A method of drilling in a subterranean formation. A method may include providing a direct emulsion drilling fluid comprising an aqueous fluid, an oil, and a polysorbate emulsifier; circulating the direct emulsion drilling fluid from a surface, through a wellbore, and back to the surface; and extending the wellbore in the subterranean formation while circulating the direct emulsion drilling fluid.

A method of controlling lost circulation includes introducing into a wellbore a lost circulation fluid comprising: an external oil phase, an internal aqueous phase, an emulsifier, a wetting agent, a magnesia sealant, and a; retarder; contacting the lost circulation fluid with a lost circulation zone; and forming a plug adjacent the lost circulation zone by reacting the magnesia sealant with water at a wellbore temperature, thereby reducing fluid loss into the lost circulation zone.

The present invention addresses to a wireline logging method using an aqueous based drilling fluid with xanthan gum and polyols in order to improve the quality of the acquisition of geological data from wireline logging (final logging) in open hole and reducing the risk of the tool getting stuck. It can also be applied in well control situations and used in the integral drilling of the reservoir, but with different application bias of the multifunctional fluid.

A fiber silica composite microsphere for a shale stratum comprises a hollow silica sphere and fibers, and the fibers are partially coated on an outer surface of the hollow silica sphere and partially embedded into an interior of the hollow silica sphere. The hollow silica sphere has an outer diameter of 1-5 μm and an inner diameter of 0.8-4.7 μm; the fibers have a length of 5-10 μm and a width of 1-3 μm.

A drilling fluid containing a liquid phase, a weighting agent (e.g. barite, calcite, ilmenite), and perlite is described. The drilling fluid may further contain one or more additives including a defoamer, a fluid-loss control agent, a viscosifier, an antiscalant, a deflocculant, a lubricant, a clay stabilizer, a bridging agent, and a surfactant. A process of drilling a subterranean geological formation utilizing the drilling fluid is also specified. The introduction of perlite to the drilling fluid is effective in reducing the thickness and permeability of filter cakes formed during the drilling process.

A method comprising drilling through a plurality of differing zones of a subterranean formation using a drilling fluid comprising a non-oleaginous continuous phase, an oleaginous discontinuous phase and at least a first salt dissolved into the non-oleaginous continuous phase. The amount of the at least first salt dissolved into the non-oleaginous continuous phase is maintained such that a density of the drilling fluid varies by no more than 10% while drilling through the plurality of zones.

A water-based drilling mud composition may include an aqueous carrier, an asphalt sulfonate salt, and insoluble latex particles. The insoluble latex particles promote stabilization of an emulsion formed in response to introduction of an oil phase in the composition. The composition may include the emulsion including an oil phase dispersed as droplets in the aqueous carrier. The dispersed insoluble latex particles may be present in an oil-water interface between the oil phase and an aqueous phase of the aqueous carrier.

Apparatus and methods for determining the fluid conductivity of a fluid network. The method includes injecting a nanoemulsion into the formation, the nanoemulsion including a carrier liquid and nanodroplets. The nanodroplets are stabilized within the carrier liquid by polymer-coated iron oxide nanoparticles. After extracting fluid from the formation, a parameter of the extracted nanodroplets is determined. Based on the determined parameter, the fluid conductivity of the fluid network is determined.

A drilling fluid containing a liquid phase, a weighting agent (e.g. barite, calcite, ilmenite), and perlite is described. The drilling fluid may further contain one or more additives including a defoamer, a fluid-loss control agent, a viscosifier, an antiscalant, a deflocculant, a lubricant, a clay stabilizer, a bridging agent, and a surfactant. A process of drilling a subterranean geological formation utilizing the drilling fluid is also specified. The introduction of perlite to the drilling fluid is effective in reducing the thickness and permeability of filter cakes formed during the drilling process.

A method of drilling in a subterranean formation. A method may include providing a direct emulsion drilling fluid comprising an aqueous fluid, an oil, and a polysorbate emulsifier; circulating the direct emulsion drilling fluid from a surface, through a wellbore, and back to the surface; and extending the wellbore in the subterranean formation while circulating the direct emulsion drilling fluid.