Prediction and evaluation method for development effect of shale oil storage volume fracturing

Energy storage volume fracturing is a pivotal early development technique for shale reservoirs, designed to supplement reservoir energy preemptively and significantly boost single well production. A method for predicting the maximum cumulative oil production during the development stage of energy storage fracturing is proposed, based on the mechanisms of imbibition and displacement coupled with the statistical analysis of actual production data. The results demonstrate that following a 30% flowback ratio, the cumulative oil production from energy storage fracturing exhibits a strong linear relationship with the logarithm of the flowback ratio. This relationship can predict the maximum cumulative oil production of a single well after fracturing. Validated by actual production data from other shale reservoirs, this method proves to be more accurate and universal than the decline curve analysis method. It encompasses a comprehensive evaluation of subjective and objective factors such as reservoir conditions, fracturing scale and technology, production system design, and drainage efficiency. Additionally, the method facilitates the determination of the liquid-to-oil ratio and the reasonable flowback rate. By controlling the average rate of discharge and production within the range of 6~8 m3/（d·km）, which aligns with the rates of oil drainage and imbibition, higher oil recovery and a lower liquid-to-oil ratio are achieved. This prediction method for maximum recoverable oil post-single well fracturing provides a basis for the economic benefit evaluation, production system optimization, and fracturing cost control of energy storage fracturing. It holds significant guiding importance for geological-engineering integration, well spacing optimization, and fracturing design.