Continental mixed shale oil reservoirs are characterized by strong lithological heterogeneity, complex reservoir architecture, and highly variable hydraulic fracture propagation, making it difficult to simultaneously maximize hydrocarbon recovery and economic performance. Existing optimization methods generally emphasize either production enhancement or economic evaluation, while lacking an integrated framework that quantitatively couples geological characterization, hydraulic fracturing design, production forecasting, and techno-economic optimization. To address this limitation, this study proposes a geology–engineering integrated workflow based on EUR–IRR response-surface co-optimization. Geological and engineering sweet spots were first identified through integrated core observations, well-log interpretation, and mineralogical analyses. A three-dimensional hydraulic fracture propagation model was subsequently established and calibrated using field production data to optimize key fracturing parameters, including cluster number, pumping rate, fluid intensity, and proppant intensity. Based on the optimized fracturing design, a series of development scenarios with different lateral lengths and well spacings were evaluated. The corresponding 15-year project-level estimated ultimate recovery (EUR) and internal rate of return (IRR) were quantitatively coupled through interpolation-based response-surface modeling, enabling identification of the optimal development window under the economic constraint of IRR ≥ 6%. The results indicate that the maximum EUR (7.215 × 105 m3) is achieved with a 5000 m lateral length and a 50 m well spacing; however, the corresponding IRR is only 5.8%, indicating that maximizing production alone does not ensure economic viability. The recommended development scheme consists of a 3500 m lateral length and a 150 m well spacing, yielding a 15-year project EUR of 4.238 × 105 m3 and an IRR of 12.5%, representing the optimal balance between production efficiency and economic return. Sensitivity analysis under ±10% oil price fluctuations further demonstrates the robustness of the optimized development strategy. The proposed workflow establishes a quantitative framework that integrates geological characterization, hydraulic fracture simulation, production prediction, and techno-economic evaluation. It provides an effective decision-support methodology for fracturing design and well pattern optimization in highly heterogeneous continental mixed shale oil reservoirs and can be readily extended to similar unconventional reservoirs.
Liu et al. (Wed,) studied this question.