Study on the Definition Principle of Reasonable Well Spacing in Tight Sandstone Gas Reservoirs

Abstract

The reasonable well spacing of tight sandstone gas reservoir not only affects the production effect of a single well, but also directly determines the reserve utilization and economic benefit of the whole gas reservoir. At present, the rational well spacing of tight sandstone gas reservoirs is determined by multiple methods. There are many calculation methods of well spacing and the calculation results are very different, and there is no definite definition principle of reasonable well spacing, the definition of reasonable well spacing obtained by comprehensive method is fuzzy and artificial. In order to standardize the calculation and effective definition of reasonable well spacing for tight sandstone gas reservoirs, this paper puts forward the definition principle of reasonable well spacing for tight sandstone gas reservoirs on the basis of in-depth investigation and classification of well spacing calculation methods, and takes Shan2 gas reservoir of Zizhou gas field as an example to evaluate reasonable well spacing. The main conclusion is that: ①The calculation methods of well spacing in tight sandstone gas reservoirs can be divided into three categories: the method based on economic benefit, the method based on production response and the method based on production demand. Based on the method of economic benefit, the economic well spacing is determined from the balance between cost and income. Based on the production response method, the technical well spacing is determined from the perspective of effectively avoiding the waste of reserves and inter-well interference. Based on the method of production demand, the proposed well spacing is determined from the reasonable production rate scheme of gas field. ②The study of reasonable well spacing in tight sandstone gas reservoirs should focus on economic well spacing and technical well spacing, and the study of scheme well spacing is not necessary; The reasonable well spacing of gas reservoir should meet the principle of "economy and technology", both of which are indispensable.③The economic well spacing of Shan2 gas reservoir in Zizhou Gas field is 816m, the technical well spacing is 1097m, and the reasonable well spacing is 1097m; At present, the well spacing of gas reservoir is 1965m, and the well pattern is not perfect. In order to avoid the waste of reserves and interference between Wells and improve the recovery rate of gas reservoir, it is recommended to adjust the well pattern according to the 1097m well spacing in subsequent development. The research results can provide reference for the calculation and effective definition of reasonable well spacing in standard tight sandstone gas reservoirs.