Well Placement Using Closure Stress Based Landing Map

Patent metadata

Field	Value
Publication number	US-2016377754-A1
Application number	US-201514748737-A
Country	US
Kind code	A1
Filing date	Jun 24, 2015
Priority date	Jun 24, 2015
Publication date	Dec 29, 2016
Grant date	—

Abstract

Desirable completion zones can be identified using closure stress in combination with one or more other attributes such as porosity. One computer-based well placement method includes using the computer to: process a seismic data volume to map the spatial distribution of a seismic-based CSS attribute; acquire logs from one or more boreholes in the subsurface region; derive from the logs a relationship between CSS and a minimum in-situ stress; apply the relationship to the CSS attribute map to produce a landing map that highlights desirable completion zones; and place one or more wells in the desirable completion zones. The borehole logs may include direct measurements of minimum in-situ stress (acquired via microfracture testing), sonic tool measurements of P-wave and S-wave velocity, and density tool measurements of bulk formation density.

First claim

What is claimed is:

1 . A computer-based well placement method that comprises:
(a) accessing a seismic survey of a subsurface region with a computer; (b) processing the seismic survey with the computer to get an attribute map of the subsurface region, wherein the attribute map represents at least a spatial distribution of a seismic-based closure stress scalar (CSS); (c) using the computer to access logs from one or more boreholes in the subsurface region, the logs including at least microfracture testing and sonic logs; (d) deriving from the logs a relationship between a borehole-based CSS and a minimum in-situ stress; (e) applying the relationship to the attribute map with the computer to produce a landing map that highlights desirable completion zones; and (f) using the landing map to place one or more wells in the desirable completion zones.

2 . The method of claim 1 , wherein the logs include measurements of p-wave velocity, s-wave velocity, and density.

3 . The method of claim 1 , wherein said logs include microfracture test-based measurements of minimum in-situ stress.

4 . The method of claim 3 , wherein said deriving includes:
(d1) determining acoustic impedances for p-waves and s-waves; (d2) calculating the borehole-based CSS from said acoustic impedances.

5 . The method of claim 1 , wherein the applying includes:
(e1) calibrating the attribute map to match the borehole-based CSS, thereby obtaining a calibrated CSS map; and (e2) converting the calibrated CSS map to a minimum in-situ stress map.

6 . The method of claim 5 , wherein the applying further includes:
(e3) cross-plotting minimum in-situ stress values with another attribute value; (e4) classifying regions of the cross-plot as representing desirable completion zones; and (e5) mapping the subsurface region using color to highlight areas associated with said regions of the cross-plot.

7 . The method of claim 5 , wherein the applying further includes:
(e3′) mapping the subsurface region using color to highlight areas associated with relatively low values of minimum in-situ stress and relatively high values of porosity.

8 . A system for modeling a subsurface region, the system comprising:
a memory having a well placement software module; and one or more processors coupled to the memory to execute the software module, the software module causing the one or more processors to perform a well placement method that includes:
getting an attribute map of the subsurface region, wherein the attribute map represents at least a spatial distribution of a seismic-based closure stress scalar (CSS);
deriving from core samples or logs acquired in one or more boreholes in the subsurface region a relationship between CSS and a minimum in-situ stress; applying the relationship to the attribute map to produce a landing map that highlights desirable completion zones; and determining placements for one or more wells in the desirable completion zones.

9 . The system of claim 8 , wherein the software module further causes the one or more processors to display a visual representation of the landing map with said well placements.

10 . The system of claim 8 , wherein said getting includes processing a seismic survey of the subsurface region to estimate P-wave impedance and S-wave impedance.

11 . The system of claim 10 , wherein said getting further includes calculating a seismic-based CSS attribute and adjusting the seismic-based CSS attribute to be calibrated with one or more borehole-based CSS values.

12 . The system of claim 8 , wherein said deriving includes:
determining acoustic impedances for p-waves and s-waves; calculating the borehole-based CSS from said acoustic impedances.

13 . The system of claim 12 , wherein said logs include at least microfracture testing measurements of minimum in-situ stress, sonic tool measurements of P-wave velocity and S-wave velocity, and density tool measurements of density.

14 . The system of claim 8 , wherein the applying further includes:
cross-plotting minimum in-situ stress values with another attribute value; classifying regions of the cross-plot as representing desirable completion zones; and mapping the subsurface region using color to highlight areas associated with said regions of the cross-plot.

15 . The system of claim 8 , wherein the applying further includes:
mapping the subsurface region using color to highlight areas associated with relatively low values of minimum in-situ stress and relatively high values of porosity.

16 . A computer-based well placement method that comprises:
(a) accessing a seismic survey of a subsurface region with a computer; (b) processing the seismic survey with the computer to get an attribute map of the subsurface region, wherein the attribute map represents at least a spatial distribution of a seismic-based closure stress scalar (CSS); (c) using the computer to access measurements of core samples from one or more boreholes in the subsurface region, the measurements including at least minimum in-situ stress, P-wave acoustic impedance, and S-wave acoustic impedance; (d) deriving from measurements a relationship between a borehole-based CSS and minimum in-situ stress; (e) applying the relationship to the attribute map with the computer to produce a landing map that highlights desirable completion zones; and (f) placing one or more wells in the desirable completion zones.

17 . The method of claim 16 , wherein said deriving includes:
(d1) calculating the borehole-based CSS from said acoustic impedances; and (d2) fitting a linear dependence of minimum in-situ stress to the borehole-based CSS

18 . The method of claim 16 , wherein the applying includes:
(e1) calibrating the attribute map to match the borehole-based CSS, thereby obtaining a calibrated CSS map; and (e2) converting the calibrated CSS map to a minimum in-situ stress map.

19 . The method of claim 18 , wherein the applying further includes:
(e3) cross-plotting minimum in-situ stress values with another attribute value; (e4) classifying regions of the cross-plot as representing desirable completion zones; and (e5) mapping the subsurface region using color to highlight areas associated with said regions of the cross-plot.

20 . The method of claim 18 , wherein the applying further includes:
(e3′) mapping the subsurface region using color to highlight areas associated with relatively low values of minimum in-situ stress and relatively high values of porosity.

Assignees

• Malik Mayank
• Desantis John
• Chen Fuju
• Jiang Li
• Huang Saijin
• Best John A
• Chevron Usa Inc

Inventors

• Malik Mayank
• Desantis John
• Chen Fuju
• Jiang Li
• Huang Saijin
• Best John A

Classifications

• G01V1/40 Primary

  specially adapted for well-logging · CPC title

• G01V13/00

  Manufacturing, calibrating, cleaning, or repairing instruments or devices covered by groups G01V1/00 – G01V11/00 · CPC title

• G01V2210/6226

  Impedance · CPC title

• G01V1/306

  for determining physical properties of the subsurface, e.g. impedance, porosity or attenuation profiles · CPC title

• G01V1/34 Primary

  Displaying seismic recordings {or visualisation of seismic data or attributes} · CPC title