A proppant includes coating of a lignin containing phenolic resin. The proppants may be used in subterranean well formations and hydraulic fracturing operations.

A date tree trunk- and rachis-based lost circulation material (LCM) is provided. The date tree trunk and rachis LCM includes superfine date tree trunk fibers produced from date tree trunks and superfine date tree rachis fibers produced from date tree rachises. The date tree trunks and rachises may be obtained from the date tree waste produced by the processing of date trees in the production of date fruits. The date tree trunk and rachis LCM may include fibers having lengths in the range of about 20 microns to about 300 microns. Methods of lost circulation control using a date tree trunk and rachis LCM and manufacture of a date tree trunk and rachis LCM are also provided.

A method for drilling a tunnel through a formation must address environmental concerns. One tunneling method comprises the steps of: preparing a mixed metal-viscosified drilling fluid including bentonite, a mixed metal viscosifier and controlling pH to 8.5 to 9.5 to permit a reaction between the bentonite and the mixed metal viscosifier; adding at least one of: (i) calcium sulfate and (ii) a potassium salt; and pumping the drilling fluid while drilling the tunnel with the pH lowered to 7-9. The amount of mixed metal viscosifier used can be limited such that the weight ratio of mixed metal viscosifier to MBT reaches up to 1:30. In the event that there is a problematic increase in viscosity, a non-toxic anionic thinner can be added to the drilling fluid. One such anionic thinner is a polyacrylate.

A date tree trunk- and rachis-based lost circulation material (LCM) is provided. The date tree trunk and rachis LCM includes superfine date tree trunk fibers produced from date tree trunks and superfine date tree rachis fibers produced from date tree rachises. The date tree trunks and rachises may be obtained from the date tree waste produced by the processing of date trees in the production of date fruits. The date tree trunk and rachis LCM may include fibers having lengths in the range of about 20 microns to about 300 microns. Methods of lost circulation control using a date tree trunk and rachis LCM and manufacture of a date tree trunk and rachis LCM are also provided.

The present invention relates to the field of drilling fluids, and discloses a strong plugging drilling fluid suitable for shale gas wells and a preparation method of the drilling fluid. The drilling fluid contains water, bentonite, a tackifier, a flow pattern regulator, a filtrate reducer, a plugging agent, and a weighting agent, wherein, based on 100 parts by weight of water, the content of the bentonite is 1-10 parts by weight, the content of the tackifier is 5-15 parts by weight, the content of the flow pattern regulator is 4-13 parts by weight, the content of the filtrate reducer is 4-13 parts by weight, the content of the plugging agent is 20-55 parts by weight, and the content of the weighting agent is 10-60 parts by weight; the drilling fluid provided in the present invention employs modified nano-silica as a plugging agent to improve dispersity and particle size distribution in the drilling fluid system. Therefore, the drilling fluid is especially suitable for well drilling in shale formations with developed micro-fractures (micro-fissures) and micro-pores, low porosity and low permeability (10.sup.3-10.sup.7 md), and prominent capillary effect.

The present invention relates to the field of drilling fluids, and discloses a strong plugging drilling fluid suitable for shale gas wells and a preparation method of the drilling fluid. The drilling fluid contains water, bentonite, a tackifier, a flow pattern regulator, a filtrate reducer, a plugging agent, and a weighting agent, wherein, based on 100 parts by weight of water, the content of the bentonite is 1-10 parts by weight, the content of the tackifier is 5-15 parts by weight, the content of the flow pattern regulator is 4-13 parts by weight, the content of the filtrate reducer is 4-13 parts by weight, the content of the plugging agent is 20-55 parts by weight, and the content of the weighting agent is 10-60 parts by weight; the drilling fluid provided in the present invention employs modified nano-silica as a plugging agent to improve dispersity and particle size distribution in the drilling fluid system. Therefore, the drilling fluid is especially suitable for well drilling in shale formations with developed micro-fractures (micro-fissures) and micro-pores, low porosity and low permeability (10.sup.3-10.sup.7 md), and prominent capillary effect.

Compositions are provided for hydrocarbon applications. In some embodiments, the composition comprises lignin, in particular technical lignin, comprising at least one of lignin nanoparticles and lignin microparticles, preferably wherein at least 20% of the lignin particles are nanoparticles, and at least one strain of bacteria capable of biosurfactant production and/or a biosurfactant produced by at least one such isolated strain of bacteria. Also provided is a related method for making the composition.

The present invention relates to the field of drilling fluids, and discloses a drilling fluid that can inhibit surface hydration of clay and a preparation method of the drilling fluid. The drilling fluid contains water, bentonite, an intercalation inhibitor, a tackifier, a flow pattern regulator, a filtrate reducer, a lubricant, and a weighting agent, wherein, based on 100 parts by weight of water, the content of the bentonite is 2-9 parts by weight, the content of the intercalation inhibitor is 0.3-4 parts by weight, the content of the tackifier is 1-10 parts by weight, the content of the flow pattern regulator is 0.8-7 parts by weight, the content of the filtrate reducer is 1-8 parts by weight, the content of the lubricant is 0.5-4 parts by weight, and the content of the weighting agent is 12-60 parts by weight; the intercalation inhibitor prepared in the present invention can effectively control the degree of surface hydration of clay and thereby greatly improve the inhibition performance of the drilling fluid system by virtue of adsorption, intercalation, and ion exchange effects, etc. attained by the adsorptive groups that have specific functions in the intercalation inhibitor, when the intercalation inhibitor is intercalated in a form of a single spread layer between grain layers of clay minerals.

A date tree trunk- and rachis-based lost circulation material (LCM) is provided. The date tree trunk and rachis LCM includes superfine date tree trunk fibers produced from date tree trunks and superfine date tree rachis fibers produced from date tree rachises. The date tree trunks and rachises may be obtained from the date tree waste produced by the processing of date trees in the production of date fruits. The date tree trunk and rachis LCM may include fibers having lengths in the range of about 20 microns to about 300 microns. Methods of lost circulation control using a date tree trunk and rachis LCM and manufacture of a date tree trunk and rachis LCM are also provided.

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 m; 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.