Types Of Complex Fault Block Group And Controlling Factors On Hydrocarbon, Southern Dongpu Depression

The complex structural features and the unique petroleum distribution characteristics haveaggravated the difficulty of further exploration in southern Dongpu Depression, it is eagerlynecessary to utilize some new methods to reevaluate the exploration potential and to implementeffective drilling in this region. Under such conditions, the concept of complex Fault Block Groupis proposed to evaluate the complex fault-block oilfield. Based on the studies of the tectonicfeatures and the fault features in three two-class tectonic belt, the classification of the basic typesof complex Fault Block Group and its distribution have received more and more attention. Basedon the understand of the petroleum accumulation macro-law , the dominant controlling factors ofpetroleum concentration is studied by means of the identification of the Petroleum AccumulationSystem and the detailed analysis of typical complex Fault Block Group reservoirs in varioussystems, as a result, the Petroleum Accumulation models is built up. The important conclusionsare obtained from the research as follow.1. The six basic types of complex faulted block group were classified according to thegeometry and kinematics characteristic, they include: Faulted steps, Overlapped faulted steps,Transferred faulted steps, Combinative rift valley, Combinative rift valleys and horsts,Combinative horsts.2. The genetic conditions for forming Complex Faulted Block Group are created by thedisplacement of the main base faults that result in the transmutation of the both side blocks, whichwill create the new sub-class faults in each block.3. There are three petroleum accumulation system in south of Dongpu Depression.Qiaokou & Xinhuo Multi-source and three locations petroleum accumulation system, Tangzhuang& Machang Multi-source and three locations oil accumulation system and Sanchunji & Zhuayingsingle source and three locations oil accumulation systems. There are different petroleumdistribution laws between the three systems.4. The sufficient of the hydrocarbon source determine the enrichment of the reservoir andmake the petroliferous difference between the traps with different distance from the source. Thestructure framework the complex fault block located play an effect on the petroleum richness.5. Migrating way of hydrocarbon and fault-sealing ability have effect on the reservoirlocation and the rich degree of Complex Fault Block Group s, there are mainly two ways, form Zmigration and net migration, through which the hydrocarbon migrate from the depressions to theshallow parts of the structures, the change of fault-sealing ability and its evolvement result in thegreat variety of petroleum enrichment in the different fault traps under the same structuralframework and the unique distribution laws.6. Source controlling is the key factor affecting the petroleum distribution of Complex FaultBlock Group. Two models of hydrocarbon accumulation is existed in Complex Fault BlockGroup because there are great difference between the distribution of source rocks and Fault BlockGroup traps and the ways petroleum migrating, they are Long Distant Multi-source and nettycharging model and Long Distant Single-source and Z form charging model.7. With the concept of Complex Fault Block Group to implement the progressiveexploration, it will be easier to understand the geological laws and to find out the location of theremaining resource and to guide the exploration effectively. We made a great performance in thepractice through the detailed analysis and drilling to Complex Fault Block Group in Qiaokouregion and Machang region.