苏北盆地古潜山岩溶储层形成机制探讨

Formation mechanism of karst reservoir in buried hill, North Jiangsu Basin

李亚辉 段宏亮 邱旭明 王红伟

Li Yahui Duan Hongliang Qiu Xuming Wang Hongwei

中国石油化工股份有限公司江苏油田分公司 无锡石油地质研究所, 江苏 扬州, 225009

Jiangsu Oil field Branch Company, SINOPEC, Yangzhou, Jiangsu 225449, China

利用岩心观察、薄片鉴定、碳氧同位素分析等手段,从基岩性质和中新生代沉积与构造背景的差异性、岩溶储层缝洞系统的形成时间等方面,分析了苏北盆地兴化古潜山XG1井与XC1井岩溶储层发育差异的原因,探讨了古潜山岩溶储层的形成机制。认为岩溶面出露的岩石类型与结构和印支—中燕山期古风化岩溶地貌是控制本区岩溶储层发育的主要因素,也是导致XG1井与XC1井岩溶储层发育差异的主要原因;三垛期末强烈的翘倾运动在改变古潜山面岩溶格局的同时,引起地下流体活跃,加剧了XC1井处岩溶强度,有利于次生溶蚀孔隙的发育,但却对古潜山油气藏保存不利。古潜山油气勘探应以中新生代凹陷的边界断层(如真武断层)被动盘、低凸起之间的鞍部、斜坡带下的下古生界结晶白云岩古潜山(或断块山)为主。

By means of core observation,thin-section identification as well as carbon and oxygen isotope analysis,the reason for the differences of karst reservoir generation between well XG1 and well XC1 in buried hill of Xinghua city of the North Jiangsu Basin has been studied,and the formation mechanism of karst reservoir in buried hill has been concluded.The rock fabric exposed on karst surface and the karst landform during Indosinian and the middle Yanshanian are the main controlling factors for karst reservoir generation in the study area.They also explain the differences of karst reservoir generation between the above-mentioned 2 wells.Strong warping at the end of Sanduo period not only deformed the karst setting on buried hill surface,but also activated underground fluid,which intensified corrosion in well XC1.It was favorable for secondary pore generation,and unfavorable for the preservation of buried hill reservoir.The explorations for buried hill reservoir should be focused on the passive side of border fault of sag,and the saddle between low uplifts of Mesozoic-Cenozoic as well as the Lower Paleozoic crystalline dolomite buried hill below slope.

江苏省自然科学基金项目(BK2008584);中国石化海相前瞻性研究项目(YPH08091)资助

https://doi.org/10.11781/sysydz201105495