注水井负压解堵的负压值设计方法

为了改善注水井负压解堵的效果,对注水井负压解堵的负压值设计方法进行了研究.根据注水井的渗流特点,利用注水产生的表皮附加压降来修正最小负压值;以防止储层出砂为原则设计最大负压值;再根据Conocophillips公司的负压值设计方法确定最佳负压值;最后,从防止套管挤毁和保证储层稳定2方面对负压值进行校核.采用新的负压值设计方法对车2井、车89井进行了解堵负压值设计,2口井应用新方法推荐的负压值进行解堵之后,注水压力均明显降低,且短时间内注水压力没有出现大幅度升高.研究结果表明,在中高渗透砂岩油层的垂直注水井中运用新方法计算的负压值解堵后,既清除了近井地带的污染,又保证了孔眼和储层的稳定性. 

A Method for Improving Underbalanced Pressure Design in Injection Wells Using Negative Pressure Blocking

In order to improve the effect of negative pressure blocking in injection wells,the design method of negative pressure blocking in injection wells was studied.According to the seepage characteristics of injection wells,an additional pressure drop due to the skin factor was utilized to correct the minimum negative pressure.The maximum negative pressure was designed following principles of sand control.Afterwards,the optimized negative pressure was determined according to the negative pressure design method of ConocoPhillips.Finally,the negative pressure was checked on the basis of preventing casing damage and ensuring the stability of pay zone.The new method of the negative pressure value design was applied to Well Che2 and Well Che89.After the utilization of the negative values recommended by the new method,both water injection pressures of Well Che 2 and Well Che 89 were lowered obviously,and the water injection pressures did not increase substantially.The results showed that using the new negative pressure plugging method in vertical wells of medium or high permeability sand stone pay zones could clear the pollution of the near well bore area and ensure the stability of bores and pay zones.