Drilling fluid comprising a lubricant
AssigneeEquus UK Topco Ltd
InventorsCraig Allan Davies, Kevin John Duncan, Helen Rachel Sarginson
Life of this patent
Estimating the term…
Abstract
The present invention provides a drilling fluid comprising a compound c) which comprises a dimer and/or trimer fatty acid residue and an alkyleneoxy chain comprising a first ethyleneoxy section, a second ethyleneoxy section and a propyleneoxy section located between said first and second ethyleneoxy sections, wherein the propyleneoxy section comprises from 1 to 20 propyleneoxy groups. Use of such a drilling fluid to lubricate a drill bit, and a method of drilling a well bore comprising circulating such a drilling fluid, are also provided.
Claims18
A drilling fluid comprising:
- a) an aqueous brine phase;
- b) a particulate solid phase;
- c) a compound comprising a dimer and/or trimer fatty residue and an alkyleneoxy chain comprising a first ethyleneoxy section, a second ethyleneoxy section, and a propyleneoxy section located between the first ethyleneoxy section and the second ethyleneoxy section, wherein the propyleneoxy section comprises from 1 to 20 propyleneoxy groups;
- and
- d) optionally, one or more additives selected from rheology modifiers, fluid loss control agents, shale inhibitors, gas hydrate inhibitors and dispersants;
- wherein the drilling fluid is suitable for lubricating a drill bit during drilling in a geological formation, and
- wherein the compound c) is a compound of the formula (I):
- R1[(EO)p(PO)q(EO)r]nR2 (I)
- wherein:
- R1 is a residue of at least one of:
- a dimer fatty diacid, a trimer fatty triacid, a dimer fatty diol and/or a trimer fatty triol;
- R2 is H or (CO)xR3 where x is 0 or 1 and R3 is a C1 to C6 aliphatic hydrocarbyl group;
- EO is an ethyleneoxy group;
- PO is a propyleneoxy group;
- P is from 1 to 20;
- q is from 1 to 20;
- r is from 1 to 20;
- n is from 1 to 3;
- a weight ratio of R1 to total ethyleneoxy and propyleneoxy groups in compound c) is 0.2:1 to 0.6:1;
- and
- wherein the ratio of (p+r) to q is from 0.5 to 8:1.
A method comprising lubricating a drill bit with a drilling fluid comprising:
- a) an aqueous brine phase;
- b) a particulate solid phase;
- c) a compound comprising a dimer and/or trimer fatty residue and an alkyleneoxy chain comprising a first ethyleneoxy section, a second ethyleneoxy section, and a propyleneoxy section located between the first ethyleneoxy section and the second ethyleneoxy section, wherein the propyleneoxy section comprises from 1 to 20 propyleneoxy groups;
- and
- d) optionally, one or more additives selected from rheology modifiers, fluid loss control agents, shale inhibitors, gas hydrate inhibitors and dispersants;
- wherein the drilling fluid is suitable for lubricating a drill bit during drilling in a geological formation, and
- wherein the compound c) is a compound of the formula (I):
- RI[(EO)p(PO)q(EO)r]nR2 (I)
- wherein:
- R1 is a residue of at least one of:
- a dimer fatty diacid, a trimer fatty triacid, a dimer fatty diol and/or a trimer fatty triol;
- R2 is H or (CO)xR3 where x is 0 or 1 and R3 is a C1 to C6 aliphatic hydrocarbyl group;
- EO is an ethyleneoxy group;
- PO is a propyleneoxy group;
- p is from 1 to 20;
- q is from 1 to 20;
- r is from 1 to 20;
- n is from 1 to 3;
- a weight ratio of R1 to total ethyleneoxy and propyleneoxy groups in compound c) is 0.2:1 to 0.6:1;
- and
- wherein the ratio of (p+r) to q is from 0.5 to 8:1.
Dependencies are inferred from the claim text.