XIANG W, WANG X F, CUI W P ,et al.Identification of ichnofabrics and their geological significance based on core and electrical imaging logging[J].Journal of Henan Polytechnic University(Natural Science) ,2024,43(6):69-81.

Received:2023/10/27

Revised:2024/02/05

Online:2024-09-24

Identification of ichnofabrics and their geological significance based on core and

electrical imaging logging

XIANG Wei1,2, WANG Xiaofei1,2, CUI Weiping1,2, NIU Yongbin3, WANG Shiyue4, TANG Di4, LI Pingjiu1,2, CHENG Yigao3, SHAO Weimeng3

1.China Offshore Oilfield Services Limited，Yanjiao  065201，Hebei，China；2.Key Laboratory of Deep Sea Deep Formation Energy Engineering of Hainan Province，Chengmai  570100，Hainan，China；3.School of Resources and Environment，Henan Polytechnic University，Jiaozuo  454000，Henan，China；4.Hainan Branch of CNOOC Ltd.，Haikou  570100，Hainan，China

Abstract: Objectives In order to ascertain the development characteristics of ichnofabric of Sanya Formation in Songtao Uplift in Qiongdongnan Basin，and to explore the hydrocarbon geological significance of these ichnofabrics， Methods on the basis of detailed observation and description of the development characteristics of trace fossils and host sediments on the core of representative coring wells，ichnofabrics were identified.By calibrating the depth of the core and electrical imaging logging，the calibration of electrical imaging log images with core was achieved.Then，the response characteristics of ichonfabrics to electrical imaging logging were carefully analyzed，and reference image templates for the identification of ichnofabrics using electrical imaging log were established.  Results （1）Five kinds of ichnofabrics were identified on the core and electrical imaging log images of the study area： Phycosiphon-Chondrites ichnofabric， Phycosiphon-Planolites  ichnofabric， Planolites-Thalassionides  ichnofabric,Palaeophycus  ichnofabric and Ophiomorpha-Thalassionides  ichnofabric.By synthesizing the sedimentological and ichnological properties of 5 types of ichnofabrics，their sedimentary environment formed was interpreted.（2）According to the comparison between the ichnofabrics identified from the cores and the electrical imaging images of 112 horizons in 9 wells in Qiongdongnan Basin，104 horizons were completely consistent，and the identification accuracy could reach 92.9%，while 8 horizons were inconsistent due to poor electrical imaging quality.It was reliable and effective to identify ichnofabrics of Sanya Formation in Songtao Uplift of Qiongdongnan Basin based on core and electrical imaging logging images. Conclusions This study was of great significance for analyzing the depositional environment and predicting the distribution pattern of reservoirs in the study area，revealing the modifying effect of ichnofabric on hydrocarbon reservoirs，and promoting increased hydrocarbon storage and production，as well as enhancing recovery in the study area.

Key words:core;electrical imaging log;ichnofabric;Sanya Formation;Qiongdongnan Basin