A drilling fluid and method for drilling in a coal containing formation. The method includes: providing a mixed metal-viscosified drilling fluid including at least 1% potassium salt; circulating the drilling fluid through the well; and drilling into a coal seam.

Provided is a method for hydraulic fracturing in a borehole in a geological formation using a process fluid including an environmentally friendly biostabiliser. The biostabiliser is characterised in that it includes at least one organic acid, or a salt, alcohol or aldehyde thereof, such that the at least one organic acid is selected from the hop acids, resin acids, fatty acids and mixtures thereof.

The present application discloses water-based drilling fluid system compositions and methods for making water-based drilling fluids systems. According to one embodiment, a drilling fluid system may include a drilling fluid and a lubricant. The lubricant may be synthesized from plant-based raw material oil.

The present invention relates to a process fluid comprising an environmentally friendly biostabiliser, for industrial scale use in the Earth's crust, preferably for use in oil and natural gas extraction, in particular in hydraulic fracturing. The biostabiliser is characterised in that it comprises at least one organic acid, or a salt, alcohol or aldehyde thereof, wherein the at least one organic acid is selected from the group consisting of hop acids, resin acids, fatty acids and mixtures thereof. The biostabiliser is preferably a mixture of hop extract, rosin and myristic acid. The invention further relates to corresponding application and production methods.

A method includes adding a clay to water to form a suspension of clay in water, the clay including pieces of clay having an average diameter of at least 2 μm; adding a dispersant to the suspension of clay in water to form a drilling fluid; and injecting the drilling fluid into a well. In the drilling fluid, the dispersant interacts with the clay to form nanoscale particles of clay having an average diameter of less than 500 nm.

Methods of stabilizing swellable clays in a subterranean formation and methods of reducing the formation of sludge in a subterranean formation using a biopolymer based cationic surfactant are described. The biopolymer based cationic surfactant in dudes a quaternary ammonium compound having an alkyl polyglucoside backbone and amino alcohol side chains.

The present invention refers to a composition for water-based foamed fluid with high thermal stability for drilling depressed areas in oil and gas wells, comprising: i) a base fluid or drilling water consisting of fresh water; ii) a stabilizing agent; ii) a viscosifying agent; iv) a filtering reducing agent; v) a clay inhibiting agent; vi) an alkalizing agent and acid gas sequestering agent; vii) a thermal stabilizing agent; and viii) a foaming agent. Also, the present invention refers to a system that uses said composition for fluid and water-based foamed fluid with high thermal stability, the method of preparing the composition for fluid, the method of preparing the fluid and application of the composition and fluid in a water-based foamed fluid system with high thermal stability for drilling depressed or low-pressure areas in oil and gas wells.

Methods and compositions for modified well fluids. One method including combining an amount of a synthetic functionalized additive with an intermediate well fluid composition to form a synthetic functionalized additive-containing well fluid composition; the synthetic functionalized additive comprising a synthetic layered magnesium silicate that is covalently bonded to a functional group, and the intermediate well fluid composition comprising a water-based continuous phase with solid particles, wherein the synthetic functionalized additive increases suspension stability of the solid particles versus a well fluid composition comprising the solid particles without the synthetic functionalized additive.

A wellbore servicing fluid comprising (a) a cationic formation stabilizer having (i) a molecular weight in a range of from equal to or greater than 0.05 to equal to or less than 2.0 kiloDaltons (kDa), or (ii) cationic charge functional groups of greater than 2 to equal to or less than 5 cationic charges per molecule, or (iii) both (i) and (ii), (b) an anionic friction reducer, and (c) an aqueous fluid.

The present invention addresses to the use of a viscous fluid in continuous pumping to contain the saline dissolution in a homogeneous way (not limited to just one type of evaporite), highlighting the results of seawater with viscosifiers, due to its simplicity, and that does not have the same impact on the logistical chain as a brine supply. The increase in fluid viscosity limits the diffusion of salt into the medium and thus better contains the dissolution of the well walls, while also promoting a laminar flow regime in the annulus of the well, variables desired to achieve the quality of the operation of cementation. The employment of viscous fluid concentrates allows “on the fly” dilutions with the in-line seawater fraction mixture. The technique can also employ solutions of pre-dispersed viscosifying additives which, when added to seawater, result in a substantial increase in the volume of drilling fluid produced, no longer limited by the unit tank capacity. This allows drilling large extensions of salt. The low salinity viscous fluid is used in drilling operations without fluid return to the drilling rig (riserless) in the presence of a predominantly saline formation, aiming at preserving the phase diameter and improve well construction conditions.