旋转导向钻井信号井下传送技术研究

对旋转导向钻井工艺中钻井液脉冲传输、电缆传输、声波传输、电磁波传输等常用指令传输方式进行了分析,选择钻井液负脉冲传输方式向地下传送地面指令,设计了地面钻井液负脉冲信号下传整体方案。综合考虑指令传输时间短、井下识别准确率高的原则,提出了改变泵排量的三降三升脉冲传输方式,优选出三降三升三进制负脉冲编码组合方式。通过检测发电机电流(频率)变化来实现井下信号接收。室内的实验测试证明,这一方式是可行的,并作为调制式旋转导向工具的一个子系统,开发了完整的指令控制系统软件。

Study on signal transmission technique in rotary steering drilling

The common pulse transmission modes in rotary steering drilling including drilling fluid pulse transmission,cable transmission,acoustic wave transmission and electromagnetic wave transmission were analyzed. The drilling fluid negative pulse transmission mode was selected to send the instruction signal to the modulating rotary steering tool. The overall scheme of the drilling fluid negative pulse signal transmission was designed. According to the change of pump displacement, three-descending and three-ascending pulse transmission modes were proposed by comprehensively considering short instruction transmission and the accurate identification. Considering the need of instruction transmission, the limit condition of magnitude and orientation of the guiding force, and the downhole storage capacity, three-descending and three-ascending ternary-notation negative pulse encoding combination mode was optimized. The receiving of downhole signal was achieved by detecting the current or frequency change of the downhole generator. The laboratory experiment proved that the method was reliable. The integrative command control software system was developed.