Analysis Of Transition Zone And Faulting System In Machang Region Of Dongpu Depression

The fault systems of this region are rather complex, Lanliao fault, Huanghe fault, Machang fault and Sanchunji fault dominate the whole faulting systems. These faults strike parallel, the dips change frequently. In the meantime, as the scales, throws and crosscutting relationship changing systematically, these faults form many kinds of fault systems and transition zones.The geometry, kinematics and dynamics of fault systems which locate in Machang, Dongpu Depression are studied in detail, by seismic sections, faults displacement distributing charts and structural evolution section, which were finished based on abundant seismic data and former research results. The characteristic of transition zones are summarized, and the relations of faults systems and the forming of petroleum reservoir are discussed finally:1. As one of the important faults of this region, the Machang fault strikes NE-NEE, can be divided into five segments based on changes of fault trends and characteristics of cross-sections. According to structure analysis, balanced-crosssections and transition zones technologies, it developed intermittently presenting alternation of climax and tenuity.2. The Madong fault system strikes NE-NNE, while dip SE-SEE. The faults situate in the eastern part of this fault system usually developed in sedimentary strata, many parts display slide patterns along different layers controlled by gravity. The southern part is not consistent with the northern.3. Based on the analysis of faulting systems, we propose that there are two main transition zones and three secondary transition zones in this area. The formation of transition zones was controlled or influenced by the strike-slip in the basement and differential extension of main faults in the fault systems.4. The distribution patterns of petroleum are correlated with the formation and development of the transition zones, palegeography and sedimentary.