Research On Well Pattern And Spacing Optimization Of Chang-7 Tight Reservoir

The Ordos Basin is rich in tight sandstone oil resources,which is an important guarantee for the sustainable development of Changqing Oilfield.The Chang 7 tight sandstone reservoir has poor physical properties,extremely low permeability,poor connectivity,and is difficult to develop.At present,fractured horizontal wells are generally used for development and production.The productivity of fractured horizontal wells is affected by the length of horizontal wells and the spacing of horizontal wells.,Fracture parameters and many other factors.Aiming at the special physical properties of Chang 7 tight oil reservoirs,based on the theory of nonlinear seepage mechanics,this paper establishes a tight oil reservoir compound trilinear seepage mathematical model,solves and calculates the model,and analyzes the impact of geological and engineering factors on tight oil reservoir fracturing horizontal wells.The influence law of production capacity is analyzed by single factor using numerical simulation method,and the optimal value interval of each factor is obtained.The optimal development plan parameters are obtained through the designed orthogonal test plan,which provides a theory for the development of Chang 7 tight oil.Basis and guidance.The main achievements of this paper are as follows:(1)The seepage flow of a fractured horizontal well in a tight oil reservoir is mainly divided into the following four stages,namely the fracturing zone and the early bilinear flow stage in the fracture zone,the early linear flow stage in the fracturing zone,and the matrix zone.The mid-term linear flow stage of the formation and the late pseudo-steady-state stage affected by the outer boundary of the reservoir.(2)The start-up pressure gradient of tight oil reservoirs mainly affects the production in the mid-term linear flow stage.The larger the start-up pressure gradient,the faster the production decline;the fracture conductivity mainly affects the production in the early bilinear flow stage,within a certain range The greater the fracture conductivity,the greater the early production;the fracture spacing mainly affects the production in the mid-term linear flow stage.The smaller the fracture spacing,the stronger the inter-fracture interference and the faster the production decline.(3)The numerical simulation results of the H6 platform show that the optimal fracture conductivity range of the H6 platform is 2D·cm?4D·cm,the optimal fracture spacing range is 50m?100m,and the optimal fracture length range is 150? 200 m,the optimal length of the horizontal well section is about 1500 m,and the optimal cloth seam method is zipper cloth seam.(4)Orthogonal design test results show that the importance sequence of factors affecting the production of fractured horizontal wells in the Chang 7 tight sandstone reservoir on the H6 platform is: horizontal section length> fracture half-length> fracture spacing>fracture conductivity.The optimal development plan parameters of the H6 platform are: the horizontal section length is 1600 m,the fracture length is 200 m,the fracture spacing is 50 m,and the fracture conductivity is 3Dcm.The recommended horizontal well spacing is about 300m.