Faultblock groups are the most important ‘cradle’ for oil/gas traps in Dongpu Sag whose distinctive tectonic setting and local deformation offered favorable conditions for the formation of complex faultblock groups. Based on exploration and development data

we studied the characteristics

formation mechanism

reservoirforming condition

and exploration potential of the complex faultblock groups. Besides the general features of faultblock groups

the distinguishing characteristics of these groups in Dongpu Sag are of mirror image relationships both in vertical and horizontal directions. The complexity of the faultblock groups is related to varying dynamics

multiphase extension

complicated local deformation condition and different deformation rocks. Dongpu Sag contains good source rocks

reservoirs and cap rocks. The fault blocks here serve as elementary oil/gas accumulation units. Although an individual fault block may be small

the faultblock groups form favorable traps with the faults acting as major migration paths. The faultblock groups in Dongpu Sag have great exploration potentials

and can still be regarded as major exploration targets in the future.