郯庐断裂南段韧性构造岩天然气突破压力的测算

A TEST ON BREAK PRESS OF NATURAL GAS IN TENACITY STRUCTURE ROCK OF SOUTH SECTION, TANCHENG LUJIANG FAULT

糜棱岩作为典型韧性构造岩广泛分布于盆地的深部、边部及与之相邻的山链中 ,其对深源天然气 (尤其是无机成因CO2 )的封闭作用尚缺乏研究。本文在扫描电镜观测的基础上 ,运用气体吸附法和压汞法对郯庐断裂系南段糜棱岩和高级片麻岩的微孔隙结构参数进行了测试。糜棱岩的突破压力多数大于 2 5MPa ,其中有 40 %的样品在 5 0MPa以上 ,中值半径多数为 0 0 1nm ,孔隙集中范围在 2 5～ 1 6nm ,含量 1 0 %左右。其微孔隙结构远远优于已知的低、中、高压气藏的实际盖层 ,表明糜棱岩是天然气的一种优质盖层。

As typical tenacity structure rock, the mylonite distributes proverbially in the depth, border and mountain area supplementing each other with basin. The sealing affection to deep natural gas, especially abiogenic CO 2, has not studied yet until now. Based on SEM observance, the methods of gas adsorption and mercury pression were used to test micro hole frame parameters of mylonite and high grade gneiss in this paper. The break presses of most samples are more than 25 MPa (about 40 percent of samples surpass 50 MPa). Most of median radiuses are 0.01 nm, and hole size vary between 2.5～16 nm whose content is 10% also. The micro hole structure of mylonite overmatch the covers of gas pools of sorts which indicate mylonite is a kind of high quality cover of natural gas.