Study On Well Pattern Arrangement Of Low Permeability Reservoir By Reservoir Engineering Methods

In this paper, porous flow mechanics in low permeability reservoirs was studied for the practical problems that occurred during the development of reservoir, which is accomplished on the base of predecessors' work. The main research results we got are as following:(1)It was revealed by the saturated single liquid seepage experiment that the movement of low speed seepage in low permeability media departs from the law of Darcy, meanwhile the curve of seepage flow would not pass through the origin of coordinates. According to the non-linear flow model of ultra-low permeable reservoir and the reservoir engineering methods, responding time of oil wells was derived. The results showed that: there was a very good correlation between responding time and well spacing, reduced well spacing can greatly shorten responding time.(2)The concept of the use coefficient was presented. According to known parameters, such as the reservoir permeability, fluid viscosity, well pattern, well spacing, hydraulic fracture length and so on, the use coefficient of the reservoir can be obtained quickly. The results can be used for low permeability reservoir well optimum pattern of site development programs and reservoir evaluation.(3) Based on the basic formula of non-Darcy flow with low velocity and nonlinear flow model, the formulas of individual well producing rate and the use coefficients were deduced. The areal well patterns included five-spot, inverted seven-spot, inverted nine-spot, rhombic inverted nine-spot well pattern and rectangular well pattern. It was verified that the formulas were reasonable.(4) The factors affecting production are illuminated. The factors included start-up pressure gradient, well spacing, fracture length and injection-production pressure drawdown. Meantime, how far each factor can affect was discussed and the approaches to enhancing the low permeability reservoir development effect in accordance with actual situation were put forward.(5) Using the established methods of reservoir engineering at Daqing, Jilin and Huabei oil fields, it discussed the problems about the adaptability research of well pattern in low permeability reservoirs. Calculated the range of reasonable well spacing. Provided accordance for future development adjustment by correctly evaluating low permeability reservoirs.