Method of releasing stuck pipe or tools and spotting fluids therefor

• US 6,148,917 A
• Filed: 02/09/1999
• Issued: 11/21/2000
• Est. Priority Date: 07/24/1998
• Status: Expired due to Term

• Current Assignee: Enventives, LLC
• Original Assignee: Actisystems, Inc.
• Inventors: Cowan, Jack C., Brookey, Tommy F.
• Primary Examiner(s): SUCHFIELD, GEORGE A
• Application Number:
  US09/246,934
• Time in Patent Office: 651 Days
• Field of Search: 166/301, 175/65, 175/69, 507/102, 507/202, 507/910, 507/940
• US Class Current: 166/301
• CPC Class Codes: C09K 2208/02 Spotting, i.e. using additives for releasing a stuck drill
• CPC Class Codes: C09K 8/02 Well-drilling compositions
• CPC Class Codes: C09K 8/08 containing natural organic compounds, e.g. polysaccharides, or derivatives thereof
• CPC Class Codes: C09K 8/206 Derivatives of other natural products, e.g. cellulose, starch, sugars
• CPC Class Codes: C09K 8/5758 of natural origin, e.g. polysaccharides, cellulose C09K8/5756 takes precedence
• CPC Class Codes: E21B 31/035 controlling differential pipe sticking
• CPC Class Codes: Y10S 507/91 Earth boring fluid devoid of discrete aqueous phase
• CPC Class Codes: Y10S 507/94 Freeing stuck object from wellbore

Abstract

Aphron-containing spotting fluids and their use in releasing pipe or tools stuck in the filter cake on the sides of a borehole are disclosed. The spotting fluids comprise a liquid, either aqueous, oleaginous, or mixtures thereof, a viscosifier which imparts a low shear rate viscosity to the fluids of at least 10,000 centipoise, an aphron-generating surfactant, and aphrons. The spotting fluids are used in a conventional method of releasing pipes or tools stuck in the filter cake on the sides of a borehole during conventional drilling or well servicing operations.

Claims

1. A spotting fluid for use in releasing stuck pipe or tools within a borehole comprising a liquid selected from the group consisting of aqueous liquids, oleaginous liquids, and mixtures thereof, having incorporated therein one or more viscosifiers such that the spotting fluid has a low shear rate viscosity as measured with a Brookfield Viscometer at 0.5 rpm of at least about 10,000 centipoise, an aphron-generating surfactant, and aphrons.

2. The spotting fluid of claim 1 wherein the density of the liquid and the concentration of aphrons are such that the spotting fluid has the desired density.

3. The spotting fluid of claim 1 which contains a continuous aqueous phase having a viscosifier therein.

4. The spotting fluid of claim 1 which contains a continuous oleaginous phase having a viscosifier therein.

5. The spotting fluid of claim 2 which contains a continuous aqueous phase having a viscosifier therein.

6. The spotting fluid of claim 2 which contains a continuous oleaginous phase having a viscosifier therein.

7. The spotting fluid of claim 1, 2, 3, 4, 5, or 6 wherein the low shear rate viscosity is at least about 40,000 centipoise.

8. A method of releasing a stuck pipe or tool within a borehole comprising introducing the spotting fluid of claim 1, 2, 3, 4, 5, or 6 to the depth of the point of the stuck pipe or tool and in a volume sufficient to displace the fluid in the borehole over the entire stuck area, and allowing the spotting fluid to soak for a period of time sufficient to release the stuck pipe or tool.

9. The method of claim 8 wherein the spotting fluid has a low shear rate viscosity of at least about 40,000 centipoise.