Spacing optimation technology for deep shale gas horizontal wells based on big data analysis: A case study of Well Block Yang 101 in the Luzhou Region, South Sichuan Basin

There are abundant deep shale gas resources and their development prospect is promising. Reasonable horizontal well spacing can maximize single well productivity while producing inter-well reserves sufficiently. When field test and numerical simulation of deep shale gas is used for well spacing optimization, the investment and time cost are high, the error is large, and the productivity prediction and evaluation results are not representative enough. In order to solve these problems, this paper takes Well Block Yang 101 of the Luzhou Region in South Sichuan Basin as an example to determine the range of hydraulic fracture parameters with probability statistical significance under the conditions of geological engineering and fracturing technology, based on the three-dimensional geological model with different natural fractures, combined with numerical simulation and big data analysis. In addition, the stochastic productivity prediction under different fracture parameter combinations and different well spacing conditions is carried out. Finally, the range of the most representative reasonable well spacing is determined by considering single well productivity, platform recovery factor and economic benefit comprehensively. And the following research results are obtained. First, the well spacing optimization technology based on numerical simulation and big data analysis can better solve the influence of diverse natural fracture characteristics and uncertain fracturing network parameters on well spacing. Second, in the area with network fractures, inter-well interference is less, so well spacing can be reduced appropriately to improve the producing degree of inter-well reserves, and the well spacing of technical and economic integration can be designed at 300–350 m. Third, in the area with single direction fracture, the well spacing can be increased appropriately to ensure single well productivity, and the well spacing of technical and economic integration can be designed at 350–400 m. In conclusion, the reasonable well spacing optimization based on big data is an important trend of big data empowerment in the future shale gas development. The new technology is well applied to the practical shale gas development in Well Block Yang 101, which provides a useful reference for the large-scale benefit development of deep shale gas. © 2022 Natural Gas Industry Journal Agency. All rights reserved.