CA-3206052-C - LIGNIN-BASED DRILLING FLUIDS AND RELATED METHODS

Abstract

Drilling fluids or muds are provided for the drilling of a borehole into an earth formation. The drilling fluid or mud may be used for drilling oil and/or natural gas wells in subterranean reservoirs. In some embodiments, the fluid is formed from an additive comprising lignin and at least one biosurfactant produced by at least one strain of bacteria capable of biosurfactant production.

Inventors

• Desmond Alexander SOMERVILLE
• Patrick Dieter WAIBEL

Assignees

• LignoSol IP Limited

Dates

Publication Date

20260505

Application Date

20220405

Priority Date

20210406

Claims (17)

1. 14 CLAIMS 1. A drilling fluid or mud suitable for drilling a borehole, well or the like in to an earth formation, the drilling fluid or mud comprising lignin and at least one isolated strain of biosurfactant producing bacteria, and/or at least one biosurfactant produced from 5 at least one such isolated strain of bacteria, the drilling fluid or mud having a solids content of above 55%.
2. 2. The drilling fluid or mud of claim 1, wherein the lignin is technical lignin. 1 0
3. 3. The drilling fluid or mud of claim 2, wherein the technical lignin comprises at least one of Kraft lignin, lignosulfonates, soda lignin, organosolv lignins, steam-explosion lignin, enzymatic hydrolysis lignin, or unhydrolyzed Kraft black liquor lignin.
4. 4. The drilling fluid or mud of claim 1, wherein the lignin is in an aqueous suspension.
5. 5. The drilling fluid or mud of claim 1, wherein the lignin comprises at least one of lignin nanoparticles and lignin microparticles. 15
6. 6. The drilling fluid or mud of claim 1, wherein the lignin includes lignin particles, at least 20 20% of the lignin particles being lignin nanoparticles.
7. 7. The drilling fluid or mud of claim 1, wherein the lignin and at least one biosurfactant are provided as an additive. 25
8. 8. The drilling fluid or mud of claim 7, wherein the at least one biosurfactant is produced by contacting the lignin with the at least one strain of biosurfactant producing bacteria, any live bacteria being removed from the additive prior to constitution of the drilling fluid or mud. 30
9. 9. The drilling fluid or mud of claim 8, wherein the at least one strain of bacteria is at least one isolated strain of Bacillus selected from the group consisting of Bacillus Date rec;:ue / Received date 2025-01-08 amyloliquefaciens, Bacillus combinations thereof. licheniformis, Bacillus pumilus, Bacillus subtilis, and 5
10. 10. The drilling fluid or mud of claim 8, wherein the at least one strain is in the form of a liquid suspension or freeze-dried spores. 1 O
11. 11. The drilling fluid or mud of claim 7, wherein the additive further comprises a stabilized or enhanced catholyte solution, the catholyte solution having been stabilized or enhanced in a pre-treatment system arranged to introduce nitrogen gas, in the form of nanobubbles and/or microbubbles, into the catholyte solution.
12. 12. The drilling fluid or mud of claim 7, wherein the additive further comprises at least one of a carboxylic acid or a salt or ester thereof.
13. 13. The drilling fluid or mud of claim 7, wherein the additive further comprises carbon black.
14. 14. The drilling fluid or mud of claim 7, wherein the additive further comprises pyrolysis oil.
15. 15. The drilling fluid or mud of claim 7, wherein the additive is gasified.
16. 16. The drilling fluid or mud of claim 15, wherein the additive is gasified with at least one of nanobubbles and microbubbles.
17. 17. The drilling fluid or mud of claim 1, which has a solids content of 55% to 60%. 20 25 Date regue / Received date 2025-01-08

Description

1 LIGNIN-BASED DRILLING FLUIDS AND RELATED METHODS CROSS-REFERENCE TO RELATED APPLICATIONS 5 This application claims priority to GB Provisional Patent Application No. 2104883.0, filed 6 April 2021, and GB Provisional Patent Application No. 2115987.6, filed 8 November 2021. BACKGROUND OF THE INVENTION 10 The present disclosure relates to drilling fluids. More particularly, the present disclosure relates to lignin-based drilling fluids for oil and gas drilling operations and related methods. Drilling fluids, also known as drill muds, are used in drilling oil and natural gas wells, with their main function being to carry cuttings out of the drill hole. Several broad 15 types of drilling fluids are used, including so-called water-based muds (WBMs), oil �based muds (OBMs), gaseous drilling fluids and synthetic-based muds (SBMs), for example. In operation, the drilling fluid is pumped through the drill string, spraying out of nozzles on the drill bit, which cleans and cools the drill bit, returning along the annular space 20 between the drill bit and the wall of the borehole or well, carrying the cuttings to the surface. Water based drilling fluids contain modified starches and carboxymethylcellulose (CMG) for filtrate control (and clay encapsulation), partially hydrolyzed polyacrylamide (PHPA) for clay encapsulation and a viscosity modifier, such as Xantham Gum 2 (XC/XCD). These polymers are acid soluble and biodegradable, thereby vulnerable to sulfate reducing bacteria in particular at pH<9. For this reason a biocide is normally added to the drilling fluid. Synthetic polymers are an alternative but expensive and not biodegradable to the same standard. 5 Two important considerations for any drilling fluid are exacting filtrate control and stable, predictable rheology. There is also a fine balance between using a thin, low rheology fluid to avoid undue pressures on the wellbore, whilst ensuring the density of the drilling fluid is such as to support the carrying of cuttings to the surface. KCI is often added for clay/shale control and/or saturated NaCl is often added when drilling 10 through salt formations. By far the biggest drilling fluid contaminants are drilled formation fines and the operation is geared to keep these under control by avoiding turbulent annular flow, efficient screening, hydrocyclones and centrifuging. Other potential contaminants from the formation are CO2 and H2S, which are best contained by pH> 1 0 and in the case 15 of severe H2S contamination by the addition of dedicated scavengers. SUMMARY OF THE INVENTION In one aspect of the invention, there is provided a drilling fluid or mud suitable for drilling a borehole, well or the like in to an earth formation, in particular a subterranean 20 reservoir for recovering hydrocarbons from the reservoir, the drilling fluid or mud comprising lignin and at least one isolated strain of bacteria capable of producing at least one biosurfactant, and/or at least one biosurfactant produced from at least one bacteria capable of producing a biosurfactant, the drilling fluid or mud having a solids content of above about 55%, in particular of about 55% to about 60%. 25 In some embodiments, the lignin is technical lignin. CA 03206052 2023-7-21 3 In some embodiments, the technical lignin comprises at least one of Kraft lignin, lignosulfonates, soda lignin, organosolv lignins, steam-explosion lignin, enzymatic hydrolysis lignin, or unhydrolyzed Kraft black liquor lignin. In some embodiments, the lignin is in an aqueous suspension. 5 In some embodiments, the lignin comprises at least one of lignin nanoparticles and lignin microparticles. In some embodiments, the lignin and at least one biosurfactant are provided as an additive. In some embodiments, the at least one biosurfactant is produced by contacting the 10 lignin with the at least one strain of bacteria capable of producing the at least one biosurfactant, any live bacteria being removed from the additive prior to constitution of the drilling fluid or mud. In some embodiments, the at least one strain of bacteria is at least one isolated strain of Bacillus. In some embodiments, the at least one isolated strain is in the form of a liquid suspension or freeze-dried spores. In some embodiments, the additive further comprises a catholyte solution. In some embodiments, the catholyte solution is a stabilized or upgraded catholyte solution. 20 In some embodiments, the additive further comprises at least one of a carboxylic acid or a salt or ester thereof. In some embodiments, the carboxylic acid ester comprises a methyl ester or a butyl ester. In some embodiments, the carboxylic acid or salt or ester thereof comprises a di�25 carboxylic acid or a salt or ester thereof. CA 03206052 2023-7-21 4 In some embodiments, the additive further comprises carbon black. In some embodiments, the additive further comprises pyrolysis oil. In some embodiments, the additive is gasified. In some embodiments, the additive is gasified wi