System and method for enhancing permeability of a subterranean zone at a horizontal well bore

• US 7,419,223 B2
• Filed: 01/14/2005
• Issued: 09/02/2008
• Est. Priority Date: 11/26/2003
• Status: Expired due to Fees

• Current Assignee: Effective Exploration LLC
• Original Assignee: CDX Gas LLC (EnerVest Ltd.)
• Inventors: Seams, Douglas P.
• Primary Examiner(s): Neuder; William P
• Application Number:
  US11/035,537
• Publication Number:
  US 20050183859A1
• Time in Patent Office: 1,327 Days
• Field of Search: 299/2, 299/19, 175/57, 175/61, 175/62
• US Class Current: 299/2
• CPC Class Codes: E21B 21/085 Underbalanced techniques, i.e. where borehole fluid pressure is below formation pressure
• CPC Class Codes: E21B 43/006 Production of coal-bed methane E21B43/243 takes precedence
• CPC Class Codes: E21B 43/13 specially adapted to dewatering of wells of gas producing reservoirs, e.g. methane producing coal beds
• CPC Class Codes: E21B 43/25 Methods for stimulating production by vibrating earth formations E21B43/003
• CPC Class Codes: E21B 43/40 Separation associated with re-injection of separated materials E21B43/385 takes precedence

Abstract

A method and system for enhancing permeability of a subterranean zone at a horizontal well bore includes determining a drilling profile for the horizontal well bore. At least one characteristic of the drilling profile is selected to aid in stabilizing the horizontal well bore during drilling. A liner is inserted into the horizontal well bore. The well bore is collapsed to increase permeability of the subterranean zone at the horizontal well bore.

Claims

1. A method for producing gas from a coal seam, comprising:

drilling a horizontal well bore in a coal seam using a non-invasive drilling fluid in an over-balanced drilling condition;

forming on the horizontal well bore with the non-invasive drilling fluid a filter cake having a depth of less than four centimeters;

inserting a liner into the horizontal well bore;

reducing a down-hole hydrostatic pressure in the horizontal well bore by removing fluid from the well bore;

collapsing the horizontal well bore around the liner; and

producing fluids flowing from the coal into the horizontal well bore.

2. The method of claim 1, wherein the non-invasive drilling fluid comprises micelles.

3. The method of claim 1, wherein the liner is perforated.

4. The method of claim 1, wherein drilling a horizontal well bore comprises forming the horizontal well bore in a subterranean zone proximate one or more aquifers.

5. The method of claim 1, wherein the liner is uncemented.

6. A method for producing gas from a coal seam, comprising:

drilling a horizontal well bore in a coal seam using a non-invasive drilling fluid in an over-balanced drilling condition;

forming a filter cake on the horizontal well bore with the non-invasive drilling fluid;

inserting a liner into the horizontal well bore;

reducing a down-hole hydrostatic pressure in the horizontal well bore by removing fluid from the well bore;

collapsing the horizontal well bore around the liner; and

producing fluids flowing from the coal scam into the horizontal well bore.

7. The method of claim 6, wherein the non-invasive drilling fluid comprises micelles.

8. The method of claim 6, wherein the liner is perforated.

9. The method of claim 6, wherein drilling a horizontal well bore comprises forming the horizontal well bore in a subterranean zone proximate one or more aquifers.

10. The method of claim 6, wherein the liner is uncemented.