Aqueous Drilling Muds

Aqueous Drilling Muds Low-Molecular-Weight Dispersants 

Aqueous Drilling Muds Liquified By Means of Zirconium and Aluminum Complexes 

Complexes of tetravalent zirconium and ligands selected from organic acids such as citric, tartaric, malic, and lactic acid and a complex of aluminum and citric acid are suitable as dispersants [288-291]. This type of dispersant is especially useful in dispersing bentonite suspensions. The muds can be used at pH values ranging from slightly acidic to strongly basic. 

A mixture of sulfonated styrene-maleic anhydride copolymer and polymers prepared from acrylic acid or acrylamide and their derivatives [759] are dispersants for drilling fluids. The rheologic characteristics of aqueous well drilling fluids are enhanced by incorporating into the fluids small amounts of sulfonated styrene-itaconic acid copolymers [761] and an acrylic acid or acrylamide polymer [755]. 

Sulfonated styrene-maleimide copolymers are similarly active [1073], Examples of maleimide monomers are maleimide, N-phenyl maleimide, N-ethyl maleimide, N-(2-chloropropyl) maleimide, and N-cyclohexyl maleimide. N-aryl and substituted aryl maleimide monomers are preferred. The polymers are obtained by free radical polymerization in solution, in bulk, or by suspension. 

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G. Burrafato and S. Carminati. Aqueous drilling muds fluidified by means of zirconium and aluminum complexes. Patent EP 623663, 1994. 

Antimicrobials. In slightly alkaline aqueous solutions, nitro alcohols are useful for the control of microorganisms, eg, in cutting fluids, cooling towers, oil-field flooding, drilling muds, etc (8—15) (see INDUSTRIAL ANTIMICROBIAL AGENTS Petroleum). However, only... 

Petroleum and Goal. The alkanolarnines have found wide use in the petroleum industry. The ethanolamines are used as lubricants and stabilizers in drilling muds. Reaction products of the ethan olamines and fatty acids are used as emulsion stabilizers, chemical washes, and bore cleaners (168). Oil recovery has been enhanced through the use of ethan olamine petroleum sulfonates (169—174). OH—water emulsions pumped from wells have been demulsifted through the addition of triethanolarnine derivatives. Alkanolarnines have been used in recovering coal in aqueous slurries and as coal—oil mix stabilizers (175—177). 

Sulfates or sulfonates Alkali metal salts of sulfated alcohols, sulfonic acid salts alkyl-aryl sulfonates sodium laiiryl sulfate Nonaqiieoiis systems mixed aqueous and nonaqiieoiis systems oil-well drilling muds spent H3SO4 recovery deep-fat frying... 

Acrylamide polymers are used as multipurpose additives in the oil-producing industry. Introduction of polymers into drilling fluids-drilling muds improves the rheological properties of the fluids in question, positively affects the size of suspended particles, and adds to filterability of well preparation to operation. Another important function is soil structure formation, which imparts additional strength to the well walls. A positive effect is also observed in secondary oil production, where acrylamide polymers additives improve the mobility of aqueous brines injections, which contribute to... 

Compositions containing mixtures of metal hydroxides a polysaccharide, partially etherified with hydroxyethyl and hydroxypropyl groups, are used as fluid loss additives for aqueous, clay-mineral-based drilling muds [1437]. 

A polymeric composition for reducing fluid loss in drilling muds and well cement compositions is obtained by the free radical-initiated polymerization of a water-soluble vinyl monomer in an aqueous suspension of lignin, modified lignins, lignite, brown coal, and modified brown coal [705,1847]. The vinyl monomers can be methacrylic acid, methacrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, vinylacetate, methyl vinyl ether, ethyl vinyl ether, N-methylmethacrylamide, N,N-dimethylmethacrylamide, vinyl sulfonate, and additional AMPS. In this process a grafting process to the coals by chain transfer may occur. 

A formulation consisting of 2-acrylamido-2-methylpropane sulfonic acid, acrylamide, and itaconic acid has been proposed [676]. Such polymers are used as fluid loss control additives for aqueous drilling fluids and are advantageous when used with lime- or gypsum-based drilling muds containing soluble calcium ions. 

The fluid loss control of aqueous, clay-based drilling mud compositions is enhanced by the addition of a hydrolyzed copolymer of acrylamide and an N-vinylamide [402], The copolymer, which is effective over a broad range of molecular weights, contains at least 5 mole-percent of the N-vinylamide units, which are hydrolyzed to N-vinylamine units. The copolymers can be made from various ratios of N-vinylamide and acrylamide by using common radical-initiated chain growth polymerization techniques. 

Copolymers of mainly acrylic acid and 2% to 20% by weight of itaconic acid are described as fluid loss additives for aqueous drilling fluids [138]. The polymers have an average molecular weight between 100,000 and 500,000 Dalton and are water dispersible. The polymers are advantageous when used with muds containing soluble calcium and muds containing chloride ions, such as seawater muds. 

A composition for dissolving filter-cake deposits left by drilling mud in wellbores is composed of an aqueous solution of citric acid and potassium chloride, alkali metal formate, acid tetraphosphate, alkaline earth chloride, and alkali metal thiophosphate [1012]. 

There are more complicated structures intermediate between pyrophyllite and talc with variable substitution of A1J and Mg2. Electroneulrality is maintained by hydrated cations between layers. Thus the montmorillonites arc unusual days forming thixotropic aqueous suspensions that arc used as well-drilling muds and in nondrip puints. They are derived from the formulation AU(OH)jSi40 ,-x-H2o with variable amounts of water, Mg3+ (in place of some Al5 ), and compensaUng cations. M"+ (M = Ca in fuller s earth, which is converted to bentonite, M = Na). Vermiculite likewise has variable amounts of water and cations, (t dehydrates to a talc-like structure with much expansion when heated (see page 750). 

In other techniques of oil production, the microlatices can be usefully employed for ground consolidation, manufacture of drilling muds and as completion or fracturation fluids. Another use concerns the prevention of water inflows into production wells. The method consists injecting from the production well into the part in the field to be treated, an aqueous solution of polymer prepared by inverse microlatex dissolution in water. The polymer is adsorbed on the walls of the formation surrounding the well. When the latter is brought in production, the oil and/or the gas selectively traverse the treated zone whereas the passage of water is inhibited. 

Use Bactericide and slimicide for aqueous systems, cutting oil emulsions, industrial water systems, drilling muds. 

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