US 5,473,939 A · Method and apparatus for pressure, volume, and temperature measurement and characterization of subsurface formations

Abstract

A method and apparatus for conducting in situ tests on a subsurface earth formation of interest which is traversed by a wellbore. A wireline formation testing instrument is positioned at formation depth and a sampling probe thereof is extended into fluid communication with the formation and isolated from wellbore pressure. Utilizing a hydraulically energized double-acting bi-directional piston pump and by valve controlled selection of pumping direction testing fluid such as completion fluid may be pumped into the formation through the sampling probe either from fluid reservoirs of the instrument or from the wellbore. After reversing the operating and control valving of the pump and instrument, the piston pump is utilized to extract formation fluid from the formation and pump it to sample tanks of the instrument, pump it into the wellbore or subject it to controlled pressure for real time formation testing and for formation characterization. The pumping mechanism of the formation testing instrument includes a pump-through capability for unlimited pumping of formation fluid to permit effective removal of filtrate, sand, rocks and other debris until an uncontaminated formation fluid sample can be recovered for testing. The piston pump and valving arrangement further permits successive draw-down of minute volumes for rapidly determining formation pressure and permits bubble point pressure and fluid compressibility testing to enable bubble point pressure and fluid compressibility profile plots for formation characterization.

Claims29

Dependent claims

A method for acquiring and testing the formation fluid of a subsurface earth formation having a wellbore defined therein and containing formation fluid, comprising:

(a) positioning within a wellbore a formation testing instrument having a sampling probe and having a bi-directional piston pump having opposed pumping chambers therein each being in valve controlled reversible pumping communication with said sampling probe for selective pumping of completion fluid into and from said subsurface earth formation and having pump pistons in said opposed pumping chambers being in fixed relation with one another and being simultaneously linearly movable and having at least one sample tank within said formation testing instrument, said bi-directional piston pump having an operating piston chamber having an operating piston therein being in fixed driving relation with said pump pistons;
(b) projecting said sampling probe from said formation testing instrument into sampling communication with said subsurface earth formation;
(c) controllably operating said bi-directional piston pump in one selected pumping direction for forcing a quantity of a selected completion fluid through said sampling probe and into said subsurface earth formation;
(d) controllably operating said bi-directional piston pump in the opposite pumping direction for pumping formation fluid from said subsurface formation through said formation testing instrument and into said wellbore to flush away any contaminants present in the surface of said wellbore at said sampling probe until uncontaminated formation fluid is present within said formation testing instrument;
(e) controllably operating said bi-directional piston pump in the opposite selected pumping direction for, pumping a quantity of said uncontaminated formation fluid from said subsurface earth formation through said sampling probe and into said formation testing instrument;
and
(f) conducting at least one test on said formation fluid within said formation testing instrument.

4 more elements

A method for acquiring and testing the formation fluid of a subsurface earth formation having a wellbore defined therein and containing formation fluid:

(a) positioning within a wellbore a formation testing instrument having a sampling probe and having a bi-directional piston pump having opposed pumping chambers therein each being in valve controlled reversible pumping communication with said sampling probe for selective pumping of wellbore fluid into and from said subsurface earth formation and having pump pistons in said opposed pumping chambers being in fixed relation with one another and being simultaneously linearly movable and having at least one sample tank within said formation testing instrument, said bi-directional piston pump having an operating piston chamber having an operating piston therein being in fixed driving relation with said pump pistons;
(b) projecting said sampling probe from said formation testing instrument into sampling communication with said subsurface earth formation;
(c) controllably operating said bi-directional piston pump in one selected pumping direction for forcing a quantity of wellbore fluid through said sampling probe and into said subsurface earth formation to flush contaminants therefrom;
(d) controllably operating said bi-directional piston pump in the opposite selected pumping direction for withdrawing a quantity of said formation fluid from said subsurface earth formation through said sampling probe and into said formation testing instrument:
(e) conducting at least one test on said formation fluid within said formation testing instrument
(f) detecting the temperature of formation fluid being withdrawn from said subsurface earth formation;
(g) capturing a selected volume of said formation fluid within at least one of said pumping chambers of said formation testing instrument by precision linear positioning said pump pistons within at least one of said pumping chambers;
and
(h) correlating said selected volume of said formation fluid with said detected formation fluid temperature for precision determination of temperature corrected volume thereof.

6 more elements

A method of for acquiring and testing the formation fluid of a subsurface earth formation having a wellbore therein and containing a formation fluid, wherein said formation fluid has a bubble point pressure, comprising:

(a) positioning within a wellbore a formation testing instrument having a sampling probe and having a bi-directional piston pump having opposed pumping chambers therein each being in valve controlled reversible pumping communication with said sampling probe for selective pumping of wellbore fluid into and from said subsurface earth formation and having pump pistons in said opposed pumping chambers being in fixed relation with one another and being simultaneously linearly movable and having at least one sample tank within said formation testing instrument, said bi-directional piston pump having an operating piston chamber having an operating piston therein being in fixed driving relation with said pump pistons, at least one pumping chamber of said bi-directional piston pump receiving said formation fluid during linear pump piston movement in one direction and from which said formation fluid is expelled upon linear pump piston movement in the opposite direction during pumping activity, said at least one pumping chamber further being a bubble point pressure and fluid compressibility test chamber of said formation testing instrument, said formation testing instrument further having means for sensing the temperature of said formation fluid, the pressure of said formation fluid within said bubble point pressure and fluid compressibility test chamber and sensing the volume of said test chamber, said pump piston trapping said formation fluid within said bubble point pressure and fluid compressibility test chamber;
(b) projecting said sampling probe from said formation testing instrument into sampling communication with said subsurface earth formation:
(c) controllably operating said bi-directional piston pump in one selected pumping direction for forcing a quantity of wellbore fluid through said sampling probe and into said subsurface earth formation to flush contaminants therefrom:
(d) controllably operating said bi-directional piston pump in the opposite selected pumping direction for withdrawing a quantity of said formation fluid from said subsurface earth formation through said sampling probe and into said formation testing instrument;
(e) conducting at least one test on said formation fluid within said formation testing instrument:
(f) trapping a finite volume of said formation fluid within said bubble point pressure and fluid compressibility test chamber;
(g) measuring the pressure and volume of said trapped finite volume of formation fluid and providing electronic signals representative thereof;
(h) controllably changing the volume of said trapped finite volume of formation fluid;
(i) observing pressure changes of said trapped finite volume of trapped formation fluid during volume change thereof;
(j) determining the bubble point pressure of said formation fluid by comparison of said formation fluid pressure, volume, volume change and pressure change;
and
(k) utilizing said bubble point pressure of multiple formation fluid tests for reservoir characterization of said subsurface earth formation.

9 more elements

A method for flushing debris from a subsurface earth formation having a wellbore defined therein and for acquiring uncontaminated samples of formation fluid from said subsurface earth formation and for testing said formation fluid for bubble point pressure, said method comprising:

(a) positioning within a wellbore of a subsurface formation a formation testing instrument having a sampling probe for fluid communicating engagement with said subsurface earth formation and having an on-board sample tank and having a double acting bi-directional piston pump therein being in selective pumping communication with said sampling probe and with said on board sample tank, said double acting bi-directional piston pump having a pump body defining a pair of pumping chambers and having an operating chamber located between said pumping chambers and a pump drive member having pump pistons fixed thereto and located within said pumping chambers and an operating piston fixed to said pump drive member and being located within said operating chamber, a valve controlled hydraulic operating circuit being located within said formation testing instrument and inducing selective linear movement to said operating piston for linear pumping movement of said pump drive member and said pump pistons, said formation testing instrument further having means therein for conducting volume temperature and formation pressure tests on said formation fluid;
(b) projecting said sampling probe from said formation testing instrument into sampling communication with said subsurface earth formation;
(c) inducing selective reciprocating movement to said operating piston and said pump pistons by said hydraulic fluid operating circuit for pumping formation fluid from said subsurface earth formation through said formation testing instrument and into said wellbore for fluid flushing of contaminants from said subsurface earth formation at said wellbore until uncontaminated formation fluid is recovered from said subsurface earth formation;
(d) selectively reciprocating said pump pistons for pumping a quantity of said uncontaminated formation fluid from said subsurface earth formation and into said onboard fluid tank;
(e) conducting volume, temperature and formation pressure tests on said uncontaminated formation fluid within said formation testing instrument;
and
(f) pumping uncontaminated formation fluid into said sample tank for analysis following removal of said formation testing instrument from said wellbore.

4 more elements

Apparatus for conducting pressure, volume and temperature tests of a connate fluid sample from a subsurface earth formation having a wellbore defined therein and for obtaining samples of connate fluid contained within said subsurface earth formation, comprising:

(a) an instrument body structure for positioning at a selected formation depth within a wellbore of a subsurface earth formation and having at least one connate fluid sample tank therein for selectively receiving connate fluid and for containing testing fluid, said instrument body structure further having means internally thereof for conducting volume, pressure and temperature tests on said connate fluid within said instrument body structure;
(b) a sample probe being laterally extensible from said instrument body structure for fluid sampling engagement with said subsurface earth formation, said sample probe defining a fluid sampling passage for admitting the connate fluid from said subsurface earth formation to said instrument body structure and for transferring the testing fluid from said sample tank of said instrument body structure to said subsurface earth formation;
(c) a double acting bi-directional piston pump having a pump body being located within said instrument body structure and having a pair of spaced and interconnected pump cylinders therein and pump pistons being linearly movable within said pump cylinders said double acting bi-directional piston pump further having an operating cylinder and having an operating piston being fixed to said pump pistons and being movable within said operating cylinder and having a hydraulic circuit for controlled reciprocation of said operating piston and pump pistons;
(d) a hydraulic fluid pumping circuit having check valves permitting unidirectional flow of fluid to and from said pumping chambers and being located within said instrument body structure for selectively controlling pumping direction of said double acting bi-directional piston pump for selective pumping of said testing fluid from said fluid tank through said sampling probe into said subsurface earth formation and pumping of the connate fluid from said subsurface earth formation through said sampling probe and into said instrument body structure;
and
(e) a hydraulic fluid reversing valve being located in said hydraulic fluid pumping circuit for selecting the direction of hydraulic fluid flow to and from said check valves.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for pressure, volume, and temperature measurement and characterization of subsurface formations

Life of this patent

Method and apparatus for pressure, volume, and temperature measurement and characterization of subsurface formations

Life of this patent

Abstract

Claims29