非洲中部大地構造演化及查德之石油系統研究(II)

The CPC Corporation Taiwan acquired three blocks in Chad for exploration in January of 2006. All three blocks are located close to the margins of sedimentary basins. Therefore, the degree of exploration is lower and with less subsurface and geophysical data. It’s highly necessary to appraise the hydrocarbon potential of this region by means of other geologic approaches. This project is designed to perform plate reconstruction technique to simulate the plate motions of Africa and Eurasia since Mesozoic in order to understand the relative motions of major tectonic blocks. It is concluded from the simulation that during the Cretaceous time, the study area was moving in the E-W direction with respect to Eurasia. Therefore, the anticlinal structures were generated by strike-slip activities. In this case, the wrench faults could have cut deeper into the strata or basement rocks which could have favored the hydrocarbon migration and storage in the fractures. The Central African Shear Zone (CASZ) splays into a N70?CCSZ (Central Cameroon Shear Zone) and a N50?TBSZ (Tchollir&eacute；-Banyo Shear Zone) in Cameroon. According to field observation and laboratory analyses, there’re two major deformational events can be identified along the TBSZ. The first one is the Dn event which formed a series NE-SW trending, dipping to the SW, low angle recumbent folds. After Dn, Dn+1 formed a series of NE-SW trending, near vertical folds. Potential reservoir quality sandstones are of fluvial origin and mainly deposited in the Cretaceous time. They have complex horizontal and vertical architectures. It’s possible to identify the channel sinuosity (meandering vs. braided) from e-logs, and sometimes, from high-quality seismic profiles as well. However, the reservoir sandstones distributions, along regional dip or strike, are hard to predict. Thus, special cautions should be taken into considerations during future oil and gas productional operations in the Doba basin. We also compiled a list of references (around 500 items) related to hydrocarbon exploration in Chad and Africa.