塔里木盆地泥质气源岩有效性判别标准

从排烃门限控油气理论的生烃量减去残烃量等于排烃量的思路出发,根据塔里木盆地样品的化学动力学模型计算的生油、生气量,和由统计模型计算残油、残气量,定量计算和探讨泥岩的排油、气量及有效性与其有机质丰度、类型和成熟度的关系,并建立了相应的判别图版。结果表明,泥岩作为可能气源岩的丰度下限值约为TOC＝0.1%,远低于其作为油源岩的丰度下限值(0.4%)。这意味着塔里木盆地许多按油源岩判别标准归入非烃源岩之列的地层,有可能成为气源岩。

DISTINGUISHING CRITERIA OF VALIDITY FOR ARGILLACEOUS GAS SOURCE ROCKS IN TARIM BASIN

According to the principle that generated hydrocarbon minus residual hydrocarbon equals to the amount of expelled hydrocarbon which is expressed by the theory of hydrocarbon expulsion threshold controlling the distribution ofoil and gas, and based on the amount of oil and gas calculated by the model of chemical kinetics using the samples of Tarim Basin and the amount of residual oil and gas calculated by the statistical model, the amount of oil and gas expelled from mudstone is calcuulated quantitatively and their relationship with the abundance, types and maturity oforganic matter is discussed, The corresponding distinguishing plates are established. The results indicate that the lowlimit of organic carbon abundance for mud gas source rock is about 0. 1%. This is much lower than that of oil sourcemek(TOC = 0.4% ) . This implies that a lot of mudstones which are regarded as non-source rocks according to thedistinguishing criteria of oil source rock may be potential gas source rocks.