大位移井摩阻和扭矩分析及其对钻深的影响

Analysis on friction drag and torque from extended reach wells and the influence on well drilling depth

对不同垂深、不同位移的大位移井在钻井和下套管过程中的摩阻和扭矩分析表明,采用水基钻井液能够钻成位移小于3000m的大位移井,且可以下入178mm套管;位移大于4000m、且垂深在1000m左右的大位移井,需要使用油基钻井液,且只能下入178mm尾管;位移大于5000m的大位移井,必须使用油基钻井液,178mm套管下入有一定难度,且在垂深较小时,需要使用部分139.7mm钻杆和倒装钻具。分析了不同垂深条件下的大位移井钻井极限,随着井深增加,制约大位移井钻井极限的因素由滑动摩阻转为钻柱强度。

The analysis on friction drag of extended reach wells with different vertical depths and different displacements in drilling and casing running indicates that a water-base drilling fluid can be used to drill extended reach wells with displacement less than 3 000 m with Φ 178 mm casing running; for 4 000 m extended reach wells with vertical depth about 1 000 m, oil-base drill fluid is needed, of which only Φ 178 mm liners can be set; for the extended reach wells with displacement higher than 5 000 m, oil-base drilling fluid must be used, where some difficulties exist for Φ 178 mm casing running, and in the situation of small vertical depth, part of Φ 139.7 mm drill pipes and inverted drill tools are used. The limits of extended reach wells are analyzed under the condition of different vertical depths, with the increase of well depth, the limit factors on the extended reach wells are turned to drill string strength from sliding friction drag.