Abstract: The carbonate reservoirs in the 4^th member of Penglai gas field in the Sichuan Basin represent one of the key targets of China’s onshore oil reserve expansion and production enhancement during China’s 14^th Five-Year Plan period. Characterized by ancient age, deep burial, and strong heterogeneity, their spatial distribution remains challenging to predict. Focusing on the geological, drilling, logging and seismic characteristics of db1 block within the gas field, this study establishes a well-seismic integrated classification and prediction technology for deep carbonate reservoirs. The approach aims to (1) analyze reservoir formation characteristics and distribution patterns, (2) implement inversion and prediction of heterogeneous reservoir distribution, and (3) delineate the spatial heterogeneity of reservoirs. The results indicate:(1) Reservoirs in the Penglai Gas Field are concentrated in the upper sub-member of 4th Member of the Dengying Formation, exhibiting three architectural models: (i) dual upper and lower reservoirs, (ii) locally distributed upper reservoirs with well-developed lower reservoirs, and (iii) a single developed reservoir. (2) “Good” and “Medium” reservoirs in the study area are thin and sporadically distributed, while “Bad” reservoirs exhibit greater thickness and better vertical-lateral continuity, primarily distributed near wells ps106, db1, ps11, and adjacent regions. (3) The successful classification and distribution prediction of deep carbonate reservoirs in this area, not only validate the applicability and reliability of the proposed technology, but also provide valuable references for reservoir prediction in the Penglai Gas Field and analogous fields.

Key words: Penglai gas field, deep carbonate reservoirs, reservoirs prediction, well-seismic integrated prediction, reservoir heterogeneity distribution