Differentiation and Prediction of Shale Gas Production in Horizontal Wells: A Case Study of the Weiyuan Shale Gas Field, China

• Published in: Energies (Basel) Vol. 15; no. 17; p. 6161
• Main Authors: Kang, Lixia, Guo, Wei, Zhang, Xiaowei, Liu, Yuyang, Shao, Zhaoyuan
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.09.2022
• Subjects: Case studies; Correlation analysis; Differentiation; estimated ultimate recovery; Gas fields; Gas industry; Gas production; Gas wells; Geology; grey correlation method; Horizontal wells; main control factor; Methods; multiple linear regression; Natural gas; Natural gas exploration; Oil and gas fields; Oil and gas production; Predictions; Production capacity; Production data; production evaluation; Shale; Shale gas; Shale oils; Silurian; System theory; China; Sichuan Basin
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en15176161

The estimated ultimate recovery (EUR) of shale gas is an important index for evaluating the production capacity of horizontal wells. The Weiyuan shale gas field has wells with considerable EUR differentiation, which hinders the prediction of the production capacity of new wells. Accordingly, 121 wells with highly differentiated production are used for analysis. First, the main control factors of well production are identified via single-factor and multi-factor analyses, with the EUR set as the production capacity index. Subsequently, the key factors are selected to perform the multiple linear regression of EUR, accompanied by the developed method for well production prediction. The thickness and drilled length of Long 111 (Substratum 1 of Long 1 submember, Lower Silurian Longmaxi Formation) are demonstrated to have the uttermost effects on the well production, while several other factors also play important roles, including the fractured horizontal wellbore length, gas saturation, brittle mineral content, fracturing stage quantity, and proppant injection intensity. The multiple linear regression method can help accurately predict EUR, with errors of no more than 10%, in wells that have smooth production curves and are free of artificial interference, such as casing deformation, frac hit, and sudden change in production schemes. The results of this study are expected to provide certain guiding significances for shale gas development.