利用断储排替压力差定量评价断层封闭性方法探讨

贝301区块主干控藏断裂B29号断裂发育及活动历史研究的基础上，通过对断层封闭机理及影响因素的分析，利用不同深度内纯泥岩及纯砂岩实际测得的排替压力，采取内插法，建立了不同泥质含量下排替压力与深度关系图版。根据地静压力与地层埋深关系计算与断点处断面压力等值时的地层埋深，同时根据断裂带中泥质含量的计算，利用图版求得断裂带的排替压力，同理，利用储层的泥质含量及与断面对应储层的埋深，求得储层的排替压力。利用储层的排替压力及与之对应的断裂带中断层岩的排替压力差定量评价了B29号断裂的封闭能力。得到目的层内发育9层储层，与第1、2、3号储层对应的断层岩的排替压力大于储层的排替压力，表明断裂对该3层储层具有封闭能力。与第4-9号储层层对应的断层岩排替压力小于储层排替压力，即使有油气运移至此，也会沿断裂渗漏出去，因此断裂对这5层储层不具有封闭能力。该评价结果与油田开发结果基本吻合，证明了该断层封闭性评价方法的可行性。

Quantitative evaluation method Discussion of fault sealing by use of different displacement pressure between fault and Reservoir

On basis of research about development and activity history of main reservoir-controlling fault-Bei29 fault in Bei301 block and analysis of fault sealing mechanism and influence factors, by use of measured displacement pressure of pure sandstone and mudstone in different depth, the displacement pressure-depth relation chart in different shale content was established by interpolation. According to the relation between geostatic pressure and buried depth of strata, the buried depth of strata which was equivalent to section pressure at breakpoint was calculated. Meanwhile according to the calculation of shale content in fault zone, the displacement pressure was obtained by use of the chart. Similarly, displacement pressure of reservoir was calculated using shale content and buried depth of reservoir equivalent to fault section. Seal ability of B29 fault was evaluated quantitatively by use of differential displacement pressure between reservoir displacement pressure and displacement pressure of fault rock in fault zone. It was considered that there developed 9 reservoirs in aim plate. The displacement pressure of fault rock which is equivalent to 1, 2 and 3 reservoir is greater than that of reservoir, which showed that fault has seal ability in the three reservoirs. The displacement pressure of fault rock which is equivalent to 4-9 reservoirs is lower than that of reservoir. Oil and gas will leak out through faults even if it can migrate here. Consequently fault has no seal ability in these five reservoirs. This evaluation result is basically tallies with oil field development result, which proves that the evaluation method of fault sealing is feasible.