Shale Fracturability Graphic Template Based on Mixed Analytic Hierar-chy Process and Mutation Theory

Abstract

Due to the depletion of conventional energy reserves, there has been a global shift towards non-conventional energy sources. Shale oil and gas have emerged as key alternatives. These resources have dense and heterogeneous reservoirs, which require hydraulic fracturing to extract. This process depends on identifying optimal fracturing layers, also known as 'sweet spots' . However, there is currently no uniform standard for locating these sweet spots. This paper presents a new model for evaluating fracturability that aims to address the current gap in the field. The model utilizes a hierarchical analysis approach and a mutation model, and is distinct in its use of original logging data to generate a fracturability evaluation map. Using this paper's shale fracturing sweet spot evaluation method based on a two-step mutation model, four wells in different blocks of Fuling and Nanchuan Districts in China were validated, and the results showed that the proportion of high-yielding wells on the sweet spot line could reach 97.6%, while the proportion of low-producing wells was only 78.67%. Meanwhile, the evaluation results of the model were compared with the microseismic data, and the matching results were consistent.