Calcareous Interlayer Causes and Logging Identification for the Shawan Formation of the Chunfeng Oilfield
Qingjie Hou1, *, Qiang Jin1, Weizhong Li2, Lamei Lin1, Wenmin Jiang3, Wenjie Han2
Identifiers and Pagination:Year: 2017
First Page: 134
Last Page: 142
Publisher Id: TOPEJ-10-134
Article History:Received Date: 01/06/2016
Revision Received Date: 06/12/2016
Acceptance Date: 16/01/2017
Electronic publication date: 26/05/2017
Collection year: 2017
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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.
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.
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.
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.