Abstract: The present invention relates to the well drilling field in petroleum industry, in particular to a drilling fluid additive composition and a water-based drilling fluid suitable for high pressure plugging while drilling. The composition contains a bridging agent, a nano-plugging agent, a rheological modifier, a bionic wall bracing agent, and a bionic shale inhibitor, wherein, the bridging agent is a weak-crosslinked copolymer, in which the content of cross-linker structures is 0.1-1 wt. %; the nano-plugging agent is modified nanometer silicon dioxide particles; the rheological modifier is a dimer acid-organic amine copolymer; and the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived base group grafted on its main chain.

Abstract: The present invention relates to the well drilling field in petroleum industry, in particular to a nano-hybrid lubricant and method thereof, and oil-based drilling fluid. The lubricant comprises: graphite oxide and a biquaternary ammonium salt compound of which the cation part is represented by formula (1). The present invention also provides a method for preparation of the lubricant and an oil-based drilling fluid containing the lubricant. The lubricant provided in the present invention can be comprehended as a nano-hybrid material. Thus, oil-based drilling fluids that contain the lucbricant provided in the present invention have lower lubrication coefficient and excellent lubricating property without or with little negative impact on rheological property of the oil fluid, and the lubricant provided in the present invention has excellent thermostability thus suitable for use in operation at a high temperature.

Abstract: The present invention relates to the well drilling field in petroleum industry, in particular to a drilling fluid additive composition that contains a lubricant, an emulsifier, and a rheological modifier, wherein, the lubricant contains: graphite oxide and a biquaternary ammonium salt compound in which the cation part is represented by formula (1); the emulsifier is one or more of compounds represented by formula (I); the rheological modifier is a dimer acid-organic amine copolymer comprising structural units from dimer acid, structural units from alkylamine and structural units from arylamine. The present invention further provides an oil-based drilling fluid containing the composition and a use thereof. The oil-based drilling fluid containing the composition provided in the present invention obtains a lower lubrication coefficient, and favorable rheological property and thermostability, and is suitable for use in operation at a high temperature.

Abstract: The present invention relates to the well drilling field in petrochemical industry, and discloses a drilling fluid additive composition comprising a nano-plugging agent, a bionic wall bracing agent, a bionic shale inhibitor, an emulsifier, and an amphiphobic wettability reversal agent, wherein, the nano-plugging agent is modified silicon dioxide nano-particle, and its modifying group includes a modifying copolymer chain; the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived group grafted on its main chain; the bionic shale inhibitor is composed of structural units of arginine and structural units of lysine; and the amphiphobic wettability reversal agent is a dual-cation fluorocarbon surfactant. The present invention further provides a pseudo oil-based drilling fluid suitable for horizontal shale gas wells containing the above composition.

Abstract: The present invention relates to the well drilling field in petrochemical industry, and discloses a drilling fluid additive composition comprising a nano-plugging agent, a bionic wall bracing agent, a bionic shale inhibitor, an emulsifier, and an amphiphobic wettability reversal agent, wherein, the nano-plugging agent is modified silicon dioxide nano-particle, and its modifying group includes a modifying copolymer chain; the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived group grafted on its main chain; the bionic shale inhibitor is composed of structural units of arginine and structural units of lysine; and the amphiphobic wettability reversal agent is a dual-cation fluorocarbon surfactant. The present invention further provides a pseudo oil-based drilling fluid suitable for horizontal shale gas wells containing the above composition.

Abstract: The present invention relates to the petroleum drilling fluid field, and discloses a modified silicon dioxide nano-particle comprising a modifying polymer chain composed of structural units provided by one or more of monomers represented by the following formula (1) and one or more of monomers represented by the following formula (2). The present invention provides a method for preparing modified silicon dioxide nano-particles and a drilling fluid suitable for shale gas wells containing the modified silicon dioxide nano-particles as a plugging agent. When the modified silicon dioxide nano-particles provided in the present invention are used as a plugging agent in a drilling fluid, they will not agglomerate into large-size particles, and can achieve a good plugging effect.

Abstract: The present invention relates to the well drilling field in petrochemical industry, and discloses a high-density water-based drilling fluid suitable for horizontal shale gas wells comprising a nano-plugging agent, a bionic wall bracing agent, a bionic shale inhibitor, a filler, an emulsifier, and an amphiphobic wettability reversal agent, wherein, the nano-plugging agent is modified silicon dioxide nano-particle, and its modifying group includes a modifying copolymer chain; the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived group grafted on its main chain; the bionic shale inhibitor is composed of structural units of arginine and structural units of lysine; the filler consists of calcium carbonate of 1,600-2,500 mesh, calcium carbonate of 1,050-1,500 mesh, and calcium carbonate of 500-1,000 mesh at a weight ratio of 1:0.55-6:0.55-6; and the amphiphobic wettability reversal agent is a dual-cation fluorocarbon surfactant.

Abstract: The present invention relates to the well drilling field in petrochemical industry, and discloses a drilling fluid additive composition and water-based drilling fluid suitable for horizontal shale gas wells. The composition comprises a nano-plugging agent, a bionic wall bracing agent, a bionic shale inhibitor, an emulsifier, and an amphiphobic wettability reversal agent, wherein, the nano-plugging agent is modified silicon dioxide nano-particles, and its modifying group includes an acrylic copolymer chain; the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived group grafted on its main chain; the bionic shale inhibitor is composed of structural units of arginine and structural units of lysine; and the amphiphobic wettability reversal agent is a dual-cation fluorocarbon surfactant.

Abstract: The present invention relates to the well drilling field in petrochemical industry, and discloses an environment-friendly water-based drilling fluid applicable to horizontal shale gas wells comprising a nano-plugging agent, a bionic wall bracing agent, a bionic shale inhibitor, a filler, an emulsifier, and an amphiphobic wettability reversal agent, wherein, the nano-plugging agent is modified silicon dioxide nano-particle, and its modifying group includes an acrylic copolymer chain; the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived group grafted on its main chain; the bionic shale inhibitor is composed of structural units of arginine and structural units of lysine; the filler consists of calcium carbonate of 1,600-2,500 mesh, calcium carbonate of 1,050-1,500 mesh, and calcium carbonate of 500-1,000 mesh at a weight ratio of 1:0.55-6:0.55-6; and the amphiphobic wettability reversal agent is a dual-cation fluorocarbon surfactant.

Abstract: The present invention relates to the well drilling field in petroleum industry, in particular to an additive composition suitable for viscosity reduction of oil-based drilling fluids, an oil-based drilling fluid and use thereof. The double-block copolymer mainly consists of a block A and a block B, wherein, the block A is composed of structural units represented by formula (1), the block B is composed of structural units represented by formula (2), and the number-average molecular weight of the block A is 1,500-10,000. The double-block copolymer provided in the present invention can be used as a viscosity reducer in oil-based drilling fluids, especially can be used as a viscosity reducer in high-density clay-free oil-based drilling fluids, and can greatly decrease the apparent viscosity and plastic viscosity of oil-based drilling fluids in high-temperature and high-pressure reservoir while maintaining appropriate shearing force, so as to increase the drilling rate and reduce drilling difficulties.

Abstract: The present invention relates to the field of petrochemical drilling and discloses a drilling fluid additive composition. The composition contains an emulsifier and a rheological modifier. The emulsifier is one or more of the compounds represented by Formula (1); the rheological modifier is dimer acid-organic amine copolymer, comprising structural units from the dimer acid, structural units from the alkylamine and structural units from the arylamine. The present invention further provides a drilling fluid containing the foregoing composition.

Abstract: The present subject matter relates to the drilling fluid field, and discloses a bionic drilling fluid and a method for preparation of the bionic drilling fluid. The bionic drilling fluid comprises a specific bionic wall bracing agent, a bionic shale inhibitor, a filtrate reducer, and an amphiphilic reservoir protectant, wherein, the filtrate reducer comprises microcrystalline cellulose. The bionic drilling fluid provided in the present subject matter can effectively solve the problem of well wall instability, and has great industrial application prospects.

Abstract: The present subject matter relates to the drilling fluid field, and discloses a bionic drilling fluid and a method for preparation of the bionic drilling fluid. The bionic drilling fluid comprises a specific bionic wall bracing agent, a bionic shale inhibitor, a filtrate reducer, and an amphiphilic reservoir protectant, wherein, the filtrate reducer comprises microcrystalline cellulose. The bionic drilling fluid provided in the present subject matter can effectively solve the problem of well wall instability, and has great industrial application prospects.

Abstract: The present invention relates to the field of petrochemical drilling and discloses a drilling fluid additive composition. The composition contains rheological modifier, emulsifier and tackifier. Among them, the rheological modifier is dimer acid-organic amine copolymer comprising structural units from dimer acid, structural units from alkylamine and structural units from arylamine; the tackifier is modified polysiloxane nano-particles, and the modifying group Z on the polysiloxane nano-particles is the emulsifier is one or more of the compounds represented by the following Formula (1). The present invention further provides a high temperature resistant clay-free whole-oil-based drilling fluid containing the foregoing composition. Through synergistic effect of the rheological modifier, the emulsifier and the tackifier in the composition, the present invention obtains a clay-free whole-oil-based drilling fluid with desirable suspending power and temperature resistance.

Abstract: The present invention discloses a bionic shale inhibitor, consisting of structural units denoted by formula (1) and structural units denoted by formula (2), wherein, the molar ratio of the structural units denoted by formula (1) to the structural units denoted by formula (2) is 0.2-6:1, and the weight-average molecular weight of the shale inhibitor is 800-4,000 g/mol. The present invention further provides a method for preparation of a bionic shale inhibitor. The present invention further provides a drilling fluid containing the bionic shale inhibitor. The bionic shale inhibitor disclosed in the present invention has high shale inhibition capability, and is environment-friendly and pollution-free.

Abstract: The present subject matter relates to an amphiphilic reservoir protecting agent, including structural units denoted by the following formula (1), (2), (3) and (4). The present subject matter further provides a method for preparation of an amphiphilic reservoir protecting agent. The present subject matter further provides a drilling fluid that contains the amphiphilic reservoir protecting agent. The amphiphilic reservoir protecting agent and drilling fluid obtained in the present subject matter have high reservoir protection property and high shale inhibition property.

Abstract: The present invention provides a biomimetic polymer for stabilizing wellbore, a method for preparation of the biomimetic polymer, and a drilling fluid. The polymer contains carboxymethyl chitosan that serves as a backbone and dopamine-derived groups grafted on the backbone. The polymer provided in the present invention can improve the strength of shale in the wellbore, seal the shale pores and reduce the filter loss of drilling fluid, and thereby attains an effect of stabilizing the wellbore in shale formation in drilling process.

Abstract: The present invention provides a biomimetic polymer for stabilizing wellbore, a method for preparation of the biomimetic polymer, and a drilling fluid. The polymer contains carboxymethyl chitosan that serves as a backbone and dopamine-derived groups grafted on the backbone. The polymer provided in the present invention can improve the strength of shale in the wellbore, seal the shale pores and reduce the filter loss of drilling fluid, and thereby attains an effect of stabilizing the wellbore in shale formation in drilling process.

Abstract: The present subject matter relates to the drilling fluid field, and discloses a viscosifier for oil-based drilling fluids and a method for preparing the viscosifier for oil-based drilling fluids. The preparation method comprises the following steps: (1) mixing an initiator with an unsaturated amide, an unsaturated organic sulfonic acid, and an unsaturated organic carboxylic acid in an aqueous phase solution and initiating a polymerization reaction with an oil phase solution that contains emulsifier and base oil, to obtain a polymer emulsion; (2) purifying and drying the polymer emulsion to obtain a composition; (3) mix the composition, sepiolite powder, and an acid while stirring, and then drying the obtained mixture. The viscosifier for oil-based drilling fluids disclosed in the present subject matter can make up for the shortage of viscosifiers for oil-based drilling fluids in the art, and has favorable temperature tolerance property, viscosity improvement property and environmental friendliness.

Abstract: The present subject matter relates to an amphiphilic reservoir protecting agent, including structural units denoted by the following formula (1), (2), (3) and (4). The present subject matter further provides a method for preparation of an amphiphilic reservoir protecting agent. The present subject matter further provides a drilling fluid that contains the amphiphilic reservoir protecting agent. The amphiphilic reservoir protecting agent and drilling fluid obtained in the present subject matter have high reservoir protection property and high shale inhibition property.