关键词: 致密砂岩气藏, 辫状河沉积体系, 储渗单元, 叠置模式, 开发井型, 采收率

Abstract: Detailed investigation of reservoir characterization and architecture is the main technique requirements for the development
of tight sandstone gas reservoir in the middle-to-later stage. Based on the similarities of porosity and permeability for different types of
sand bodies, channel-filling and channel bar of braided river sedimentary system were classified into the same reservoir permeability
unit. Concept and methodology of such permeability units were put forward and the developmental model in the unit was studied.
Through outcrop observation and analysis of logging facies, four superimposed patterns within the unit were identified, including
channel bar superposition, channel filling superposition, bar and channel filling superposition, and bar or channel filling isolated types.
Based on developmental patterns of the units, well types suitable for the development of tight sandstone gas reservoirs were proposed.
Channel superimposed belts in braided river sedimentary system are favorable for the development of superimposed permeability units
and horizontal drilling. The transition and depression zones of braided river sedimentary system are favorable for the development of
isolated permeability units and vertical or cluster wells. Case studies in the Low Permian Shihezi outcrops of the Ordos Basin and
interference well tests in the pilot infill areas of the Sulige gas field show that permeability units of braided river sedimentary system
have a length of 600 m along the paleocurrent and width of 400 m perpendicular to the flow direction. This implies that the well pattern