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 lubricant 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.

Abstract: The present invention relates to the well drilling field in petroleum industry, in particular to a drilling fluid additive composition suitable for coal-bed gas wells, and a water-based drilling fluid and use of the water-based drilling fluid. The drilling fluid additive composition suitable for coal-bed gas wells, comprising a tackifying and shear improver, a capsulating agent, a filtrate reducer, and an amphiphobic wettability reversal agent, wherein, the tackifying and shear improver is a copolymer comprising structural units represented by formula (1), structural units represented by formula (2), and structural units represented by formula (3); the capsulating agent is a comb-like polysaccharide compound; the filtrate reducer is nanocrystalline cellulose, 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 a drilling fluid additive composition suitable for coal-bed gas wells, and a water-based drilling fluid and use of the water-based drilling fluid. The drilling fluid additive composition suitable for coal-bed gas wells, comprising a tackifying and shear improver, a capsulating agent, a filtrate reducer, and an amphiphobic wettability reversal agent, wherein, the tackifying and shear improver is a copolymer comprising structural units represented by formula (1), structural units represented by formula (2), and structural units represented by formula (3); the capsulating agent is a comb-like polysaccharide compound; the filtrate reducer is nanocrystalline cellulose, 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 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 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 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 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: A method for controlling well bore pressure based on model prediction control theory and systems theory, includes: detecting a well bottom pressure, a stand pipe pressure, a casing pressure, an injection flow rate and an outlet flow rate during the drilling operation process and determining the presence of overflow or leakage; if there is no overflow or leakage, then fine-adjusting the wellhead casing pressure according to the slight fluctuations of the well bottom pressure, the stand pipe pressure or the casing pressure; if there is overflow or leakage, simulating and calculating the overflow or leakage position and starting time of the overflow or leakage, predicting the variation over a future time period of the well bore pressure in the well drilling process, and utilizing an optimization algorithm to calculate the control parameter under a minimum of an actual well bottom pressure difference during the future period.

Abstract: A method for controlling well bore pressure based on model prediction control theory and systems theory, which belongs to the field of well bore pressure control technique, includes: detecting a well bottom pressure, a stand pipe pressure, a casing pressure, an injection flow rate and an outlet flow rate during construction process, and determining the presence of overflow or leakage; if there is no overflow or leakage, then fine-adjusting the wellhead casing pressure according to the slight fluctuations of the well bottom pressure, the stand pipe pressure or the casing pressure, ensuring that the well bottom pressure, the stand pipe pressure or the casing pressure are at a set value; if there is overflow or leakage, then using a well bore multi-phase flow dynamic model to simulate and calculate the overflow or leakage position and starting time of the overflow or leakage, predicting the variation over a future time period of the well bore pressure in the well drilling process, and utilizing an optimization a