铜川焦坪矿区油气显示及成因探讨

RESEARCH ON THE DISPLAY AND GENESIS OF OIL-GAS IN TONGCHUAN JIAOPING MINE AREA

在焦坪矿区内,煤、油、气是共生的,无论是勘探钻孔,还是在井下煤矿生产中油气显示明显。矿区油气显示集中分布于三叠统延长群T_3y^4砂岩段和侏罗统延安组中、上段及直罗组下部含砾砂岩中;平面上沿走向方向由北东向南西,显示愈趋明显。且分布于地层的浅部。化验资料表明,三选统与侏罗统中的油气在组分和物性上具有明显差异。前者产自延长群第二段(T_3y^2)中的Ⅰ型或Ⅱ型干酪根,后者产自延安组下段含煤层的Ⅲ型干酪根。区内生储盖组合条件良好,平面上矿区内油气赋存主要沿地层走向分布在矿区的浅部,严格地受岩性和构造的双重控制。探讨矿区油气显示及其成因分析,对指导煤矿开采具有重要意义。

In Jiaoping mine area, coal, oil and gas are in symbiosis. The display of oil-gas is obvious either in boreholes for exploration or in underground coal production. Oil and gas are concentratedly distributed in Yanchang Group sandstone member T_3Y^4 of Triassic Series and in the conglomeratic sandstone of middle-upper Yanan Formation and the lower Zhilo Formation of Jurassic Series. Horizontally along the strike from NE to SW, the display becomes more obvious, and the oil and gas distribute in the shallow Part of stratum. The test data indicate that there is a marked difference in composition and physical property between Triassic and Jurassic Series. The former originates from kerogen types Ⅰ or Ⅱ in the second member T_3Y^2 of Yanchang Group, and the latter from kerogen type Ⅲ of coal-bearing strata in the lower member of Yanan Formation. The combined condition of source bed, reservoir and cap rock is exallent in the area. The inherent oil-gas mainly distributed along the strata strike horizontally in the shallow part is double controlled by the rock property and structure stictly. The research is of important significance in directing