Logging Classification and Evaluation Criteria for Marine ShaleReservoirs of Wujiaping Formation in Eastern Sichuan Basin

Mature technical methods of Longmaxi marine shale logging reservoir classification and evaluation standard have been built through previous studies, however, the Wujiaping formation, due to its complex geological conditions, is difficult to involve into these evaluation criteria. Based on element logging calibration, coring experiment calibration and logging processing interpretation, this paper establishes the fine classification standard of marine shale reservoirs of Wujiaping formation in the eastern part of Sichuan Basin. The marine shale reservoir of Wujiaping formation is characterized by “four high, three low and one expanded diameter”. Using the established classification standard, the shale of Wujiaping formation is evaluated and divided into class I, II and III reservoirs. Among them, class I reservoir is a high-quality reservoir with total organic carbon content  > 4%, porosity >6%, gas content >6 m3 / T, brittleness index  > 60% and comprehensive evaluation factor > 0.85. The evaluation standard has good application effect in subsequent wells G36 and FT1.