川东北元坝地区长兴组生物礁的识别

Identification of reef reservoir of Changxing formation in Yuanba area of Northeastern Sichuan Basin

(中国石油化工股份有限公司勘探南方分公司研究院,四川成都610041)

Southern Exploration Branch Company,SINOPEC,Chengdu 610041,China

Reef-flat reservoirs are developed in Changxing formation of Yuanba area.With this sedimentary background,some reef-lat seismic abnormal bodies have been discovered here.Commercial gas flow was obtained by gas testing in the wells encountered the reef reservoirs.The Changxing grouop is deep buried and its seismic data is with low resolution,which leads to the difficulty in reef reservoir prediction.Aiming at the problem,some methods were integrated to identify the reef in Yuanba area.Firstly,based on forward modeling results and well-tie seismic sections,the seismic response patterns of reef were concluded.Then,based on 3-D seismic data,the sedimentary facies of Changxing telophase was identified.Finally,based on 3-D seismic data volume,waveform classification recovery technique,frequency-division processing,coherent cube recognition technique and paleo-geomorphology technique were used to describe the plane distribution of reef in Changxing formation.The method has good effect,and well describes the shape and distribution characteristics of reef in Changxing formation.