摘要
为研究声信号在钻柱中的传播,建立了近钻头声传输试验系统和周期性钻柱结构声传输试验系统。在试验系统上对声信号在周期性钻柱结构中的传输特性进行试验。结果发现,若采用动力钻具和MWD探管组成的随钻系统,可实现声信号的近钻头传输,但由于探管与钻具连接方式和尺寸结构差别大等原因会引起接收声信号的严重衰减。在周期性钻柱结构中,激振器输入激励信号为方波时占空比的变化对接收信号峰峰值影响明显,且方波作为激励信号,占空比在50%以内时,接收信号较理想;对于同一钻柱结构,信号频率增大会引起接收信号幅值减小;在同一频率条件下,钻柱组合的变化对接收信号的幅值存在较明显的影响。
To study the transmission of sound signal in drillstring,a near-bit sound transmission test system and a periodical drillstring structural sound transmission test system were established. An experiment of the transmission properties of sound signals in the periodical drillstring structure was conducted in the test system. The results show that adoption of the LWD system consisting of the dynamic drilling tool and the MWD pipe locator can achieve the near-bit transmission of sound signals. However,due to the great differences of the pipe locator and the drilling tool in connection mode and dimensions,serious attenuation of the transmitted sound signals will arise. In the periodical drillstring structure,when the excitation signal imported by the vibrator is the square wave,the change of duty ratio has a noticeable effect on the peak value of the receipt signal. When the duty ratio falls into the scope of 50% with the square wave as the excitation signal,the receipt signal is relatively desirable. So far as the same drillstring structure is concerned,the increase of signal frequency will lead to the decrease of the amplitude of the receipt signal. Under the condition of the same frequency,the change of the drillstring combination has a remarkable effect on the amplitude of the receipt signal.
出处
《石油机械》
北大核心
2010年第1期1-4,共4页
China Petroleum Machinery
基金
国家自然科学基金项目"基于钻柱的声信号传输系统和声传播特性研究"(50974131)
中国石油化工集团公司科技攻关项目"近钻头无线随钻测斜技术研究"(JP05006)
高等学校博士学科点专项科研基金项目"钻柱中声的传播和衰减特性研究"(20090133110005)
中国石油大学研究生创新基金资助项目"钻柱中声的传播和衰减特性实验研究"
关键词
钻柱
周期性
声信号
信号频率
占空比
drillstring,periodical,sound signal,signal frequency,duty ratio
