烃源岩层系地层破裂情况的定量评价及应用

Quantitative assessment for the formation fractures in source rock strata and its application

地层破裂情况定量评价、破裂岩石对地层输导能力的促进作用研究,对非常规油气藏勘探具有重要的作用。通过同围压条件下岩石破裂压力与烃源岩层系围压影响范围的对比,对渤海湾盆地济阳坳陷渤南—四扣地区烃源岩层系静岩压力作用下的岩石破裂情况进行了定量研究,并实测了烃源岩层系岩石破裂对输导能力的影响。在此基础上提出了围压、破裂压力、破裂后输导能力综合比对研究地层破裂情况的方法。渤南—四扣区域烃源岩层系中,古近系沙河街组三段上、中亚段,区域较深部位砂岩、泥页岩岩层普遍产生破裂,中部位砂岩岩层产生破裂;沙河街组三段下亚段,区域中、深部位岩层普遍产生破裂;沙河街组四段上亚段,区域中、深部位岩层普遍产生破裂、高部位部分砂岩岩层产生破裂。破裂的地层渗透率大幅提升,能够作为有效输导通道。上述方法对现有“甜点”评价提供了有力补充。

Quantitative evaluation of formation fractures and research on the promotion of fractured rocks on formation transport capacity are of certain importance to the exploration of unconventional oil and gas reservoirs.By comparing the rock fracturing pressure under the same confining pressure condition with the confining pressure range of the source rock series,the rock fracturing situation of the source rock series under the action of static rock pressure in the Bonan-Sikou area of Jiyang Depression,Bohai Bay Basin was analyzed.The effect of source rock fractures to the transporting capacity was quantitatively measured.On this basis,a method of comprehensive comparison of confining pressure,fracture pressure and post⁃fracture conductivity was proposed to study formation fracture.In the upper and middle sections of the third member of Paleogene Shahejie Formation in Bonan-Sikou area,the sandstones and shale rocks in the deeper strata are generally ruptured,and the sandstone layers in the middle strata are regionally ruptured.In the lower section of the third member of Shahejie Formation,the middle and deep strata are generally ruptured.In the uppersection of the third member of Shahejie Formation,the middle and deep strata are generally ruptured,whilst only part of sandstone layer in the upper part is ruptured.The fractured formation has greatly increased permeability and can be used as an effective conduction channel.The methods described above provide a powerful complement to existing“sweet spot”evaluations.