水平井砾石充填数值模拟研究

对于疏松砂岩油藏水平井,较好的防砂方法是绕丝筛管砾石充填防砂,但目前成功率很低.本文在分析水平井砾石充填过程和充填机理的基础上,运用固液两相流理论分析了充填过程中的流动阻力,对Gruesbeck提出的模型进行了改进,建立了考虑流体滤失的水平井砾石充填数学模型.通过计算分析了各种因素对充填效率的影响,表明:(1)在一定范围内,充填效率随充填排量、携砂液粘度、冲管与筛管直径比的增加而增加,但这些数值过大不利于充填成功率的提高.(2)充填效率随携砂液中砾石浓度、滤失量及砾石直径的增加而降低.运用此方法可系统优化水平井砾石充填施工参数,制定科学合理的施工方案,提高防砂成功率.

NUMERICAL SIMULATION STUDY OF GRAVEL PACKING IN HORIZONTAL WELL

Wire wrapped screen combined with gravel pack has been recognized as an effective practice for controlling the movement of sand particles from an unconsolidated reservoir into wellbore during production of oil and gas.However,the operation success rate of gravel pack is very low.Based on the analysis of the gravel packing process and mechanism of horizontal well,this paper has discussed the flow resistance in gravel packing horizontal well,and improves the Gruesbeck model by using two phases solid liquid theory.A horizontal well gravel packing model that consider fluid loss to formation have been established.The effects of all factors on packing efficiency have been analyzed by the calculation results obtained from this model.The results are that (1) in some range,packing efficiency increases with the parameters,such as flow rate,fluid viscosity,the diameter ratio of tailpipe to screen.However,it is not good for gravel packing if these factors are too big.(2) The packing efficiency decreases with the increase of gravel concentration in injected liquid,fluid loss to formation and gravel size.The operation factors can be optimized,and the option design can be made more scientific and rational by this method.As a result,the successful rate of sand control can be enhanced.