吐哈盆地生物气-低熟气评价的元素平衡法及其应用

吐哈盆地探明的源于非高温热成因天然气(生物气—低熟气)的储量虽然已近千亿方,但尚未见评价其生成量及资源量的有效方法报道,这影响了对其勘探潜力及有利目标的决策。针对这一难题,考虑到无论生物气、低熟气的生成机理如何,都是一个有机元素之间的物质平衡过程,探索并建立了评价生物气—低熟气生成量的元素平衡法。利用吐哈盆地大量的实际分析数据,对这一评价方法(模型)进行了标定和应用。结果表明,吐哈盆地Ⅱ型有机质产生物气—低熟气的成气率高于Ⅲ型,二者分别累计可达134.40 ml/g和83.99 ml/g,吐哈盆地生物气—低熟气的生成总量约为1 436.28×1012 m3；资源量可能介于7.09×1011～24.42×1011m3之间。表明吐哈盆地的非高温热成因气具有较大的勘探潜力。台北凹陷的J2x和J1及其附近层位是勘探的有利目标。

Element Balance Method and Application of Appraising Biogenic Gas-Low Maturity Gas in Tuha Basin

The proved reserves of non high temperature originated natural gas (biogenic gas low maturity gas)in Tuha basin is already near 100×109 m3, but we didn’t sees the reported about appraises to the effective method of generation quantity and resource quantum yet, this has affected the decision making to its exploration potential and the favorable target. In view of this problem, considering regardless the generation mechanism of biogenic gas and low maturity gas, they were an organic element balance process; this article explored and established element balance method to appraise the gas generated amount of biogenic gas and low maturity gas.We use massive actual analysis data of Tuha basin to demarcate and apply this assessment method. The result indicated that biogenic gas low maturity gas generation rate of ⅡOM is higher than III OM in Tuha basin, the two accumulate separately may reach 134.40ml/g and 83.99ml/g, total generation quantity of biogenic gas low maturity gas in Tuha basin approximately 1436.28×1012m3; The resource quantum is possibly situated between 7.09×1011m3~24.42×1011m3 it indicated that non high temperature originated natural gas in the Tuha basin has big exploration potential. J2x and J1 and the nearby position in Taibei hollow are the favorable exploration target.