哈萨克斯坦KKM油田钻具强稳降振提速技术研究

Research on enhancing stability and reducing vibration ofthe drilling string in KKM Oilfield in Kazakhstan

摘要:

KKM油田下部砂泥岩互层非均质性强导致井下钻具振动剧烈、PDC切削齿寿命低，且井眼易偏斜。目前在用PDC钻头多采用5刀翼或6刀翼16 mm切削齿以降低井下振动保证PDC钻头寿命，但降低了钻头攻击性导致机械钻速较低。针对KKM油田下部地层特点，优选了4刀翼19 mm复合片PDC钻头。该钻头具有较高的破岩效率和攻击性，可大幅度提高机械钻速；同时通过底部钻具组合动力学分析，优化形成了双稳定器+单稳单弯（0.5°）钻具组合，3个稳定器串联具有较强的稳定降振作用，配合小弯角螺杆钻进可有效提高防斜能力，降低了井下振动，配合大尺寸聚晶金刚石复合片PDC钻头实现了三开井段一趟钻完成的目标，机械钻速提高115.35%。

Abstract:

The heterogeneity of the sand-shale interbeds in the lower part of the oilfield produced strong vibration of the downhole drilling string, leading to short life of PDC cutting teeth and easy hole deviation. At present, PDC drill bits are designed with 5 blades or 6 blades with 16mm cutting teeth to reduce the downhole tool vibration to ensure the life of the PDC bit, but the drill bit aggression is reduced and the mechanical drilling speed is lower. Based on the characteristics of lower formation in KKM Oilfield, a 4-blade 19mm composite PDC bit was selected. The drill bit provided high rock breaking efficiency and aggression capacity, which can greatly increase ROP. At the same time, through the bottom hole assembly dynamic analysis, the bisector + single stable single bending (0.5°) drilling tool combination was optimized. The application of three stabilizers can achieve strong vibration reduction effect, which can effectively improve the anti-deviation ability and reduce the downhole vibration with the small-angle downhole motor tool, and also with large-size PDC bit, the goal of drilling the lower section in one run was achieved. The ROP was increased by 115.35%.