大位移井套管磨损量分析模型

ANALYSIS MODEL OF CASING WEAR IN EXTENDED REACH WELL

在大位移井钻井过程中,由于裸眼井段长、井斜角大、井眼曲率变化大,从而使得钻柱与套管之间的接触力较大,导致套管会发生严重的磨损。根据套管内表面的磨损体积与旋转钻柱在相同位置所作的功成正比的原理,建立了套管磨损厚度与井眼曲率、钻具组合、机械钻速、钻井时间及套管磨损量之间的关系,计算出了大位移井井筒内钻杆与套管之间的接触力沿井深分布,分析了机械钻速和钻井时间对套管磨损厚度的影响。计算结果表明,井眼曲率越大、钻井时间越长、机械钻速越低,套管磨损越严重。

During extended reach well drilling,due to long open hole section,high deviation angle and high borehole curvature,the contact force between drilling string and the casing leads to serious casing wear.Based on the energy principle that the wear volume on the inner wall of casing is proportion to the work that is done at the same position by the rotation of drilling string,a quantitative model was established to predict the residual wall thickness of intermediate casing.The effects of borehole curvature,make-up of string,penetration rate,drilling time,and wear coefficient on casing wear were discussed.The contact force between drill pile and casing was calculated,effects of penetration rate and drilling time on the casing wear thickness were analyzed.The calculation results showed that the DLS was larger,the drilling time was longer,the ROP was slower,casing wear was severer.