Modified composite barite for drilling fluid

Abstract

The invention discloses a modified composite barite for drilling fluid. The barite is composed of composite barite, modifier sodium hexametaphosphate, acrylic copolymer, octylphenol polyoxyethylene ether-30, polyoxyethylene Made of ethylene glycol 400. The modified composite barite is based on the composite of ultrafine barite and barite, and is improved by using sodium hexametaphosphate and an acrylic copolymer hyperdispersant synthesized with phthalic anhydride, acrylic acid, and n-butanol as monomers. The surface properties of the weighting agent, supplemented with surfactants octylphenol polyoxyethylene ether-30, polyethylene glycol 400 to further enhance its hydrophilic dispersion performance to obtain modified composite barite, suitable for water-based drilling and completion fluids , excellent suspension, the density reduction rate of the drilling fluid system after weighting is less than 3%; the acid solubility rate is ≥ 45%; the viscosity coefficient of the filter cake of the drilling fluid system is more than 30% lower than that of conventional barite; the apparent viscosity before and after adding calcium sulfate Rate of change ≤ 3mPa·s.

Description

technical field

[0001] The invention belongs to the field of drilling fluid in petroleum and natural gas and geological exploration and development, and discloses a modified composite barite for drilling fluid. Background technique

[0002] In oil and gas exploration and development drilling, weighting agent is an indispensable additive in drilling fluid. Its main function is to add to drilling fluid to increase the density of drilling fluid, to stabilize the well wall, to balance the formation pressure, and to prevent blowout and blowout out of control accidents. purpose of occurrence. The weighting agent itself has high density, low abrasiveness, and is easy to crush. It is generally prepared by grinding and processing inert substances that are insoluble in water. interaction. Currently commonly used weighting agents mainly include barite powder, limestone powder, iron ore powder, ilmenite powder, and galena powder. Among them, limestone powder is suitable for use in pro...

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