Open Access

ARTICLE

Reservoir Characteristics and Production Performance of Shale Oil in the MX Block, the Fengcheng Formation, Mahu Sag, China

Lin Chen¹, Anqi Zhao², Yunpei Zhang¹, Sai-Mi-La XiaFuKaiTi¹, Yao Qin¹, Chuan Wang¹, Gang Chen², Jiqiang Li², Shilai Hu^2,*
1 PetroChina Xinjiang Oilfield Company, Karamay, 834000, China
2 School of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China
* Corresponding Author: Shilai Hu. Email:
(This article belongs to the Special Issue: Progress and Prospects of Hydraulic Fracture Network Morphology Characterization, Flow Simulation and Optimization Technology for Unconventional Oil and Gas Reservoirs)

Energy Engineering https://doi.org/10.32604/ee.2025.075878

Received 10 November 2025; Accepted 19 December 2025; Published online 06 January 2026

Abstract

The shale oil resources in the Permian Fengcheng Formation of the Mahu Sag exhibit significant potential but are characterized by strong heterogeneity and complex production dynamics, posing challenges for development. This study conducts a comprehensive analysis of the reservoir characteristics and production performance of the shale oil reservoir in the second member of the Fengcheng Formation within the MX Block. Utilizing data from three appraisal wells (M1X, M2X, M3H), we systematically evaluated the geological structural features, sedimentary characteristics, complex mineralogy, and petrophysical properties of the reservoir. The production dynamics of all wells display a multi-stage decline behavior, indicative of a dual-control flow mechanism dominated by both fracture networks and matrix supply. Based on wellhead pressure and production data, the production lifecycle can be divided into three distinct stages, with the final stage governing the long-term production potential and Estimated Ultimate Recovery (EUR). To address the challenge of predicting EUR in such multi-stage production, integrate Blasingame type-curve analysis to identify the start of the boundary-dominated flow regime and employ a hyperbolic decline model fitted via the Levenberg-Marquardt algorithm for forecasting. The EURs of the three appraisal wells were successfully predicted, all exceeding 40,000 t, confirming the commercial viability of the reservoir. The findings highlight the critical roles of optimized fracturing design, appropriate well type selection, and controlled initial production rates in enhancing recovery. This research provides a robust technical framework for evaluating development potential and formulating effective development strategies for similar shale oil reservoirs.

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Keywords

Shale oil; reservoir characteristics; production performance; decline curve analysis; estimated ultimate recovery; Fengcheng Formation

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