The present invention relates to the field of petroleum industry phase oilfield chemistry, and specifically relates to a bionic and dual-phobic drilling fluid. The drilling fluid contains a bionic wall-fixing agent, a bionic lubricant, a super dual-phobic agent, a scrap-carrying agent and a bionic shale inhibitor. The present invention uses the theory of bionics and the theory of a downhole rock surface being double phobic as a basis. By means of using the bionic wall-fixing agent, the bionic lubricant, the super dual-phobic agent, the scrap-carrying agent and the bionic shale inhibitor, which have special properties of imitating animals and plants in nature, and using a series of bionic treatment agents, a set of bionic and dual-phobic drilling fluid systems, which corresponds to an unconventional, complex oil and gas well, is formed.

The present invention relates to the field of petroleum industry phase oilfield chemistry, and specifically relates to a bionic and dual-phobic drilling fluid. The drilling fluid contains a bionic wall-fixing agent, a bionic lubricant, a super dual-phobic agent, a scrap-carrying agent and a bionic shale inhibitor. The present invention uses the theory of bionics and the theory of a downhole rock surface being double phobic as a basis. By means of using the bionic wall-fixing agent, the bionic lubricant, the super dual-phobic agent, the scrap-carrying agent and the bionic shale inhibitor, which have special properties of imitating animals and plants in nature, and using a series of bionic treatment agents, a set of bionic and dual-phobic drilling fluid systems, which corresponds to an unconventional, complex oil and gas well, is formed.

A crosslinked polymer comprising reactants of a first repeating unit, a second repeating unit, and a crosslinker that react to form the crosslinked polymer, wherein the first repeating unit is a sulfonic acid-containing monomer present from 50% to 99% by weight of the reactants, wherein the second repeating unit is selected from the group consisting of an N-vinyl amide-containing monomer, a terminal double bond-containing monomer, and any combination thereof, and is present from 1% to 50% by weight of the reactants, and wherein the crosslinker comprises at least two olefinic bonds, and is present in the range of about 9% to about 25% by weight of the reactants.

A crosslinked polymer comprising reactants of a first repeating unit, a second repeating unit, and a crosslinker that react to form the crosslinked polymer, wherein the first repeating unit is a sulfonic acid-containing monomer present from 50% to 99% by weight of the reactants, wherein the second repeating unit is selected from the group consisting of an N-vinyl amide-containing monomer, a terminal double bond-containing monomer, and any combination thereof, and is present from 1% to 50% by weight of the reactants, and wherein the crosslinker comprises at least two olefinic bonds, and is present in the range of about 9% to about 25% by weight of the reactants.

The invention relates to powdered lubricants for water based drilling fluids. Conventional liquid lubricants containing particularly divalent ions have the tendency to grease out. The powdered lubricants have excellent dispersion properties and hence do not grease out, when added to the drilling mud in the concentrations, preferably of the order of about 3% or less. The powdered lubricant is a combination of inert fillers with fatty acids that are essentially free from fatty acid esters and metal soaps and have organic acids containing C10-C24 alkyl groups fatty acids. The improved lubricating properties of the drilling muds result in greatly increased life of the rotary drilling bits and marked reduction in torque required to rotate the bit. Solid powdered additives compositions greatly reduce transportation costs and simplify the logistics and environmental concerns associated with shipping large volumes of liquids and overcome the pour point issues associated with liquid additives.

The invention relates to powdered lubricants for water based drilling fluids. Conventional liquid lubricants containing particularly divalent ions have the tendency to grease out. The powdered lubricants have excellent dispersion properties and hence do not grease out, when added to the drilling mud in the concentrations, preferably of the order of about 3% or less. The powdered lubricant is a combination of inert fillers with fatty acids that are essentially free from fatty acid esters and metal soaps and have organic acids containing C10-C24 alkyl groups fatty acids. The improved lubricating properties of the drilling muds result in greatly increased life of the rotary drilling bits and marked reduction in torque required to rotate the bit. Solid powdered additives compositions greatly reduce transportation costs and simplify the logistics and environmental concerns associated with shipping large volumes of liquids and overcome the pour point issues associated with liquid additives.

A nanometer plugging water-based drilling fluid and preparation method and use thereof are within this disclosure. The nanometer plugging water-based drilling fluid comprise a nanometer plugging agent. The nanometer plugging agent may be surface modified SiO.sub.2 powder with the surfactant. The surfactant may be sodium dodecyl benzene sulfonate and/or sodium dodecyl sulfate. The nanometer plugging water-based drilling fluid may perform effective anti-collapse of stratum and maintain the stability of stratum.

A nanometer plugging water-based drilling fluid and preparation method and use thereof are within this disclosure. The nanometer plugging water-based drilling fluid comprise a nanometer plugging agent. The nanometer plugging agent may be surface modified SiO.sub.2 powder with the surfactant. The surfactant may be sodium dodecyl benzene sulfonate and/or sodium dodecyl sulfate. The nanometer plugging water-based drilling fluid may perform effective anti-collapse of stratum and maintain the stability of stratum.

A method of treating a well that includes introducing a well treatment fluid into the well, and a well treatment fluid, are provided. The well treatment fluid comprises an aqueous base fluid, a bridging agent, a viscosifying agent, and a water soluble, biodegradable graft copolymer. In one embodiment, for example, the method is a method of cementing a casing in a well. In this embodiment, the well treatment fluid is a cement spacer fluid.

A method of treating a well that includes introducing a well treatment fluid into the well, and a well treatment fluid, are provided. The well treatment fluid comprises an aqueous base fluid, a bridging agent, a viscosifying agent, and a water soluble, biodegradable graft copolymer. In one embodiment, for example, the method is a method of cementing a casing in a well. In this embodiment, the well treatment fluid is a cement spacer fluid.