Basic characteristics and exploration direction of lacustrine shale oil and gas in Da'anzhai member of Jurassic in Sichuan Basin

This paper is the result of oil and gas exploration engineering.

Objective In order to confirm that the Da'anzhai member in the central part of Sichuan Basin has great shale oil and gas exploration potential.

Methods This paper analyzes the formation conditions and enrichment factors of the shale oil and gas of Da 1, 3 sub-member by cores, thin section, scanning electron microscope, whole rock X-ray diffraction, organic geochemistry, triaxial stress test, nuclear magnetic resonance test and other methods.

Results The results show that the shale in Da 1, 3 sub-member has the characteristics of mixed lacustrine system, wide distribution, large thickness, multiple types of reservoir space, better physical conditions, high hydrocarbon generation potential, high higher Youngs modulus, low Poissons ratio and high content of brittle minerals, which is conducive to the enrichment and fracturing transformation of shale oil and gas. On this basis, comprehensive analysis shows that the superposition of high TOC and type II organic matter is the basis of shale oil and gas enrichment; favorable mixed sedimentary system is the key to shale oil and gas enrichment; (micro) fractures control shale oil and gas high-production.

Conclusions Combine the above understanding, Longgang block and the Xichong-Lianchi block are selected as one of the favorable exploration areas for Lake shale oil and gas in Da'anzhai section of Sichuan Basin, which will provide guidance for the further exploration and development of shale oil and gas in the central Sichuan area.