考虑粒径分布的深水环空岩屑浓度研究及应用

Research and Application of Annulus Solid Content Considering the Cuttings Size Distribution during Deep-water Drilling

深水低温对钻井液性能影响显著,其黏度和切力的改变使深水携岩与常规陆上钻井不同。由于温度降低带来钻井液性能的改变对不同粒径岩屑上返速度的影响程度不同,因此在深水携岩研究中,考虑岩屑粒径分布是必要的。分析了温度变化对钻井液影响,建立了考虑岩屑粒径大小及粒径分布、机械钻速及钻井循环时间等影响因素的深水钻井分岩屑粒径的环空浓度计算新模型,从而获得了深水钻井中全井及井眼各段环空内岩屑浓度大小及其浓度随循环时间变化的分布与变化规律;并在现场深水钻井岩屑浓度的分析计算中,取得了良好的应用效果。

Drilling fluid performance can be influenced significantly under low temperature in deep-water drilling.The change of viscosity and shear force make cutting transport in deep-water drilling different from onshore drilling.Due to the different influence on sinking speed of different size cuttings with temperature changed,it is necessary to consider the particle size distribution for the cutting carry in deepwater drilling.The factor of rheological behavior varied with temperature changing,drilling cuttings size and its distribution,rate of penetration（ROP） and circulation time in drilling are considered,the new model of cuttings proportion calculation in wellbore annular is established,which can calculate the proportion in each hole and the full well sections and indicate the rule of proportion changed with time-varying.The model is applied in the calculation of solid content in the oil field and a good effect has been achieved.