Pressure-sensitivity research on porosity, permeability and acoustic slowness in tight sandstone reservoir

The pressure-sensitivity is obvious in tight sandstone reservoir. In order to verify pressure sensitivity of tight sandstone in Sulige gas field, we conducted a pressure-sensitivity experiment with equipment AP608 from American CoreTest Company and AutoLab 1500 from American NER Company to test porosity, permeability and acoustic slowness. The results show that with the rising confining pressure, porosity decreases logarithmically, permeability decreasing in pattern of power, and acoustic slowness decreases logarithmically. Porosity and permeability of tight rocks are more sensitive to confining pressure, acoustic slowness of rock samples with high porosity are more sensitive to confining pressure. The drop amplitudes of the three parameters with confining pressure increasing also studied: permeability drops far more than porosity does, the drop amplitude of acoustic slowness is less than that of porosity, and the reasons were analyzed. © 2016 ejge.