华北东濮凹陷异常高压与流体活动及其对储集砂岩成岩作用的制约  

Overpressure and Fluid Flow in the Dongpu Depression, North China: Their Constraints on Diagenesis of Reservoir Sandstones

作　　者：李忠[1] 费卫红[2] 寿建峰[3] 王生朗[4] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]德克萨斯大学岩石圈研究中心 [3]中国石油天然气集团公司杭州石油地质研究所,310023 [4]中国石油化工集团公司中原股份有限公司,河南濮阳457001

出　　处：《地质学报》2003年第1期126-134,共9页Acta Geologica Sinica

基　　金：国家自然科学基金(编号49702025);国家973项目(编号G1999043303)资助成果

摘　　要：Basin-Mod软件模拟显示东濮凹陷35Ma左右孔隙流体已出现较高异常压力,综合分析表明欠压实作用是发育异常高压的主要机制。处于异常高压带内的泥岩存在微裂隙带,是异常高压流体压裂的直接结果井可以成为流体运移的通道。通过典型研究区砂岩压实(溶)量、压实-胶结关系、沉积参数-储集物性的对比,表明异常高压流体的确对砂岩的压实作用具有抑制作用。另一方面,自生石英流体包体均一温度大部分在105～145℃之间,频数呈多峰式展布,可能显示幕式流体活动。该温度范围内由于没有有机酸的大规模生成,泥岩频繁发生的幕式流体泄压活动,使得富含CO_3^(2-)的高压流体在注入砂岩(低压区)孔隙后易与Ca^(2+)、Mg^(2+)、Fe^(2+)等离子结合,导致砂岩储层发生强烈的(晚期)碳酸盐沉淀和胶结作用。Distinct fluid flow and transport pathways generally occur in abnormal high pressure (AHP) systems of sedimentary basins. Computer modeling by the Basin-Mod software shows that high abnormal pressure was developed as early as 35 Ma in the Dongpu depression, North China, which mainly resulted from rapid deposition and undercompaction effects. A lot of micro-fractures have been found in mudstones under AHP regimes. They are considered to have resulted from direct fracturing of AHP fluids and may become fluid flow pathways. Through a quantitative contrast analysis of compaction (pressure-solution), relative importance of compaction and cementation, relation of sedimentary parameters and reservoir features in sandstones of the study areas, it is proved that the occurrence of AHP fluids really constrain the sandstone compaction. On the other hand, homogeneous temperatures of fluid inclusions in overgrowth bands of quartz grains, mostly ranging from 105-145℃, show a multi-peak frequency distribution and may display episodic fluid flow, which have controlled sandstone cementation-dissolution. In the temperature interval, due to lack of intensive organic acid generation, high-pressure fluids containing abundant CO32- are easy bonded to the Ca2+ , Mg2+ and Fe2+ ions after being injected into sandstones with frequent hydraulic fracturing and episodic fluid-pressure discharge, which will result in intensive (late) carbonate precipitation and cementation in sandstone reservoirs (low-pressure zones) and destroy the reservoir capabilities.

关 键 词：欠压实作用 流体活动 成岩作用 砂岩 储层 东濮凹陷 胶结作用 

分 类 号：P544.4[天文地球—构造地质学]