Abstract:

To make full use of the actual oilfield production test data to determine the effective injection-production well spacing for low-permeability reservoirs，the parametric equation of mobility function with the oil productivity index and the starting pressure was obtained by considering the low-permeability starting pressure gradient. The equation and the production test data can be used to get the mobility and drainage radius of the tested reservoir intervals. The regression analysis found that there is a semi-logarithmic relationship between the effective injection-production well spacing of low-permeability reservoirs and the physical property. Based on the relationship curve，the effective well spacing for directional well pattern development for low-permeability reservoirs can be determined. The application shows that the worse the reservoir properties，the smaller the effective well spacing；the effective well spacing of low-permeability reservoirs is 2 times the drainage radius，which means the valid producing coefficient has to reach 78.5% to ensure high efficiency between the producers and injectors. Using this method，the effective well spacing map of Bohai B Oilfield at different mobility was obtained. It’s suggested that the well spacing should be set between 300 m and 450 m at physical property range of 5 mD  to 20 mD.

Key words:

production test, starting pressure gradient, low-permeability reservoir, effective injection-production well spacing

摘要：

为充分利用矿场实际产能测试数据来确定低渗油藏有效注采井距，在考虑低渗启动压力梯度基础上，利用产能公式推导了流度与米采油指数以及启动压力的参数方程，利用该方程及产能测试数据可以得到测试储层段的流度和动用半径。通过回归分析发现低渗油藏的有效注采井距与物性之间存在半对数关系，根据该关系曲线可以确定低渗透油藏定向井开发的有效注采井距。实例应用表明：储层物性越差，有效注采井距越小；低渗油藏的有效注采井距为2倍动用半径，即有效动用系数达到78.5%才能保证注采井间受效良好。利用该方法获得了渤海B油田不同流度下的有效注采井距图版，建议物性在5~20 mD之间储层的注采井距控制在300~450 m之间较为合理。

关键词:

产能测试, 启动压力梯度, 低渗透油藏, 有效注采井距