Abstract
The old well sidetracking technology is an effective means to stabilize production and increase recovery in later stage of gas field development. Based on economical and reservoir geologic parameters of Sulige low-permeability gas field in China, method and procedure of old well sidetracking selection standards are established, which can effectively improve the sidetracking effect and adequately develop remaining gas. Comprehensively considering corresponding economic parameters including sidetracking drilling cost, operating cost, management cost, gas production rate and gas price, recoverable reserve standard of sidetracking well is determined first. According to gas recovery, gas-bearing area, porosity and gas saturation, standards of remaining geological reserve, reserve abundance and gas pay thickness of sidetracking well are obtained. According to extension direction and distribution characteristics of the sand body in research area, numerical simulation conceptual model of typical sidetracking horizontal well is established, and then standards of old gas well production rate and gas cumulative production rate for sidetracking are obtained. According to the standards, well Su 36-6-9CH is selected to be sidetracked as a horizontal well and its development effect is good. The method has important value of popularization and application in similar low-permeability gas reservoir.
Highlights
Geological characteristics and distribution law of sand body in low-permeability gas reservoir are very complex (Hu et al 2015)
When cumulative production rate of the old well is smaller than 1570 × 104 m3, sidetracking well cumulative production rate is bigger than 1770 × 104 m3, which can meet the standard of the minimum recoverable reserve for sidetracking well
Based on economical and reservoir geologic parameters of Sulige low-permeability gas field in China, method and procedure of old well sidetracking selection standards are established, which provides a theoretical basis for quan
Summary
Geological characteristics and distribution law of sand body in low-permeability gas reservoir are very complex (Hu et al 2015). The influences of reservoir geological conditions on sidetracking well trajectory are rarely considered in these studies (Khosravanian et al 2018; Manshad et al 2019). Reservoir distribution and resource condition are the bases of sidetracking well location design and optimization, especially in low-permeability oil/gas field where the reservoir is discontinuous. The old wells which are close to the limit of shutin with low production and low efficiency, and those abandoned wells without production, can all be used to sidetrack horizontal well, develop the remaining reserve, increase the production rate of gas wells and increase the recovery factor. Based on economical and reservoir geologic parameters of Sulige low-permeability gas field, old well sidetracking selection standards are established, which provides a theoretical basis for efficient development of low permeability or tight sandstone gas reservoir in Sulige and other similar gas field
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