Bp Exploration Operating Company Limited

Schlumberger Technology Corporation

Dowell, a Division of Schlumberger Technology Corporation

Other

Dowell Schlumberger Incorporated

Christopher Alan Sawdon

Andrew J Bradbury

Simon Neil Duncum

Sonny Clary

William M Reid

Tom Heinz

David Antony Ballard

Jarrod Massam

Patrick Perrin

Mostafa Ahmadi Tehrani

Trevor G Jappy

Nathalie Monfreux-Gaillard

Françoise LaFuma

Gary John Tustin

Timothy Gareth John Jones

Paul R Howard

Mark Shelton Aston

Hemant K J Ladva

Geoffrey Maitland

Anthony Lawson

Hemant Kuman Jethalal Ladva

Paul Craddock

Shreekant Babulal Mehta

Mary Ann George

Andrew James Bradbury

Oil-based wellbore fluid in the form of an emulsion having a continuous phase containing an oil and, dispersed therein, a first dispersed liquid phase and a second separate dispersed liquid phase. The first dispersed liquid phase is a brine phase containing at least 5% by weight of a dissolved salt or a mixture of salts, and the second dispersed liquid phase is a polar organic liquid which is insoluble or sparingly soluble in the brine and contains the first dispersed liquid phase, but is soluble in pure water. The second dispersed liquid phase is in the form of droplets having an average diameter of not less than 5 microns.

Wellbore fluid

The invention relates to the use of one or more water-soluble reactive liquid component capable of subsequent polymerization or cross-linking to form a solid to improve the zonal isolation and alleviate the impacts of cracks and fissures in the cement sheath around a completed subterranean well. It includes the steps of injecting a wellbore fluid carrying the reactive component or additive into the wellbore, injecting a cementitious composition as slurry into the wellbore and letting said reactive liquid component pass through at least one of the interfaces between cement and formation, cement and filter cake, and filter cake and formation before forming a solid of said reactive liquid component that traverses said at least one of the interfaces.

Methods and materials for zonal isolation

A wellbore fluid comprising a base fluid and a particulate bridging agent comprised of a sparingly water-soluble material selected from the group consisting of melamine (2,4,5-triamino-1,3,5-triazine), lithium carbonate, lithium phosphate (LiPO), and magnesium sulfite.

Wellbore fluid comprising a base fluid and a particulate bridging agent

Wellbore fluid having a continuous aqueous phase, and containing at least one polymer which (a) has a number average molecular weight in the range of from 10,000 to less than 100,000; (b) contains hydrophilic units such that the polymer is at least 2% soluble in water at a temperature of 20&#xb0; C. wherein none of said hydrophilic units comprise &#x2014;CH.CH.O&#x2014; units; and (c) contains pendant alkyl groups having at least 10 carbon atoms. The combined molecular weight of the pendant alkyl groups is in the range of from 15 to 70% by weight based on the weight of the polymer. The polymer is selected from (A) a homopolymer of a compound of general formula HO(O)CCH&#x2550;CHC(O)OR where R is a Cto Calkyl group; and (B) a copolymer of (i) at least one hydrophilic monomer selected from acrylic acid, methacrylic acid, hydroxyethylmethacrylate, hydroxypropylmethacrylate, maleic acid, maleic anhydride, fumaric acid, itaconic acid, vinyl acetate, acrylamide, N,N-dimethylacrylamide, and N-vinyl pyrrolidone, and (ii) at least one hydrophobic monomer that provides a pendant alkyl group selected from a Cto Calpha-olefin, a Cto Calkyl vinyl ether, an acrylamide of the general formula CH&#x2550;CRC(O)NHR(I) where Ris selected from H and Cto Calkyl groups and Ris a Cto Calkyl group, and an acrylate of the general formula CH&#x2550;CRC(O)OR(II) where Ris H or methyl and Ris a Cto Calkyl group; and additionally containing at least one additive selected from additional fluid loss control agents, bridging particulate materials, finely dispersed additives for increasing the fluid density, thinners, and shale inhibitors.

Wellbore fluid comprising at least one polymer containing pendant alkyl groups

The invention concerns modified hydrophobic polyelectrolytes by amide formation of a hydrophilic skeleton by n-alkylamines whereof the alkyl chain comprises 6 to 22 carbon atoms. Preferably, the amide formation is obtained by di-n-dodecylamine. The hydrophilic skeleton is preferably a sodium polyacrylate or polyacrylic acid corresponding to a statistical acrylate-AMPS copolymer. Said polymers can be used for stabilizing direct or invert emulsions likely to be destabilized or inverted by a modification in the degree of salinity of the aqueous phase or a pH modification. The invention is particularly useful for stabilizing oil drilling fluids or the like in particular drilling, fracturation, acidification or completion fluids.

Reversible emulsions stabilized by amphiphilic polymers

Wellbore fluid having a continuous aqueous phase, and comprising at least one polymer which has a number average molecular weight in the range of from 10,000 to less than 100,000, wherein the polymer is selected from a copolymer of at least one hydrophilic monomer and at least one hydrophobic monomer containing an alkyl group having at least 8 carbon atoms. The hydrophilic monomer is selected from acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and itaconic acid, and sulfonate groups have been introduced into the copolymer by reaction of at least a portion of the carboxylic acid and/or anhydride groups with a compound of general formula RN(CH)SOX (I) or a compound of general formula HO(CH)SOX (II). Each Ris independently selected from hydrogen, methyl or ethyl, X is either H or a Group IA metal, and n is an integer of from 1 to 6. The combined molecular weight of the pendant alkyl groups that are introduced into the copolymer by the hydrophobic monomer is in the range of from 15 to 70% by weight based on the molecular weight of the polymer such that the polymer has a solubility of at least 2% in water at 20&#xb0; C. The fluid further comprises at least one additive selected from additional fluid loss control agents, bridging particulate materials, finely dispersed additives for increasing the fluid density, thinners, and shale inhibitors.

Wellbore fluid comprising sulfonated copolymers with pendant alkyl groups

Wellbore fluid containing a base fluid and a particulate bridging agent comprised of melamine. A method is also described of forming a removable filter cake on the walls of a wellbore that penetrates a porous and permeable rock formation by placing in the wellbore a wellbore fluid containing a base fluid and melamine, and permitting the melamine to deposit from the wellbore fluid onto or into the walls of the wellbore to form the filter cake, whereby fluid loss to the formation through the removable filter cake is reduced.

A method of treating a wellbore that includes circulating a wellbore fluid in the wellbore, wherein the wellbore fluid comprises an oleaginous base fluid and a wellbore additive colloidal solid material, and wherein the wellbore additive colloidal solid material is formed by grinding a solid particulate material and a polymeric dispersing agent for a sufficient time so that the polymeric dispersing agent is absorbed to the surface of the resulting colloidal solid particles and less than 10% of the resulting colloidal solid particles have a diameter greater than 10 microns, but not more than five percent of the particles are less than 0.2 micron in diameter, wherein the grinding is carried out in the presence of an oleaginous base fluid and wherein the grinding is carried out so that the wellbore additive colloidal solid material has a weight average particle diameter dless than 2.0 microns.

Additive for increasing the density of a fluid for casing annulus pressure control

A method of controlling the pressure of a casing annulus in a subterranean well that includes injecting into the casing annulus a composition including a base fluid and a polymer coated colloidal solid material. The polymer coated colloidal solid material includes: a solid particle having an weight average particle diameter (d) of less than two microns, and a polymeric dispersing agent coated onto the surface of the solid particle during the cominution (i.e. grinding) process utilized to make the colloidal particles. The polymeric dispersing agent may be a water soluble polymer having a molecular weight of at least 2000 Daltons. The solid particulate material may be selected from materials having of specific gravity of at least 2.68 and preferably the solid particulate material may be selected from barium sulfate (barite), calcium carbonate, dolomite, ilmenite, hematite, olivine, siderite, strontium sulfate, combinations and mixtures of these and other similar solids that should be apparent to one of skill in the art.

Composition of base fluid and polymeric dispersing agent-absorbed polymer-coated colloidal particles

A method of formulating a wellbore fluid that includes grinding a solid particulate material and a polymeric dispersing agent to provide a resulting polymer coated solid material, and suspending the resulting polymer coated solid material in the wellbore fluid. At least a portion of the resulting polymer coated solid material has a particle diameter less than 2.0 microns, wherein the polymeric dispersing agent has a molecular weight greater than 10,000. Exemplary starting materials for the solid material include weighting agents including barite, calcium carbonate, dolomite, ilmenite, hematite or other iron ores, olivine, siderite and strontium sulfate as well as mixture and combinations of these and other similar weighting materials. The dispersant in one illustrative embodiment is a polymeric acrylate ester made from the monomers of stearyl methacrylate, butylacrylate, and acrylic acid.

Additive for increasing the density of an oil-based fluid and fluid comprising such additive

Additive for increasing the density of a fluid for casing annulus pressure

A wellbore fluid having an oleaginous phase and an additive for increasing the density of the wellbore fluid. The additive comprises solid colloidal particles coated with a dispersant coated onto the colloidal particle during the comminution process of forming the particles. Exemplary starting materials for the colloidal particles include commonly known weighting agents including barite, calcium carbonate, dolomite, ilmenite, hematite or other iron ores, olivine, siderite, and strontium sulfate as well as mixture and combinations of these and other similar weighting materials. The dispersant in one illustrative embodiment, is selected from carboxylic acids of molecular weight of at least 150 Daltons. Alternatively, the dispersant coating may be made of compounds including oleic acid, polybasic fatty acids, alkylbenzene sulfonic acids, alkane sulfonic acids, linear alpha-olefin sulfonic acid or the alkaline earth metal salts of any of the above acids, and phospholipids as well as mixtures and combinations of these compounds. In another illustrative embodiment the dispersant is a polyacrylate ester. The illustrative polymeric dispersant should have an average molecular weight from about 10,000 Daltons to about 200,000 Daltons.

A method of controlling the pressure of a casing annulus in a subterranean well that includes injecting into the casing annulus a composition including a base fluid and a polymer coated colloidal solid material. The polymer coated colloidal solid material includes: a solid particle having an weight average particle diameter (d) of less than two microns, and a polymeric dispersing agent coated onto the surface of the solid particle during the comminution (i.e. grinding) process utilized to make the colloidal particles. The polymeric dispersing agent may be a water soluble polymer having a molecular weight of at least 2000 Daltons. The solid particulate material may be selected from materials having of specific gravity of at least 2.68 and preferably the solid particulate material may be selected from barium sulfate (barite), calcium carbonate, dolomite, ilmenite, hematite, olivine, siderite, strontium sulfate, combinations and mixtures of these-and other similar solids.

A wellbore fluid including a peroxide degradable polymer and an encapsulated peroxide source. The peroxide degradable polymer may be a polysaccharide. The peroxide source may include an inorganic peroxide, including zinc and alkaline earth metal peroxides, such as magnesium peroxide. The encapsulating material may be a polymer, including enteric polymers. The release of peroxide, from peroxide sources generally, can be controlled by means of pH such that peroxide source can be activated, and peroxide released, by a change in pH. In a wellbore, this pH change can be effected by using produced fluids to lower the pH of a more basic wellbore fluid.

Internal breaker

A wellbore fluid having an oleaginous phase and an additive for increasing the density of the wellbore fluid. The additive comprises solid colloidal particles coated with a dispersant during the comminution process of forming the particles. Exemplary starting materials for the colloidal particles include commonly known weighting agents as well as mixture and combinations thereof. The dispersant in one embodiment, is selected from carboxylic acids of molecular weight of at least 150 Daltons. Alternatively, the dispersant coating may be made of compounds including oleic acid, polybasic fatty acids, alkylbenzene sulfonic acids, alkane sulfonic acids, linear alpha-olefin sulfonic acid or the alkaline earth metal salts of any of the above acids, and phospholipids as well as mixtures and combinations of these compounds. In another embodiment the dispersant is a polyacrylate ester having an average molecular weight from about 10,000 Daltons to about 200,000 Daltons.

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Par, United Kingdom

Christopher Alan Sawdon