影响高演化泥岩盖层封闭性的主控因素分析  

Controlling Factors Affect Sealing Capability of Well-Developed Muddy Cap Rock

作　　者：李双建[1] 沃玉进[1] 周雁[1] 刘伟新[1] 

机构地区：[1]中国石化石油勘探开发研究院,北京100083

出　　处：《地质学报》2011年第10期1691-1697,共7页Acta Geologica Sinica

基　　金：国家自然科学基金委项目(编号40739904);国家重点基础研究发展规划"973"项目(编号2005CB422101);国家科技重大专项项目(编号2008ZX05005-001-001)联合资助成果

摘　　要：一般认为泥岩盖层的封闭性随着成岩作用的加深而变差,但是大量油气藏发现和实验测试结果证明高演化泥岩仍具有较高的突破压力和较好的油气封闭性。影响高演化泥岩盖层封闭性的主要因素是什么?如何确定高演化泥岩盖层产生破裂的边界条件,一直是影响其有效性评价的重要基础问题,本文通过对野外泥岩中脉体的包裹体测温,结合地层埋藏史恢复,重建了不同地层中脉体的形成时代,结果表明年代较轻的地层较早产生破裂,年代较老的地层较晚产生破裂,由此证明泥岩盖层在抬升量达到一定值后,会集中产生破裂。通过三轴应力-应变实验模拟了地层条件下泥岩盖层的韧脆性变化特征,结果表明高演化泥岩在一定埋深下,仍具有良好的塑性和封闭性能,影响其封闭性的关键因素是埋深与最大主应力差的变化。It is commonly considered that sealing capability of muddy cap rock tends to worsen with diagenesis deepening. However, discoveries of numerous hydrocarbon reservoirs and test results demonstrate that well-developed muddy cap rock has high breakthrough pressure and good sealing capability. What the controlling factors affecting the sealing capability of muddy cap rock are and how to determine boundary condition for cracking in well-evolved muddy cap rock have been two basic problems that constrain the validity evaluation of cap rock. Based on thermometry of fluid inclusions in veins of mudstone and restoration of burial history of sequences, this study reconstructed the formation time of various veins in sequences. The results show that younger cap rocks break, followed by older cap rocks. The results suggest that muddy cap rock will crack with its uplift to a certain magnitude. Triaxial stress-strain modeling experiment was performed to simulate ductile and brittle features of mudstone under the same condition of sequences. Our results show that well-evolved mudstone, even buried at depth, is still of good plasticity property and good sealing capacity. The key factors affecting the sealing capacity are burial depth and maximum difference of main stress.

关 键 词：泥岩 盖层 封闭性 三轴应力实验 破裂 

分 类 号：P618.13[天文地球—矿床学]