US20150247493A1

US20150247493A1 - High pressure transfer motor-pump

Info

Publication number: US20150247493A1
Application number: US14/192,902
Authority: US
Inventors: Bernard Theron; Malcolm Atkinson
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 2014-02-28
Filing date: 2014-02-28
Publication date: 2015-09-03

Abstract

A high pressure transfer motor-pump providing for pumping a wide range of process fluids (e.g. chemicals, multiphase fluids, and particle polluted fluids) between intake and outlet ports at high pressure with little to zero leak to the environment and little to no contamination between the pumped process fluid and the driving hydraulic fluid. In accordance to an embodiment a high pressure transfer motor-pump includes a process fluid path extending between an inlet port and an outlet port, a cylinder having a barrier separating a hydraulic fluid path from the process fluid path, a motor coupled across a dynamic seal to a hydraulic pump to manipulate the cylinder barrier by circulating a hydraulic fluid through the hydraulic supply fluid path and a housing pressurized at an inlet pressure of the inlet port and encapsulating the motor, the pump, the dynamic seal and the hydraulic fluid.

Description

BACKGROUND

This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
In the oil and gas industry, fluid samples are collected for analysis in many well applications. For example, in a subsea environment tubing is used to convey well fluid to a desired location. Measurements and samples of the fluid moving through the tubing can provide useful information for improved operation of the well.
Fluid samples, for example, may be collected for reservoir characterization or to deduce reservoir fluid properties. The analysis is generally performed at a pressure, volume, temperature (PVT) laboratory. The information derived is used for periodic reservoir characterization over the life of a well to facilitate the evaluation of reserves and for production planning. PVT data can be used, for example, to correct volumetric correlations applied to flow meters pipelines and other downstream assets.
Fluid samples are collected to enable deposition studies, for example, asphaltene deposition. For example, in a subsea application, problematic deposition can occur as a result of the temperature and pressure gradients between a subsea wellhead and the surface.

SUMMARY

In accordance to an embodiment a high pressure transfer motor-pump includes a process fluid path extending between an inlet port and an outlet port, a cylinder having a barrier separating a hydraulic fluid path from the process fluid path, a motor coupled across a dynamic seal to a hydraulic pump to manipulate the cylinder barrier by circulating a hydraulic fluid through the hydraulic supply fluid path and a housing pressurized at an inlet pressure of the inlet port and encapsulating the motor, the pump, the dynamic seal and the hydraulic fluid. A fluid sampling system in accordance to an embodiment includes a sensor in communication with the process fluid path of a motor-pump to detect a characteristic of a process fluid. A method in accordance to an embodiment includes operating a motor-pump to transfer a process fluid from an inlet port at an inlet pressure to an outlet port at an outlet pressure, the motor-pump including a process fluid path extending between the inlet port and the outlet port, a cylinder having a barrier separating a hydraulic fluid path from the process fluid path, a motor coupled across a dynamic seal to a hydraulic pump, and a housing pressurized at the inlet pressure and encapsulating the motor, the pump, the dynamic seal and the hydraulic fluid.
The foregoing has outlined some of the features and technical advantages in order that the detailed description of the transfer motor-pump that follows may be better understood. Additional features and advantages of the transfer motor-pump will be described hereinafter which form the subject of the claims of the invention. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 is a schematic view of a transfer motor-pump according to one or more aspects of the disclosure.

FIG. 2 is a schematic view of a transfer motor-pump according to one or more aspects of the disclosure.

FIG. 3 is schematic illustration of well system utilizing a transfer motor-pump according to one or more aspects of the disclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
A high pressure transfer motor-pump, generally denoted by the numeral 10, provides for pumping a wide range of process fluids (e.g. chemicals, multiphase fluids, and particle polluted fluids) between intake and outlet ports at high pressure with little to zero leaks to the environment and little to no contamination between the pumped process fluid and the driving hydraulic fluid. In accordance to embodiments, the dynamic seals that are exposed to a high differential pressure are isolated from the environment. If the inlet port and internals of the pump are connected to a high pressure inlet port relative to the pressure of the environment, the seal at the pump shaft and motor connection is subject to a high pressure differential. Utilizing a magnetic coupler to drive the pump shaft across a housing provides a manner of removing this dynamic seal in low power systems. However, in high pressure pumping applications the thickness of the pump housing limits the coupling torque that can be transmitted to the pump by the magnetic coupler.
In the examples illustrated in FIGS. 1 and 2, the motor and pump are encapsulated in a housing pressurized at the inlet pressure of the process fluid. Therefore no dynamic seal that is submitted to a high differential pressure is exposed to the environment. All the sealing between the housing and the environment is made with standard static seals and electric pressure feed through. Additionally, the hydraulic fluid circuit isolates the process fluid from the internal dynamic seal holding the differential pressure generated by the pump. The dynamic piston seal (i.e. barrier) between the process fluid and the hydraulic fluid may operate with near zero differential pressure, therefore minimizing any contamination between the two fluids. For example, the pressure differential across the cylinder barrier generated by the pump to transfer the process fluid from the high pressure inlet pressure to the similar high pressure at the outlet port is zero or near zero. In FIG. 1, the cylinder barrier is provided by a piston presenting a dynamic seal between the process fluid and the hydraulic fluid, but the pressure across the dynamic seal is zero or near zero. In the example of FIG. 2, a membrane replaces the piston to promote a perfect zero contamination (i.e. no dynamic seal) between the hydraulic fluid and the process fluid, apart from diffusion process across the membrane.
A non-limiting application of motor-pump 10 is in fluid sampling operations from a high pressure flowline, e.g. vessel. The pump can be used to drive the process fluid from the inlet port at line pressure through a sampling/analysis system maintained at line pressure and back to an outlet port at line pressure. The pump need only provide enough power to circulate the process fluid, but needs to contain the high inlet/outlet pressure from the environment. By way of example, motor-pump 10 is described with reference to FIG. 3 in use in a sampling system in a well application. However, motor-pump 10 may be utilized in various wellbore and non-wellbore applications as well as various environments (e.g., subsea, surface based, and downhole). As will be understood by those skilled in the art with benefit of this disclosure, motor-pump 10 can be utilized in various applications including without limitation fluid sampling systems.
With reference to FIGS. 1 and 2, motor-pump 10 includes a pump 12, i.e. hydraulic pump, coupled to a driving motor 14 for example by a shaft 16. Pump 12 is depicted with two pump cylinders or accumulators 18, although the pump may have various numbers of pump cylinders. Pump 12 and motor 14 are enclosed in a housing 20 that serves as the reservoir 22 for hydraulic fluid 24. In the illustrated example, two cylinders 18 are provided to work in opposition so as to maintain the total enclosed volume of hydraulic fluid 24 constant.
In the depicted example, motor 14 is an electric motor and connected by an electrical conductor or line 26 to an operating system 28. Depending on the application, operating system 28 may include various components such as an electric power source and control systems for controlling the speed and direction of motor-pump 10. Line 26 is shown passing through housing 20 at a static seal 30, e.g. electric feed through. Pressure housing 20 isolates the environment 32 from any leaks across dynamic seal 9 between motor 14 and pump 12, e.g., at shaft 16.
A hydraulic fluid path 34 extends between pump 12 and cylinders 18. Pump cylinders 18 are in fluid communication with an inlet port 36 through inlet conduit or path 38 and an outlet port 40 through outlet conduit or path 42. Check valves 44 are positioned in the respective inlet and outlet paths 38, 42. The hydraulic circuit 46 of motor-pump 10 includes hydraulic fluid path 34 and a process fluid path 48 extending between inlet port 36 and outlet port 40. Each pump cylinder 18 includes a dynamic or cylinder barrier 50 separating the hydraulic fluid in hydraulic fluid path 34 from process fluid 52 in the process fluid path. Housing 20, i.e. hydraulic fluid 24, may be pressurized at inlet pressure 54 for example via hydraulic circuit 46.
Cylinder barriers 50 are illustrated as pistons (i.e. a dynamic seal) in the example of FIG. 1 and as a membrane or bladder (i.e. no seal) in the example illustrated in FIG. 2. The pressure across the cylinder barrier may be zero or near zero, for example the pressure generated by the friction of a dynamic seal. As will be understood by those skilled in the art with benefit of this disclosure, inlet port 36 and outlet port 40 may be connected to the same vessel 58, e.g. a flowline, as illustrated in FIG. 1 or may be connected to different vessels 58, 60 as illustrated in FIG. 2. Pump 12 manipulates cylinder barriers 50 via circulating hydraulic fluid 24 through hydraulic fluid path 34 to transfer process fluid 52 through process fluid path 48.
In the illustrated examples, motor-pump 10 is configured to transfer process fluid 52 from inlet port 36 and to drive process fluid 52 through a sampling system 62 (e.g. sampling and analyzing system) at line pressure 54 (i.e. inlet pressure) to ensure representative samples of the process fluid are analyzed and/or collected. All or part of the process fluid may be discharged at outlet port 40 at an outlet pressure 56 that is substantially equal to inlet pressure 54. For example, with reference to FIG. 1, inlet pressure 54 and outlet pressure 56 are both the pressure of vessel 58, i.e. line pressure.
Sampling system 62 is in fluid communication with process fluid path 48 and is illustrated as including one or more sensors 64, 66 (e.g. meters, optic probes, electric probes) and a sample bottle 68. Sampling system 62 may be in communication with process fluid path 48 upstream and/or downstream of pump cylinders 18. For example and without limitation, sensors 64 may monitor pressure and temperature and sensor 66 may detect the phase and/or other characteristics of process fluid 52. Sensors 64 and 66 may include without limitation viscosity sensors, density sensors, flow rate gauges, sensor of chemicals such as hydrogen sulfide and carbon dioxide, fluorescence detectors, gas-oil ratio sensors, spectral sensors and the like.
FIG. 3 illustrates a well system 100 utilizing a sampling system 62 incorporating a motor-pump 10 in accordance to one or more embodiments. Well system 100 includes a surface system 102 and a subsea system 104. Surface system 102 includes a rig 106, a platform 108, a vessel 110 and a surface controller 112. Surface controller 112 may be provided with hardware and software for operating surface system 102 and subsea system 104.
Subsea system 104 includes a tubing 114, e.g., riser, extending from the platform 108 to a subsea unit 116, a tubular 118 extending downhole from the subsea unit 116 into a wellbore 120, sampling system 62, and a remote operated vehicle (ROV) 122 deployable from vessel 110 to sampling system 62. Other subsea devices, such as a conveyance delivery system, manifold, jumper, etc. may also be provided in subsea system 104. While well system 100 is depicted as a subsea operation, it will be appreciated that it may be land or water based.
Sampling system 62 is connectable to a port 123 in the subsea unit 116 for sampling fluid flowing through tubular 118. As shown, subsea unit or component 116 is located proximate the wellhead 117, but may be any component of the well that has fluids, i.e. process fluid, flowing therethrough, such as the manifold, jumper or other devices. Sampling system 62 is fluidly connectable to port 123 of component 116 for receiving process fluid therefrom and for returning process fluid thereto. Fluid may be passed between subsea component 116 and motor-pump 10 during sampling operations as described for example with reference to FIGS. 1 and 2. For example, inlet and outlet ports 36, 40 of motor-pump 10 may be in fluid communication with tubular 118 via port 123 to transfer process fluid 52, for example production fluid, through sampling system at line pressure.
Sampling system 62 and motor-pump 10 may be deployed to on a skid 125. Skid 125 may be self-sufficient, or deployed and/or operated by ROV 122. ROV 122 may be linked to vessel 110 and controlled thereby. ROV 122 may be used to provide power and/or control signals to the sampling system 62, and/or to retrieve data and/or samples from sampling system 62. Process fluid samples collected, for example in sample bottle 68 (FIG. 1) may be taken back to the surface for analysis by the ROV 122. While ROV 122 may be used to provide communication, power, transportation of samples and/or other capabilities, such features may be provided by other devices and/or within sampling system 62 and the like.
To operate surface system 102, subsea system 104 and/or other devices associated with well system 100, surface unit 112 and/or other controllers may be positioned and placed in communication with various components of surface system 102 and/or subsea system 104. These controllers may be any suitable communication means, such as hydraulic lines, pneumatic lines, wiring, fiber optics, telemetry, acoustics, wireless communication, etc. The surface system and/or subsea systems may be automatically, manually and/or selectively operated via one or more controllers (e.g., surface unit 112). Some such controllers may be separate units at the surface, such as surface unit 112, or at other locations, such as incorporated as part of sampling system 62.
Motor-pump 10 is operated to transfer process fluid 52 through a process fluid path 48 extending from an inlet 36 at inlet pressure 54 to an outlet 40 at an outlet pressure 56. In operation motor-pump 10 circulates hydraulic fluid 24 through a hydraulic fluid supply path 34 to manipulate cylinder barrier 50 that separates the process fluid from the hydraulic fluid. The manipulation of the cylinder barrier pumps the process fluid through the process fluid path. In accordance to some of embodiments, the cylinder barrier is a piston providing a dynamic seal between the process fluid and the hydraulic fluid. The pressure differential across the dynamic seal may be very low, for example, the pressure generated by the friction of the piston. In accordance to some embodiments, the cylinder barrier is a membrane type of member and therefore does not have a seal.
Housing 20 encloses motor 14, pump 12, dynamic seal 9 between the motor and the pump, and the hydraulic fluid. In accordance to some embodiments, the pump is connected via the hydraulic fluid path to at least two cylinders 18 that work in opposition to maintain the total volume of hydraulic fluid enclosed in the housing (i.e. reservoir) constant. In accordance to embodiments, the housing is pressurized at the inlet pressure. The inlet pressure may be significantly greater than the environmental pressure exterior of the housing.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the disclosure. Those skilled in the art should appreciate that they may readily use the disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the disclosure. The scope of the invention should be determined only by the language of the claims that follow. The term “comprising” within the claims is intended to mean “including at least” such that the recited listing of elements in a claim are an open group. The terms “a,” “an” and other singular terms are intended to include the plural forms thereof unless specifically excluded.

Claims

What is claimed is:

1. A high pressure transfer motor-pump, the motor-pump comprising:

a process fluid path extending between an inlet port and an outlet port;

a cylinder having a barrier separating a hydraulic fluid path from the process fluid path;

a motor coupled across a dynamic seal to a hydraulic pump to manipulate the cylinder barrier by circulating a hydraulic fluid through the hydraulic supply fluid path; and

a housing encapsulating the motor, the pump, the dynamic seal and the hydraulic fluid, wherein the housing is pressurized at an inlet pressure of the inlet port.

2. The motor-pump of claim 1, wherein the cylinder barrier is a piston.

3. The motor-pump of claim 1, wherein the cylinder barrier is a membrane.

4. The motor-pump of claim 1, wherein the cylinder comprises at least two cylinders.

5. The motor-pump of claim 1, wherein:

the cylinder barrier is a piston; and

the cylinder comprises at least two cylinders.

6. The motor-pump of claim 1, wherein:

the cylinder barrier is a membrane; and

the cylinder comprises at least two cylinders.

7. A fluid sampling system; comprising:

a process fluid path extending between an inlet port and an outlet port;

a sensor in communication with the process fluid path to detect a characteristic of a process fluid;

8. The sampling system of claim 7, wherein the cylinder barrier is a piston.

9. The sampling system of claim 7, wherein the cylinder barrier is a membrane.

10. The sampling system of claim 7, wherein:

the cylinder barrier is a piston; and

the cylinder comprises at least two cylinders.

11. The sampling system of claim 7, wherein:

the cylinder barrier is a membrane; and

the cylinder comprises at least two cylinders.

12. A method comprising:

operating a motor-pump to transfer a process fluid from an inlet port at an inlet pressure to an outlet port at an outlet pressure, the motor-pump comprising:

a process fluid path extending between the inlet port and the outlet port;

a housing encapsulating the motor, the pump, the dynamic seal and the hydraulic fluid, wherein the housing is pressurized at the inlet pressure.

13. The method of claim 15, wherein the inlet pressure is higher than a pressure of the environment exterior of the housing.

14. The method of claim 15, wherein the inlet pressure and the outlet pressure are substantially equal.

15. The method of claim 15, wherein the cylinder barrier is a piston.

16. The method of claim 15, wherein the cylinder barrier is a membrane.

17. The method of claim 15, comprising transferring the process fluid at the inlet pressure through a sampling system in fluid communication with the process fluid path.

18. The method of claim 15, comprising transferring the process fluid at the inlet pressure through a sampling system in fluid communication with the process fluid path; and

the inlet pressure and the outlet pressure are substantial equal.

19. The method of claim 18, wherein the cylinder barrier is a piston.

20. The method of claim 18, wherein the cylinder barrier is a membrane.