应用水驱特征曲线法计算可采储量应注意的几个问题

水驱曲线法是评价油田开发中后期可采储量的主要方法之一.从理论与实际应用的角度,讨论在现场应用水驱特征曲线时需要注意的问题.当计算单元的油藏类型、开采方式及含水率相当时,水驱特征曲线才具有叠加性,可以合并开发单元笼统计算可采储量,否则各开发单元应分别计算再叠加.在目前可采储量计算方法行业标准(SY/T5367-1998)推荐的6种水驱特征曲线中,认为计算可采储量最合适的是西帕切夫曲线法和张金庆曲线法,纳扎洛夫曲线法及俞启泰曲线法次之,马克西莫夫-童宪章曲线法和沙卓诺夫曲线法相对误差较大,计算结果偏大.宜采用斜率法判断回归直线段.标定年度及阶段可采储量所用方法要有继承性和延续性,应选取与生产动态比较吻合的计算结果作为标定值,不能把所有方法计算结果的平均值作为标定值.根据油田的可采储量采出程度与综合含水率的关系曲线,或根据开发指标与剩余可采储量的匹配关系,可以判断可采储量标定结果的合理性.图2表3参8(王孝陵摘)

Some considerations on the application of water drive characteristics curve in recoverable reserves calculation.

Water drive characteristic curve is one of the main method s to estimate recoverable reserves of oilfield at mid/late development stage. Fr om both the theoretical and practical view points, this article points out that some attention should be paid to once applying water drive characteristic cur ve. Only when the reservoir types, recovery methods and water cut are matched, t he water drive characteristic curve will possess the characteristics of reduplic ation and the development units can be merged and the recoverable reserves can b e calculated approximately, otherwise the development units can be calculated se parately and then sum them up. At present, among the six water drive characteris tic curves that are recommended by the industrial standards (SY/T?5367-1998) i n recoverable reserves calibration, Sipachef curve and ZHANG Jin-qing curve are regarded as most appropriate to calculate the recoverable reserves. The results of Nazalorf curve and YU Qi-tai curve have small error while that of Marksimof -TONG Xian-zhang curve and Shazonov curve have bigger error. Gradient method s hould be adopted in the judgment of regression straight line. Inheritance and co ntinuity must be included in the method of year/phase recoverable reserves calib ration. Those calculation results, which match relatively with production perfor mance, should be selected as standards but not the average value of total result s of all the methods. According to the relation curve of recovery percentage of recoverable reserves and accumulative water cut or the matching relationship of development index and remaining recoverable reserves, we can judge the rationali ty of the results in recoverable reserves calibration.