The present disclosure to a cementitious plugging wall solidifier for water-based drilling fluid and a preparation method thereof and a water-based drilling fluid.

Amidoamine-based gemini surfactants having dual chains connected via an alkenylene or alkynylene linker. Each chain contains a quaternary ammonium head group and an ethoxylated alkyl tail. A water-based drilling fluid containing the gemini surfactant is also provided. As examined by linear swelling and free swelling tests, the gemini surfactant is effective in reducing clay swelling.

Amidoamine-based gemini surfactants having dual chains connected via an alkenylene or alkynylene linker. Each chain contains a quaternary ammonium head group and an ethoxylated alkyl tail. A water-based drilling fluid containing the gemini surfactant is also provided. As examined by linear swelling and free swelling tests, the gemini surfactant is effective in reducing clay swelling.

One or more embodiments presently described are directed to drilling fluid compositions that include lubricants, methods for making the drilling fluids, and methods for drilling subterranean wells utilizing the drilling fluids. According to one embodiment, a drilling fluid composition may include a base fluid including water, a weighting agent in an amount of from 0.1 weight percent (wt. %) to 75 wt. % relative to the total weight of the water-based drilling fluid, and a lubricant in an amount of from 1 wt. % to 10 wt. % relative to the total weight of the water-based drilling fluid. The lubricant may include one or more alkyl esters and a fatty acid blend including one or more medium-chain fatty acids. The one or more medium-chain fatty acids may be at least 50 wt. % of the fatty acid blend.

One or more embodiments presently described are directed to drilling fluid compositions that include lubricants, methods for making the drilling fluids, and methods for drilling subterranean wells utilizing the drilling fluids. According to one embodiment, a drilling fluid composition may include a base fluid including water, a weighting agent in an amount of from 0.1 weight percent (wt. %) to 75 wt. % relative to the total weight of the water-based drilling fluid, and a lubricant in an amount of from 1 wt. % to 10 wt. % relative to the total weight of the water-based drilling fluid. The lubricant may include one or more alkyl esters and a fatty acid blend including one or more medium-chain fatty acids. The one or more medium-chain fatty acids may be at least 50 wt. % of the fatty acid blend.

Methods and compositions for using shale inhibitor additives in subterranean formations, and specifically, to dried shale inhibitor additives and methods for use are provided. In one embodiment, the methods include providing a dried shale inhibitor additive that includes a precipitate of at least one liquid amine shale inhibitor; allowing at least a portion of the dried shale inhibitor additive to dissolve in a treatment fluid including an aqueous base fluid; and introducing the treatment fluid into a wellbore penetrating at least a portion of a subterranean formation.

The present invention relates to the technical field of petroleum drilling, specifically provides an encapsulating agent and preparing method thereof, and a drilling fluid, wherein the encapsulating agent comprises an acrylamide monomer structure unit represented by formula (I), an anti-temperature monomer structure unit represented by formula (II) and an cation monomer structure unit represented by formula (III); ##STR00001##
wherein R.sub.1 and R.sub.2 are each independently H, and linear or branched alkyl of C1-C15, and R.sub.3 is H or the linear or branched alkyl of C1-C5. The drilling fluid provided in the present invention has strong inhibition property and stable rheological property.

Some examples of producing water-based drilling fluids including ecofriendly lubricating additives are described. A raw material oil including fatty acids with a short chain alcohol is esterified in the presence of a catalyst to produce alkyl ester products and triglycerides. The alkyl ester products are washed and heated to remove any residual water or the short chain alcohol. A first quantity of the alkyl ester products is mixed with a second quantity of a water-based wellbore drilling fluid.

Some examples of producing water-based drilling fluids including ecofriendly lubricating additives are described. A raw material oil including fatty acids with a short chain alcohol is esterified in the presence of a catalyst to produce alkyl ester products and triglycerides. The alkyl ester products are washed and heated to remove any residual water or the short chain alcohol. A first quantity of the alkyl ester products is mixed with a second quantity of a water-based wellbore drilling fluid.

The methods of suspending at least one weighting agent in a drilling fluid include synthesizing carbon nanotubes via chemical vapor deposition on iron oxide catalyst nanoparticles to form a quantity of nanoparticles. Individual nanoparticles of the iron oxide catalyst nanoparticles include a transition metal disposed on iron oxide. The embodiments further include adding a quantity of nanoparticles to the drilling fluid which results in an amount of carbon nanotubes dispersed within the drilling fluid. The dispersion of the quantity of nanoparticles increases the value of at least one of a Newtonian viscosity, a yield point, a plastic viscosity, and a density of the drilling fluid with the dispersed nanoparticles versus a similar or equivalent drilling fluid without the nanoparticle dispersion. The method may further include adding at least one weighting agent which will become suspended in the drilling fluid.