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), doi: 10.16186/j.cnki.1673-9787. 2023100059

Received：2023-10-27

Revised：2024-02-05

Online：2024-04-19

Identification of ichnofabrics and their geological significance based on core and electrical imaging

 logging（Online）

XIANG Wei^1,2，WANG Xiaofei^1,2, CUI Weiping^1,2, NIU Yongbin³, WANG Shiyue⁴, TANG Di⁴, LI Pingjiu^1,2, 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. College of Resource & Environment, Henan Polytechnic University, Jiaozuo 454000，Henan，China; 4. Hainan Branch of Cnooc (China) Limited，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 geolocical 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 ichnfabrics 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 ichnofabric were identified on the core and electrical imaging log images of the study area: Ophiomorpha-Thalassionides ichnofabric, Palaeophycus ichnofabric, Planolites-Thalassionides ichnofabric, Phycosiphon-Planolites ichnofabric and Phycosiphon-Chondrites ichnofabric. By synthesizing the sedimentological and ichnological properties of 5 kinds of ichnofabrics, their sedimentary environment formed is 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 are completely consistent, and the identification accuracy can reach 92.9%, while 8 horizons are inconsistent due to poor electrical imaging quality. Conclusions It is reliable and effective to identify ichnofabrics of Sanya Formation in Songtao Uplift of Qiongdongnan Basin based on core and electrical imaging logging images. This study is 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

CLC：P531