Method and apparatus for separating and measuring solids from multi-phase well fluids

• US 6,790,367 B2
• Filed: 10/31/2002
• Issued: 09/14/2004
• Est. Priority Date: 08/02/2002
• Status: Expired due to Term

• Current Assignee: Weatherford Canada Limited (Weatherford International PLC)
• Original Assignee: Northland Energy Corporation
• Inventors: Schmigel, Kevin, Speed, David, Stefureak, Peter
• Primary Examiner(s): Reifsnyder, David A.
• Application Number:
  US10/284,173
• Publication Number:
  US 20040020860A1
• Time in Patent Office: 684 Days
• Field of Search: 210/739, 210/740, 210/744, 210/747, 210/767, 210/787, 210/788, 210/800, 210/808, 210/97, 210/103, 210/104, 210/109, 210/116, 210/117, 210/138, 210/143, 210/170, 210/188, 210/512.1, 210/513, 210/533, 494/1, 494/2, 494/10, 494/37, 209/715, 209/725, 166/53, 166/267, 961/56, 961/57, 962/09, 964/08, 952/41, 952/61, 554/591
• US Class Current: 210/740
• CPC Class Codes: B01D 21/245 Discharge mechanisms for the sediments
• CPC Class Codes: B01D 21/30 Control equipment
• CPC Class Codes: B01D 21/302 Active control mechanisms with external energy, e.g. with solenoid valve
• CPC Class Codes: B01D 21/32 Density control of clear liquid or sediment, e.g. optical control ; Control of physical properties
• CPC Class Codes: B01D 21/34 Controlling the feed distribution; Controlling the liquid level ; Control of process parameters

Abstract

A method and an apparatus for separating and measuring solids from multi-phase well fluids. The apparatus comprises a separator; an upper solids level and a lower solids level sensor, both connected to the separator; a dump valve operatively connected to the separator; and a control module operatively connected to the dump valve to move the dump valve between an open and a closed position. The upper solids level sensor generates a first signal when the upper level of accumulated solids-within the separator reaches a pre-determined upper level. The lower solids level sensor generates a second signal when the upper level of accumulated solids within the separator reaches a predetermined lower level. The control module receives the first and second generated signals such that upon receipt of the first signal the control module causes the dump valve to open and upon receipt of the second signal the control module causes the dump valve to close.

Claims

1. A method for separating and measuring solids from multi-phase well fluids extracted from a well, the method comprising the steps of:

(i) directing said multi-phase well fluids to a separator to separate at least a portion of any solids present in said well fluids from gas phase components of said well fluid;

(ii) establishing an upper maximum and a lower minimum limit within said separator for accumulated solids separated from said multi-phase well fluids, said upper maximum and lower minimum limits established through the use of at least one upper sensor and at least one lower sensor;

(iii) upon said accumulated solids in said separator reaching said upper maximum limit, generating a first signal with said upper sensor and directing said first signal to a control module;

(iv) upon said accumulated solids in said separator reaching said lower minimum limit, generating a second signal with said lower sensor and directing said second signal to said control module; and

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(v) upon receipt of said first signal said control module causing a dump valve operatively connected to said separator to open allowing a portion of said accumulated solids to be removed from said separator, upon receipt of said second signal said control module causing said dump valve to close and prevent further removal of accumulated solids from said separator to thereby gas carry under where said multi-phase well fluids include a gas component.

2. The method as claimed in claim 1 wherein said separator is a centrifugal separator, a horizontal separation vessel, or a vertical vessel with a non-centrifugal internal separation device.

3. The method as claimed in claim 1 including the further step of measuring and determining the volume of solids extracted from said multi-phase well fluids by said separator.

4. The method as claimed in claim 3 including monitoring the time between the opening and closing of said dump valve, and thereafter utilizing the time between the opening and closing of said dump valve and the measurement of the volume of solids extracted from said multi-phase well fluids by said separator to determine an approximate rate of production of solids from the well.

5. The method as claimed in claim 4 wherein said step of measuring and determining the volume of solids separated from said multi-phase well fluids comprises determining the fixed volume of said separator between said upper and said lower sensors and monitoring the generation of said first and said second signals by said upper and said lower sensors over time, and thereafter calculating a volume for said solids separated from said multi-phase well fluids and determining a solids production rate.

6. The method as claimed in claim 1 including the further step of directing said solids that flow from said separator through said dump valve to a choke such that said solids exit said choke at a reduced pressure.

7. The method as claimed in claim 6 including the step of determining the volume of solids extracted from said multi-phase well fluids through determining the flow rate of solids exiting said separator, said flow rate approximated using the differential pressure as measured across said choke to calculate a flow rate on the basis of incompressible liquid flow through an orifice.

8. The method as claimed in claim 1 including the step of measuring the density of said solids separated from said multi-phase well fluids by said separator through the use of a density measuring device.

9. The method as claimed in claim 8 including the further step of utilizing a flow measurement device to calculate the flow of said solids from said separator when said dump valve is open, and thereafter utilizing said calculated flow and said measured density of said solids to determine a volumetric measurement for said solids separated from said multi-phase well fluids by said separator.

10. The method as claimed in claim 9 including the step of monitoring and determining the time between the opening and closing of said dump valve, said time in conjunction with said volumetric measurement of solids separated from said multi-phase well fluids by said separator together used to generate a rate of production of solids from the well.

11. A method for separating and measuring solids from multi-phase well fluids from a wellbore, the method comprising the steps of:

(i) directing multi-phase well fluids generated from the wellbore to a separator designed to separate at least a portion of any solids from gas phase components present in said multi-phase well fluids;

(ii) through the use of at least one upper level sensor connected to said separator, establishing an upper maximum limit within said separator for the accumulation of solids separated from said multi-phase well fluids;

(iii) through the use of at least one lower level sensor connected to said separator, establishing a lower minimum limit within said separator for accumulated solids separated from said multi-phase well fluid, said lower minimum limit designed to maintain a minimum volume of solids within said separator and to thereby help prevent gas carry under when solids are extracted from said separator;

(iv) generating a first signal with said upper level sensor when the upper level of said accumulated solids in said separator reaches said upper maximum limit and generating a second signal with said lower level sensor when the upper level of said accumulated solids in said separator reaches said lower minimum limit, said first and second signals directed to a control module, said control module operating a dump valve connected to said separator and causing said dump valve to open and close to thereby maintain the level of said accumulated solids in said separator between said upper maximum and said lower minimum limits; and

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(v) with a density measuring device and a flow measurement device, measuring the density of solids separated from said multi-phase well fluids and calculating the flow of solids from said separator when said dump valve is open, thereafter, with said measured density and said calculated flow rate determining a volumetric measurement of solids separated from said multi-phase well fluids by said separator.

12. The method as claimed in claim 11 including the further step of monitoring and determining the time between the opening and closing of said dump valve and thereafter utilizing said determined time together with said volumetric measurement of solids separated from said multi-phase well fluids by said separator and calculating an approximate rate of solids production from the well.

13. An apparatus for separating and measuring solids from multi-phase well fluids from a wellbore, the apparatus comprising:

(i) a separator for separating at least a portion of any solids from gas phase components present in said multi-phase well fluids;

(ii) an upper solids level sensor connected to said separator, said upper solids level sensor generating a first signal when the upper level of accumulated solids within said separator reaches a predetermined upper maximum level;

(iii) a lower solids level sensor connected to said separator, said lower solids level sensor generating a second signal when the upper level of accumulated solids within said separator reaches a pre-determined lower minimum level;

(iv) a dump valve operatively connected to said separator, said dump valve having an open and a closed position; and

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(v) a control module operatively connected to said dump valve to move said dump valve between said open and said closed positions, said control module receiving said first and second generated signals such that upon receipt of said first signal said control module causes said dump valve to move to said open position and upon receipt of said second signal said control module causes said dump valve to move to said closed position.

14. The apparatus as claimed in claim 13 including a flow rate measurement device positioned between said separator and said dump valve, said flow measurement device generating a signal corresponding to the flow of solids from said separator through said dump valve upon the opening of said valve.

15. The apparatus as claimed in claim 14 including a density measuring device positioned between said separator and said dump valve, said density measuring device generating a signal corresponding to the density of material flowing from said separator through said dump valve, said control module receiving said signals generated by said flow rate measurement device and said density measuring device and calculating the volume of solids extracted from said multiphase well fluids by said separator.

16. The apparatus as claimed in claim 15 wherein said control module includes a timer that monitors and determines the time between the opening and closing of said dump valve such that said determined time, in conjunction with said calculated volume of solids extracted from said multi-phase well fluids by said separator, may be utilized to generate an approximate solids production rate for the wellbore.

17. The apparatus as claimed in claim 13 wherein said dump valve is hydraulically, pneumatically or electrically operated by said control module.

18. The apparatus as claimed in claim 13 wherein said upper solids level sensor and said lower solids level sensor are comprised of nuclear density gauge detectors.

19. The apparatus as claimed in claim 13 wherein said separator is a centrifugal separator, a horizontal separation vessel, or a vertical vessel with a non-centrifugal internal separation device.

20. The apparatus as claimed in claim 13 including a choke positioned downstream of said dump valve, said choke having a fixed pressure drop across its orifice such that solids exit said choke at a pressure that approximates atmospheric pressure.