Predicting economic benefit of deep shale gas fracturing prediction based on comprehensive fracability

Hydraulic fracturing is a key technology to develop deep shale gas reservoirs economically and efficiently. However, the comprehensive fracability evaluation method for middle-shallow shale is not suitable for deep shale gas reservoirs with complex reservoir structure, difficult sweet spot identification and poor geological conditions. In addition, the construction, fracturing and other engineering of deep shale gas well has high cost, and its production test rate is low, leading to sharp contradictions of economic development. In this paper, the factors influencing shale gas production rate were determined by researching the influence laws of different geological engineering parameters on shale gas production rate of horizontal well. A fracturing economic benefit prediction method based on geology-engineering comprehensive fracability was established by integrating five major characteristics of shale reservoir according to the catastrophe theory, i.e., geology, fracture network development degree, rock matrix, fluid consumption and construction parameter. The interference of subjective factors was decreased by using the complementary criterion, and the economic benefit prediction model was established based on the evaluation classification of fracability model. Finally, the reliability of the model was verified by taking Well DS2 of X Block as an example, combined with the production rate of well test. It is shown that this model can objectively evaluate shale gas development and predict engineering economic benefit. The case calculation results indicate that the fracturing economic benefit prediction method can be used to predict economic return cycle, net present value and internal rate of return, and can improve the economic prediction results by optimizing and adjusting engineering parameters. The research is of important guiding significance and field application value for preparing field production plan and improving fracability evaluation prediction and benefit prediction of deep shale gas, so as to achieve the goal of “cost reduction and efficiency improvement”.