A method of drilling a subterranean geological formation having a permeability of no more than 0.1 mD with a drilling fluid comprising a continuous phase, a viscosifier, a weighting agent, and sodium silicate, wherein the sodium silicate is present in the drilling fluid at a concentration of 0.01-0.2% by weight, relative to the total weight of the drilling fluid. Various combinations of embodiments of the drilling fluid and the method of drilling the subterranean geological formation are provided.

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.

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.

Invert emulsion treatment fluids can be used in oil and gas operations. A fluid loss control additive (FLCA) is a component of the fluid that can be utilized to control or minimize fluid loss into a subterranean formation. The FLCA can be a biodegradable surfactant of a sorbitan ester. The treatment fluid can include a bridging agent of insoluble particles. The biodegradable surfactant can aid the bridging agent to enter into permeable areas of the subterranean formation and consolidate to reduce or prevent fluid loss.

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.