Abstract
A process to extract work from raw high pressure hydrocarbon production fluids to power gas cleaning and contaminant disposal. This process takes raw high-pressure hydrocarbon well production fluids via pipeline, moderates the pressure through suppressor, separates the fluids into gaseous and liquid phases via separator, passes the gaseous phases through particle filter, then through liquid separator, then passes the gaseous phases through a work extraction machine to extract work. Work can rotate electrical generator, or a pump. Contaminants such as CO2 can be isolated using other cleaning plant, the pass via pipeline and disposed of subsurface via well/s and pipeline, with the pump running directly off the work extraction machine or separate pumps running off electricity generated by generator and distributed via cabling.
Claims
1-19. (canceled)
20. A process for recovering energy in a natural gas production system comprising : extracting natural gas from a subterranean natural gas reservoir, passing said gas through an overpressure separator, separating the liquid and gas phases, filtering the gas phase stream to remove entrained solids, drying the gaseous phase, passing the gaseous phase through a work recovery engine to convert the high pressure, high temperature gaseous phase into lower pressure, lower temperature gaseous phase and thereby generate energy.
21. The process as claimed in claim 20, wherein the subterranean natural gas reservoir comprises a High Pressure High Temperature (HPHT) Acid/Sour gas fields or a sweet gas fields.
22. The process as claimed in claim 21, wherein the subterranean natural gas reservoir has an initial reservoir pressure of about 10,000 psia (690 bara) and reservoir temperature of about 300 oF. (149 oC.).
23. The process as claimed in claim 20, wherein the work recovery engine comprises means to convert changes in pressure into electricity.
24. The process as claimed in claim 20, wherein the work recovery engine comprises a turboexpander.
25. The process as claimed in claim 24, wherein the work created by the turboexpander is used to power a piggy-backed compressor and/or to generate electricity.
26. The process as claimed in claim 20, further comprising the step of pre-treatment to remove solids and/or liquids from the inlet fluid stream.
27. The process as claimed in claim 20, further comprising filtration upstream of the work recovery engine to reduce any contaminant particles to a size of about 2-3 m in diameter.
28. The process as claimed in claim 20, further comprising the separation of liquids upstream of the work recovery engine to separate and/or reduce the volume of liquid droplets from the feed gas.
29. An energy recovery system comprising a subterranean natural gas reservoir in fluid communication with an overpressure protector, in fluid communication with a separator for separating liquid phase from gaseous phase; a filter system for separating entrained solids and comprising at least one filter unit cleaning the gaseous phase; means for drying the gaseous phase; and at least one work recovery engine for recovering work from the expansion of the gas phase.
30. The system as claimed in claim 29, wherein the work recovery engine receives high pressure, high temperature fluids and delivers lower pressure, lower temperature fluids downstream and thereby generates energy that can be utilised in other systems.
31. The system as claimed in claim 29, wherein the at least one work recovery engine is coupled to means for making use of the recovered energy.
32. The system as claimed in claim 31, wherein the means for making use of the recovered energy comprises a compressor pump and/or electrical generator
33. The system as claimed in claim 32, wherein the electricity produced may be utilised to clean the hydrocarbon gas and/or powering sequestration pumps for subsurface disposal of contaminants, such as carbon dioxide.
34. The system as claimed in claim 29, wherein the work recovery engine may be in fluid communication with a production fluids conduit such that gaseous phase may be comingled therewith.
35. The system as claimed in claim 34, wherein the comingled gaseous phase and liquid phase may pass to an ammonia cleaning plant in which hydrogen sulphide and carbon dioxide may be removed from the hydrocarbon gas phase.
36. The system as claimed in claim 29, wherein the work recovery engine is coupled to a compressor pump to provide energy thereto and which may operate to pump carbon dioxide and/or other contaminants into substrata for sequestration or to compress hydrocarbon gas for LPG transportation.
37. The system as claimed in claim 29, wherein the work recovery engine is coupled to a cleaning plant in which hydrogen sulphide and carbon dioxide may be removed from the hydrocarbon gas phase.
38. The system as claimed in claim 37, wherein the carbon dioxide is isolated and delivered to a sequestration pump which may itself be powered by electricity provided by an electricity generator upstream.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0048] The invention will now be described solely by way of example and with reference to the accompanying drawings in which:
[0049] FIG. 1 shows the process in its stages with electricity production
[0050] FIG. 2 shows the process in its stages with electricity production and an aqueous ammonia gas cleaning plant
[0051] FIG. 3 shows the process in its stages with a compressor element for CO2 sequestration or LPG compression
[0052] FIG. 4 shows the process in its stages with electricity production, gas cleaning plant and sequestration of CO2, etc., separated from the hydrocarbons
[0053] FIG. 5 shows a turbo expander in accordance with the present invention
DETAILED DESCRIPTION
[0054] In FIG. 1, high pressure pipeline or 1 which carries the production flow from a gas well or wells drilled into a deep hydrocarbon reservoir, is connected to an overpressure protector 2 that sets the maximum fluid pressure that can pass beyond the protector 2 and limits the pressure to a pressure compatible with the next stages of the process. Overpressure protector 2 is connected by conduit to bulk separator 3 which crudely separates liquid phases from gaseous phases, liquid phases bypass the rest of the system via conduit 4 to be comingled later with the rest of the well production phases in pipeline 5. Gaseous phases pass onwards through conduit 6 into filter system 7 which removes entrained solids and has a plurality of selectable filter units 8 to allow for switching and cleaning without restricting the continuous flow of gaseous phases. The filtered gaseous phases then pass further down conduit 6 to a final separator 9 to ensure that the gaseous phases are completely dry. Any liquid phases separated out pass through conduit 10 to eventually connect with pipeline 5, in this illustration via connection with conduit 4. The dry and clean, high pressure gaseous phases pass through conduit 11 into one or more work recovery engines 12 before exiting into conduit 13 at a lower pressure than they entered. Conduit 13 connects to pipeline 5 to be comingled with the rest of the production fluids in pipe 5. Each work recovery engine 12 is connected to an electrical generator 14. Electricity produced passes down wire 15 and can be used for any purpose but cleaning the hydrocarbon gas and running sequestration pumps for subsurface disposal of contaminants like carbon dioxide is preferable. This entire process from wellhead to end runs at very high pressures, with high temperatures and can contain dangerous gases like H2S, CH4, etc., so safety is paramount. A plethora of control valves, isolation valves, pressure sensors, temperature sensors, level sensors, gas sensors and an emergency shutdown system (and electrification) is essential for safe operation but have been omitted for clarity in the illustrations.
[0055] In FIG. 2, high pressure pipeline or 1 which carries the production flow from a gas well or wells drilled into a deep hydrocarbon reservoir, is connected to an overpressure protector 2 that sets the maximum fluid pressure that can pass beyond the protector 2 and limits the pressure to a pressure compatible with the next stages of the process. Overpressure protector 2 is connected by conduit to bulk separator 3 which crudely separates liquid phases from gaseous phases, liquid phases bypass the rest of the system via conduit 4 to be comingled later with the rest of the well production phases in pipeline 5. Gaseous phases pass onwards through conduit 6 into filter system 7 which removes entrained solids and has a plurality of selectable filter units 8 to allow for switching and cleaning without restricting the continuous flow of gaseous phases. The filtered gaseous phases then pass further down conduit 6 to a final separator 9 to ensure that the gaseous phases are completely dry. Any liquid phases separated out, pass though conduit 10 to eventually connect with pipeline 5, in this illustration via connection with conduit 4. The dry and clean, high pressure gaseous phases pass on down conduit 11 into one or more work recovery engines 12 before exiting into conduit 13 at a lower pressure than it entered. Conduit 13 connects pipeline 5 to be comingled with the rest of the production fluids in pipe 5. Each work recovery engine 12 is connected to an electrical generator 14. Electricity produced passes down wire 15 and can be used for any purpose but cleaning the hydrocarbon gas and running sequestration pumps for subsurface disposal of contaminants like carbon dioxide is preferable. The pipeline 5 passes on to an aqueous ammonia cleaning plant 17 in which hydrogen sulphide (H2S) and carbon dioxide are removed from the hydrocarbon gas. An aqueous ammonia cleaning plant 17 functions at a lower pressure than other gas cleaning plants allowing for the generation of more electricity from the process described above.
[0056] This entire process from wellhead to end runs at very high pressures, with high temperatures and can contain dangerous gases like H2S, CH4, etc., so safety is paramount. A plethora of control valves, isolation valves, pressure sensors, temperature sensors, level sensors, gas sensors and an emergency shutdown system (and electrification) is essential for safe operation but have been omitted for clarity in the illustrations.
[0057] In FIG. 3, high pressure pipeline or 1 which carries the production flow from a gas well or wells drilled into a deep hydrocarbon reservoir, is connected to an overpressure protector 2 that sets the maximum fluid pressure that can pass beyond the protector 2 and limits the pressure to a pressure compatible with the next stages of the process. Overpressure protector 2 is connected by conduit to bulk separator 3 which crudely separates liquid phases from gaseous phases, liquid phases bypass the rest of the system via conduit 4 to be comingled later with the rest of the well production phases in pipeline 5. Gaseous phases pass onwards through conduit 6 into filter system 7 which removes entrained solids and has a plurality of selectable filter units 8 to allow for switching and cleaning without restricting the continuous flow of gaseous phases. The filtered gaseous phases then pass further down conduit 6 to a final separator 9 to ensure the gaseous phases are completely dry. Any liquid phases separated out pass through conduit 10 to eventually connect with pipeline 5, in this illustration via connection with conduit 4. The dry and clean, high pressure gaseous phases pass on down conduit 11 into one or more work recovery engine 12 before exiting into conduit 13 at a lower pressure than it entered. Conduit 13 connects pipeline 5 to be comingled with the rest of the production fluids in pipe 5. Each work recovery engine 12 is connected to a compressor pump 18. Compressor pump 18 can be used pump CO2 and other contaminants into subsurface strata for sequestration or to compress hydrocarbon gas for LPG transportation.
[0058] This entire process from wellhead to end runs at very high pressures, with high temperatures and can contain dangerous gases like H2S, CH4, etc., so safety is paramount. A plethora of control valves, isolation valves, pressure sensors, temperature sensors, level sensors, gas sensors and an emergency shutdown system (and electrification) is essential for safe operation but have been omitted for clarity in the illustrations.
[0059] In FIG. 4, high pressure pipeline or 1 which carries the production flow from a gas well or wells drilled into a deep hydrocarbon reservoir, is connected to an overpressure protector 2 that sets the maximum fluid pressure that can pass beyond the protector 2 and limits the pressure to a pressure compatible with the next stages of the process. Overpressure protector 2 is connected by conduit to bulk separator 3 which crudely separates liquid phases from gaseous phases, liquid phases bypass the rest of the system via conduit 4 to be comingled later with the rest of the well production phases in pipeline 5. Gaseous phases pass onwards through conduit 6 into filter system 7 which removes entrained solids and has a plurality of selectable filter units 8 to allow for switching and cleaning without restricting the continuous flow of gaseous phases. The filtered gaseous phases then pass further down conduit 6 to a final separator 9 to ensure the gaseous phases are completely dry. Any liquid phases separated out flow down conduit 10 to eventually connect with pipeline 5, in this illustration via connection with conduit 4. The dry and clean, high pressure gaseous phases pass on down conduit 11 into one or more work recovery engines 12 before exiting into conduit 13 at a lower pressure than it entered. Conduit 13 connects pipeline 5 to be comingled with the rest of the production fluids in pipe 5. Each work recovery engine 12 is connected to electrical generator 14. Electricity produced passes down wire 15 and can be used for any purpose but cleaning the hydrocarbon gas and running sequestration pumps for subsurface disposal of contaminants like carbon dioxide is preferable. The pipeline 5 passes on to a cleaning plant 19 in which hydrogen sulphide (H2S) and carbon dioxide are removed from the hydrocarbon gas. Isolated CO2 passes into pipeline 20 and into sequestration pump 21, which can be powered by electricity from generator 14 via wiring 15. CO2 then travels deep underground via well 22.
[0060] FIG. 5 shows a turbo expander 100 in accordance with the present invention in cross-sectional view. High pressure (HP) gas 102 is fed into the inlet 104 of the body 106 of the turbo expander 100. The turbo expander 100 has a turbine 108 mounted on a shaft 110 which is rotatably housed within the body of the turboexpander. As the HP gas enters the expansion chamber 112 the turbine is rotated which in turn rotates the shaft which can be used to generate electricity, for example. Lower Pressure (LP) gas 114 exits the expansion chamber and the turbo expander.
[0061] This entire process from wellhead to end runs at very high pressures, with high temperatures and can contain dangerous gases like H2S, CH4, etc., so safety is paramount. A plethora of control valves, isolation valves, pressure sensors, temperature sensors, level sensors, gas sensors and an emergency shutdown system (and electrification) is essential for safe operation but have been omitted for clarity in the illustrations.
