四川盆地罗场向斜黄金坝建产区五峰组-龙马溪组页岩气藏特征

罗场向斜位于四川盆地南缘，主要目的层五峰组-龙马溪组页岩在历经印支、燕山、喜马拉雅等多期造山事件改造后，页岩变形相对较弱、埋藏适中，页岩气形成与保存条件良好，成为上扬子页岩气核心区的重要组成部分。据岩性、电性、矿物组成、有机质赋存及含气性特征分析，本套页岩地层可划分为3个三级层序、3个岩性段、3种沉积相及4种沉积亚相与多种沉积微相；总体以深水陆棚相沉积期发育的富有机质页岩段（Ⅰ层）含气性最好，并可细分为Ⅰ₁，Ⅰ₂，Ⅰ₃，Ⅰ₄，Ⅰ₅5个小层。综合向斜内黄金坝建产区页岩物性与压力系数特征分析，昭通示范区页岩气主要赋存于现今残留的深水陆棚相复向斜内，气藏以观音桥段灰岩分隔为龙马溪组底部与五峰组两套，结合压后评估与单井试采成果，评价认为建产区以龙马溪组底部Ⅰ₃与Ⅰ₄小层压后改造与采气效果最好。

Shale gas reservoir characteristics of the Wufeng-Longmaxi Formations in Huangjinba construction block of the Luochang Syncline,the Sichuan Basin

Luochang Syncline is located in the southern Sichuan Basin.The main target layer of Wufeng-Longmaxi Formations shale has been deformed during Indosinian,Yanshanian and Himalayan.The shale deformation was relatively weak with moderate burial,promising good condition for shale gas accumulation and preservation.Thus the syncline has become an important part of the core shale gas area in the upper Yangtze region.According to characteristics of lithology,electrical,mineral composition,organic matter and gas bearing property,Wufeng-Longmaxi Formations shale of the Syncline can be divided into three third-order sequences,three lithologic sections,three types of facies and four types of sub-facies and various of micro-facies.Deep water shelf depositional stage is the best stage (layerⅠ) for possible organic rich shale deposition and could be subdivided into five layers,namely Ⅰ₁,Ⅰ₂ and Ⅰ₃,Ⅰ₄,Ⅰ₅.Integrated analysis of physical property and pressure coefficient of the shale in the Huangjinba development block,shale gas is mainly preserved in the residual syncline which was the main part of deep shelf.The gas reservoirs are divided into two sets,the bottom of the Longmaxi Formation and the Wufeng Formation,separated by the Guanyinqiao Member limestone.Based on fracturing evaluation and production test results,the bottom of Longmaxi Formation Ⅰ₃ and Ⅰ₄ are the best production layers after fracture transformation.