The Open Petroleum Engineering Journal
2017, 10 : 134-142Published online 2017 May 26. DOI: 10.2174/1874834101710010134
Publisher ID: TOPEJ-10-134
RESEARCH ARTICLE
Calcareous Interlayer Causes and Logging Identification for the Shawan Formation of the Chunfeng Oilfield
* Address correspondence to this author at the School of Geosciences, China University of Petroleum, No.66 Changjiang West Road, Huangdao District, Qingdao, Shandong 266580, P.R. China, Tel: 8618678679199; E-mails: , houqingjie87@163.com
ABSTRACT
Background:
Many sets of calcareous interlayers are present in the Shawan Formation in the Chunfeng oilfield, which leads to scattered residual oil that is difficult to extract.
Objective:
Observations of core samples and thin sections, analyses of trace element compositions and interpretations of logging data were used to identify the calcareous interlayers and identify their possible origin.
Method:
First, the petrologic characteristics of the calcareous interlayers were identified; then, we developed a quantitative function for identifying the calcareous interlayers based on well log data. Finally, the possible origin of these calcareous interlayers was identified based on these findings.
Conclusion:
The results show that the quantitative function has a high accuracy of 91.8% and average uranium content of calcareous interlayers can reach as high as 27×10-6, indicating that the quantitative identification function provided accurate identification of the calcareous interlayers, and highly radioactive uranium is one explanation for the origin of the calcium cementation.