Optimization Of Productivity And Fracture Parameters Of Fractured Horizontal Wells In Three Low-conglomerate Reservoirs

M reservoir,whose characteristics are low porosity,low permeability and lowsaturation,is a typical three low conglomerate reservoir.Fluid shows non-linear characteristics when it flows through such reservoir,so the impact of starting pressure on reservoir development can not be ignored, which resulting in the development of conventional vertical wells for such reservoirs is not cost-effective. Therefore, a reasonable choice of well-type and well pattern become a prerequisite for the effective development of three low reservoir. Fractured horizontal well has become the main well-type of the three low reservoir development because of the obvious advantages in increasing drainage area, reducing filtrational resistance, getting higher initial productivity, improving the ultimate recovery. But there are many factors that influence the initial productivity of fractured horizontal wells and the effect law of different factors is different. Therefore, studying the factors which influence the fractured horizontal well productivity through rational way and getting the relationship between production and the influence parameters, at the same time, optimizing the value of influence factors have an important guiding significance for fractured horizontal well design and mine production.Based on the basic reservoir and geology characteristics of M reservoir, this paper applied reservoir engineering,fluid mechanics theory,reservoir numerical simulation and orthogonal optimization analysis methods, carried out these studies which include that reasonable well-type of M reservoir,the productivity of fractured horizontal wells and fracture parameter optimization.Paper made the following findings:(1)Obtained the reasonable well type of M reservoir through studying the distance between the injector and producer under different injection and production systems.The study method is using models which were established by simulation software and combined with the single-phase incompressible fluid steady flow differential equations which based on two-parameter model;(2)Based on the existing productivity calculation theory, and taken the starting pressure gradient into account to establish mathematical model of fractured horizontal well productivity computing which is more in line with the low permeability reservoir. Then calculated the production capacity under different value of influence factors by means of Matlab programming, analyzed the optimal value of influence factors;(3)By introducing capacity correction coefficient, considered the crack factors that affect the production capacity indirectly and formation factor, well factor which have direct impact on the capacity into an integrated parameter. Then computed productivity through the productivity computation theory and integrated parameter of different parameter values, established relationship plate between productivity of fractured horizontal well and integrated parameter. Finally, the application of capacity of well which are put on production and corresponding integrated parameter data have verified the reliability of the plate;(4)Combined orthogonal experimental design method,single factor optimization method and numerical simulation, through mechanism model, carried out the optimization research of univariate and multivariate of M reservoir, got the factors' impact order of recovery and the optimal level value of all factors.