基于Dr指数的动态储量计算新方法

New method to predict performance reserves based on Dr index

雷源 陈晓明 常会江 孙广义 吴晓慧

中海石油（中国）有限公司天津分公司渤海石油研究院，天津 300459

Bohai Oilfield Research Institute, Tianjin Branch of CNOOC Ltd., Tianjin 300459, China

针对传统方法计算动态储量精度低，现代产量递减分析方法求解过程复杂等问题，从矿场角度出发，引入了能够反映储层产油能力的物理量——Dr指数，并结合单井数值模拟技术开展了敏感性分析。结果表明，Dr指数随油井生产时间的延长，先是增加，增加到一定值后即稳定不变，影响其稳定值的主要因素是储层产状和油井产量。为了定量表征Dr指数与上述因素之间的关系，文中以渗流理论为基础，推导了变产量、变井底流压条件下Dr指数的解析表达式。以解析式为基础，结合反函数理论，运用牛顿迭代算法，提出了一种求解动态储量的新方法。该方法求解过程简单，且受主观因素影响小。应用对比表明，新方法求得的动态储量与现代产量递减分析方法结果相近，证明新方法可靠，具有矿场推广意义。

Traditional ways to calculate dynamic reserves hardly reach a precise result while modern production decline analysis works in a complicated process. Therefore, a new physical quantity describing reservoir drainage capacity, Dr index, is proposed. Using single well numerical simulation, sensitivity analysis shows that Dr index increases with production time, and finally stabilizes to a certain value. The main factors affecting the stability value are production data and reservoir shape. In order to quantitatively describe the relationship between Dr index and other parameters, using seepage law, the analytic expression of Dr index is deduced with variable production and down hole flow pressure. Then, based on the monotonic function of Dr index with the drainage radius, combined with inverse function theory and Newton iterative algorithm, a new method for calculating dynamic reserves is suggested. This method functions easily and excludes subjective factors. Field application shows the results of the new method is nearly the same as that from modern production decline analysis, which proves this method is accurate and reliable.

10.6056/dkyqt201805013