Pneumatic gas booster operating on a remote wellsite

Abstract

A device may include a remote pump jack configured to lift reservoir fluids from underground. A device may include an oil tank connected to the remote pump tank, the oil tank being configured to store the reservoir fluids and allow the reservoir fluids to separate into one or more of oil and a headspace vapor. A device may include a pneumatic gas booster connected to the oil tank, wherein the pneumatic gas booster is configured to draw in the headspace vapor during a vapor recovery operation. A device may include the pneumatic gas booster being connected to a liquid nitrogen tank that provides a motive gas to the pneumatic gas booster such that as the pneumatic gas booster draws in the headspace vapor, the motive gas furnishes a stable drive pressure during the vapor recovery operation.

Description

[0001] PNEUMATIC GAS BOOSTER OPERATING ON A REMOTE WELLSITE

[0002] BACKGROUND

[0003] The present disclosure relates to gas venting using a pneumatic gas booster on a wellsite.

[0004] Conventional wellsite operations result in the release of methane gas. Conventional solutions that exist to capture and reuse that methane gas are only financially viable for installations that manage hundreds of thousands or more barrels of oil. For smaller wellsite locations with smaller outputs, the conventional solutions would render these smaller sites unviable commercially.

[0005] SUMMARY

[0006] In some aspects, the techniques described herein relate to a remote wellsite system including: a remote pump jack configured to lift reservoir fluids from underground; an oil tank connected to the remote pump tank, the oil tank being configured to store the reservoir fluids and allow the reservoir fluids to separate into one or more of oil and a headspace vapor; a pneumatic gas booster connected to the oil tank, wherein the pneumatic gas booster is configured to draw in the headspace vapor during a vapor recovery operation; and the pneumatic gas booster being connected to a liquid nitrogen tank that provides a motive gas to the pneumatic gas booster such that as the pneumatic gas booster draws in the headspace vapor, the motive gas furnishes a stable drive pressure during the vapor recovery operation.

[0007] In some aspects, the techniques described herein relate to a remote wellsite system, wherein the motive gas is a nitrogen gas.

[0008] In some aspects, the techniques described herein relate to a remote wellsite system, wherein the nitrogen gas is stored as a liquid in the liquid nitrogen tank.

[0009] In some aspects, the techniques described herein relate to a remote wellsite system, wherein the liquid nitrogen tank includes a vaporizer configured to draw the liquid nitrogen out of the liquid nitrogen tank as the nitrogen gas, such that the nitrogen gas can be provided to the pneumatic gas booster.

[0010] In some aspects, the techniques described herein relate to a remote wellsite system, wherein the pneumatic gas booster includes a reciprocating piston system, where the reciprocating piston system creates a vacuum within the pneumatic gas booster during a receding movement to draw in the headspace vapor into the vacuum. Atty Docket No. 4992-0006PCT _ 2 -

[0011] In some aspects, the techniques described herein relate to a remote wellsite system, wherein the reciprocating piston system is further configured to compress the headspace vapor after the headspace vapor is drawn into the vacuum.

[0012] In some aspects, the techniques described herein relate to a remote wellsite system, wherein the compressed headspace vapor can be transferred to one or more of a recovery pipeline or a storage tank.

[0013] In some aspects, the techniques described herein relate to a remote wellsite system, wherein the headspace vapor is one or more of methane, ethane, propone, or isobutane.

[0014] In some aspects, the techniques described herein relate to a remote wellsite system, wherein by using the pneumatic gas booster with the motive gas, an amount of the motive gas consumed is reduced to only the motive gas needed to drive the pneumatic gas booster.

[0015] In some aspects, the techniques described herein relate to a remote wellsite, wherein the liquid nitrogen tank includes a sensor that can provide an alert when a status of the liquid nitrogen tank changes.

[0016] In some aspects, the techniques described herein relate to a remote wellsite, wherein the status can be one or more of an empty tank and a decreased flow rate.

[0017] In some aspects, the techniques described herein relate to a remote wellsite, wherein the pneumatic gas booster is a single stage, single acting pneumatic gas booster.

[0018] In some aspects, the techniques described herein relate to a remote wellsite, wherein the pneumatic gas booster is configured to provide a recovered gas to an end-device for an operation by the end-device on the remote wellsite.

[0019] In some aspects, the techniques described herein relate to a remote wellsite, wherein the pneumatic gas booster is configured to provide a recovered gas to one or more of a recovery pipeline or a storage tank.

[0020] In some aspects, the techniques described herein relate to a pneumatic gas booster system positioned in a remote wellsite operation, the pneumatic gas booster system including: a nitrogen piston configured to receives a drive gas from a liquid nitrogen tank, the drive gas being a nitrogen gas admitted through a nitrogen drive inlet port; a connecting rod actuated by the nitrogen piston; a gas piston that is actuated by the connecting rod to cause a receding movement; a compression chamber connected to the gas piston, wherein a vacuum is formed in a compression chamber during the receding movement by the gas piston as the nitrogen piston is operated, wherein as the vacuum is formed a working gas is drawing in to the compression chamber and the working gas is compressed; and a booster outlet is connected to the Atty Docket No. 4992-0006PCT . 3 . compression chamber, wherein the compressed working gas exits out of the booster outlet and is provided to an end-device to assist in an operation of a remote wellsite.

[0021] In some aspects, the techniques described herein relate to a pneumatic gas booster system, wherein the working gas is received from an oil tank.

[0022] In some aspects, the techniques described herein relate to a pneumatic gas booster system, wherein the working gas is methane.

[0023] In some aspects, the techniques described herein relate to a pneumatic gas booster system, wherein the end-device is a device that previously operated using a propone storage tank.

[0024] In some aspects, the techniques described herein relate to a pneumatic gas booster system, wherein liquid nitrogen tank includes a vaporizer to provide the drive gas.

[0025] In some aspects, the techniques described herein relate to a pneumatic gas booster system, wherein the end-device is a storage tank and the compressed working gas is a methane gas that has been captured during the operation of the remote wellsite to reduce a methane emission at the remote wellsite.

[0026] BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The disclosure is illustrated by way of example, and not by way of limitation in the figures of the accompanying drawings in which like reference numerals are used to refer to similar elements.

[0028] Figure 1 illustrates an example configuration of a gas venting system 100 with a pneumatic driven gas booster.

[0029] Figure 2 illustrates an example pneumatic driven gas booster.

[0030] Figures 3 A-3B illustrate wellsites with casing gas.

[0031] DETAILED DESCRIPTION

[0032] The present disclosure relates to a system that uses a pneumatic driven gas booster on a wellsite. As an example, a gas is used to operate a reciprocating piston system, the piston can create a vacuum during a receding movement to draw in gas. The piston can then compress this gas that has been drawn in and eject it from a pump. This gas, which is now compressed, can then be transferred into a recovery pipeline or pressurized storage tank or pushed into a burner for elimination. When used on a wellsite, such as a remote wellsite, this system can be used to reduce various gases, such as methane gas and keep it from being vented into the atmosphere. Atty Docket No. 4992-0006PCT _ 4 >

[0033] This reduction of various gases, such as methane gas is desirable to reduce methane emissions that can trap heat in the atmosphere at greater rate than CO2. Additionally, the current government regulatory agencies have set goals for methane gas emission reduction with compliance and incentives being provided to reduce these methane emissions. By using a pneumatic gas driven booster, this methane emission can be compressed and ejected from a wellsite to reduce methane emissions at the wellsite.

[0034] Figure 1 illustrates an example system 100 using a pneumatic gas booster for methane venting. As shown in Figure 1, the system 100 may include the following components:

[0035] 1 - Pump Jack

[0036] 2 - Well Head

[0037] 3 - Surface Casing

[0038] 4 - Production Tubing

[0039] 5 - Production Line to Tank

[0040] 6 - Production Line to Discharge

[0041] 7 - Oil Tank

[0042] 8 - Oil Level in Tank

[0043] 9 - Produced or Released Gas

[0044] 10 - Vent Line (optional)

[0045] 11 - Pneumatic Gas Booster

[0046] 12 - Line for Recovered Gas to Operator Recover Unit

[0047] 14 - Liquid Nitrogen Tank

[0048] 15 - Vaporizer for Liquid Nitrogen

[0049] 16 - Compressed Gas Tank

[0050] 17 - Communication Unit

[0051] As shown in Figure 1, the pneumatic gas booster 11 can be the a pneumatic gas driven booster, such as the examples described elsewhere herein.

[0052] With reference to FIG. 1, a production and vapor-recovery system 100 is shown in which a pump jack 1 actuates a downhole pump to lift reservoir fluids from underground and through production tubing 4 to a well head 2 mounted to surface casing 3. The well head 2 fluidly couples to a production line to tank 5, which directs the produced stream into an oil tank 7 via an internal production line to discharge 6 that may terminate below the oil level 8 to reduce agitation and foaming. Within the oil tank 7, lighter hydrocarbons evolve into a headspace Atty Docket No. 4992-0006PCT . 5 . defining produced or released gas 9. An optional vent line 10 may be provided for pressure relief and maintenance events.

[0053] In some embodiments, the headspace vapors 9 (such as methane, but may also include ethane, propone, isobutane, or other light hydrocarbons) are captured by a pneumatic gas booster 11 configured to draw from the tank 7 and elevate vapor pressure for delivery through a line for recovered gas 12 to an operator recovery unit (e.g., a Vapor Recovery Unit “VRU” header or sales line). The recovered-gas line 12 may include one or more of a check valve, regulator, and instrumentation. In some implementations, the recovered gas 12 may be used to operate one or more end-devices that were conventionally operated by propane provided separately to the end device, such as by a propane storage. The end-device may be used to run or assist in the operations of the remote wellsite.

[0054] The booster 11 may be driven by an inert motive gas supplied from a liquid nitrogen tank 14, which feeds a vaporizer 15 arranged to convert liquid nitrogen to gaseous nitrogen. The gaseous nitrogen is accumulated in a compressed gas tank 16 and provided to the booster 11 (and, in some cases, associated instruments) to furnish a stable drive pressure during vaporrecovery operation.

[0055] As shown in Figure 1, the flow rate of the nitrogen may act as the driver for the pneumatic gas booster 11, and this can then move out the methane gas from the tanks and into a storage facility or pipeline. In some embodiments, the flow of the nitrogen can be tailored and start the pneumatic gas booster 11, with the goal being to minimize the consumption of the nitrogen as needed, or to only consume the amount of nitrogen needed to drive the pneumatic gas booster as compared to a conventional system only using nitrogen to draw out the methane (or other headspace gas) where a greater amount of nitrogen is used. In some implementations, a sensor (not shown) can be included on the liquid nitrogen tank that can signal the consumption of the nitrogen as it is used. Additionally, the sensor can communicate with the communication unit 17 to provide alerts or status indicator and signals to an off-site system, such as a computer network. For example, the sensor can provide an empty tank notification or a reduced / unexpected flow rate to signal an error for review or if a status changes of the liquid nitrogen tank (full, empty, half full, temperature drops / changes, leak detection, etc.). In some implementations, the amount of methane that can be moved out of the tank is variable at any given time and a sensor 18 can be used to monitor the amount of methane and the sensor 18 can trigger events when the amount of methane reaches a level that the pneumatic gas booster 11 should be turned on and as needed. Atty Docket No. 4992-0006PCT . 6 -

[0056] As shown, in Figure 2, in some implementations, a single stage, single acting pneumatic gas booster 200 can be used and include the below elements in some configurations:

[0057] 21 - Pilot Valve

[0058] 22 - Nitrogen Piston

[0059] 23 - Nitrogen Drive Barrel

[0060] 24 - Connecting Rod

[0061] 25 - Exhaust Muffler

[0062] 26 - High Pressure Barrel

[0063] 27 - Booster Outlet

[0064] 28 - Check Valve

[0065] 29 - Booster Inlet

[0066] 30 - Cooling Jacket

[0067] 31 - Nitrogen Exhaust Tube

[0068] 32 - Gas Piston

[0069] 33 - Nitrogen Cycling Valve

[0070] 34 - Nitrogen Drive Inlet Port

[0071] 35 - Upper and Lower Caps

[0072] 36 - Vent Port Breather

[0073] With reference to FIG. 2, a pneumatically driven gas booster 200 is shown in which a nitrogen piston 22 reciprocates within a nitrogen drive barrel 23 to actuate a connecting rod 24 that in turn drives a gas piston 32 disposed in a high-pressure barrel 26. Drive gas (e.g., nitrogen) may be admitted through a nitrogen drive inlet port 34 and selectively routed by a nitrogen cycling valve 33, the operation of which can be initiated or shifted by a pilot valve 21. During each stroke, spent drive gas is discharged through a nitrogen exhaust tube 21 and may pass to atmosphere via an exhaust muffler 25; a vent port breather 36 can be provided to equalize pressure at a valve or housing cavity.

[0074] On the process side, a working gas (such as methane or another headspace vapor) is drawn into the pneumatically driven gas booster 200 through a booster inlet 29 and along or through a cooling jacket 30 for heat exchange before entering the compression chamber defined by the high-pressure barrel 26 and gas piston 32. Upon compression, the working gas flows through a check valve 28 and exits at a booster outlet 27 (where the compressed working gas may be used, such as for various operations by the remote wellsite, or stored as described above with reference to the line for recovered gas 12), the check valve 28 inhibiting reverse flow back Atty Docket No. 4992-0006PCT . 7 . into the chamber. Structural end closures, shown as upper and lower caps 35, may seal and support the barrels and internal components.

[0075] Additionally, other types of example gas booster models can be used to capture gases and improve the performance of the well site. It should be understood that other types of gas boosters can be used besides the example shown in Figure 2. Specifically, the gas booster comprises a drive section configured to receive a motive gas via a drive inlet port and to exhaust spent motive gas via an exhaust outlet (e.g., through a muffler), and a gas section configured to compress a process gas between a gas inlet port and a gas outlet port. The drive section includes a drive cylinder within which a drive piston reciprocates. The gas section includes a gas cylinder within which a gas piston reciprocates, the gas piston being mechanically coupled to the drive piston by a common rod or crosshead so that movement of the drive piston effects corresponding movement of the gas piston.

[0076] An internal cycling valve (e.g., a pilot-operated spool) is operatively coupled to the drive section and is configured to alternately admit the motive gas to opposing chambers of the drive cylinder and to exhaust the opposite chamber, thereby causing the drive piston to reverse direction at the end of each stroke and to self-cycle without external actuation. In some embodiments, the cycling valve is shifted by a pilot signal generated by the position of the piston or by pressure differentials within the drive section.

[0077] The gas section further comprises an inlet check valve disposed upstream of the gas cylinder and an outlet check valve disposed downstream of the gas cylinder. During a suction stroke, retraction of the gas piston reduces pressure in the gas cylinder below the pressure at the gas inlet port, thereby opening the inlet check valve and admitting the process gas into the cylinder. During a compression stroke, advancement of the gas piston increases pressure in the gas cylinder above the downstream pressure, thereby opening the outlet check valve and discharging compressed gas through the gas outlet port while inhibiting reverse flow through the inlet.

[0078] In operation, the drive section applies a force approximately proportional to the product of motive-gas pressure and the effective area of the drive piston. Because the gas piston has a smaller effective area, the gas booster multiplies pressure on the gas side according to the ratio of the drive-piston area to the gas-piston area. The unit may stall at an outlet pressure at which the opposing forces balance; reducing backpressure or increasing motive-gas pressure resumes cycling. Flow rate may decrease as outlet pressure approaches the stall condition.

[0079] In some embodiments, the gas booster further includes one or more of: (i) a cooling structure (e.g., fins, heat sink mass, or a cooling jacket) thermally coupled to the gas section; (ii) Atty Docket No. 4992-0006PCT _ 8 - pressure-sensing elements or switches configured to start / stop cycling at selected pressures; (iii) relief devices such as pressure-relief valves and burst disks; (iv) filters on the drive and / or gas inlets; and (v) mounting features to secure the unit during operation. The booster may be singleacting or double-acting on the gas side, and may be provided as a single stage or as multiple stages in series to achieve higher pressure ratios. Materials and seals can be selected to accommodate different gases (e.g., nitrogen, hydrocarbons, oxygen-compatible service) and environmental classifications. Orientation, port locations, and dimensional relationships shown in the figures are non-limiting and may be varied without departing from the scope of the described embodiments.

[0080] In other implementations, storage tanks are responsible for 6% of methane emissions in natural gas and oil production sector in the U.S. Often, these wellsite systems use propane, natural gas, or casing gas to run the pump jack. Additionally, in other embodiments, common off-grid pumpjack engines run on natural gas, often casing gas produced from the well, but pumpjacks have been run on many types of fuel, such as propane and / or natural gas. In some implementations, the gas scavenging units mentioned herein can be powered by one or more of liquid natural gas (LNG), propane, methane, other gases or liquids that could then be directed to the engine powering the pump jack.

[0081] If the casing gas is of a purity that allows for such a use, then the casing gas could also be used. The benefit of using casing gas if it is possible from the purity is that the casing gas has high pressure and a virtually unlimited supply. Casing gas is available at a wellsite as shown in Figures 3A and 3B. That casing gas can be harnessed to drive other aspects described herein, such as one or more end-devices controlling operations of the remote wellsite. The casing gas may be a high pressure high volume source of gas available on most wellsites. As shown in Figure 3 A, a typical wellsite installation includes a polished rod 41 and a stuffing box 42. The production tubing 43 extends down into a casing 44 and as a fluid level 45 changes (from the extraction, such as through the perforations 46) the pressure in the casing 44 changes. In the typical installation shown in Figure 3B, the produced oil 47 is combined with the pressure produced gas 48 and both are extracted out the outlet 49 together. The pressure produced gas 48 comes out as a high flow line because the typical installation does not allow the casing gas to be used for anything else. As shown in Figure 3B, the pressure in the casing 44b may be increased compared to the typical installation in Figure 3 A as shown by the higher fluid level 45. With this higher pressure in the casing 44b, the produced oil 50 can be extracted separately from the produced gas 51 and the produced gas 51 can be drawn out at a lower pressure separate from the Atty Docket No. 4992-0006PCT _ 9 > produced oil 50. This casing gas could be used as shown as the produced gas 51 to drive various aspects of the wellsite as described elsewhere herein.

[0082] Typically, the pressures of this casing gas range up to and occasionally exceed 1000 psi. The gas make up is random on a well by well basis. In many cases this casing gas is directed into the pipeline and moves away from the location, however, the casing gas could instead be used to drive the turbine.

[0083] Additionally, some technologies like solar panels which require batteries are particularly sensitive to weather and theft as these assets are readily disposable. In other embodiments, compressed gas is also an option, but it is also weather sensitive and produces water which can freeze in the winter and damage the systems proposed. In some common wellsite locations, like North America, such weather is typically available in most oil producing states. In some implementations, constant operation is an option if driving energy is low enough, where the driving energy being Nitrogen / Electricity / Compressed Air / Gas, Methane.

[0084] It should be understood that the above-described example embodiments are provided by way of illustration and not limitation and that numerous additional use cases are contemplated and encompassed by the present disclosure. In the above description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it should be understood that the hardware and technology described herein may be practiced without these specific details.

[0085] The foregoing description has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the specification to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the disclosure be limited not by this detailed description, but rather by the claims of this application. As will be understood by those familiar with the art, the specification may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Likewise, the particular naming and division of the modules, routines, features, attributes, methodologies and other aspects are not mandatory or significant, and the mechanisms that implement the specification or its features may have different names, divisions and / or formats.

Claims

Atty Docket No. 4992-0006PCT - 10 -WHAT IS CLAIMED IS:

1. A remote wellsite system comprising: a remote pump jack configured to lift reservoir fluids from underground; an oil tank connected to the remote pump tank, the oil tank being configured to store the reservoir fluids and allow the reservoir fluids to separate into one or more of oil and a headspace vapor; a pneumatic gas booster connected to the oil tank, wherein the pneumatic gas booster is configured to draw in the headspace vapor during a vapor recovery operation; and the pneumatic gas booster being connected to a liquid nitrogen tank that provides a motive gas to the pneumatic gas booster such that as the pneumatic gas booster draws in the headspace vapor, the motive gas furnishes a stable drive pressure during the vapor recovery operation.

2. The remote wellsite system of claim 1, wherein the motive gas is a nitrogen gas.

3. The remote wellsite system of claim 2, wherein the nitrogen gas is stored as a liquid in the liquid nitrogen tank.

4. The remote wellsite system of claim 3, wherein the liquid nitrogen tank includes a vaporizer configured to draw the liquid nitrogen out of the liquid nitrogen tank as the nitrogen gas, such that the nitrogen gas can be provided to the pneumatic gas booster.

5. The remote wellsite system of claim 1, wherein the pneumatic gas booster includes a reciprocating piston system, where the reciprocating piston system creates a vacuum within the pneumatic gas booster during a receding movement to draw in the headspace vapor into the vacuum.

6. The remote wellsite system of claim 5, wherein the reciprocating piston system is further configured to compress the headspace vapor after the headspace vapor is drawn into the vacuum.Atty Docket No. 4992-0006PCT - 11 -7. The remote wellsite system of claim 6, wherein the compressed headspace vapor can be transferred to one or more of a recovery pipeline or a storage tank.

8. The remote wellsite system of claim 1, wherein the headspace vapor is one or more of methane, ethane, propone, or isobutane.

9. The remote wellsite system of claim 1, wherein by using the pneumatic gas booster with the motive gas, an amount of the motive gas consumed is reduced to only the motive gas needed to drive the pneumatic gas booster.

10. The remote wellsite of claim 1, wherein the liquid nitrogen tank includes a sensor that can provide an alert when a status of the liquid nitrogen tank changes.

11. The remote wellsite of claim 10, wherein the status can be one or more of an empty tank and a decreased flow rate.

12. The remote wellsite of claim 1, wherein the pneumatic gas booster is a single stage, single acting pneumatic gas booster.

13. The remote wellsite of claim 1, wherein the pneumatic gas booster is configured to provide a recovered gas to an end-device for an operation by the enddevice on the remote wellsite.

14. The remote wellsite of claim 1, wherein the pneumatic gas booster is configured to provide a recovered gas to one or more of a recovery pipeline or a storage tank.

15. A pneumatic gas booster system positioned in a remote wellsite operation, the pneumatic gas booster system comprising: a nitrogen piston configured to receives a drive gas from a liquid nitrogen tank, the drive gas being a nitrogen gas admitted through a nitrogen drive inlet port; a connecting rod actuated by the nitrogen piston; a gas piston that is actuated by the connecting rod to cause a receding movement;Atty Docket No. 4992-0006PCT - 12 - a compression chamber connected to the gas piston, wherein a vacuum is formed in a compression chamber during the receding movement by the gas piston as the nitrogen piston is operated, wherein as the vacuum is formed a working gas is drawing in to the compression chamber and the working gas is compressed; and a booster outlet is connected to the compression chamber, wherein the compressed working gas exits out of the booster outlet and is provided to an enddevice to assist in an operation of a remote wellsite.

16. The pneumatic gas booster system of claim 15, wherein the working gas is received from an oil tank.

17. The pneumatic gas booster system of claim 16, wherein the working gas is methane.

18. The pneumatic gas booster system of claim 15, wherein the end-device is a device that previously operated using a propone storage tank.

19. The pneumatic gas booster system of claim 15, wherein liquid nitrogen tank includes a vaporizer to provide the drive gas.

20. The pneumatic gas booster system of claim 15, wherein the end-device is a storage tank and the compressed working gas is a methane gas that has been captured during the operation of the remote wellsite to reduce a methane emission at the remote wellsite.

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