海相砂岩油田新型水驱特征曲线的改进与应用——以XJX油田为例

Modification and Application of New Water Drive Curve in Marine Sandstone Reservoirs——A Case of XJX Oilfield

标准的童氏图版广泛应用于水驱油田开发中后期采收率标定或者含水率预测,但由于该图版主要来自陆相油田的统计资料,因此预测海相砂岩的采收率误差较大。在标准童氏图版基础之上,根据南海东部XJX油田的基础地质资料和实际生产动态数据,采用统计学方法 ,把童氏图版标准公式中的经验系数7.5修正为由XJX实际油藏回归得到的系数4.12。通过分析标准童氏图版公式的不足,引入了修正系数a、c,得到修正后的童氏图版公式,并运用该公式对XJX油田采收率进行预测,发现修正后童氏图版预测采收率与水驱特征曲线法、递减法以及数值模拟法预测的采收率接近,相对误差较小。为了验证改进公式的精度,选取XJY、XJZ油田进行验证。结果表明:用改进后的童氏图版预测的含水率和采收率与实际值更接近,说明改进后公式具有一定的精度,适用于XJ油田群。

Tong＇s chart is widely applied to recovery calibration or water cut forecast in middle-later devel- opment period of water drive oilfields.As a normal way,Tong＇s chart is not accurate to predict recovery of marine sandstone reservoirs,because it gets from data of the land sandstone reservoirs.The empirical factor of Tong＇s chart was modified from 7.5 to 4.12 regressive by using statistic method based on the standard Tong＇ s chart according to basic geological data and actual production performance of XJX oilfield in the eastern South China Sea.After the shortcomings of the Tong＇s chart formula were analyzed,it was modified through the introduction of parameters a and c.The modified formula was used to predict the recovery factor of XJX oilfield.The predicted recovery factor by the modified formula was close to that by the method of water drive curve,decline and numerical simulation with few relative errors.XJX and XJZ oilfields were selected as sam- ples to test the accuracy of the improved Tong＇s chart formula.The results show that water cut and recovery factor are closer to the actual values.It indicates that it has certain accuracy and fit for XJ oilfield group.