基于动态地质储量计算的海上油田滚动开发评价思路及实践

海上油田由于探井、评价井有限,部分油藏储量边界不落实,导致开发评价井或调整井实施存在较大的风险。为了降低实施风险,提出了基于动态地质储量计算的海上油田滚动开发评价思路,即通过生产数据计算动态地质储量,对静态地质储量进行诊断,对储量边界进行再落实,进而指导储量复核算和开发评价井、调整井部署与实施。为了提高动态地质储量计算的精度,根据所需参数的不同和方法的适应性差异,优选了物质平衡法、现代产量递减法和水驱曲线法建立动态地质储量计算方法体系。引入了结合水侵量计算的视储量线性物质平衡法,提出了考虑有限封闭水体的现代产量递减法。参考“7.5”法,建立了南海西部海域甲型水驱曲线计算动态地质储量的区域公式,优选了俞启泰型水驱曲线,用以计算南海西部的可动油储量和技术可采储量。该思路在南海西部海域取得了较好的实践效果,指导了该类油藏的储量复核算,推动了滚动开发和调整挖潜,降低了开发评价井和调整井的实施风险。

Evaluation thoughts and practice of progressive development of offshore oilfields based on dynamic OOIP calculation

Due to the limited number of exploration and appraisal wells in offshore oil fields,reserve boundaries of some reservoirs are difficult to be identified,which leads to a great risk in deployment of development appraisal wells or adjustment wells.In order to reduce risks,evaluation method of progressive development in offshore oilfields based on dynamic OOIP calculation is proposed,which is to calculate dynamic OOIP based on production data,re-check the static OOIP,re-define the reserves boundaries,so as to guide the re-calculation of reserves,deployment and implementation of development appraisal wells and adjustment wells.In order to improve the accuracy of dynamic OOIP calculation,according to different parameters applied and adaptability of the methods,the material balance method,modern production decline method and water drive curve method are selected to establish the method system for dynamic OOIP calculation.The linear material balance method of apparent reserves combined with water influx calculation has been introduced,and the modern production decline method with consideration of restricted and closed aquifer has been proposed.Referring to the“7.5”rule,the regional formula for dynamic OOIP calculation with Type A water drive curve in the western South China Sea has been established.And the Yu Qitai Type water drive curve has been preferred to calculate the movable OOIP and technical recoverable reserves in the western South China Sea.This evaluation method has achieved good practical performance in the western South China Sea,which guided the OOIP re-calculation for this type of reservoirs,promoted progressive development and adjustment of tapping potential,and reduced the risks of development appraisal wells and adjustment wells.