海上稠油地热水驱提高采收率矿场实践--以珠江口盆地EP油田HJ油藏为例

南海EP油田为低品位稠油油田,开采过程中面临地层天然能量不足、原油流动性差、平台有限空间布置地面人工注水设施困难等问题。为有效开发EP油田,提出了一种利用深部高温含水砂层在井下人工注水的闭式地热水驱技术。从深部巨厚水层加热效应、自源闭式注水方式适应性、井筒流动性改善的“拐点”效应、井筒再造技术释放油井产能等4个方面,分析了EP油田地热驱油的可行性。运用油藏工程方法、物理模拟实验和数值模拟法,评价和预测了该油田地热水驱采收率。物模结果表明,地热驱油可以使地层温度提高40℃,最终驱油效率提高14.72个百分点;数模方法预测地热水驱可提高采收率13.09个百分点。选取EP油田A14井组进行了现场试验,实施地热水驱后,井区压力得到恢复,水井对应的3口油井产量上升,首口见效井日产油由30 m 3提高到102 m 3,地热水驱效果显著;目前已实施2口地热注水井。

Field practice of offshore heavy oil geothermal water flooding for EOR:Taking HJ reservoir in EP oilfield in Pearl River Mouth basin as an example

As a low-grade heavy oil field in the South China Sea,the development of EP oilfield is faced with many problems,such as insufficient formation natural energy,poor crude oil fluidity,limited platform space where ground artificial water injection facilities are difficult to be arranged,etc.In order to develop EP oilfield effectively,a kind of closed geothermal water flooding technology which makes use of deep-buried high temperature water sandstone to inject water downhole artificially is proposed.The feasibility of geothermal water flooding in EP oilfield was analyzed from four aspects:heating effect of deep super-thick aquifer,adaptability of proximal down-hole water injection mode,inflection point effect of wellbore fluidity improvement,and wellbore reconstruction technology for releasing oil well productivity.By means of reservoir engineering method,physical simulation experiment and numerical simulation method,the EOR by geothermal water flooding was evaluated and predicted.The physical model results show that the formation temperature and the ultimate oil displacement efficiency are respectively increased by 40℃and 14.72%when the geothermal water flooding method is used;it is predicted by the numerical simulation model that the oil recovery by geothermal water flooding can be increased by 13.09%.The field test was conducted in A14 well group of EP oilfield.After geothermal water flooding was implemented,the wellblock pressure level was restored,the production of three oil wells corresponding to the water well was increased,with the daily oil production of the first responding producers increased from 30 m 3 to 102 m 3,which indicates that the effect of geothermal water flooding is remarkable.At present,two geothermal water injection wells have been implemented.