Volume 56

Evaluation of CO2 Sealing Effectiveness in Balixi Buried Mountain of Huabei Oilfield Sun Honghua, Zhang Mingyang, Fan Wei, Guo Sujie, Zhang Wenping

Abstract

Carbon Capture, Utilization, and Storage is a greenhouse gas emission reduction . To achieve a win-win target of improving oil recovery and carbon sequestration through gas injection, Huabei Oilfield has conducted carbon dioxide-enhanced oil recovery and carbon sequestration pilot tests in the Balixi Buried Mountain Oil Reservoir. With a increase in gas injection wells, CO2 was detected in Dongying Formation and Shahejie Formation of the upper strata of the buried mountain in new drilled wells. A carbon isotope investigation was conducted on those wells to further clarify the source of CO2 and evaluate the effectiveness of the buried mountain closure,. Based on this investigation, an novel method evaluating the CO2 storage and injection capacities of the heterogeneous carbonate reservoirs in Balixi Buried Mountain was established. A total of 4000 sampling points of 3 wells are used to establish the new model. From the results, it was clarified that the isotope in the active sections of CO2 gas measurement is lighter in the Dongying Formation of Balixi Buried Mountain. Meanwhile, the composition in those sections is dry, showing the characteristics of mainly biogenic gas. In contrast, the carbon isotope of the active sections of CO2 gas measurement is heavier in the Shahejie Formation had a heavier carbon isotope weight and higher Meanwhile, the composition in those sections is humidity, showing the characteristics of thermogenic gas. Therefore, CO2 in the Dongying Formation and Shahejie Formation of the upper strata of Balixi Buried Mountain is self-generated in the strata, further confirming the effective closure of the buried mountain.

Keywords CCUS, Balixi Buried Mountain, Carbon Isotope Technology, Effectiveness