Flow regime identification with filtrate contamination monitoring

Patent metadata

Field	Value
Publication number	US-10858935-B2
Application number	US-201414164991-A
Country	US
Kind code	B2
Filing date	Jan 27, 2014
Priority date	Jan 27, 2014
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

Implementations of the present disclosure relate to apparatuses, systems, and methods for determining when a well cleanup process has established developed flow and then extrapolating out modeled fluid parameter values to determine parameter values for a formation fluid. The model fluid parameter values may be modeled using a power law function having a specified exponent value.

First claim

We claim:

1. A method for determining a contamination ratio of a formation fluid in a reservoir, the method comprising:
lowering a downhole sampling tool into a wellbore traversing the reservoir,
obtaining a measured data array including at least a sample fluid parameter and a durational value via the downhole sampling tool by drawing sample fluid through a flowline that provides fluid communication between one or more inlets and an outlet and using a fluid analyzer operatively disposed in the downhole sampling tool;
in a processor coupled to the downhole sampling tool, fitting a model to the measured data array, the model being defined by
a power law function containing the durational value;
in the processor, extrapolating the model according to the power law function when the durational value equals infinity to find a formation fluid parameter, wherein the power law function is FP=α+β*D γ , wherein FP is the sample fluid parameter, α is the formation fluid parameter, β is a fitting constant, D is the durational value, and γ is an exponent value;
in the processor, determining a fitting interval start point by determining when values of Log|FP−α| overlay values of (γ Log V+Log β), wherein the durational value is volume (V);
in the processor, confirming the fitting interval start point overlays a linear portion of the measured data array when compared on log-log scales;
repeating said steps of obtaining, fitting, extrapolating, determining and confirming, to ensure consistency of the fitting interval start point; and
outputting the contamination ratio based on the fitting interval start point for the formation fluid using Beer-Lambert's mixing law and plotting the contamination ratio for the formation fluid on a graph for presentation on a display.

2. The method of claim 1 , wherein the sample fluid parameter is optical density, gas-oil-ratio, compressibility, density, or conductivity.

3. The method of claim 1 , wherein obtaining the measured data array further comprises obtaining the measured data array using a radial probe.

4. The method of claim 1 , wherein confirming the fitting interval start point comprises changing the fitting interval start point and verifying the formation fluid parameter remains within a predetermined tolerance.

5. The method of claim 1 , wherein the power law function comprises the exponent value of −⅔.

6. The method of claim 1 , wherein determining the fitting interval start point further comprises:
plotting on a plot the values of Log|FP−α| versus values of Log V;
plotting on the plot the values of (γ Log V+Log β) versus the values of Log V;
comparing the values of Log|FP−α| to the values of (γ Log V+Log β); and
determining when the values of Log|FP−α| overlay the values of (γ Log V+Log β).

7. The method of claim 1 , wherein determining the fitting interval start point further comprises:
plotting on a graph a first plot of values of Log|η| versus values of Log V according to η=(FP Oil −FP)/(FP Oil −FP Filtrate ), wherein FP Oil is the formation fluid parameter and FP Filtrate is a fluid parameter of a filtrate in the sample fluid;
plotting on the graph a second plot of the values of Log|η| versus the values of Log V according to Log|η|=−γ Log V−Log [β/(FP Oil −FP Filtrate )];
comparing the first and second plots on the graph; and
determining whether the first and second plots overlay one another.

8. A method for determining a contamination ratio of a formation fluid in a reservoir, the method comprising:
lowering a downhole sampling tool into a wellbore traversing the reservoir,
obtaining a measured data array including at least a sample fluid parameter (FP) and a durational value (D) via the downhole sampling tool by drawing sample fluid through a flowline that provides fluid communication between one or more inlets and an outlet and using a fluid analyzer operatively disposed in the downhole sampling tool);
in a processor coupled to the downhole sampling tool, fitting a model to the measured data array, wherein α is a formation fluid parameter and β is a fitting constant, the model being defined by a power law function:
FP=α+β* D γ

where γ is −⅔;

in the processor, extrapolating FP=α+β*D γ when the durational value equals infinity to find α;
in the processor, determining a fitting interval start when values of Log|FP−α| and values of (γ Log D+Log β) remain within a predetermined tolerance;
in the processor, confirming the fitting interval start overlays a start of a linear portion of the measured data array when compared on log-log scales; and
in the processor, outputting the contamination ratio based on the fitting interval start point for the formation fluid using Beer-Lambert's mixing law and plotting the contamination ratio for the formation fluid on a graph for presentation on a display.

9. The method of claim 8 , wherein the sample fluid parameter is optical density, gas-oil ratio, compressibility, density, or conductivity.

10. The method of claim 8 , wherein determining the fitting interval start when the values of Log|FP−α| and the values of (γ Log D+Log β) remain within the predetermined tolerance comprises measuring an inflection point in the values of (γ Log D+Log β) versus the values of Log|FP−α| when compared on log-log scales.

11. The method of claim 8 , wherein determining the fitting interval start when the values of Log|FP−α| and the values of (γ Log D+Log β) remain within the predetermined tolerance comprises calculating the contamination ratio less than 30%.

12. The method of claim 8 , further comprising confirming the fitting interval start by changing the fitting interval start and verifying the formation fluid parameter remains within the predetermined tolerance.

13. A computer program product for determining a contamination ratio of a formation fluid in a reservoir from contaminated fluid in a system, the computer program product comprising one or more non-transitory computer-readable storage media having stored thereon computer-executable instructions that, when executed by one or more processors of a computing system, cause the computing system to perform a method comprising:
accessing a measured data array including at least a sample fluid parameter and a durational value, said data array being measured by a downhole sampling tool lowered into a wellbore traversing the reservoir;
fitting a model to the measured data array, the model being defined by a power law function containing the durational value, wherein the power law function is FP=α+β*D γ , wherein FP is the sample fluid parameter, α is a formation fluid parameter, β is a fitting constant, D is the durational value, and γ is an exponent value;
extrapolating the model according to the power law function when the durational value equals infinity to find the formation fluid parameter;
determining a fitting interval start by determining when values of Log|FP−α| overlay values of (γ Log D+Log β); and
confirming the fitting interval start overlays a linear portion of the measured data array when compared on log-log scales;
outputting the contamination ratio based on the fitting interval start for the formation fluid using Beer-Lambert's mixing law and plotting the contamination ratio for the formation fluid on a graph for presentation on a display.

14. The computer program product for implementing the method of claim 13 , wherein determining the fitting interval start when the values of Log|FP−α| overlay the values of (γ Log D+Log β) comprises calculating the contamination ratio less than 30%.

15. The computer program product for implementing the method of claim 1

Assignees

• Schlumberger Technology Corp

Inventors

• Gisolf Adriaan
• Zuo Youxiang
• Lee Ryan Sangjun
• Leonard Jonathan

Classifications

• E21B49/0875

  determining specific fluid parameters · CPC title

• E21B49/08 Primary

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

• E21B41/0092

  Fixed Constructions · mapped topic

• E21B47/10 Primary

  Locating fluid leaks, intrusions or movements · CPC title