井研—犍为地区筇竹寺组页岩气保存条件研究  

Conservation of Shale Gas in Qiongzhusi Formation, Jingyan-Qianwei Area

作　　者：谢丹[1] 韩书勇 周伟韬 袁玥[3] 任街平 贺洪强 

机构地区：[1]中国石化西南石油工程有限公司临盘钻井分公司,山东德州253000 [2]中国石化西南油气分公司工程技术研究院,四川德阳618000 [3]中国石化西南油气分公司川西采气厂,四川德阳618000

出　　处：《天然气技术与经济》2018年第2期24-27,共4页Natural Gas Technology and Economy

摘　　要：在分析井研—犍为地区页岩气保存条件影响因素的基础上,探讨了影响研究区筇竹寺组页岩气保存条件的主要因素。首先,明确了断裂作用对页岩气保存条件的影响:断裂作用形成的微裂缝对页岩气藏起改善储层渗滤条件的作用,而强烈的断裂作用所形成的断层及宏观裂缝则对页岩气藏起破环作用。研究区远离褶皱冲断带,褶皱变形强度较弱,断层规模小、相对不发育,未破坏页岩气的保存,并且断层、裂缝系统对储集条件有一定的改善作用。其次,明确了顶、底板条件对页岩气保存条件的影响:良好的顶、底板可以形成封闭系统,可完好地封存页岩气。研究区含气页岩段顶板发育完整,岩性致密且具有较好的屏蔽作用,底板由于存在风化壳,相对较为薄弱。最后,明确了地层压力对页岩气保存条件的影响:大断裂较为发育的地区地层压力下降明显,吸附气含量较低,为保存条件较差的地区,反之较好。研究区筇竹寺组页岩地层为异常高压,页岩气层封闭性较好。With regard to shale gas in Qiongzhusi Formation, Jingyan-Qianwei area, we analyzed the main factors affecting its conservation, including that(1) faulting, faulting-induced microfractures may improve reservoir seepage whereas both faults and macrofractures generated from stronger faulting are destructive to shalegas reservoirs. The study area is far from fold and thrust belts, and its folding and deformational strength is weaker, all bringing about undeveloped small faults not to destruct shale-gas conservation.Moreover, faults and fractures have a certain effect on reservoir conditions;(2) roof and floor, better roof and floor just constituting a sealing system can block shale gas. In most gas-bearing intervals of Jingyan-Qianwei area, the roof is fully developed with tight lithology and better shielding effect, whereas the floor developed by weathering crust with good effect; and(3) formation pressure, for one region with large faults well developed, the formation pressure drops very evidently and the adsorption-gas content is less, all resulting in worse conservation and vice versa. With abnormal overpressure, the Qiongzhusi Formation has a better sealing capability.

关 键 词：筇竹寺组 页岩气 断裂作用 顶、底板条件 地层压力 

分 类 号：P618.13[天文地球—矿床学]