The disclosure relates to an electrocrushing drilling fluid with an electrocrushing drilling base fluid including a non-polar oil, water, and glycerin. The base fluid may further include a polar oil and an alkylene carbonate. The electrocrushing drilling fluid may further contain at least one additive. The electrocrushing drilling fluid may have a dielectric constant or dielectric strength of at least a set amount, an electric conductivity less than a set amount, or a combination of these properties. The disclosure further relates to an electrocrushing drilling system containing the electrocrushing drilling fluid and an electrocrushing drill bit.

In accordance with one or more embodiments of the present disclosure, a method of inhibiting shale formation during water-based drilling of subterranean formations includes introducing a shale inhibitor to the subterranean formation during the water-based drilling, the shale inhibitor comprising a cationic polymer comprising repeating units of [A-B]. A is a substituted benzene or a substituted triazine of formula (2). B is a N-containing heterocycle. The cationic polymer and a method of making the cationic polymer are also described.

Well fluids and methods are provided that can be used for stabilizing a shale formation, especially during drilling of a well into or through a shale formation. The well fluids include: (i) a continuous water phase; (ii) a viscosity-increasing agent, wherein the viscosity-increasing agent comprises water-soluble hydrophilic polymer; (iii) a fluid loss control agent; and (iv) a cyclodextrin-based compound. The methods of drilling include the steps of: (A) introducing the well fluid into a zone of a subterranean formation; and (b) drilling the zone.

Disclosed are compositions and methods for the pressure protection of existing wells during infill drilling operations.

Methods and compositions including silicate shale inhibitor additives. In some embodiments, the methods include introducing a shale inhibitor additive comprising a silicate anion and a quaternary ammonium cation into a treatment fluid; introducing the treatment fluid into a wellbore penetrating at least a portion of a subterranean formation that comprises shale; and allowing the shale inhibitor additive to interact with the shale in the subterranean formation to at least partially inhibit the shale.

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. When the water-based drilling fluid contains the drilling fluid additive composition provided in the present invention, the water-based drilling fluid would have high temperature-resistance, high plugging and high inhibition performance, is environment friendly, especially have high density, and is especially suitable for horizontal shale gas well mining.

A method including introducing a treatment fluid into a subterranean formation having a downhole temperature in the range of between about 60° C. to about 95° C. The treatment fluid comprises an aqueous fluid, a swelling agent, and an oxidizing agent. Forming a diverter plug at a first permeable zone in the subterranean formation with the swelling agent, and breaking at least a portion of the swelling agent with the oxidizing agent.

Wellbore fluids and methods of use thereof are disclosed. Wellbore fluids may include an aqueous base fluid, a rate of penetration enhancer, and a shale dispersion inhibitor, wherein the volume ratio of the rate of penetration enhancer to the shale dispersion inhibitor is greater than 1:1. Methods may include circulating the wellbore fluid into a wellbore.

According to one or more embodiments of the present disclosure, a cement slurry includes cement particles, an aqueous fluid in an amount of from 10 wt. % to 70 wt. % relative to the total weight of the cement particles, and a clay stabilizer consisting of one or more polyethylene polyamines having a first structure H.sub.2NCH.sub.2CH.sub.2(NHCH.sub.2CH.sub.2).sub.xNH.sub.2, where x is an integer greater than or equal to 3. The amount of the clay stabilizer may be from 1 wt. % to 10 wt. % relative to the total weight of the cement particles. The average molecular weight of the polyethylene polyamines in the cement slurry having the first chemical structure may be from 200 g/mol to 400 g/mol. All of the polyethylene polyamines in the cement slurry having the first chemical structure may be encompassed in the clay stabilizer. Methods for cementing a casing in a wellbore using the cement slurry are also disclosed.

An oil-based drilling fluid composition, includes a base fluid and a treating agent. The base fluid comprises a base oil and an inhibitor; the treating agent comprises an organic soil, a main emulsifier, an auxiliary emulsifier, a plugging agent, a weighting agent, a humectant, an alkaline regulator and a filtrate reducer. 5-25 parts by weight of the inhibitor, 5-12 parts by weight of the organic soil, 1-6 parts by weight of the main emulsifier, 2-8 parts by weight of the auxiliary emulsifier, 3-18 parts by weight of the plugging agent, 5-30 parts by weight of the weighting agent, 2-6 parts by weight of the humectant, 2-7 parts by weight of the alkaline regulator and 2-10 parts by weight of the filtrate reducer are used, based on 100 parts by weight of base oil.