Relationship between anomalies in the deep zonality of organic matter catagenesis and dynamocatagenaise manifestations (on example of the Chezhen sag of the Bohai oil and gas basin)

Abstract

Background. The role of dynamocatagenesis in oil and gas formation has been confirmed in a number of publications. However, all of them indicate that dynamocatagenesis manifestations are associated with tectonic disorders selectively. It remains unclear which morphodynamic characteristics of tectonic disorders relate to dynamocatagenesis manifestations, and which values the actual quantitative characteristics of dynamocatagenesis manifestations obtain. Research in this direction is of importance for assessing oil and gas formation in any area, particularly when forecasting unconventional oil and gas resources.Aim. To determine the reasons for the appearance of anomalies recorded in the deep zonality of the catagenetic transformation of organic matter within the Chezhen Sag of the Bohai oil and gas basin in order to understand conditions for the formation of hydrocarbons.Materials and methods. Studies were conducted at the borehole level, based on a comprehensive analysis of the latest geological, geophysical, and geochemical information obtained by the Sinopec Shengli Oilfield Company.Results. At the borehole level, the dynamic type of catagenesis of organic matter was established. A structural-kinematic-age characteristic of faults, to which dynamocatagenesis manifestations are confined, was described. Actual quantitative expressions of thermal impact of faults on the rocks of sedimentary strata were determined.Conclusion. The conducted research confirmed that anomalies in the deep zonality of organic matter catagenesis are related to dynamocatagenesis manifestations, rather than to the regional immersion.