Method of drilling a substerranean geological formation with a drilling fluid composition comprising copper nitrate

Patent metadata

Field	Value
Publication number	US-10301524-B2
Application number	US-201715724809-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Oct 4, 2017
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

A drilling fluid composition comprising an aqueous base fluid, a viscosifier, and a H2S scavenger comprising copper nitrate, wherein the drilling fluid composition has a H2S sorption capacity from about 4.0 to about 6.0 gram per one milliliter of the drilling fluid composition; and a method of drilling a subterranean geological formation using thereof are provided. Various embodiments of the drilling fluid composition and the method are also provided.

First claim

The invention claimed is:

1. A method of drilling a subterranean geological formation, comprising:
driving a drill bit to form a wellbore into the subterranean geological formation thereby producing a formation fluid that contains H 2 S; and
injecting a drilling fluid composition into the subterranean geological formation through the wellbore,
wherein the drilling fluid composition comprises
an aqueous base fluid,
a viscosifier, and
a H 2 S scavenger comprising copper nitrate, and

wherein copper nitrate present in the drilling fluid composition reacts with H 2 S present in the formation fluid to form copper sulfide;

recovering the copper sulfide from the drilling fluid composition; and
treating the copper sulfide with nitric acid to regenerate copper nitrate while concurrently forming elemental sulfur.

2. The method of claim 1 , wherein the wellbore is a horizontal or a multilateral wellbore.

3. The method of claim 1 , wherein a temperature of the wellbore ranges from 50 to 200° C.

4. The method of claim 1 ,
wherein the wellbore contains a casing that is made of at least one metal selected from the group consisting of stainless steel, aluminum, and titanium, the casing is exposed to a gaseous mixture containing up to 12 vol % of H 2 S, and
wherein a corrosion rate of the casing is no more than 0.0006 lb/ft 2 after 6 hours of contacting with the drilling fluid composition.

5. The method of claim 4 , wherein the corrosion rate of the casing is no more than 0.00084 lb/ft 2 after 24 hours of contacting with the drilling fluid composition.

6. The method of claim 1 ,
wherein the formation fluid is produced for at least 1 hour but no more than 4 hours, and
wherein a concentration of H 2 S in the formation fluid is no more than 40 ppm.

7. The method of claim 1 , further comprising:
circulating the drilling fluid composition within the wellbore for at least 30 minutes but no more than 3 hours, after the injecting.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Elkatatny Salah El-Din
• Shawabkeh Reyad Awwad
• Mahmoud Mohamed Ahmed Nasr El-Din

Classifications

• E21B41/02

  in situ inhibition of corrosion in boreholes or wells · CPC title

• C09K8/532

  Sulfur · CPC title

• E21B21/003

  Means for stopping loss of drilling fluid (plastering the borehole wall E21B33/138) · CPC title

• C09K8/16

  characterised by the inorganic compounds other than clay · CPC title

• E21B21/062

  by mixing components · CPC title