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An indispensable tool, Theory, Measurement and Interpretation of Well Logs introduces the three primary phases of well-logging technology to engineering and geosciences students. This text offers an in-depth study of the electric, radioactive, and acoustic properties of sedimentary rocks. Mathematical and empirical models relate a formation property of interest to the property measured with the logging tool. Openhole logging techniques are covered, along with concepts of traditional and modern tools.

Résumé -Estimation de la saturation irréductible en eau à partir de la pression capillaire et des mesures de la résistivité électrique -Cet article présente les résultats de mesures de la pression capillaire et de la résistance électrique de trois types de roches : le sable argileux (Berea), le quartz et le calcaire. Nous rapportons également des données expérimentales pour l'indice de résistivité, le facteur de formation, la tortuosité, la pression capillaire et les exposants de saturation en eau de ces roches dans le système air/saumure. Les données de résistivité électrique sont évaluées par la loi d'Archie modifiée. Les résultats des mesures de la pression capillaire et de la résistivité électrique en fonction de la saturation en saumure montrent l'existence de deux saturations irréductibles en eau correspondant à deux phénomènes physiques différents. Les deux valeurs des saturations irréductibles forment des limites hautes et basses qui peuvent être utilisées pour estimer la capacité de la production d'un milieu poreux. L'analyse détaillée des données a aussi montré un changement de valeur de l'exposant de saturation. Ce changement pourrait également être observé à la saturation irréductible en saumure obtenu lors des mesures de pression capillaire. Abstract -Irreducible Water Saturation from Capillary Pressure and Electrical Resistivity

Laboratory corefloods were performed to investigate the effects of CO2 injection rate, reservoir dip, and the use of a drive gas on the cyclic CO2 stimulation process. Experiments were conducted in 6 foot long Berea sandstone cores using Timbalier Bay, a light oil, under immiscible conditions (500 psig and 78 °F). Process performance was maximized at moderate injection rates. Oil recovery efficiencies and gas utilization factors were poorer at very high or low injection rates. The inclination of the core and the site of injection substantially influenced oil recovery efficiencies and gas utilization factors. Process performance was favored when CO2 was injected into the lower end of a core tilted at a 45 or 90 degree angle. The use of a horizontal core or injection into the top of a tilted core yielded a poorer response. The benefits of a nitrogen drive (or chase) gas were evaluated by comparing the results of injecting CO2 followed by nitrogen with injection of CO2 or nitrogen alone. First cycle injection of a certain mass of CO2 followed by nitrogen yielded over twice as much oil as injection of that mass of CO2 alone. In the second injection cycle, the drive gas experiment recovered over three times as much oil as recovered by CO2 alone.

Coproduction, the simultaneous production of gas and water, is used to control water influx into water-drive gas reservoirs. The coproduction technique can increase gas recovery by as much as 20%. Reservoir selection criteria and study methodology are presented and illustrated with aU. S. gulf coast reservoir.Basic material-balance analysis, tank-model simulation, and a preliminary economic analysis demonstrated the technical and economic feasibility of the process for a case study of the Louisiana gulf coast Eugene Island Block 305 1O,300-ft [3140-m] -sand gas reservoir. This study also shows that the coproduction technique could result in a substantial increase in recovery efficiencies in many other water-drive gas reservoirs under specific economic conditions.