低熟气评价方法及其在松辽盆地北部的应用

Evaluation Method of Low-Mature Gaseous and Its Application in North Songliao Basin

针对目前尚无公认的有效的评价低熟气生成量方法这一难题,从低熟气的(低温)热成因机理出发,认为当前被广泛、成功应用于成熟的热成因天然气生成量评价的化学动力学方法仍应是评价低熟气生成量的有效方法,在此基础上建立并标定了松辽盆地代表性源岩干酪根成气的化学动力学模型,进而与可能成为低熟气先质的非烃、沥青质的化学动力学模型一起,构成了评价低熟气生成量的方法,同时指出有机质中少量的低活化能组分的存在是低熟气生成的内因。实际应用表明,松辽盆地北部低熟气的总生成量为41992×108m3,如果采用1%的运聚系数,则松辽盆地低熟气的资源量约为420×108m3,远低于松辽盆地常规热成因气的资源量;由化学动力学方法来评价低熟气生成量是可行的,这一方法也可以推广应用到其它富含低熟气的盆地。

Aimed at the problem of no an effective method to evaluate the generation amount of low-mature gas quantitatively, this paper deduces, based on the formation mechanism of low temperature thermal thermogenesis of low mature gas, that the chemical kinetics theory, which has been applied widely and successfully in evaluating generation amount of normal thermal thermogeneicsis natural gas, remains to be an effective meothod of evaluating the low-mature gas generation amount of low-mature gaseous. On this foundation, the chemical kinetics models of representative kerogen samples of kerogen are constructed and calibrated, and in accompany with the kineticals models of resine and asphatene, which may be the precursor of low mature gas partly, they constitutes the evaluation meothod of low mature gas. It is the few minor compoenents with of low activation energy that results in the generation of low mature gas. The initial application indicates that the total generation amount of low mature gas is about 41 992×10^8m^3 in north Songliao basin. In case of 1% of migration and accumulation coefficient, the resource amount of low mature gas is about 420×10^8m^3 , much lower than that of the normal thermal thermogenesisic natural gas. This suggests that it is workable to evaluate the generation amount of low mature gas using the chemical kinetic models and it can be also to popularize to other basins rich in low mature gas.