The Fan 147 Thin Alternating Layers Of Low Permeability Reservoirs And Fractured Horizontal Wells In The Seepage Law And Well Optimization Study

The low permeability and thin interbed reservoir is an important component of energy resources in china, which has characteristics, such as the large number of vertical layers, the thin thickness, and the wide plane distribution, etc. This kind of reservoir generally has many problems, such as the low recovery, the obsolescent natural fracture, and the less chance of drilling fractures for horizontal well, etc. Hence, adopting the conventional horizontal well usually can not achieve the anticipated development effect. In order to expand the well drainage area and develop the potential reserves of upper and lower thin bed to realize effective development of low permeability and thin interbed reservoir, it is necessary to selectively fracture the horizontal well to produce vertical multi-fracture, which will improve the well controlled drainage volume and increase well deliverability. Therefore, study on the filtration law and well pattern optimization procedure of hydraulically fractured horizontal wells has extremely significance to increase the production rate and recovery of reservoir and improve the development effect, etc.Taking the thin interbed and low permeability reservoir-Fan 147 as the object and addressing these problems during this reservoir development period, this paper performs a study on the filtration law and well pattern optimization procedure of hydraulically fractured horizontal wells, from the reservoir characteristics, the flow characteristics of well, and the combined well pattern design of hydraulically fractured horizontal wells and vertical wells, forming adaptable development mode of fractured horizontal wells in the thin interbed and low permeability sandstone reservoir and acquiring the following research achievement:(1)According to various static geological test data and the dynamic data of well test and production test provided by oilfield, the geologic model is established, and the geologic characteristic of Fan 147 reservoir is further understood.(2)Using the filtration theory, the unstable seepage flow mathematical model for hydraulically fractured horizontal well is built and solved, and dynamic feature of seepage pressure is analyzed.(3)Using the equivalent well radius model of fracture, the deliverability prediction equation of multiple fractured horizontal well is obtained, and the influence on deliverability of fracture number, length and flow conductivity to well production is discussed.(4)Using the numerical simulation method, the certain typical geologic model consistent with the true geologic features is established. And then, research on optimization of horizontal wellbore trajectory for single well model and actual well pattern model is performed on the basis of this practical model; and based on ideal model, study on optimization of the well pattern of different kinds of fractured horizontal well is done. So the suitable development pattern of thin interbed and low permeability reservoir is gained.(5)Using the numerical simulation and combining with the ideal model and the practical model, the reasonable development index, which is suitable for the combined well pattern of hydraulically fractured horizontal wells and vertical wells for thin interbed and low permeability reservoir is studied.