Study On Pore Pressure Prediction Technique In Volcanic Reservoir

The exact pore pressure prediction is not only premise for good, efficiency and safe drilling and completion,but also the key portion for protecting hydrocarbon reservoir. There must be precise parameters of reservoir pressure, then drilling and completing quality can be improved with reasonable density of drilling and completion fluid. It will set concrete basement for future exploitation.Most of present pore pressure predicting methods based on formation uncompaction which causes abnormal pressure and increased porosity in the area of argillaceous sediment don't consider the forming mechanism of abnormal pressure beyond uncompaction . These methods are not suitable for non-argillutite formation and the fragmental sediment. Because the forming of Volcanic Reservoir pore volume isn't effected by sedimentary compaction, pore pressure prediction technique based on sedimentary compaction theory has deficiency in theory when it is applied in Volcanic Reservoir. Based on the limitations of present methods, the forming mechanism of abnormal pressure is researched, aiming at the volcanic reservoir developing characteristic. Rock mechanics is inducted and the forming macro mechanism of abnormal pressure is reflected by effective stress law. By rock supersonic testing, we have searched the functional relation between effective stresses of volcanic reservoir rock and sonic logging datas. From the rock strained balance equation, the predicting model of volcanic pore pressure is built in Xu-Jiaweizi volcanic reservoir.The new method is based on effective stress law, which has compact theoretical base. This method doesn't need to build normal compact trend line, which greatly declines the effect of artificial factor on testing result , it has high accuracy and excellent certainty and provides new clue and method for pore pressure prediction technique in volcanic reservoir.