the flowline 124 into the flowline branch 126 and away from the sample container 130. Also, in such operations, the pressure gauge 144c can measure a pressure in the annular region between the perforated shield 110 and the wellbore 102. The pressure gauge 144c can periodically (e.g., at a frequency of once per second, more than once per second or other frequency) transmit the measured pressure to the controller 142. The controller 142 can compare the received pressure with a threshold pressure. When the controller 142 determines that the received pressure is less than the threshold pressure (indicating that most of the fluid from the internal volume of the perforated shield 110 has been drawn), the controller 142 can de-activate the uphole pump 116a.
At this stage, hydrocarbons from the hydrocarbon zone 106 begin to flow into the isolated space between the two packers. Such hydrocarbons can include heavy hydrocarbons or high-viscosity hydrocarbons. The hydrocarbons enter the internal volume of the perforated shield 110 through the multiple perforations on the shield 110. At 204, the downhole pump 116b flows VR to the isolated hydrocarbon zone 104. To do so, the controller 142 activates the downhole pump 116b to draw VR from the VR container 132 and to flow the drawn VR through the flowline 134 into the internal volume of the perforated shield 110. After a pre-determined quantity of the VR has been flowed into the internal volume of the perforated shield 110, the controller 142 de-activates the downhole pump 116b. In some implementations, the pressure gauge 144b can measure a pressure in the isolated hydrocarbon zone 106. The pressure gauge 144b can periodically transmit the measured pressure to the controller 142. The controller 142 can compare the received pressure with a threshold overbalance pressure. The controller 142 can continue operation of the downhole pump 116b until the received pressure is less than or equal to the threshold overbalance pressure. Once the controller 142 determines that the threshold overbalance pressure has been exceeded, the controller 142 can de-activate the downhole pump 116b. Doing so ceases flow of the VR into the internal volume of the perforated shield 110.
The controller 142 can be configured to pause all operations (i.e., not transmit any signals to any of the components) for a pre-determined time duration sufficient to allow the VR to react with the hydrocarbons that have flowed into the isolated space between the two packers. The pre-determined time can be determined based on a pre-job simulation from offset wells. After the pre-determined time duration has expired, a viscosity of the hydrocarbons would have reduced.
At 206, the uphole pump 116a draws a sample of hydrocarbons from the isolated hydrocarbon zone. To do so, the controller 142 can activate the uphole pump 116b to draw a sample of the hydrocarbons through the flowline 124. The controller 142 can set the valves so that the drawn sample flows to the sample container 122 and avoids the flowline branch 126.
In some implementations, the controller 142 can operate the uphole pump 116a to work in a safe pressure operating envelop avoiding collapse of the perforated shield 110 while retrieving maximum amount of sample without reaching Asphalting Onset Pressure (AOP). To do so, the controller 142 can initially activate the uphole pump 116a at a high rate. The pressure gauge 114c can measure and transmit measured pressure in the flowline 124 to the controller 142. Once the controller 142 determines a drop in pressure where no more fluid can be retrieved in the safe pressure envelop, the controller 142 can de-activate the uphole pump 116a.
The controller 142 can then monitor the pressure measured by the pressure gauge 144c allowing time for hydrocarbons to once again fill the internal volume of the perforated shield 110. If the pressure measured by the pressure gauge 144c indicates the presence of sufficient hydrocarbons, then the controller 142 can once again activate the uphole pump 116b at a high rate to draw the hydrocarbons until the controller 142 once again determines a pressure drop. If the controller 142 determines that a threshold duration of time has expired without an increase in pressure measured by the pressure gauge 144c, the controller 142 determines that not enough hydrocarbons have flowed into the inner volume of the perforated shield 110. In response, the controller 142 activates the downhole pump 116b to flow more VR from the VR container 132 into the internal volume of the perforated shield 110 and the annular region between the perforated shield 110 and the wellbore 102. The process described earlier of waiting a duration for the VR to react with the hydrocarbons to reduce the viscosity, and operating the uphole pump 116a to draw the reduced-viscosity hydrocarbons will be repeated until the sample container 122 is filled.
Subsequently, the controller 142 sets the valve 128 so that the flowline 124 is opened to flow from the flowline branch 126 while avoiding flow to the sample container 122. Drilling mud or other well fluid can be flushed through the flowline 124 to push any remaining hydrocarbons back into the isolated space between the two packers. The controller 142 can then de-activate both packers, after which an operator can retrieve the well tool assembly 100 either out of the wellbore 102 or move the assembly 100 to a different depth.
Thus, particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims.
