Disclosed herein are water-based drilling fluids for protecting high-permeability reservoirs. The drilling fluid comprises bentonite, a tackifier, a thinner, a filtrate reducer, an anti-collapse agent, a reservoir protectant, a lubricant, and water.

Disclosed herein are water-based drilling fluids for protecting high-permeability reservoirs. The drilling fluid comprises bentonite, a tackifier, a thinner, a filtrate reducer, an anti-collapse agent, a reservoir protectant, a lubricant, and water.

Drilling fluids or muds are provided for the drilling of a borehole into an earth formation. The drilling fluid or mud may be used for drilling oil and/or natural gas wells in subterranean reservoirs. In some embodiments, the fluid is formed from an additive comprising lignin and at least one biosurfactant produced by at least one strain of bacteria capable of biosurfactant production.

A method for drilling a wellbore into a formation. The method includes: providing a mixed metal-viscosified drilling fluid including at least 1% potassium salt and/or at least 0.05% calcium sulfate; circulating the drilling fluid through the well; and drilling into a formation. An anionic thinner may be added if the clay concentration of the drilling fluid reaches a problematic level to adversely affect pumpability of the fluid.

A method for drilling a wellbore into a formation uses a mixed metal-viscosified drilling fluid including at least 1% potassium salt and/or at least 0.05% calcium sulfate; circulating the drilling fluid through the well; and drilling into a formation. An anionic thinner may be added if the clay concentration of the drilling fluid reaches a problematic level to adversely affect pumpability of the fluid.

Drilling fluids or muds are provided for the drilling of a borehole into an earth formation. The drilling fluid or mud may be used for drilling oil and/or natural gas wells in subterranean reservoirs. In some embodiments, the fluid is formed from an additive comprising lignin and at least one biosurfactant produced by at least one strain of bacteria capable of biosurfactant production.