Horizontal Oil Wells Flow Field Characteristics Of Injection And Production Systems And Well Network Optimization

Offshore oil fields usually use horizontal wells for the high&stable yield, and formed with horizontal-vertical, horizontal-horizontal injection-production systems. Identify the seepage characteristics and development law of horizontal well injection-production system, has an important guiding significance to the optimization of horizontal well injection-production system.As an example of M oilfield in the Bohai Sea, thesis mainly has carried out the following research work and obtained the corresponding results:(1) Based on the main characteristics of M oilfield, thesis summarized the development experience, and analyzed the feasibility of using horizontal well. Shows that M oilfield using horizontal well development advantage is obvious.(2) Using numerical simulation, studied the differences between horizontal and vertical injection-production system in water cut-recovery degree curve, stable time and areal sweep efficiency. Demonstrated the advantage and rationality of using horizontal well in M oilfield.(3) In M oilfield typical injection-production system, use conformal transformation and potential superposition principle, analyzed the four injection-production patterns of potential field, pressure gradient field and dimensionless production change rule. Shows that horizontal well can effectively improve Seepage environment.(4) Using percolation mechanics theory and streamline simulation method, studied the water drive front characteristics, obtained the mainstream line equation of horizontal well system with one injection-two productions. Through different injection-production system of potential field and dimensionless production research, set up different injection-production system water breakthrough time analysis method, obtained water breakthrough time chart of different dimensionless longitudinal distance. Shows that horizontal wells one injection-one production model has the longest Water breakthrough time.(5) Based on the average reservoir parameters of M oilfield, studied the changing of the water cut&sweep area efficiency under different injection-production system, oil-water viscosity ratio, obtain the corresponding regression equations and change charts.Shows that horizontal wells one injection-one production model has the biggest sweep area efficiency.(6) Based on the research results, analyzed the main characteristics of different injection-production system in the dimensionless yield, water breakthrough time, water cut and areal sweep efficiency, etc.(7) Adopt the methods of reservoir engineering and numerical simulation, studied the production well’s reasonable bottom-hole flowing pressure, the injection well’s maximum injection pressure, economic limit water cut and reasonable injection-production ratio, etc. On the basis of history matching, studied the well pattern optimization adjustment in typical area of low degree reserves control. Shows that the best model is two horizontal wells production one vertical Well injection, and horizontal wells shot upper, injection well shot the bottom of the reservoir.(8) Compared the simulation of actual model and the calculation of equation. Preliminary evaluated the development effect of optimal well patterns. For close to the edge water area, in the development process should fully consider the influence of the natural water invasion.