構(gòu)造熱演化與頁巖氣的改造和保存研究

尹宏偉 邱楠生 劉紹文 王勤 劉大永

摘 要：該文重點開展了中國南方典型盆地構(gòu)造熱演化特征及頁巖氣形成的地質(zhì)背景的研究，初步開展了構(gòu)造改造對頁巖儲層物性和頁巖氣賦存形式的影響的研究。所取得的主要進展有：（1）以全面調(diào)研及大量野外地質(zhì)調(diào)查為基礎(chǔ)，結(jié)合地球物理資料解釋與分析，多尺度詳細剖析下?lián)P子地區(qū)的構(gòu)造特征，盆地演化及其對關(guān)鍵暗色頁巖分布與保存的影響，揭示江陰-無錫滑脫褶皺帶為相對穩(wěn)定區(qū)塊；（2）以野外地質(zhì)調(diào)查、樣品采集及室內(nèi)掃描電鏡觀測為基礎(chǔ)，結(jié)合擠壓構(gòu)造活動數(shù)值模擬，探索了構(gòu)造改造對下?lián)P子頁巖儲集空間的影響，揭示了強烈的擠壓、剪切會嚴重破壞頁巖中的孔洞結(jié)構(gòu)，但斷層活動影響的范圍有限，褶皺沖斷帶內(nèi)的寬緩向斜頁巖氣保存條件較好；（3）Ro以及新獲得的低溫熱年代學測試數(shù)據(jù)研究結(jié)果表明四川盆地熱歷史可大致以260 Ma為界分為P2末期之前的熱流升高階段和之后的熱流降低階段及隨后的低熱流發(fā)展階段，晚二疊世峨眉山地幔柱和中晚三疊世以來前陸盆地演化是四川盆地熱演化主要影響因素。

關(guān)鍵詞：下?lián)P子地區(qū) 四川盆地 構(gòu)造演化 構(gòu)造變形樣式 頁巖氣保存

Abstract：For the first two years， our research focused on the Tectono-thermal evolution and shale gas formation geological background of typical basins in southern China. And we have started to investigate the influences of structural alternation on the shale reservoir and shale gas occurrence. 10 faculties and 12 graduate students worked in this project. More than 2000 papers of geological background have been collected. 653 samples from 128 observation sites were collected during the past 7 field works. And we have mapped 10 geological cross sections and accomplished more than 700 experimental tests. The major progresses so far include： 1）Based on the analysis of field observation，drilling data and geophysical data，we interpreted the structural deformation characteristics and basin evolution of Lower Yangtze region and its influence on the distribution and preservation potential of the key shale layers. We suggest that the detachment-fold belt of Jiangyin-Wuxi is relative structural stable belt in the Lower Yangtze region； 2）Based on the field observation， sample collection and SEM analysis， and DEM modeling of compressional structural deformation， we investigated the influence of structural alternation on the reservoir properties of the Lower Yangtze shale， and concluded that strong compression and shear deformation do great damage to the pore structure of the shale， but the damage resulted from faulting is limited to the zone close to the fault， the broad synclines within the fold-and-thrust belts still have good shale gas preservation potential； 3）Based on Ro and low temperature thermochronology data， we divided the thermal history of Sichuan basin into two stages， the heat flux increasing and decreasing stages before and after later permian respectively. Emeishan mantle plume in the later permian and the tectono-thermal evolution of foreland basin since mid-later triassic are the controlling factors for the thermal evolution of the Sichuan basin.

Key Words：Lower Yangtze region；Sichuan basin；Tectonic revolution；Structural deformation styles；Shale gas preservation

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