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

Key words: 
• abnormal compaction strata /
• ancient pressure of strata /
• statistics Modelling /
• abnormal compaction factor

Abstract: 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.