Gerald Thomas Adams

US Patent:

53460103, Sep 13, 1994

Filed:

Mar 31, 1993

Appl. No.:

8/040784

Inventors:

Gerald C. Adams - Sugar Land TX
Robert J. Faircloth - Houston TX
Jimmie B. Lawson - Houston TX

Assignee:

Shell Oil Company - Houston TX

International Classification:

E21B 4312
E21B 4322

US Classification:

166279

Abstract:

Scale inhibitors are precipitated in a formation by injection in an acidic solution comprising a base generating component and a chelating agent. The inhibitor is preferably a calcium salt of an organic phosphonate. The chelating agent prevents iron ions from causing premature hydrolysis of the base generating component.

US Patent:

53928598, Feb 28, 1995

Filed:

Dec 2, 1993

Appl. No.:

8/160995

Inventors:

Gerald C. Adams - Sugar Land TX
Jimmie B. Lawson - Houston TX
Lee N. Morgenthaler - Houston TX

Assignee:

Shell Oil Company - Houston TX

International Classification:

E21B 4327

US Classification:

166300

Abstract:

The present invention is a method to improve permeability of a formation in the vicinity of a production wellbore. An acid treatment composition is placed in the formation after a foaming composition is injected and a foam created from the foaming composition, thus forcing the acid treatment composition into less permeable strata. The foaming composition contains a sulfate surfactant as a foam stabilization agent. The sulfate hydrolyzes after a time period that is long enough to permit placement of the acid treatment composition. After the sulfate hydrolyzes, it becomes ineffective as a surfactant. Fluids produced from the formation after the acid treatment according to the present invention therefore do not contain significant concentrations of active surfactants, and therefore do not create foams or emulsions in surface separation equipment.

US Patent:

54602262, Oct 24, 1995

Filed:

May 18, 1994

Appl. No.:

8/245730

Inventors:

Jimmie B. Lawson - Houston TX
Gerald C. Adams - Sugar Land TX
Robert J. Faircloth - Houston TX

Assignee:

Shell Oil Company - Houston TX

International Classification:

E21B 4326

US Classification:

166300

Abstract:

A method is provided to fracture a subterranean formation along with a fracturing fluid useful in this method, the method comprising the steps of: a) providing a fracturing fluid, the fracturing fluid is an aqueous solution having an initial pH greater than about 8 and comprising a polysaccharide, a source of borate in an amount that is effective to crosslink the polysaccharide at a pH greater than 8, an oxidative breaker, and a precursor that hydrolyzes in an amount that is effective to lower the pH of the fracturing fluid after a time period that is greater than about one half hour and less than about two days; b) injecting the fracturing fluid into the formation at a pressure the is effective to fracture the formation and force at least a portion of the fracturing fluid into the fracture; and c) permitting the precursor to hydrolyze and thereby lowering the pH of the fracturing fluid to a pH that is less than about 8.