水驱后天然气水交替非混相驱开发效果影响因素分析

Influential factors on immiscible water alternating natural gas displacement after water flooding

针对研究区块的地质及开发特点,建立了典型剖面模型,在压力体积温度(PVT)实验和相态拟合的基础上,应用数值模拟技术,对影响水驱后天然气水交替非混相驱开发效果的主要因素进行了分析。结果表明,转气驱时机、段塞尺寸、气水段塞比、注入速度等因素对于改善开发效果均存在最佳取值,现场应用时要综合考虑这些因素的影响。该区块最佳转气驱时机为注水0.4Vp(总烃类孔隙体积)后,最佳注入段塞尺寸为0.05Vp^0.1Vp,最佳气水比为1∶1,合理注入速度为30~45 m3/d,建议注气时各油层全部射开。

Aimed at the reservoir properties and deveLopment characteristics in study block, the profiLe model was developed. Based on the pressure-voLume-temperature experiment and matching of phase state, the influential factors on the water alternating natural gas immiscible displacement after water flooding were studied by numerical simulation technology. The results show that the main influential factors incLuding the best time of conversion, slug size, gas-water ratio, injection rate and so on, exist optimal values for improving the development effect and these factors should be integrally considered in the practical applications, For the study area, gas drive may be carried out when the ratio of water injection volume and pore volume（Vp） is 0.4. The optimal slug size reges from 0.05 Vp to 0.1 Vp, and the gas-water ratio is 1. The injection rate rages from 30 m^3/d to 45 m^3/d, and the perforation of all oil layers is optimized parameter.