Oil-based drilling fluids containing an alkaline-earth diamondoid compound as rheology modifier

Patent metadata

Field	Value
Publication number	US-2017267910-A1
Application number	US-201715449347-A
Country	US
Kind code	A1
Filing date	Mar 3, 2017
Priority date	Mar 17, 2016
Publication date	Sep 21, 2017
Grant date	—

Abstract

An oil-based drilling fluid and method of preparing an oil-based drilling fluid are disclosed. The oil-based drilling fluid comprising a base oil continuous phase, an aqueous discontinuous phase, and at least one rheology modifier. The at least one rheology modifier including an alkaline-earth diamondoid compound. The method of preparing the oil-based drilling fluid including mixing a base oil, at least one emulsifier, and at least one wetting agent to form a first mixture, adding and mixing at least one rheology modifier into the first mixture to form a second mixture, adding and mixing at least one fluid-loss control additive into the second mixture to form a third mixture, adding and mixing a brine solution into the third mixture to form a fourth mixture, and adding and mixing a weighting additive into the fourth mixture to form the oil-based drilling fluid.

First claim

What is claimed is:

1 . An oil-based drilling fluid comprising:
a base oil continuous phase; an aqueous discontinuous phase; and at least one rheology modifier, the at least one rheology modifier comprising an alkaline-earth diamonoid compound.

2 . The oil-based drilling fluid of claim 1 , where the alkaline-earth diamondoid compound is a magnesium adamantane carboxylate compound.

3 . The oil-based drilling fluid of claim 1 , where the alkaline-earth diamondoid compound is a magnesium adamantane carboxylate compound prepared by:
mixing a magnesium salt and a diamondoid compound having at least one carboxylic acid moiety to form a reactant mixture; and hydrothermally treating the reactant mixture at a reaction temperature for a reaction time to form the magnesium adamantane carboxylate salt.

4 . The oil-based drilling fluid of claim 3 , where the magnesium salt and the diamondoid compound are mixed in amounts that provide a ratio of Mg 2+ to diamondoid compound in the reaction mixture of from 0.5:1 to 1.0:1.

5 . The oil-based drilling fluid of claim 3 , where the diamondoid compound is 1-adamantane carboxylic acid.

6 . The oil-based drilling fluid of claim 3 , where the magnesium adamantane carboxylate salt comprises a layered morphology.

7 . The oil-based drilling fluid of claim 1 , where the oil-based drilling fluid comprises from 0.1 wt. % to 1.0 wt. % rheology modifier, based on the total weight of the oil-based drilling fluid.

8 . The oil-based drilling fluid of claim 1 , where the oil-based drilling fluid exhibits physical characteristics suitable for use of the oil-based drilling fluid under high-pressure high-temperature conditions during drilling operations, where high-pressure high-temperature conditions during drilling operations comprise a wellbore pressure greater than 10,000 psi and a wellbore temperature greater than 300° F.

9 . The oil-based drilling fluid of claim 1 , where the oil-based drilling fluid with the rheology modifier has lower viscosity both before hot rolling and after hot rolling at 100 rpm, compared to a drilling fluid having an identical specific gravity and oil-to-water ratio and identical ingredients in identical proportions to the oil-based drilling fluid but lacking the rheology modifier.

10 . The oil-based drilling fluid of claim 1 , where the oil-based drilling fluid with the rheology modifier has a lower after-hot rolling fluid loss at 350° F. (177° C.) and 500 psi, compared to a drilling fluid having an identical specific gravity and oil-to-water ratio and identical ingredients in identical proportions to the oil-based drilling fluid but lacking the rheology modifier.

11 . The oil-based drilling fluid of claim 1 , where the oil-based drilling fluid with the rheology modifier has higher electrical stability, compared to a drilling fluid having an identical specific gravity and oil-to-water ratio and identical ingredients in identical proportions to the oil-based drilling fluid but lacking the rheology modifier.

12 . A method for preparing an oil-based drilling fluid, the method comprising:
mixing a base oil, at least one emulsifier, and at least one wetting agent to form a first mixture; adding and mixing at least one rheology modifier into the first mixture to form a second mixture, wherein the at least one rheology modifier comprises an alkaline-earth diamondoid compound; adding and mixing at least one fluid-loss control additive into the second mixture to form a third mixture; adding and mixing a brine solution into the third mixture to form a fourth mixture; and adding and mixing a weighting additive into the fourth mixture to form the oil-based drilling fluid.

13 . The method of claim 12 , where the alkaline-earth diamondoid compound is a magnesium adamantane carboxylate compound prepared by:
mixing a magnesium salt and a diamondoid compound having at least one carboxylic acid moiety to form a reactant mixture; and hydrothermally treating the reactant mixture at a reaction temperature for a reaction time to form the magnesium adamantane carboxylate salt.

14 . The method of claim 13 , where the magnesium salt and the diamondoid compound are mixed in amounts that provide a ratio of Mg 2+ to diamondoid compound in the reaction mixture of from 0.5:1 to 1.0:1.

15 . The method of claim 13 , where the magnesium salt is Mg(OH) 2 .

16 . The method of claim 13 , where the reaction temperature is from 100° C. to 180° C.

17 . The method of claim 13 , where the magnesium adamantane carboxylate salt comprises a layered morphology.

18 . The method of claim 12 , where the oil-based drilling fluid comprises from 0.1 wt. % to 1.0 wt. % rheology modifier, based on the total weight of the oil-based drilling fluid.

19 . A method for drilling in a subterranean formation under high-pressure high-temperature conditions, the method comprising:
providing or using in the drilling of a wellbore into the subterranean formation an oil-based drilling fluid, the oil-based drilling fluid comprising:
a base oil continuous phase;
an aqueous discontinuous phase; and
at least one rheology modifier, the at least one rheology modifier comprising an alkaline-earth diamonoid compound.

20 . The method of claim 19 , where high-pressure high-temperature conditions comprise a wellbore pressure greater than 10,000 psi and a wellbore temperature greater than 300° F.

Assignees

• Saudi Arabian Oil Co
• Univ Durham
• M-I Drilling Fluids U K Ltd

Inventors

• Mohammed Musarrat H
• Greenwell Hugh Christopher
• Veerabhadrappa Manohara Gudiyor
• Hall John Adrian
• Alabedi Gasan Selman
• Whiting Andrew
• Hodder Michael Hayward

Classifications

• C09K2208/10

  Nanoparticle-containing well treatment fluids · CPC title

• C09K2208/28

  Friction or drag reducing additives · CPC title

• C09K8/502

  Oil-based compositions · CPC title

• C09K8/82 Primary

  Oil-based compositions (C09K8/64 takes precedence) · CPC title

• C07C51/60

  by conversion of carboxylic acids or their anhydrides {or esters, lactones, salts} into halides with the same carboxylic acid part · CPC title