Apparatus and methodology for measuring properties of microporous material at multiple scales

Patent metadata

Field	Value
Publication number	US-9709478-B2
Application number	US-201414762519-A
Country	US
Kind code	B2
Filing date	Feb 5, 2014
Priority date	Feb 8, 2013
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A test apparatus (and method of operation) for characterizing properties of a sample under test (such as porous material, for example, samples of reservoir rock) that operates in conjunction with a source of test fluid. The test apparatus includes an intake valve fluidly coupled to the source of test fluid, a reference cell fluidly coupled to the source of test fluid via the intake valve, a sample cell that holds the sample under test, an isolation valve fluidly coupled between the reference cell and the sample cell, an exhaust port, an exhaust valve fluidly coupled between the sample cell and the exhaust port, a first pressure sensor associated with the reference cell for measuring pressure within the reference cell, and a second pressure sensor associated with the sample cell for measuring pressure within the sample cell. The method of operation includes calibration procedures to compensate for systematic measurement errors.

First claim

What is claimed is:

1. A test apparatus for use with a source of test fluid, the test apparatus for characterizing properties of a sample under test, the test apparatus comprising:
an intake valve fluidly coupled to the source of test fluid;
a reference cell fluidly coupled to the source of test fluid via the intake valve;
a sample cell that holds the sample under test;
an isolation valve fluidly coupled between the reference cell and the sample cell;
an exhaust port;
an exhaust valve fluidly coupled between the sample cell and the exhaust port;
wherein the intake valve, the isolation valve, and the exhaust valve are electronically-controlled;
a first pressure sensor associated with the reference cell for measuring pressure within the reference cell;
a second pressure sensor associated with the sample cell for measuring pressure within the sample cell;
a data processing system that interfaces with the intake valve, the isolation valve, and the exhaust valve via electronic signals communicated therebetween in order to control operation of the intake valve, the isolation valve, and the exhaust valve;
a first temperature sensor associated with the reference cell for measuring temperature within the reference cell;
a second temperature sensor associated with the sample cell for measuring temperature within the sample cell; and
wherein the data processing system interfaces to the first and second temperature sensors via electronic signals communicated therebetween in order to generate and store first and second temperature data representing the temperatures measured by the first and second temperature sensors, respectively, over time.

2. A test apparatus according to claim 1 , wherein the fluidic coupling between the reference cell and the sample cell, pressure sensors, valves, and intake and exhaust port is implemented as a single manifold.

3. A test apparatus according to claim 1 , wherein:
the data processing system interfaces with the first and second pressure sensors via electronic signals communicated therebetween in order to generate and store first and second pressure data representing the pressures measured by the first and second pressure sensors, respectively, over time.

4. A test apparatus according to claim 1 , wherein:
the first pressure sensor has a configuration that measures pressure within the reference cell in a manner that is independent of pressure within the sample cell when the reference cell is isolated from the sample cell by the isolation valve; and
the second pressure sensor has a configuration that measures pressure within the sample cell in a manner that is independent of pressure within the reference cell when the sample cell is isolated from the reference cell by the isolation valve.

5. A test apparatus according to claim 1 , wherein the exhaust port is in communication with ambient atmosphere.

6. A test apparatus according to claim 3 , further comprising:
a housing that encloses at least the sample cell, the reference cell, the isolation valve, the first and second pressure sensors, and the first and second temperature sensors; and
a third temperature sensor disposed within the housing for measuring temperature within the housing.

7. A test apparatus according to claim 1 , wherein:
thermal capacity of the reference cell and the sample cell and fluid flow paths therebetween is larger than thermal capacity of the test fluid and the sample under test; and/or thermal conductivity between the test fluid and the sample cell itself provides fast temperature equilibration between the test fluid and the sample cell.

8. A test apparatus according to claim 7 , wherein elements of known volume with low heat capacity and high thermal conductivity are added to the sample cell to accelerate temperature equilibration between the test fluid and sample under test and the sample cell.

9. A test apparatus according to claim 1 , wherein the test fluid comprises a gas.

10. A test apparatus according to claim 9 , wherein the gas is helium.

11. A method for characterizing properties of a sample under test, comprising:
a) providing the test apparatus of claim 3 and a source of test fluid;
b) loading the sample under test into the sample cell of the test apparatus, wherein the sample under test comprises a porous rock sample;
c) subsequent to b), configuring the test apparatus to perform a sequence of test operations under control of the data processing system of the test apparatus, wherein the sequence of test operations includes
c1) with the reference cell isolated from the sample cell by operation of the isolation valve and the reference cell fluidly coupled to the source of test fluid via the intake valve, filling the reference cell with test fluid at a predetermined elevated pressure,
c2) subsequent to c1), operating the isolation valve to flow test fluid from the reference cell into the loaded sample cell and then to isolate the sample cell from the reference cell in order to fill the sample cell with test fluid under pressure, and
c3) for a first predetermined time period subsequent to c2) with the loaded sample cell isolated from the reference cell via operation of the isolation valve and the loaded sample cell filled with test fluid under pressure, using the second pressure sensor and the data processing system to generate and store second pressure data that represents pressures measured by the second pressure sensor over the first predetermined time period;
wherein the second pressure data stored in c3) for a test with a porous rock sample and billets loaded in the sample cell is compared against the second pressure data stored in c3) for a test with the same billets without a porous rock sample to identify measurements with reduced quality;

d) using the data processing system to process the second pressure data generated and stored in c3) in conjunction with a computational model that includes a set of pressure curves with a number of curve-related variables and associated values in order to identify a matching pressure curve; and
e) using the data processing system to process the values of the curve-related variables for the matching pressure curve identified in d) in order to derive properties of the sample under test.

12. A method according to claim 11 , wherein:
the sequence of test operations of c) further includes
c4) subsequent to c3), operating the exhaust valve to fluidly couple the loaded sample cell to the exhaust port to drop pressure in the loaded sample cell and to then isolate the loaded sample cell from the exhaust port, and
c5) for a second predetermined time period subsequent to c4) with the loaded sample cell isolated from the exhaust port, using the second pressure sensor and the data processing system to generate and store second pressure data that represents pressures measured by the second pressure sensor over the second predetermined time period; and
wherein the processing performed by the data processing system in d) processes the second pressure data derived in c5) in conjunction the computational model in order to identify the matching pressure curve.

13. A method according to claim 11 , wherein the properties of the sample under test derived in e) are selected from the group consisting of bulk volume, porosity, permeability, and grain volume.

14. A method according to claim 11 , wherein the computational model is based on an analytical decay function that includes three parameters α, β and τ, where the parameter α is a storage coefficient that defines the ratio of pore volume to dead volume in the sample under test, the parameter β relates to the final pr

Assignees

• Schlumberger Technology Corp

Inventors

• Chertov Maxim Andreevich
• Suarez-Rivera Roberto
• Willberg Dean M
• Green Sindey J

Classifications

• G01N15/08

  Investigating permeability, pore-volume, or surface area of porous materials · CPC title

• G01N33/24

  Earth materials (G01N33/42 takes precedence) · CPC title

• G01N7/00 Primary

  Analysing materials by measuring the pressure or volume of a gas or vapour · CPC title

• G01N15/0806

  Details, e.g. sample holders, mounting samples for testing · CPC title

• G01N15/088

  Investigating volume, surface area, size or distribution of pores; Porosimetry · CPC title