欠压实地层古地层压力恢复的统计模拟法及其在松辽盆地中的应用

The Statistics Modelling Method of Recovering the Ancient Pressures of Abnormal Compaction Strata and its Application to Songliao Basin

恢复烃源岩古地层压力和对于研究其生留排烃过程具有重要意义。Ｎａｋａｙａｍａ［１］等在开展盆地模拟研究时应用Ｒｕｂｅｙ（１９５９）和Ｃｈａｐｍａｎ（１９７）等人提出的数学地质模型对欠压实地层的古地层压力进行恢复。本文通过对松辽盆地欠压实地层的研究发现欠压实因子随地层厚度、埋深、围岩渗透性等地质条件的不同而改变，在此基础上提出了欠压实地层压力恢复的统计模拟法，克服了目前Ｎａｋａｙａｍａ［１］等将地层埋藏过程中的欠压实因子视为常数的不足，从而使计算结果更接近实际。统计模拟法在松辽盆地的应用结果表明了这一方法在实用中的可行性和有效性。

It is important to recover ancient pressures for the research of the He generation and expulsion process of source rocks and He migration, accumulation and forming pools. Nakayama (1981) recovered ancient pressures of abnormal compaction strata by using the math matical models put forward by Rubey (1959) and Chapman (1972) when they made basin modelling research. However, when researching the abnormal compaction strata in Songliao Basin, this paper found that the abnormal compaction factor varies with geological conditions of stratigraphic thickness, depth and the permeability of surrounding rocks, etc.. Based on it, this paper puts forward a statistics modelling method of recovering pressures of abnormal compaction strata. This method overcomes the shortcomings that the abnormal compaction factor was not to be changed in the buried process of strata considered by Nakayama. This paper uses it in researching the ancient pressures of abnormal compaction strata in Songliao Basin. The application results are identical with the drilling results in the basin. It indicates that the method is feasible and effective.