气体钻井超前探测震源工具设计及力学性能模拟研究

Design and Mechanical Property Simulation of a Impact Source Tool for the Advanced Detection of Gas Drilling

为了实现气体钻井钻头前方风险地层的超前探测,设计了适用于气体钻井环境的井下冲击震源工具,并对其力学性能进行了研究。基于气体钻井的环境,设计了冲击震源工具的关键结构;根据室内冲击试验,优化了震源工具的吸振结构和冲击能量;使用RecurDyn软件,分析了冲击块的运动过程,优化了关键结构的参数;模拟研究了底部吸振圆盘的抗冲击能力和传动杆限位结构的抗拉强度,以及冲击震源工具的力学性能;给出了现场施工方案,分析了其主要优势。研究结果表明:聚四氟乙烯能显著衰减钻铤波及尾波,有利于识别时域内的地层弱反射波信号;冲击能量为50 J时,冲击振动波的传播距离为18.61 m,可满足气体钻井超前探测的目的;聚四氟乙烯受到的最大冲击力为1796.88 N时,其相对变形不超过0.03%,且传动杆限位结构处承受下部钻具的重量不能超过1150 kN。通过气体钻井随钻超前探测震源工具结构设计及力学性能模拟研究,为近钻头冲击震源工具的研制与应用提供了依据。

In order to detect of risky formations in advance and in front of the bit during gas drilling, a downhole impact source tool suitable for gas drilling environment was designed. Based on the gas drilling environment, the key structure of the impact source tool was designed. Through the indoor impact test, the vibration-absorbing structure and impact energy of the impact source tool were optimized. The RecurDyn simulation software was used to analyze impact block movements and optimize the parameters of the key structure. The impact resistance of the bottom vibrationabsorbing disc and the tensile strength of the limit structure of the transmission rod were simulated to analyze the mechanical properties of the impact source tool. The field operation plan was made and the main advantages of the tool was analyzed. The results showed that polytetrafluoroethylene(PTFE) could significantly attenuate drill collar waves and coda waves, helpful in pinpointing weak reflection wave signals in the time domain. When the impact energy was50 J, the propagation distance of impact vibration waves was 18.61 m, which could achieve advanced detection of gas drilling. The maximum impact force on PTFE was 1 796.88 N, and its relative deformation was not more than 0.03%. In addition, the weight of bottom hole assembly(BHA) borne by the limit structure of the transmission rod cannot exceed 1 150 kN. As a result, the structural design and mechanical property simulation of the impact tool for advanced detection while drilling for gas drilling could provide a theoretical basis for the development and application of near-bit impact source tools.