Optimization Of Development Parameters For Horizontal Wells Multi-Stage Fracturing In Tight Oil Reservoir In Jiyang Depression,Bohai Bay Basin

Tight oil is a kind of unconventional resource with huge potential,which is called "black gold".Its reasonable and efficient development is of great significance to the protection of China's energy security.It is the focus of China's development.Due to the poor physical properties of tight oil reservoirs in China,with low porosity and low permeability,strong heterogeneity and other geological characteristics,the development of tight oil requires the use of fracturing methods.The horizontal well staged fracturing technology is the main technology used in the production of tight oil.It is the most effective technology at present.Therefore,the optimization of multi-stage fracturing technology for horizontal wells is of great significance for the rational exploitation of tight oil,the improvement of tight oil production,recovery and economic benefits.In this paper,the tight oil reservoir in Jiyang depression of Bohai Bay basin is studied and summarized from the aspects of regional geological structure,development characteristics of sand body,reservoir physical properties,clay minerals and so on.On this basis,the model structure including the model selection,grid selection which can best represent the production performance of the reservoir is considered.According to the rock characteristics and fluid properties of Jiyang depression in Bohai Bay Basin,combining with the type of development well pattern,well spacing and injection-production relationship,the well layout scheme is designed.Then,based on the actual block conceptual model,the fracturing parameters and development methods were changed and a variety of numerical simulation schemes were set up,and the development effect of every scheme was obtained.Finally,based on the development effects of various reservoir numerical simulation schemes,the fracture parameters and development parameters are combined with different well patterns,and the development effect of each combination is compared and analyzed to optimize the optimal fracture parameters and development parameters under the optimal well pattern for the block.The following work has been completed:(1)Through the investigation of relevant literature at home and abroad,combined with the actual survey and development data,the geological characteristics,development characteristics of sand body and reservoir physical properties of the block have been studied,and the reservoir characteristics and development dynamic characteristics of the block have been summarized.(2)Starting from the selection of model,grid system and preparation of numerical simulation data,the model structure which can best represent the production performance of reservoir is optimized,and the conceptual model of typical block in Jiyang depression of Bohai Bay basin is established.(3)Several groups of numerical simulation schemes are set up,and the numerical simulation under different fracturing parameters(length of horizontal section,fracture length,penetration ratio,etc.)and development modes(oil recovery rate,injection-production ratio,water injection mode,etc.)are carried out,and the development effect of each scheme is tested.(4)Combined fracture parameters and production parameters with different well patterns,the development effects of different combinations analyzed,and the optimal fracture parameters and development parameters are optimized under the optimal well pattern for the block.The work of this paper is of great significance to guide the adjustment of multi-stage fracturing parameters of horizontal wells and injection-production mode on-site of tight oil in Jiyang depression,Bohai Bay basin.