鄂西—渝东地区五峰组—龙马溪组页岩气富集规律及有利区预测

发布时间：2018-06-02 18:05

本文选题：页岩气 + 五峰组-龙马溪组　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：鄂西-渝东地区上奥陶统五峰组-下志留统龙马溪组是目前页岩气勘探的主要层系,研究区内的焦页1井是国内目前勘探最为成功的页岩气井之一,但是区内其他一些页岩气钻井勘探效果并不理想。本文通过基础地质资料调研,结合地区野外剖面和钻井岩心观察、采样和测试分析等工作,对五峰组下部页岩段、五峰组顶部观音桥段、龙马溪组下部页岩层段的沉积环境、平面展布、埋深、地化指标、矿物组成、微观孔隙类型及特征以及研究区页岩构造演化、生排烃史和地层水条件等方面进行研究,并考虑页岩演化和保存建立了评价标准,预测了页岩气发育有利区,主要取得以下主要认识:(1)鄂西-渝东地区上奥陶统五峰组-下志留统龙马溪组下部WF2-LM4笔石页岩段具有良好的页岩气发育的物质基础,位于沉积中心位置WF2-LM4笔石页岩段厚度大的地区页岩气勘探效果较好,受古隆起和水下高地的影响,WF2-LM4笔石页岩段厚度薄的地区勘探效果较差。(2)WF2-LM4笔石页岩段页岩硅质含量较高,一般大于40%,从LM5笔石页岩段开始硅质含量逐渐降低。WF2-LM4笔石页岩段有机质含量高、有机质孔发育程度高、有机质孔孔径也较大且形成三维连通的孔隙结构,矿物质孔发育程度低,裂缝发育程度低且裂缝被有机质填充较多。LM5及以上笔石页岩段有机碳含量低、有机质孔发育程度低、矿物质孔发育程度高,裂缝发育程度高且呈开启状态。(3)上奥陶统五峰组-下志留统龙马溪组页岩燕山期晚白垩世开始抬升的地区,具有抬升时间晚、生烃时间长、生烃终止时间晚以及上覆盖层保存好等特点;晚侏罗世至早白垩世开始抬升的地区,具有抬升时间早、生烃终止时间早以及上覆盖层遭受破坏时间长等特点。抬升时间在晚白垩世及之后、地层水矿化度及地化指标较好的地区,具有良好的页岩气保存条件。(4)建立了考虑页岩原始沉积条件和后期保存条件的选区评价方法,优选了有利区,认为渝东的涪陵地区以及渝东北城口东南部至巫溪一带区域为本次研究的页岩气藏发育的核心区。
[Abstract]:The Upper Ordovician Wufeng formation and Lower Silurian Longmaxi formation are the main strata of shale gas exploration in the western Hubei and eastern Chongqing areas. Well Jiaoye 1 is one of the most successful shale gas exploration wells in China. But some other shale gas drilling in the area is not satisfactory. Based on the investigation of basic geological data, combined with field profile and drilling core observation, sampling and test analysis, the sedimentary environment of the lower shale section of Wufeng formation, the top of Guanyinqiao section of Wufeng formation and the lower shale formation of Longmaxi formation is studied. The plane distribution, burial depth, geochemistry index, mineral composition, micropore type and characteristics, shale tectonic evolution, hydrocarbon generation and expulsion history and formation water condition in the study area are studied, and the evaluation criteria are established considering the evolution and preservation of shale. The favorable areas for shale gas development are predicted, and the following main understandings are obtained: (1) the upper Ordovician Wufeng formation and lower Silurian WF2-LM4 graptolite shale formation has a good material basis for shale gas development in the western Hubei and eastern Chongqing regions. The shale gas exploration effect is better in the area with large thickness of the WF2-LM4 graptolite shale section located in the sedimentary center, and the exploration effect is poor in the area with thin thickness of the WF2-LM4 graptolite shale segment affected by the paleouplift and the underwater highlands. The shale siliceous content of the WF2-LM4 graptolite shale section is relatively high. Generally larger than 40, the siliceous content of the LM5 graptolite shale section gradually decreases from the beginning. WF2-LM4 graptolite shale has a high organic matter content, a high degree of organic matter pore development, a larger pore size of organic matter and a three-dimensional connected pore structure, and a low degree of mineral pore development. The fracture development degree is low and the fracture is filled with more organic matter. The organic carbon content of graptolite shale and above is low, the organic matter pore development degree is low, and the mineral pore development degree is high. The area where the upper Ordovician Wufeng formation and Lower Silurian Longmaxi formation began to uplift in the late Cretaceous of shale period, has the characteristics of late uplift time and long hydrocarbon generation time. The late termination time of hydrocarbon generation and the preservation of the upper overburden are characterized by early uplift from late Jurassic to early Cretaceous, early termination of hydrocarbon generation and long time of destruction of the overburden. In the area with better mineralization degree and geochemical index of formation water in the late Cretaceous and after the uplift time, and with good shale gas preservation conditions, a selection evaluation method considering the original and late storage conditions of shale was established. It is considered that the Fuling area in the east of Chongqing and the area from the southeast of Chengkou to Wuxi in northeast Chongqing are the core areas of shale gas reservoir development in this study.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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