Particularity of petroleum exploration on marine carbonate strata in China sedimentary basins
Particularity of petroleum exploration on marine carbonate strata in China sedimentary basins
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作者：
Jin Zhijun
海相碳酸盐岩地层是我国重要的油气勘探目标，其油气储量至少在300×10~8 t以上，虽然近50年来我国已发现了塔河油田、普光气田等大型碳酸盐岩油气田，但由于勘探投入少，油气资源量仍然很小，因此，碳酸盐岩地层的油气勘探开发具有重要意义。但主要原因在于中国海相碳酸盐岩地层石油地质的特殊性，主要表现在以下7个方面：（1）碳酸盐岩地层埋藏于多旋回叠合盆地中，（2）碳酸盐岩地层埋藏深度大，年代古老，（3）碳酸盐岩地层埋藏深度大，埋藏深度大，埋藏时间长，埋藏深度大，埋藏时间长。（3）烃源岩具有多岩性、多期生烃的特点;（4）储集岩类型多样，非均质性强;（5）圈闭类型多样，以隐蔽型和复合型圈闭为主;（6）储层普遍调整破坏，保存条件复杂;（7）储层分布复杂，预测难度大，为了在碳酸盐岩地层中发现更多的石油，缓解石油资源的供需矛盾，应加强海相碳酸盐岩盆地油气分布规律和勘探技术的理论研究，根据碳酸盐岩地层的石油地质特征，提出了中国海相碳酸盐岩盆地油气成藏需要解决的三个理论问题：（1）海相碳酸盐岩地层的发育环境、构造演化及其对有效烃源岩的控制;（3）油气多期成藏与保存机制，提出地震方法、在碳酸盐岩地层中勘探石油，应改进钻井和测井技术。
Marine carbonate strata,at least bearing 300×10~8 t petroleum,is very important exploration objective in China.Although some large carbonate oil-gas fields such as Tahe oilfield and Puguang gasfield have been found for last 50 years,the found petroleum reserves in carbonate strata is still small.This is due to low investment of exploration,but the main reason lies in the particularity of petroleum geology of marine carbonate layer in China,including the following 7 aspects:(1)carbonate strata are buried in multiple cyclic superimposed basins;(2)the depth to the carbonate strata is large and its age is old;(3)the source rocks are characterized by multiple lithology and multi-stage hydrocarbons generation;(4)types of reservoir rocks are diverse and the heterogeneities are strong;(5)types of trap are diverse and mainly subtle and compound;(6)the reservoirs were generally adjusted and destroyed and its condition of preservation is complex;(7) the distribution of reservoirs are complex and it is difficult to be predicted.In order to discover more petroleum in carbonate strata and to lighten the conflict of supply and demand of petroleum resources,research on theories of the laws of the petroleum distribution and exploration technologies in marine carbonate basin should be strengthened.On basis of petroleum geologic characteristics of carbonate strata,three theoretical problems to be solved of petroleum accumulation in Chinese marine carbonate basins are put forward as follows:(1) the developing environment and evolution of tectonics of marine carbonate strata and their control of effective source rocks;(2)hydrocarbon accumulation mechanism in the carbonate carrier beds;(3)mechanisms of multi-stage hydrocarbon accumulation and preservation.The paper also suggests that seismic method,drilling and well logging should be improved in exploration for petroleum in carbonate strata.