Recovering to Formation and Evolution of Restraining Concentration Sealof Mudstone Caprock and Its Significance

Key words: 
• mudstone aprock /
• restraining oncentration seal /
• evolution /
• abnormal ore fluid pressure /
• formation /
• recovering /
• forecasting /

Abstract: Based on the analysis of restraining concentration seal mechanism of mudstone caprock and its formation conditions, by studying formation and evolution law of abnormal pore fluid pressure, this paper tries to study formation and evolution of restraining concentration seal of mudstone caprock. According to the formation and evolution of abnormal pore fluid pressure, this paper has established a method recovering and forecasting the formation and evolution law of abnormal gasbearing concentration. This method can not only recover the formation period of restraining concentration seal of mudstone caprock , but also forecast its evolution process, in the mean time, determine the present evolution stage of restraining concentration seal. The method was applied in recovering and forecasting the evolution of restraining concentration seal of K1qn and K1n1+2〖KG*2〗mudstone of Well Gu11 in Gulong sag of Songliao Basin .The results are in accordance with the actual geological conditions, which indicates that the method is practical to study the formation and evolution of restraining concentration seal of mudstone caprock and the method is effective.