Abstract: An apparatus, method and computer-readable medium for estimating a resistivity property of an earth formation in a borehole filled with oil-based mud. The method includes conveying a logging tool into a borehole; measuring a plurality of impedance values of the earth formation, each of the plurality of impedance values being obtained at one of a plurality of measure electrodes on the logging tool; determining a coefficient related to an electrical property of the mud from a plurality of pairs of impedance values; estimating the resistivity property of the formation from the determined coefficient; and recording the resistivity property on a suitable medium.

Abstract: Nanoemulsion, macroemulsions, miniemulsions, microemulsion systems with excess oil or water or both (Winsor I, II or III phase behavior) or single phase microemulsions (Winsor IV) improve the removal of filter cakes formed during hydrocarbon reservoir wellbore drilling with OBM. Such filter cakes and their particles can contact, impact and affect the movement of the drill string undesirably resulting in a “stuck pipe” condition. The macroemulsion, nanoemulsion, miniemulsion, microemulsion systems with excess oil or water or both or single phase microemulsion removes oil and solids from the filter cake, thereby releasing the drill string from its stuck condition. In one non-limiting embodiment, the emulsion system may be formed in situ (downhole) rather than produced or prepared in advance and pumped downhole.

Abstract: Gas hydrate formation in a well completion fluid in the annular space of a hydrocarbon producing well may be controlled by the incorporation of effective amounts of one or more low dose gas hydrate inhibitors, including but not limited to, low dosage hydrate inhibitors (LDHIs), kinetic hydrate inhibitors, dendrimeric or branched compounds, linear polymers and copolymers, grafted or branched linear polymers and copolymers, and onium compounds.

Abstract: A gamma ray detector uses a scintillation detector having a response that matches a response characteristic of a photodiode. The detector may be used to measure natural gamma rays and/or gamma rays produced by interaction of neutrons from a neutron source with the earth formation.