Contribution to the Characterization Study of the Surface Indices of the Lotshi Block and Its Surroundings in the Coastal Basin of Congo

The Lotshi block with an area of 506 Km², is located in the coastal basin in central Congo. It is between 12°31' and 12°53' east longitude and 05°33' and 05°44' south latitude. As part of this research, we carried out geological observations in the field, and sampled rocky materials in sites of petroleum interest in the Lotshi Block and surroundings in order to contribute to the understanding of the petroleum geology of this block, more particularly of its petroleum system. The samples brought back from the field were subjected to microscopic, mineralogical, (DRX), chemical (XRF) analyses and to the extraction of the hydrocarbon binder contained therein at the laboratories of ULG (Belgium), CRGM and OR in Kinshasa. The results obtained are summarized as follows: 1) Mineralogically: quartz, k-feldspar, plagioclase, calcite and dolomite are the dominant minerals in the samples analyzed; 2) Lithologically: two lithofacies (quartz sandstone and carbonate sandstone); 3) On the petroleum level: the sandstone rock of Lotshi and its surroundings are impregnated with hydrocarbons. It contains between 12% and 25% of hydrocarbon binder.