Feasibility Analysis of Existing Recoverable Oil and Gas Resource in the Palaeogene Shale of Dongying Depression
Feasibility Analysis of Existing Recoverable Oil and Gas Resource in the Palaeogene Shale of Dongying Depression
复制标题
作者：
Sun Xi-nian
北美地区的勘探实践表明，页岩气作为一种非常规天然气资源，是目前的一种替代能源，根据东营凹陷下第三系地层的地球化学、矿物、测井、钻井和地震记录等实测资料，沙三下、沙四上段页岩具有厚度大、有机质丰度高、本区页岩类型多、热成熟度范围广，与北美地区的气成页岩具有相似的地质地球化学特征，石英、碳酸盐含量高，粘土含量小于50%，页岩脆性大，微裂缝普遍发育，有利于页岩气的勘探，对沙三下、沙四上段页岩气测分析显示异常现象，修井过程中井涌、井漏频繁，两种顶空气藏中轻烃丰度随深度增加而增加，在深度大于3400 m时，C5-7/C1-4值小于0.15。含油率和埋深的关系，东营凹陷页岩气藏的勘探在埋深小于3400 m时应采取油气并举的勘探方式，而在埋深大于3400 m时应优先勘探页岩气藏，因此，认为东营凹陷古近系页岩蕴藏着巨大的可采油气资源，在新的开发领域进行页岩气勘探是一项值得注意的风险投资。
The exploration practice in the North America suggests that shale gas as an unconventional natural gas resource,is a kind of current alternative energy resource.According to measured data of geochemistry,mineral,logging,drilling and seismogram on the Palaeogene strata in the Dongying depression,the shale in the lower Es3 and upper Es4 is characterized by large thickness,high abundance of organic matter,favorable types and wide range of thermal maturity.It has similar geological and geochemical characteristic comparing with the gas-generated shale in the North America.The shale in this area has high content of quartz and carbonate as well as less than 50% clay content.In addition,the shale has the brittleness and generally developed micro-fractures,which are useful to exploration of shale gas.The gas logging analysis on the shale of lower Es3 and upper Es4 shows the abnormal phenomena.The well kick and leak occurred frequently during well servicing,indicating the existence of gas.The light hydrocarbon abundance in the two setting of head space gases increase with depth,with C5-7/C1-4 value less than 0.15 while the depth is more than 3 400m.According to correlation of light hydrocarbon composition of head space gases and gas-to-oil ratio as well as buried depth,the exploration of the shale gas reservoir in the Dongying depression should be oil and gas concurrent exploration,when the buried depth is less than 3 400m,in contract that the exploration should give priority to shale gas reservoir if it is more than 3 400 meters.Therefore,we proposes that it should be a remarkable notable and risk invest in new exploitation field since the Paleogene shale in the Dongying depression exists great recoverable oil and gas resource.