Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
  • C09K8/02—Well-drilling compositions
  • C09K8/04—Aqueous well-drilling compositions
  • C09K8/06—Clay-free compositions
  • C09K8/12—Clay-free compositions containing synthetic organic macromolecular compounds or their precursors
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
  • C09K8/02—Well-drilling compositions
  • C09K8/03—Specific additives for general use in well-drilling compositions
  • C09K8/035—Organic additives
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K2208/00—Aspects relating to compositions of drilling or well treatment fluids
  • C09K2208/12—Swell inhibition, i.e. using additives to drilling or well treatment fluids for inhibiting clay or shale swelling or disintegrating
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K2208/00—Aspects relating to compositions of drilling or well treatment fluids
  • C09K2208/34—Lubricant additives

Definitions

• drilling fluids intended to lubricate, clean and cool the drilling tools and the drilling head and/or to discharge the material given off during drilling (cleared rocks).
• Drilling fluids are also used to clean the well. They also provide the pressure necessary to support the wall of the well before consolidation.
• the fluids are usually known as “drilling muds”. After drilling, the walls of the well are generally consolidated with a cement material.
• the walls of the rock in particular of water-sensitive argillaceous rocks, have a tendency to swell. Operational problems are related to these clays.
• the swelling can interfere with the flow of the fluid or the passage of the drilling tool.
• the swelling can lead to disintegration of the wall. This disintegration can cause irregularities in the well and can thus create points of mechanical weakness.
• the disintegrated argillaceous material is released into the fluid and can present problems of control of the viscosity of the fluid: argillaceous materials, in the presence or absence of a high concentration of salts (brine), have a tendency to greatly increase the viscosity. This increase may be harmful: if it becomes too high, the movement of the fluid may be interfered with and the latter then no longer fulfills its functions.
• cleared argillaceous rocks may have a tendency to aggregate together in the drilling fluid. This phenomenon is referred to as an accretion phenomenon.
• the accretion may interfere with the circulation of the fluids and can mechanically block the drilling head (bit-balling phenomenon).
• copolymers based on acrylamide and on sulfobetaines or on phosphobetaines are disclosed in the document WO 00/01746 (Institut für du Pperile). It is indicated in this document that these copolymers are effective as viscosifying agents and as agents for modifying the surfaces of suspended particles.
• the document U.S. Pat. No. 5,026,490 discloses other copolymers comprising sulfobetaine units and their use as deflocculating agents for drilling muds.
• the document U.S. Pat. No. 6,346,588 discloses other copolymers comprising sulfobetaine units, the formulation of which in a drilling fluid is facilitated.
• the document U.S. Pat. No. 4,607,076 discloses other copolymers comprising sulfobetaine units and their use as viscosifying agents in the presence of brine.
• silicates intended to consolidate the walls (well bore consolidation).
• the terms used are then silicate-based fluids or silicate-based muds.
• the agents known for inhibiting swelling of clays may promote accretion.
• silicates have a tendency to enhance accretion phenomena. Consequently, the proposal has been made to add, to silicate-based fluids, additives targeted at limiting accretion phenomena.
• the document WO 99/42539 provides for the addition of small molecules exhibiting a phosphonate group and a group comprising less than 100 atoms, for example phosphonosuccinic acid.
• the performances of these additives with regard to inhibition of accretion are limited and attempts are being made to improve them.
• the present invention is targeted at solving at least one of the problems mentioned above.
• the present invention provides novel drilling fluids comprising a polymer, the said polymer comprising at least 65% by weight, preferably at least 90% by weight, of hydroxylated units comprising an —OH group.
• Another object of the invention is to provide the use of the polymer in aqueous or nonaqueous drilling fluids, in particular in silicate-based fluids, as:
• Another subject matter of the invention is a drilling process in which use is made of a drilling fluid comprising the polymer.
• the polymer can in particular be used as 2-in-1 or more agents, fulfilling several of the functions mentioned above, for example as accretion-inhibiting agent and lubricating agent.
• the invention relates more particularly to a drilling fluid for oil and/or gas wells comprising the polymer.
• the fluid can in particular be a silicate-based fluid.
• the polymer used in the drilling fluid comprises at least 65% by weight of hydroxylated units. It preferably comprises at least 90% by weight and more preferably still at least 95% by weight of such units. According to a preferred form, the polymer is a homo-polymer not comprising (0% by weight or at most 1% by weight) units other than the hydroxylated units.
• molar mass when used, the reference will be to the absolute weight-average molar mass, expressed in g/mol.
• the latter can be determined by aqueous gel permeation chromatography (GPC), by light scattering (DDL or also MALLS), with an aqueous eluent or an organic eluent (for example, dimethylacetamide, dimethylformamide, and the like), depending on the composition of the polymer.
• a unit deriving from a monomer denotes a unit which can be obtained directly from said monomer by polymerization.
• a unit deriving from an acrylic or methacrylic acid ester does not include a unit of formula —CH 2 —CH(COOH)—, —CH 2 —C(CH 3 ) (COOH)—or —CH 2 —CH(OH)—, respectively, for example obtained by polymerizing an acrylic acid ester, a methacrylic acid ester or vinyl acetate respectively, and then hydrolyzing.
• a unit deriving from acrylic or methacrylic acid includes, for example, a unit obtained by polymerizing a monomer (for example, an acrylic or methacrylic acid ester) and by then reacting the polymer obtained (for example by hydrolysis), so as to obtain units of formula —CH 2 —CH(COOH)—or —CH 2 —C(CH 3 ) (COOH)—.
• a unit deriving from a vinyl alcohol includes, for example, a unit obtained by polymerizing a monomer (for example a vinyl ester) and by then reacting the polymer obtained (for example by hydrolysis), so as to obtain units of formula —CH 2 —CH(OH)—.
• the hydroxylated units are units of following formula:
• GMAc glycerol monoacrylate
• GMMA glycerol monomethacrylate
• the hydroxylated units can also be obtained by chemical modification of a precursor polymer comprising, for example, epoxy units:
• R is a hydrogen atom or a methyl group.
• GABA glycidyl methacrylate
• Use may in particular be made of a homopolymer of GMMA, polyGMMA (CAS 28474-30-8) or glyceryl polymethacrylate.
• a polymer is in particular sold by Guardian under the name Lubragel BP.
• GMAc GMAc
• GMAc polyGMAc
• glyceryl polyacrylate a polymer of GMAc, polyGMAc or glyceryl polyacrylate.
• Hispagel a polymer of GMAc, polyGMAc or glyceryl polyacrylate.
• the hydroxylated units are units of following formula:
• the polymer is a polymer based on polyvinyl alcohol.
• the weight-average molar mass of the polymer is preferably between 1000 g/mol and 400 000 g/mol (relative value, calibrated in aqueous GPC with poly(ethylene oxide) standards), preferably between 2000 g/mol and 20 000 g/mol.
• the absolute weight-average molar mass can preferably be between 2000 and 4 000 000 g/mol.
• It can be an aqueous or nonaqueous fluid. It can be a silicate-based aqueous fluid (or “silicate-based mud”) or silicate-free aqueous fluid. It can be a phosphate-based or phosphate-free aqueous fluid. It is preferably a silicate-based fluid.
• the polymer content of the drilling fluid is advantageously between 0.1% and 10% by weight, preferably between 0.1% and 5% by weight and more preferably still between 1% and 3% by weight.
• the drilling operations consist in excavating a hole using a bit, made in particular of tungsten carbide, attached to hollow pipes screwed end to end.
• mud or drilling fluid, comprising additives in a liquid vehicle is injected into the string of pipes.
• This mud subsequently comes back up via the borehole, outside the pipes, and carries along rock components detached during the drilling operation.
• the rock-laden mud establishes a counterpressure which consolidates the hole.
• the mud is subsequently extracted from the drilling hole in order to be freed from the rocks which are present therein before being reinjected into the hollow drilling pipes.
• additives added to the mud confer a specific rheological behavior thereon. This is because, when it is subjected to very high shear stresses and high temperatures, as is the case in the bit, the fluid has to have a sufficiently low viscosity to facilitate the discharge thereof towards the outside of the hollow pipes. In contrast, the same fluid, laden with rocks, has to exhibit a high viscosity in order to keep in suspension the cuttings entrained during the drilling.
• Drilling fluids are known to a person skilled in the art.
• the exact composition of the fluid can depend on the destination of the fluid. It can depend in particular on the temperatures and pressures to which the fluid will be subjected, on the nature of the rocks through which the well passes and on the nature of the drilling equipment.
• Drilling fluids generally comprise a liquid vehicle and additives dissolved or dispersed in the liquid vehicle.
• Well bore consolidation agents and filtrate-reducing agents are such additives.
• the liquid vehicle can be water (the drilling fluid being a water-based composition comprising additives dissolved or dispersed in water).
• water mud is often used. It should be mentioned that the water is often seawater.
• the liquid vehicle is a silicate-based vehicle (“silicate-based mud”).
• Silicate-based muds are a category of water muds comprising silicates. They are known to a person skilled in the art. These muds are highly effective in terms of protecting water-sensitive clays, they are not very expensive and are regarded as having a low impact on the environment. They are capable of blocking fissures in clays with a size from a few nanometers up to tens of micrometers.
• Liquid sodium or potassium silicates are solutions of water-soluble glasses with the chemical formula M 2 On(SiO 2 ), where M can be Na+ or K+ and n is the molar ratio (the number of SiO 2 molecules per one M 2 O molecule). n preferably varies from 1.5 to 3.3 for commercial products. In drilling fluids, the ratio 2.0 is typically used. It is believed that the silicates protect water-sensitive native clays from invasion by water via two mechanisms:
• the liquid vehicle can also be a water-in-oil emulsion.
• oil mud is often used. The latter are more expensive than water muds but may be preferred in the case of the drilling of very deep wells (HPHT (high pressure high temperature) conditions).
• HPHT high pressure high temperature
• the polymer can be used with both types of vehicles. However, water-based vehicles (water mud) are preferred, in particular silicate-based vehicles (silicate-based mud).
• the polymer can participate in the composition of the drilling fluid by replacing or by complementing a well bore consolidation agent and/or filtrate-reducing agents and/or lubricating agents and/or accretion-inhibiting agents.
• Drilling fluids can comprise polyphosphates, tannins, lignosulfonates, lignin derivatives, peats and lignites, polyacrylates or polynaphthalenesulfonates, alone or as a mixture.
• the amount of thinning agent or dispersant can vary. By way of indication, this amount can be between 0 and 1%, with respect to the total weight of the fluid.
• the drilling fluid according to the invention can additionally comprise an oxygen scavenger.
• the object of this type of additive is to scavenge the oxygen present in the drilling muds, which can bring about decomposition of certain additives.
• the content of additive of this type varies between 0 and 0.25%.
• the drilling fluid according to the invention can furthermore comprise at least one weighting compound and/or at least one inorganic colloid.
• the weighting components contribute to maintaining a sufficient hydrostatic pressure in the well and to keeping in suspension the rocks entrained during the drilling operation.
• Such compounds are conventionally chosen from the abovementioned soluble salts and from salts of low or very low solubility. Mention may be made, among salts of low solubility, without intending to be restricted thereto, of alkaline earth metal sulfates, silicates or carbonates, such as barium sulfate or calcium carbonate.
• Use may likewise be made of alkaline earth metal or zinc bromides, such as potassium bromide or zinc bromide. Use may also be made of iron oxides or sulfide or subarsenate. Use may also be made of strontium sulfate, indeed even, in some cases of high density, of galene (lead sulfide).
• Inorganic colloids which are compounds substantially insoluble under the conditions of use of the fluid according to the invention are agents which modify the rheology of the medium and which make it possible to keep the cuttings in suspension in the latter.
• Attapulgite, barite or bentonite, alone or as a mixture, are the most commonly used examples thereof. It should be noted that, if use is made of a fluid comprising an inorganic colloid, the latter will preferably be attapulgite.
• the preparation of the drilling fluid is carried out with the water present on the drilling site.
• formation water in contrast to composition water types, that is to say to water types prepared for a specific purpose
• salts such as seawater, briny water types or hard water types.
• the content of salts in the water employed varies according to the provenance of the latter.
• salts such as chlorides
• inorganic salts in order to promote the precipitation of certain ions, if they are present, in particular divalent ions.
• Mention may be made, for example, of the addition of sodium carbonate, in order to precipitate calcium, or sodium bicarbonate, in order to precipitate lime, in particular during redrilling operations in cement.
• Mention may also be made of the addition of gypsum or calcium chloride, in order to limit the swelling of clays, or the addition of calcium hydroxide or slate lime, in order to remove bicarbonates from muds contaminated by carbon dioxide.
• the content of salts depends on the rocks through which the well passes and on the water types available on the operating site and the operations can be carried out in the presence of fluids saturated with salts.
• the drilling fluid according to the present invention can comprise standard additives from the category of high-molecular-weight polysaccharides, such as succinoglycan, wellan or gellan, of use as viscosifying agents.
• high-molecular-weight polysaccharides such as succinoglycan, wellan or gellan
• a clay-swelling inhibitor is targeted at preventing the penetration of the fluid into the rocks along the walls, and inhibiting the swelling and/or the disintegration.
• Well bore consolidation may be concerned.
• the cleared argillaceous rocks, in particular the shales, in suspension in the fluids can present problems. These suspended rocks may swell, break up, and thus modify the rheological properties of the fluids, as explained above.
• a clay-swelling inhibitor is targeted at preventing the penetration of the water into the suspended cleared rocks and/or inhibiting the disintegration.
• the suspended rocks have a tendency to aggregate together.
• the term used is accretion.
• the aggregates formed can interfere with the movement of the fluid and tools. Furthermore, they can surround the drilling head and thus block it (bit-balling phenomenon).
• An accretion-inhibiting agent for cleared drilled rocks is targeted at preventing these phenomena.
• a conventional agent can form a film or be adsorbed at the surface of cleared rocks without, however, preventing their agglomeration (accretion).
• a poorly suited clay-swelling inhibitor can even promote this accretion. This is the case with silicates, for example.
• Filtrate reduction is the avoidance of loss of fluid in the well by infiltration into the rocks. Loss of fluid is to be avoided for economic reasons (cost of the fluid), for safety reasons and for productivity reasons. This is because, if the fluid should be lacking, the drilling tools may be damaged, because of overheating, poor lubrication or mechanical blocking by poorly discharged rocks, and require temporary shutdown of the drilling operation.
• the polymers can in particular be used as 2-in-1 agents, or higher value agents, combining several functions chosen from the following:
• Uses as 2-in-1 agents simplify technically and economically the formulations of the fluids. Uses as accretion-inhibiting agents and lubricating agents are particularly advantageous.
• the drilling fluid is preferably a fluid for the drilling of a well intended for the recovery of oil and/or gas.
• the polymer content of the drilling fluid is advantageously between 0.1% and 10% by weight, preferably between 0.1% and 5% by weight and more preferably still between 1% and 3% by weight.
• the polymer is an accretion-inhibiting agent for cleared drilled rocks.
• the polymer can be, also or alternatively, a lubricating agent.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Lubricants (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Earth Drilling (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)

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• 2005
  • 2005-06-15 FR FR0506057A patent/FR2887256B1/fr not_active Expired - Fee Related
• 2006
  • 2006-06-15 MX MX2007015934A patent/MX2007015934A/es active IP Right Grant
  • 2006-06-15 BR BRPI0611571-3A patent/BRPI0611571B1/pt not_active IP Right Cessation
  • 2006-06-15 WO PCT/FR2006/001358 patent/WO2006134273A1/fr not_active Ceased
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  • 2006-06-15 EP EP06764793.3A patent/EP1891179B1/fr not_active Not-in-force
  • 2006-06-15 CN CN200680021268.7A patent/CN101356250A/zh active Pending
  • 2006-06-15 US US11/922,332 patent/US20090281001A1/en not_active Abandoned
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