Disclosed are methods of preparing drilling fluid compositions containing treated calcium bentonite. One such method includes mixing calcium bentonite with an aqueous mixture containing soda ash, followed by adding starch to form the treated bentonite mixture that is used to prepare a drilling fluid composition. Another method includes mixing the calcium bentonite with an aqueous mixture containing soda ash and magnesium oxide, followed by adding starch to form the treated bentonite mixture that is used to prepare a drilling fluid composition.

A method of drilling a subterranean geological formation is described. The method includes driving a drill bit to form a wellbore in the subterranean geological formation thereby producing a formation fluid. The method includes injecting a drilling fluid into the subterranean geological formation through the wellbore. The drilling fluid includes 0.05 to 1 wt. % of a rhamnolipid surfactant based on a total weight of the drilling fluid. The drilling fluid includes an invert emulsion including a continuous phase and a dispersive phase including water.

A method of drilling a subterranean geological formation is described. The method includes driving a drill bit to form a wellbore into the subterranean geological formation thereby producing a formation fluid including hydrogen sulfide (H.sub.2S). The method includes injecting a drilling fluid into the subterranean geological formation through the wellbore. The drilling fluid composition includes 0.25 to 2 wt. % of a primary H.sub.2S scavenger which is potassium permanganate. The drilling fluid composition includes an invert emulsion which includes a continuous phase including mineral oil and a dispersive phase including water. The potassium permanganate present in the drilling fluid composition reacts with the H.sub.2S present in the formation fluid to produce a dispersion of manganese-containing particles which are at least one selected from the group consisting of manganese sulfide and manganese sulfate.

The present application discloses a nanometer self-locking bentonite film-forming agent, a method for preparing the same, and a film-forming drilling fluid.

A method may include providing a cement composition comprising ground vitrified clay, hydrated lime, and water; and introducing the cement composition into a subterranean formation.

The invention relates to the field of drilling fluid, in particular to a saturated salt water drilling fluid of salt response type intelligent polymer and preparation method thereof. The drilling fluid contains two or more of the following components stored in admixture or separately: bentonite, NaOH, KCl, calcium carbonate, barite, NaCl, supramolecular fluid loss additive, supramolecular shear-enhancing agent, plugging agent, coating agent and water. The drilling fluid provided by the invention has the characteristics of salt response and self-assembly, can keep rheological properties such as rapid recovery of the sheared structure, low extreme high shear rate viscosity, good shear dilution property and the like in a high-salt environment, has good fluid loss reduction performance, reservoir protection performance and debris dispersion inhibition performance, and has good temperature resistance and pollution resistance performance.

Nano-sized clay minerals enhance the viscosity of aqueous fluids that have increased viscosity due to the presence of viscoelastic surfactants (VESs). In one non-limiting theory, the nano-sized phyllosilicate mineral viscosity enhancers associate, link, connect, or relate the VES elongated micelles into associations thereby increasing the viscosity of the fluid, possibly by mechanisms involving chemisorption or surface charge attractions. The nano-sized phyllosilicate mineral particles, also called clay mineral nanoparticles, may have irregular surface charges. The higher fluid viscosity is beneficial to crack the formation rock during a fracturing operation, to reduce fluid leakoff, and to carry high loading proppants to maintain the high conductivity of fractures.

Some embodiments of the present disclosure are directed to synthetic functionalized additives, which may comprise a layered magnesium silicate. The present disclosure is also directed to drilling fluids that may comprise an aqueous base fluid and a synthetic functionalized additive. The present disclosure is further directed to methods for producing drilling fluids.

Described herein are methods of enhancing the rheological properties of a colloidal mineral suspension in a liquid with high-intensity acoustical energy. In some examples, the colloidal mineral suspension may be dehydrated after treatment with high-intensity acoustical energy.

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.