Use of polylysine as a shale inhibitor

Patent metadata

Field	Value
Publication number	US-9890315-B2
Application number	US-201213528317-A
Country	US
Kind code	B2
Filing date	Jun 20, 2012
Priority date	Jul 28, 2011
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

What is proposed is the use of hyperbranched polylysine in the development, exploitation and completion of underground mineral oil and natural gas deposits, and in deep wells, especially as a shale inhibitor in water-based drilling muds, completion fluids or stimulation fluids.

First claim

The invention claimed is:

1. A method of providing a shale inhibitor in a water-based drilling mud, completion fluid, or stimulation fluid, the method comprising:
adding to a drilling fluid an effective amount of a hyperbranched polylysine having a degree of branching and
conducting a drilling operation in an oil or natural gas well with the drilling fluid comprising the hyperbranched polylysine,
thereby providing a shale-inhibiting effect during the drilling operation in an oil or a natural gas well,
wherein the degree of branching (DB) of the polylysine is 10 to 99.9% as defined by a combined molar amount of terminal monomer units and branched monomer units in the polylysine, with respect to a total molar amount of monomers in the polylysine;
wherein the molecular weight (M w ) of the polylysine is in the range of 500 to 10,000 g/mol; and
wherein the polylysine is present in the drilling fluid in a concentration of 1 to 30 of water.

2. The method according to claim 1 , wherein the nitrogen atoms of the polylysine are quaternized with C 1-4 -alkyl groups.

3. The method according to claim 1 , wherein the polylysine is used in a concentration of 1 g/l of water.

4. The method according to claim 1 , wherein the polylysine is used in a concentration of 3 to 25 g/l.

5. The method according to claim 1 , wherein the polylysine is used in a concentration of 5 to 10 g/l.

6. The method according to claim 1 , wherein the biodegradability of the polylysine, as measured by the method described in “OECD Guidelines for Testing of Chemicals—1992 OECD 306: Biodegradability in Seawater, Closed Bottle Method”, is at least 15% after 28 days and at least 50% after 60 days.

7. The method according to claim 3 , wherein the biodegradability of the polylysine, as measured by the method described in “OECD Guidelines for Testing of Chemicals—1992 OECD 306: Biodegradability in Seawater, Closed Bottle Method”, is at least 15% after 28 days and at least 50% after 60 days.

8. The method according to claim 3 , wherein the drilling fluid further comprises at least one member selected from the group consisting of water retention agent, a rheology modifier, a dispersant, a thinner and a lubricant.

9. The method according to claim 1 , wherein DB is from 20-99%.

10. The method according to claim 1 , wherein DB is from 20-95%.

11. The method according to claim 1 , wherein the molecular weight of the polylysine is from 750 to 7,500 g/mol.

12. The method according to claim 1 , wherein the molecular weight of the polylysine is from 750 to 1,500 g/mol.

13. The method of claim 1 , wherein the hyperbranched polylysine consists of polycondensed lysine.

Assignees

• Lafuente Cerda Oscar
• Bruchmann Bernd
• Maitro Vogel Sophie
• Reinoso Garcia Marta
• Basf Se

Inventors

• Lafuente Cerda Oscar
• Bruchmann Bernd
• Maitro Vogel Sophie
• Reinoso Garcia Marta

Classifications

• C09K8/22 Primary

  Synthetic organic compounds · CPC title

• C09K8/08 Primary

  containing natural organic compounds, e.g. polysaccharides, or derivatives thereof · CPC title

• C09K2208/12

  Swell inhibition, i.e. using additives to drilling or well treatment fluids for inhibiting clay or shale swelling or disintegrating · CPC title