影响调整井固井质量的主要因素及计算方法

油田开发已进入高含水后期，调整井数量越来越多，长期的注水开发，使地层结构遭到严重破坏，调整井固井质量受到严重影响。针对井径扩大率、钻井液性能、水泥浆密度、地层孔隙压力和孔隙流体渗流速度等影响调整井固井质量的主要因素进行了分析，并建立了地层孔隙压力和孔隙流体渗流速度的计算方法。结果表明：随着井径扩大率、钻井液密度、黏度、失水量的增大，调整井固井优质率降低；地层孔隙压力越大，孔隙流体渗流速度超过临界渗流速度时，调整井固井质量变差；建立的地层孔隙压力和孔隙流体渗流速度的计算方法能准确地预测地层孔隙压力和孔隙流体渗流速度，为提高调整井固井质量提供可靠的依据。

Main Factors Affecting Cementing Job Quality of Adjustment Wells and the Calculation Method Thereof

Much more adjustment wells need to be drilled in the later development phase of an oilfield when water production becomes comparatively high.Water injection during the long period of development make the formation structures seriously damaged,thus negatively affecting the quality of the adjustment wells.Analyses were done on the factors affecting the quality of the adjustment wells,such as hole enlargement,mud properties,density of cement slurry,pore pressures of the formations and the flow velocity of the fluids through porous media.A calculation method was constructed computing the pore pressures of the formations and the flow velocity of the fluids through porous media.The calculation shows that an increase in hole enlargement,mud density,mud viscosity and water loss will deteriorate the quality of the cementing job in adjustment wells.The higher the pore pressures,the poorer the quality of the cementing job in adjustment wells when the flow velocity of the fluids through porous media exceeds the critical value.The constructed method can accurately predict the pore pressures of the formations and the flow velocity of the fluids through porous media,and provide a base on which high cement job quality in adjustment wells can be achieved.