A study of lithofacies-palaeogeography as a guide to geological survey of shale gas

Benefited from the development of horizontal well and the fracturing technology, shale gas has become a hot field in oil and gas exploration and development in China. Sedimentary environment determines the characteristics of basic geology elements of shale gas, such as the organic carbon content and type, mineral composition and content, thickness and the buried depth of hydrocar-bon source rocks. On the basis of the study of the regional sedimentary facies, according to the litheofacies palaeogeographic map-ping, it can explicit the spatio-temporal distribution of favorable facies belt of the hydrocarbon source rocks, which can provide the basic direction of the shale gas exploration. A case study of shale gas geological survey work on Longmaxi Formation in Southern of Sichuan Basin and its periphery was carried out, it can confirm favorable facies belt and the characters of the roomage distribution of hydrocarbon source rocks. Based on the litheofacies palaeogeographic, through superimpose the composition of the mineral, organic carbon content, maturity and the thickness, which are the evaluation parameters of shale gas, it can forecast the prospects and favor-able area of shale gas on Longmaxi Formation in Southern of Sichuan Basin and its periphery. The fundamental target of geological survey work about shale gas is to find the prospects and favorable area, which can provide scientific basis for shale gas exploration and development. As a result, the study of lithofacies palaeogeography can be a guide for geology survey of shale gas.