Formation testing

• US 10,107,096 B2
• Filed: 06/30/2014
• Issued: 10/23/2018
• Est. Priority Date: 04/27/2010
• Status: Active Grant

• Current Assignee: Statoil ASA (Asa Equinor), Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Statoil ASA (Asa Equinor), Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Bedouet, Sylvain, Eriksen, Kare Otto
• Primary Examiner(s): Andrews, D.
• Application Number:
  US14/320,025
• Publication Number:
  US 20140311737A1
• Time in Patent Office: 1,576 Days
• CPC Class Codes: E21B 49/005 Testing the nature of borehole walls or the formation by using drilling mud or cutting data
• CPC Class Codes: E21B 49/088 combined with sampling
• CPC Class Codes: E21B 49/10 using side-wall fluid samplers or testers

Abstract

Formation testing which may involve circulating mud in a pipe string from a mud pit through a port in the pipe string to a downhole diverter sub, wherein the pipe string is suspended in a wellbore extending into a subterranean formation, operating a downhole pump to pump formation fluid from the formation, wherein the formation fluid comprises gas, and mixing the pumped formation fluid with circulated mud such that a proportion of the pumped formation gas in the circulated mud is maintained below a threshold value.

Claims

1. An apparatus, comprising:

a tool string suspended by a pipe string in a wellbore extending into a subterranean formation comprising a formation fluid, wherein the tool string comprises;

a first packer fluidly isolating a first portion of the wellbore from a second portion of the wellbore;

a second packer fluidly isolating the second portion of the wellbore from a third portion of the wellbore;

a first fluid communicator disposed between the first and second packers;

a flow line conducting the formation fluid from the second portion of the wellbore, through the first fluid communicator, to a second fluid communicator, wherein the formation fluid comprises gas;

a mixer mixing the formation fluid, received via the second fluid communicator, with a drilling fluid, received via the pipe string; and

a third fluid communicator expelling the mixed formation and drilling fluids into the first portion of the wellbore, wherein the third fluid communicator is disposed downhole from the second fluid communicator; and

a controller communicatively coupled to the tool string and configured to;

determine a first threshold value of a proportion of gas in the mixed formation and drilling fluids based on fluid properties of the formation fluid as measured via downhole fluid analysis using a fluid analyzer positioned in the flow line of the tool string;

determine a second threshold value of a ratio of formation fluid pumping rate and drilling fluid circulation rate based on the first threshold value;

simulate response of formation fluid conditions to the second threshold value, wherein the formation fluid conditions comprise wellbore pressure and/or wellbore temperature;

determine whether a well integrity problem would be expected.

2. The apparatus of claim 1, wherein the first portion of the wellbore extends uphole from the first packer, and wherein the third portion of the wellbore extends downhole from the second packer.

3. The apparatus of claim 2, wherein the first fluid communicator is disposed downhole from the second fluid communicator.

4. The apparatus of claim 2, wherein the first fluid communicator is disposed downhole from the third fluid communicator.

5. The apparatus of claim 4, wherein the mixer comprises a flow area restriction establishing a low pressure zone and a high pressure zone, and wherein the second fluid communicator is disposed in the low pressure zone.

6. The apparatus of claim 5, wherein the high pressure zone is disposed uphole from the low pressure zone.

7. The apparatus of claim 1, wherein the tool string comprises an upper portion coupled with the pipe string, a lower portion, and a slip-joint slidably coupling the upper and lower portions, and wherein the lower portion of the tool string comprises the first and second packers, the flow line, the mixer, and the first, second, and third fluid communicators.

8. The apparatus of claim 7, wherein the lower portion of the tool string further comprises:

a telemetry cartridge comprising a downhole controller, transmitting data from the downhole controller to a wireline cable extending the length of the slip-joint and the pipe string, and receiving data from the wireline cable;

a pump module pumping the first fluid from the first fluid communicator to the second fluid communicator via the flow line; and

a power cartridge distributing electrical power received from the wireline cable to the pump module.

9. The apparatus of claim 8, wherein the lower portion of the tool string further comprises a fluid analyzer module analyzing the first fluid flowing in the flow line, wherein the power cartridge further distributes the electrical power to the fluid analyzer module.

10. The apparatus of claim 9, wherein the lower portion of the tool string further comprises a sample chamber module operable to selectively receive a sample of the first fluid flowing in the flow line based on the fluid analyzer module analysis.

11. The apparatus of claim 9, wherein the fluid analyzer module comprises a sensor operable in obtaining at least one of density and viscosity of the first fluid flowing in the flow line.

12. The apparatus of claim 9, wherein the fluid analyzer module comprises an optical fluid analyzer operable to obtain optical spectral data associated with the first fluid flowing in the flow line.

13. The apparatus of claim 12, wherein at least one of the downhole controller and the fluid analyzer module is operable to estimate at least one of composition, gas-to-oil ratio (GOR), and gas content of the first fluid flowing in the flow line based on the obtained optical spectral data.

14. The apparatus of claim 9, wherein the fluid analyzer module comprises a sensor operable to sense a phase boundary of the first fluid flowing in the flow line.