关键词:

产能测试, 启动压力梯度, 低渗透油藏, 有效注采井距

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