Diagenesis and Thermal Maturity of the Cogollo Group rocks in the ANH-CR-Montecarlo-1X well, Cesar-Ranchería Basin, Colombia

The exploration well ANH-CR-Montecarlo-1X, in the southern part of Cesar-Ranchería basin Colombia, cuts sedimentary rocks assigned to Cogollo Group (Barremian-Cenomanian). present study integrates petrographic techniques (thin section microscopy and scanning electron microscopy), geochemistry (total organic carbon pyrolysis rock-eval) basic petrophysics establish thermal maturity potential these as a conventional or unconventional hydrocarbon reservoir. results analysis revealed that correspond quartz sandstones greywackes carbonate mudstones wackestones. These were affected by diagenetic processes such compaction mineral neoformations. latter include minerals from clays group cover grains rock framework, other types precipitates, silica, ferrous non-ferrous cement them. Some partial total dissolution, for which secondary porosity is recognized. Chloritization illitization argillaceous matrix feldspars alteration are also observed, affects permeability rock. Additionally, during diagenesis micrite recrystallized sparite precipitation ocurred calcareous rocks. shows more than different cement, thus reducing their permeability. Based on parameters siliciclastic area have low reservoir but good non-conventional (tight sandstones). geochemical studies exhibit content (between 0 4.5% with an average 0.71%), kerogens type III IV. They high levels matter conversion, indicative did generate hydrocarbons, currently depleted mature state, compatible generation.