摘要
为了加快推进四川盆地寒武系筇竹寺组页岩气勘探开发进程,以近期获得重大突破的JS103井为研究对象,分析了井研—犍为地区筇竹寺组粉砂质页岩的矿物岩石学、有机地球化学及储层特征,探讨了储层发育的影响因素,指出了其与志留系龙马溪组优质页岩的差异。研究结果表明:①研究区粉砂质页岩具有低有机碳含量、低含气量、中等孔隙度、高硅质矿物含量的特征,明显区别于龙马溪组优质页岩高有机碳含量、高含气量、高孔隙度、高脆性矿物含量的特征;②粉砂质页岩储层以发育无机孔为主,介孔和大孔是储集空间的主体,孔隙形态主要为墨水瓶形和狭缝形;③硅质矿物的抗压实及溶蚀作用、适量稳定黏土矿物的存在有利于孔隙发育,碳酸盐矿物的胶结作用是导致储层物性变差的重要因素。结论认为:①粉砂质页岩紧邻优质烃源岩、自身具有一定的生烃能力,物性相对较好,为页岩气的形成和富集创造了有利条件;②现场含气量作为海相页岩储层评价的重要参数对粉砂质页岩的适用性较差,钻井过程中活跃的气测显示与良好储集条件的耦合关系可以作为现阶段判别粉砂质页岩含气性的重要指标。
In order to accelerate the exploration and development process of shale gas in Qiongzhusi Formation,Sichuan Basin,with JS103 well recently made a significant breakthrough as an example,the mineralogical,organic geochemical and reservoir characteristics were analyzed for silty shale in this formation in Jingyan-Qianwei area.Influential factors on reser⁃voir development were explored,and some differences between the silty shale in Qiongzhusi Formation and the high-quali⁃ty shale in Longmaxi Formation were determined.Results show that(i)the silty shale in the study area is characterized by low TOC and gas content,moderate porosity and high content of siliceous minerals,apparently different from the high-qual⁃ity shale in Longmaxi Formation with high TOC and gas content,high porosity and high content of brittle minerals;(ii)with developed inorganic pores as the soul,the silty shale reservoirs character mesopores and macropores as the main res⁃ervoir space along with the pores primarily in inkpot and slot shapes;and(iii)the anti-compaction and dissolution of sili⁃ceous minerals and the presence of moderate and stable clay minerals are conducive to pore extension,and the cementa⁃tion of carbonate minerals is an important factor affecting mineral deterioration.In conclusion,adjacent to quality source rocks,the silty shale enjoys a certain hydrocarbon-generating capacity and relatively good physical properties,creating fa⁃vorable conditions for shale-gas formation and enrichment.The gas content in field,as an important parameter for evaluat⁃ing marine shale reservoirs,is not at all applicable to the silty shale.The coupling between active gas-testing shows while drilling and better reservoir conditions can be taken as a critical indicator to discriminate the gas content in the silty shale now.
作者
周桦
董晓霞
魏力民
王同
张南希
罗思聪
ZHOU Hua;DONG Xiaoxia;WEI Limin;WANG Tong;ZHANG Nanxi;LUO Sicong(Exploration and Development Research Institute,Sinopec Southwest Oil&Gas Company,Chengdu,Sichuan 610041,China)
出处
《天然气技术与经济》
2023年第2期23-31,46,共10页
Natural Gas Technology and Economy
基金
中国石化科技部重点项目“川西南筇竹寺组页岩气甜点评价及目标优选”(编号:P22490)。
关键词
四川盆地
井研—犍为地区
寒武系筇竹寺组
储层特征
粉砂质页岩
Sichuan Basin
Jingyan-Qianwei area
Cambrian Qiongzhusi Formation
Reservoir characteristics
Silty shale
