摘要
明确储层流体敏感性及其评价方法对优选入井工作液体系和性能至关重要。超深致密砂岩气藏储层流体敏感性受矿物组成、孔喉特征及高温流体环境等因素的影响,目前行业常用的评价方法已不再适用。以塔里木盆地超深致密砂岩气藏为研究对象,提出了改进的稳态流体敏感性实验评价方法,包括实验全过程模拟地层温度、出口端预加高回压等,并选取12块具有代表性的超深致密砂岩基块样品开展了水敏、盐敏和碱敏实验评价。结果表明:储层基块水敏指数0.41~0.52,盐敏指数0.72~0.73,碱敏指数0.83~0.92。数据对比显示本方法获得的流体敏感性损害程度强于以往室温条件下获得的评价结果,与矿场数据契合度更高。分析认为改进的评价方法能更好地反映储层实际情况,降低实验误差;细微孔喉及发育的粘土矿物是产生流体敏感性的内因;高温条件增大矿物表面水膜厚度、降低有效渗流通道半径,加剧粘土矿物水化膨胀、促进地层微粒分散/运移,加速矿物溶解/沉淀是加剧超深致密砂岩储层流体敏感程度的主要机制。
It is critical to understand the fluid sensitivity of reservoir and its corresponding evaluation method to optimize the selection of working fluids in the wells and their properties.The fluid sensitivity,which is influenced by mineral composition,pore throat characteristics,high-temperature fluid environment,etc,refers to damage of ultra-deep tight sandstone reservoirs.So the conventional evaluation methods in the industry seem to be not applicable any more.The ultra-deep tight sandstone gas reservoirs located in Tarim Basin are taken as the objects in this paper,and a modified fluid sensitivity evaluation method is proposed,which requires the simulation of the formation temperature and maintaining high back pressure on the outlet throughout the experiments.Twelve typical ultra-deep tight sandstone base blocks are chosen to carry out water,salt and alkali sensitivity experiments.The results show that the index of water,salt and alkali sensitivity is 0.41-0.52,0.72-0.73 and 0.83-0.92,respectively.By comparison,the degree of damage derived through this method,which maches well with the field measured data,is higher than that obtained at the room temperature experiments in the past.After analysis the paper indicates that(1)the modified evaluation method could reflect the actual condition of reservoirs and also reduce experimental errors,(2)the narrow pore throat and abundant clay minerals are the fundamental causes of fluid sensitivity,(3)the major mechanisms for increased fluid sensitivity for ultra-deep tight sandstone gas reservoirs,can be summarized as follows:in higher temperature,the thickness of the water film on mineral surface increases,reducing the effective pore throats’radius,and the intensified clay hydration and swelling accelerate the expansion/migration of formation particles and the dissolution/deposition of minerals.
作者
康毅力
张杜杰
游利军
王哲
田键
Kang Yili;Zhang Dujie;You Lijun;Wang Zhe;Tian Jian(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Sichuan,Chengdu 610500,China)
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2018年第4期738-748,共11页
Oil & Gas Geology
基金
国家自然科学基金项目(51604236)
"非常规油气层保护"四川省青年科技创新研究团队项目(2016TD0016)
关键词
高温
高回压
流体敏感性
水膜
超深储层
致密砂岩
塔里木盆地
high temperature
high back pressure
fluid sensitivity
water film
ultra-deep reservoir
tight sandstone
Tarim Basin
