王庄油田强水敏性稠油油藏热采开发研究

RESEARCH ON THERMAL RECOVERY OF STRONG WATER SENSITIVE HEAVY OIL RESERVOIR IN THE WANGZHUANG OIL FIELD

王庄油田位于山东东营凹陷北部陡坡带,其主力含油层系沙一段黏土含量高达13%,水敏指数超过70%,属强水敏性稠油油藏。强水敏性成为制约其能否采用注蒸汽开发的关键。为此,在分析形成储层强水敏地质原因的基础上,采用水敏流动试验、高温物理模拟实验和数值模拟等方法,利用激光拉曼、X-衍射、核磁和CT等技术手段,开展了储层水敏机理、热采过程中骨架矿物、黏土矿物和储层物性变化规律研究。结果表明:随温度的升高骨架矿物逐步溶蚀、膨胀性黏土矿物发生转化;在温度高于250℃时渗透率可恢复到原始值的80%左右,证明了该类油藏热采开发的可行性;结合热采过程中温度场的变化,建立了强水敏稠油油藏热采储层物性变化模式。该成果在矿场应用中取得理想效果,可为同类油藏的开发提供借鉴。

The Wangzhuang Oil field is located at the actic region in the north Dongying Sag, Shandong Province, where the reservoir of the Member 1 of Shahejie Formation is the main oil-bearing series. The clay content is up to 13% and the water-sensitive index is more than 70%, and the heavy oil reservoir is quite sensitive to water. Consequently, the strong water sensitivity becomes the key restrictions of whether it is developed with steam injection or not. Therefore, based on the analysis of geologic reasons for strong water sensitivity of the reservoir, using technology methods, such as laser raman, X-ray diffraction, nuclear magnetism and CT, the water sensitivity mechanism and the change laws of matrix minerals, clay minerals and physical property in the thermal process are researched by using water sensitivity flow test, high temperature physical simulation experiment and numerical simulation, etc. The results show that the corrosion of the matrix minerals occurred gradually and the transformation of swelling clay minerals happened step by step with the increase of the temperature; the permeability could increase to approximately 80% of initial value when the temperature is over 250℃. It proves that thermal recovery is feasible and available. Moreover, combined with the evolution of temperature field in the thermal process, the physical property change mode is established in strong water-sensitive heavy oil reservoir. The ideal development results are obtained in field application, producing reserves are 1 920×104t and the annual deliverability of oil is 47.1×104t. The research provides reference to the development of this kind of reservoir.