Abstract: Disclosed is a coated rubber particle, preparation thereof and its application as a plugging material in drilling fluids. The coated rubber particle comprises a rubber core and a coating layer, wherein the core has a fluorine content (at %) of 0-15%, the coating layer has a fluorine content (at %) of 30-80%, and the coated rubber particle has a 24-hour oil absorption rate of 4% or less. The coated rubber particle has good oil resistance, and is particularly suitable for use as a plugging material in drilling fluids, particularly oil-based drilling fluids.

Abstract: A cyclic thioether compound has a structure represented by the following formula (I). A vegetable oil composition contains the cyclic thioether compound. When the cyclic thioether compound is used as a drilling fluid lubricant in a drilling fluid. The lubrication performance of the drilling fluid can be significantly improved.

Abstract: The present invention discloses temporary plugging agent for drilling fluid and preparation method thereof, and water-based drilling fluid and use thereof. The temporary plugging agent for drilling fluid is obtained by controlling gelatinized starch and a vinyl grafted monomer to have a polymerization reaction in an activator solution in the presence of a cross-linking agent and an initiator; the vinyl grafted monomer comprises acrylic acid, acrylamide, and 2-acrylamide-2-methyl propanesulfonic acid; the gelatinized starch is obtained by adding starch into deionized water to have a gelatinization reaction.

Abstract: The present disclosure discloses a comb polymer or a salt thereof, wherein the structural formula of the comb polymer containing the following constitutional units. When the comb polymer provided in the present disclosure is used in a water-based drilling fluid as a filtration control agent, it can eliminate the defects of conventional filtration control agents which would be subject to ineffectiveness under high temperature and high salinity conditions. The comb polymer has high temperature and salt resistance, and can be produced through simple processes at comparatively low costs. When the comb polymer provided by the present disclosure is used as a filtration control agent, even being added into the drilling fluid at a comparatively low amount, it can still present rather good effects in lowering the amount of filter loss.

Abstract: The present disclosure discloses a comb polymer or a salt thereof, wherein the structural formula of the comb polymer containing the following constitutional units. When the comb polymer provided in the present disclosure is used in a water-based drilling fluid as a filtration control agent, it can eliminate the defects of conventional filtration control agents which would be subject to ineffectiveness under high temperature and high salinity conditions. The comb polymer has high temperature and salt resistance, and can be produced through simple processes at comparatively low costs. When the comb polymer provided by the present disclosure is used as a filtration control agent, even being added into the drilling fluid at a comparatively low amount, it can still present rather good effects in lowering the amount of filter loss.