塔里木盆地东河1油田石炭系油藏注气开发气油比上升问题及对策

Problems and countermeasures of gas-oil ratio rise in gas injection development of Carboniferous oil reservoirs in Oilfield Donghe-1 of Tarim Basin

自开展注气开发试验以来,塔里木盆地东河1油田石炭系油藏整体呈现出地层压力升、日产油量升、自然递减降、综合含水率降的"两升两降"开发特征。但与此同时,随着油藏向气藏转变、低压向高压转变,注气受效井气油比逐渐上升。为了解决气油比上升引发的诸多问题,基于注气开发机理研究,立足现场试验和应用,从工艺流程、采油方式和注采关系等方面提出针对性措施。主要对策为:优化地面工艺流程、强化参数监测,保证井控和地面安全;转变采油方式,明确气举采油为注气受效井从机采到自喷生产必要的过渡阶段,解决了机采不适问题,保证油井开井率和生产时率;完善注采井网,部署实现平面和纵向三环接替模式,严格控制注气受效井产气量和气油比,有效减缓气窜的发生。研究成果为东河1油田石炭系油藏注气提采提供了技术支撑。

Since the development of gas injection test,Carboniferous oil reservoirs in Oilfield Donghe-1 in Tarim Basin are characterized by“two rises and two drops”,that is,formation pressure and daily oil production rise,while natural decline rate and composite water cut decrease.In the meanwhile,with the changes from the oil reservoirs to gas reservoirs and from the low pressure to high pressure,the gas-oil ratio of the gas injection response wells increases gradually.In order to solve the problems caused by the the rise of gas-oil ratio,based on the mechanism research,field test and application,the pointed measurements are put forward from the aspects of technical process,oil producing mode and injection-production relationship.The countermeasures are shown as follows:optimizing surface process and enhancing parameter monitoring to ensure well control and surface safety;transforming oil producing mode and ensuring gas-lift production is a necessary transition phase from the mechanical production to natural flowing for the gas injection response wells,thus the problem of unsuitable mechanical flowing can be solved,and producer working rate and oil production time efficiency can be guaranteed;perfecting injection-production well pattern and realizing tri-cycle replacement mode in planar and vertical dimensions,so as to strictly control gas production and gas-oil ratio of the gas injection response wells,moreover effectively slow down the occurrence of gas channeling.The achievements provide a technical support for the gas injection development of Carboniferous oil reservoir in Oilfield Donghe-1.