Productivity Prediction And Reasonable Drawdown Pressure Optimization Of Fractured Horizontal Well In Tight Sandstone Reservoir

Sand production in oil well is one of the important difficulties during the oil exploitation, especially when the production tail,water cut would increase,and subsurface liquid would much easier to carry sand into wellbore,it makes the sand production get more serious. When failure to take sand control measure,the sand product seriously causes problems for oil production,the sand production in oil well may lead to strata damage and sidewall instability, and serious abrasion wear on down-hole and surface equipment, the pipeline corrosion and plugging, even casing failure and oil well abandonment, increasing the original development cost, etc. If we control sand completely,it will not only increase the operating cost,but also results in blocking of particles in the pores near the wellbores,and therefore reduce the productivity of oil wells. But adapting Sand management methods, the cost of operation can be reduced effectively, and produce with limited sand increases the porosity and permeability of formations, it will enhance the well productivity and oil rete and create better economic benefits.Sand management is to find the optimal policy between sand sand production and sand control. this paper analysis the sand production characteristics from the geological and development factors, and studies the sand production mechanism from the macro and micro levels, applies the theory of shear failure of rocks to determine the critical pressure of sand production, laid the theoretical foundations for providing reasonable production pressure. Applicating the liquid-solid filtration theory, material balance equations, Darcy’s law, Coulomb-Mohr theory to establish the prediction models about the relationship between liquid-producing capacity and sand production. According to the mass balance method to deduce the changes of porosity and physical equilibrium equations of the cumulative amount of sanding to visually observe the porosity changes caused by sand production, providing the theoretical basis for moderate sanding production. The relationship between prop-carrying capacity and fluid production is defined according to jamming settlement theory. The optimization of sand control technologies for enhancing production is conducted by calculating skin factors and production predicting of common sand control technologies in an oilfield.When determined sand control method,design of process parameters becomes the critical factor of affecting sand management. Gravel-packing sand-control is most widely used in sand control currently. The gravel size of a traditional design approach is determined by the Saucier method with the known formation median grain size. But it often could not be gotten timely and effectively in fact. In the absence of the median sand grain size, this paper designed the gravel size with the maximum carrying sand diameter; In addition,the width of screen guage could be designed by using a combination of traditional sand bridge principle and the Chempolis theory.