石油和天然气运聚效率的主控因素及定量评价

烃源岩生砀的石油和天然气大部分在运成藏过程中损失了，因此石油和天然气运聚效率主要取决于油气运聚过程中的损耗量的大小。损耗量包括烃源残留烃量、储集滞留烃量、运移流散烃量和构造破坏烃量。天然气的运聚效率远小于石油，是由于天然气在溶解性、扩散性、吸附性等物理性质方面与石油有差异。通过对塔里木盆地寒武系一下奥陶统及中、上奥陶统烃源岩的模拟计算，认为影响石油运聚效率的主要因素是构造破坏作用和储集层滞留作用，而影响天然气运聚效率的主控因素是运移过程中的扩散、溶解及构造破坏作用。构造作用同时控制塔里木盆地石油和天然气的运聚效率，对正确评价油气资源量有重大意义。

Key factors controlling migration and accumulation efficiency of oil and gas and their quantitative evaluation

Since a large amount of oil and natural gas would be lost during the progress of migration and accumulation, the migration and accumulation efficiency of oil and natural gas are determined by the hydrocarbon quantity wasted during migration and accumulation, which includes four parts, i.e., hydrocarbon retention quantity in source rock, hydrocarbon retention quantity in reservoir, hydrocarbon dissipation quantity during migration and hydrocarbon quantity destroyed by tectonic movements. That the migration and accumulation efficiency of natural gas is far less than that of oil results from their differences in physical properties such as solubility, diffusion and absorptivity. It is shown by simulation results of source rocks of Cambrian Lower Ordovician and Middle Upper Ordovician in Tarim basin that the key factors determining the migration and accumulation efficiency of oil are tectonic movements and retention in reservoir and those of natural gas are dissipation during migration and tectonic movements. Tectonic movements is most important for proper evaluation of oil and natural resources since it determines both migration and accumulation efficiencies of oil and gas.