Study on the Formation Mechanism of Overpressure in Carbonate Strata in Tabei Region
The Paleozoic carbonate formation in the Tabei region is commonly developed with anomalous pressure,and multiple pressure systems exist in the formation pressure.In order to improve the accuracy of pressure prediction in carbonate reservoirs in Tabei region,the causes of abnormal pressure in the reservoirs are studied.Through the comprehensive analysis of the measured pressure,logging curve,sonic velocity-density intersection diagram,sonic velocity-vertical effective stress intersection diagram,gas logging data and seismic data in the Tabei region,it is shown that the deep carbonate stratum develops normal pressure,weak overpressure and overpressure system in the longitudinal direction,and the pressure coefficient of the weak overpressure system is generally greater than 1.10,and the pressure coefficient of some overpressure points is greater than 1.50,and the main controlling factor of overpressure are tectonic extrusion and hydrocarbon production.The Bowers method is selected for the prediction of formation pressure in deep carbonate formation with the introduction of an overpressure genesis mechanism.Compared with the measured data,the relative error of the predicted formation pressure is less than 5.000%,which is of high prediction accuracy and meets the needs of field engineering,and is of guiding significance for the study of overpressure formation and pressure prediction of deep and ultra-deep carbonate reservoirs in the Tabei and similar region.
pressure coefficientgenetic mechanismformation pressureBowers methodTabei region
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