Abstract: The concentration of unspent zinc-based hydrogen sulfide scavenger in an aqueous drilling fluid is controlled by selectively extracting the unspent scavenger in a solvent, such as glacial acetic acid, measuring the concentration of dissolved zinc, for example, with an X-ray fluorescence spectrograph, and utilizing the results of the measurements to proportion the extent of changes to be made in the concentration of the scavenger.

Abstract: During oil and gas well drilling operations, drilling fluid volume circulated per preselected vertical borehole increment drilled is continuously measured as well as the percentage by volume of hydrocarbon gas present in the return fluid. The gas is periodically sampled and analyzed to derive a relative ratio of C.sub.1 and C.sub.2 present therein. A functional relationship is then periodically computed relating the drilling fluid volume circulated per vertical increment drilled, and percentage of hydrocarbon gas therein, the rock volume of cuttings from which the gas evolved, and borehole pressure and temperature conditions at which each mud sample received respective cuttings to provide a percentage gas saturation parameter per vertical foot of reservoir. In functional response to the C.sub.1 /C.sub.

Abstract: A method for tagging an oil so that subsequently it may be identified as to source by incorporating into the oil as a tracer material an oil-soluble or oil-dispersible Group VIB, Group VIIB or lanthanum series rare earth metal salt of a fatty acid. The so-tagged oil may be utilized in any desired manner. Thereafter, an oil suspected to contain at least a portion of the so-tagged oil is analyzed for the presence of the added metal moiety. The method is especially useful in tracing a complex oleaginous and petroliferous material so that it may be recovered and identified following a theft or spill or to trace the flow of such oil injected through a subterranean reservoir.

Abstract: A fluorescently labeled complex hydrophobic fluid produced by dissolving a porphyrin therein. The porphyrin must be substantially soluble in acidic aqueous solutions, substantially insoluble in neutral or alkaline aqueous solutions and fluoresce at a wavelength between about 600 nm and 800 nm when irradiated at a wavelength between about 350 nm and 550 nm. The fluorescently labeled complex hydrophobic fluid may be identified by observation of the above-mentioned characteristic fluorescence upon irradiation. For identification purposes the porphyrin may be first extracted into an acidic aqueous solution for determination of fluorescence. In cases where the labeled hydrophobic fluid has been dispersed in a quantity of neutral or alkaline aqueous solution or suspension, this latter solution or suspension is first extracted with a hydrophobic solvent for the porphyrin to form a porphyrin solution. The prophyrin, in turn is extracted from this prophyrin solution with an acidic aqueous solution.

Abstract: Apparatus and method for detecting the level of gases entrained within a circulating drilling fluid used in subterranean well operations are disclosed. Detection of incipient gas kicks during drilling operations is accomplished by detecting the level of entrained gases. A gas-air sample is gathered at the surface of the well, and a gas-air sample having a constant relative humidity is delivered at a constant volumetric flow rate to gas sensors. Dilution air is automatically added to the sample when the gas concentration exceeds a known limit. Automatic periodic calibration of the sensors is provided. Stable signals from the gas sensor are obtained at two distinct flow rates.

Abstract: A method of subterranean exploration which comprises locating areas of anomalously high concentrations of helium indicative of geothermal reservoirs, geopressurized zones, petroleum reservoirs and radioactive ore deposits. Also disclosed is a method of producing helium which comprises collecting gases from a geothermal source and separating helium from such gases.

Abstract: A method for determining the concentration of a brine tolerant sulfonate surfactant in a complex mixture containing, in addition to said brine tolerant sulfonate surfactant, lignosulfonates, crude oil, salts, and water and, optionally, petroleum sulfonates and alcohols, that comprises incorporating into the brine tolerant sulfonate surfactant molecule a small amount of deuterium prior to addition to the complex mixture and determining the concentration of the brine tolerant sulfonate surfactant by measuring its infrared absorption at 2150 cm.sup.-1.