Life-cycle optimization of shale oil extraction and drainage system

As global energy demand grows, oil and gas exploration moves into unconventional fields, with shale oil key. Shale reservoirs are tight, have low productivity and recovery, and are developed by horizontal wells and hydraulic fracturing. However, production drops fast, and stable periods are short. New strategies based on seepage and life-cycle stages are needed to enhance oil recovery, optimize the mining effect, and extend the economic life of the oil well. This study, based on the full-life-cycle concept, presents an optimized extraction and drainage strategy for shale oil. First, a mathematical model of seepage for vertical wells in shale oil reservoirs was established to study the seepage laws in different development stages and to analyze the impacts of key parameters such as bottom-hole pressure, fracture conductivity, and permeability on the production of oil wells. Second, a three-stage division method for the full-life cycle of shale oil was proposed, namely, the unstable production stage, the pseudo-steady production stage, and the depletion production stage. The pressure and pressure-derivative curves were used to verify the rationality of this division method. Finally, reasonable production systems and development strategies were formulated for different life-cycle stages. The research results show that this method can significantly extend the economic production cycle of shale oil wells, effectively enhance the crude oil recovery rate, and provide a scientific theoretical basis and an innovative methodological path for promoting the efficient and sustainable development of shale oil reservoirs.