System and method for controlled pumping in a downhole sampling tool

Patent metadata

Field	Value
Publication number	US-9845673-B2
Application number	US-201414301963-A
Country	US
Kind code	B2
Filing date	Jun 11, 2014
Priority date	Jun 11, 2014
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A downhole tool designed to be disposed in a borehole of a subterranean formation is provided. The downhole tool includes a probe used to interface with the subterranean formation in order to sample fluid from or to inject fluid into the subterranean formation. The downhole tool also includes a sample flowline fluidly coupled to the probe and used to direct fluid through the downhole tool. The downhole tool further includes at least two volume chambers. These volume chambers each include a first side fluidly coupled to the sample flowline, a second side fluidly coupled to the guard flowline, and a piston separating the first side from the second side. The downhole tool is able to control a flow of fluid from a high pressure environment to a low pressure environment via the at least two volume chambers, the sample flowline, and the guard flowline.

First claim

What is claimed is:

1. A method, comprising:
engaging a subterranean formation via a probe of a downhole tool disposed in a borehole of the subterranean formation, wherein the downhole tool comprises a sample flowline, a guard flowline, and a first volume chamber, wherein the first volume chamber comprises a first side fluidly coupled to the sample flowline, a second side fluidly coupled to the guard flowline, and a piston separating the first side from the second side;
controlling a first fluid flow from the first volume chamber into and through the guard flowline, the first fluid flow entering the guard flowline at a first pressure;
controlling a second fluid flow through the sample flowline based on the first fluid flow through the guard flowline, wherein controlling the second fluid flow comprises moving the second fluid flow from an environment with a second pressure to an environment with a third pressure, wherein the second pressure is higher than the third pressure; and
pumping, via a reciprocating pump in fluid communication with the guard flowline, the first fluid flow from the first volume chamber through the guard flowline and into a second volume chamber, wherein the second volume chamber comprises a first side fluidly coupled to the sample flowline, a second side fluidly coupled to the guard flowline, and a piston separating fluid in the first side from fluid in the second side; and
pushing the second fluid flow from the first side of the second volume chamber at a controlled rate based on a rate of the first fluid flow entering the second side of the second volume chamber from the guard flowline.

2. The method of claim 1 , wherein the second fluid flow comprises a formation fluid sampled from the subterranean formation into the downhole tool via the probe, and wherein pushing the second fluid flow from the first side of the second volume chamber at a controlled rate comprises re-injecting the formation fluid into the subterranean formation.

3. The method of claim 1 , wherein the second fluid flow comprises a chemical configured to alter a property of the subterranean formation, wherein the chemical is loaded into the downhole tool prior to disposing the downhole tool in the borehole, and wherein pushing the second fluid flow from the first side of the second volume chamber at a controlled rate comprises injecting the chemical into the subterranean formation.

4. The method of claim 1 , wherein the second fluid flow comprises a tracer that is identifiable via the downhole tool, wherein the tracer is loaded into the downhole tool prior to disposing the downhole tool in the borehole, wherein pushing the second fluid flow from the first side of the second volume chamber at a controlled rate comprises injecting the tracer into the subterranean formation.

5. The method of claim 4 , comprising:
injecting the tracer into the subterranean formation via the probe of the downhole tool;
pumping formation fluid from the subterranean formation through a second probe and into the downhole tool via a second reciprocating pump; and
detecting, via sensing components of the downhole tool, the tracer entering the downhole tool through the second probe; and
controlling an operation of the downhole tool based on detection of the tracer.

6. The method of claim 1 , comprising:
sampling a heavy oil or emulsion into the sample flowline via the probe;
circulating the heavy oil or emulsion between the sample flowline and the guard flowline via a reciprocating pump;
sensing, via pressure sensors, a pressure drop through a portion of the sample flowline, the guard flowline, or both; and
calculating a viscosity of the heavy oil or emulsion based on the sensed pressure drop.

7. A method, comprising:
engaging a subterranean formation via a probe of a downhole tool disposed in a borehole of the subterranean formation, wherein the downhole tool comprises a sample flowline, a guard flowline, and a first volume chamber, wherein the first volume chamber comprises a first side fluidly coupled to the sample flowline, a second side fluidly coupled to the guard flowline, and a piston separating the first side from the second side;
controlling a first fluid flow from the first volume chamber into and through the guard flowline, the first fluid flow entering the guard flowline at a first pressure;
controlling a second fluid flow through the sample flowline based on the first fluid flow through the guard flowline, wherein controlling the second fluid flow comprises moving the second fluid flow from an environment with a second pressure to an environment with a third pressure, wherein the second pressure is higher than the third pressure; and
controlling the first fluid flow from the first volume chamber into and through the guard flowline via a flow restrictor disposed between the second side and the guard flowline;
wherein controlling the second fluid flow through the sample flowline comprises receiving the second fluid flow into the first side of the first volume chamber at a controlled rate based on a rate of the first fluid flow exiting the second side of the first volume chamber.

8. The method of claim 7 , wherein the second fluid flow comprises a flowback fluid resulting from a micro-frac operation performed on the subterranean formation via the downhole tool.

Assignees

• Schlumberger Technology Corp

Inventors

• Gisolf Adriaan
• Landsiedel Nathan
• Ayan Cosan
• Moelhoff Kenneth

Classifications

• E21B49/00

  Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells · CPC title

• E21B49/08

  Obtaining fluid samples or testing fluids, in boreholes or wells · CPC title

• E21B49/008 Primary

  by injection test; by analysing pressure variations in an injection or production test, e.g. for estimating the skin factor (measuring pressure E21B47/06) · CPC title

• E21B49/10

  using side-wall fluid samplers or testers · CPC title

• E21B49/087

  Well testing, e.g. testing for reservoir productivity or formation parameters · CPC title