肯基亚克油田钻井施工措施及轨迹控制技术

Drilling Operating Measure and Trajectory Control Techniques in Kenkyak Oilfield

哈萨克斯坦肯基亚克盐下油田油层埋藏深,地质条件复杂。以H8068井为例,肯基亚克盐下油藏复杂地质条件下的钻井施工措施包括:①钻遇敏感性弱胶结、易坍塌地层时,采用快速钻进的方案,以减少地层在钻井液中浸泡的时间;②钻遇易膨胀缩径和塑性流动的地层时,采取减少扶正器的使用量,小钻压、低钻速钻进,适当提高钻井液密度等措施,来减少缩径,平衡膏岩层的塑性流动;③钻遇高压层段时,起下钻及短起下作业控制起下速度,钻井液密度严格控制在1.97～1.98g/cm3;④钻遇下部井段泥板岩地层时,应对增斜钻具发生屈曲的临界钻压和疲劳破坏系数进行校核。该油田H8068井定向井段轨迹控制钻具组合及实钻轨迹控制过程表明,H8068井纯钻进时效高(占钻井时效的56.40%)的原因在于后期合理的钻头选型,减少了起下钻更换钻头所用的时间。

Kenkyak oilfield in Kazakhstan is characterized by deep buried depth in oil reservoirs and complex geological conditions.Drilling operating measures taken in well H8068 in the oil reservoirs were analyzed and introduced first.When weakly consolidated and caving formations are drilled,faster penetration will be done so as to decrease soak time of the formations in drilling fluid.When the formations of expanding and reducing easily and plastic flow are drilled ,centering device will be used at fewer times ,and drilling and speed should be low;density of the drilling fluid should be enhanced properly.Reducing will pressure be decreased and the plastic flow will be balanced.When high-pressure intervals are drilled,the speed will be controlled during trip and short trip,and the density of the drilling fluid should be 1.97-1.98g/cm3.When argillite formations at the lower part of intervals are drilled,critical bit weight and endurance failure factor of buckle formed by building assembly should be checked.Then,the rig assembly by trajectory control at orient- ed section and actual trajectory control process in well H8068 were introduced.It points out that the reason of high-efficient net drilling is reasonable bit type selection at later stage,and the time of bitchange was shortened during round trip operation.