气体钻井MMWD随钻测量方法研究

气体钻井中EM-MWD技术受复杂地层影响大、信号衰减快和抗噪声能力差，导致其信号测传深度受限，为此提出了在气体钻井中利用钻杆作为微波波导实现井下参数随钻测量与信号传输的MMWD技术。在研究钻杆内高频波传输特性与影响微波传输的主要因素基础上，优选了微波频率并验证了其适用性，得到了可在钻杆中传播的8个波形及其衰减系数，研制出了MMWD样机，并开发了配套的控制处理软件。该样机在元坝气田元陆x井进行了多次下井试验，单次入井无故障工作时间达120.0 h，总工作时间234.0 h，最大测传深度超过3 000.00 m，测传的井下温度数据基本符合地层温度分布规律，且测传井斜角与测井井斜角也较为吻合。研究表明，MMWD技术弥补了EM-MWD技术测传深度受限的不足，测量结果准确可靠，为气体钻井提供了一种新的高效随钻测量手段。 

Research on Measurement Methods of MMWD during Gas Drilling

EM-MWD technology has limited signal transmission efficiency during gas drilling,because of a high degree of interference from complex strata,rapid signal attenuation,and poor noise-resistance capacity.To solve the problems,MMWD technology would be used because it can use the drillstring as a microwave waveguide to use the MWD for parameters and signal transmission during the gas drilling.Based on the study of the high frequency wave transmission characteristics and the main influencing factors of microwave transmission along the string,the selected microwave frequency was verified,and eight wave types that could propagate along the string and their attenuation coefficients were obtained.After completing that phase,the MMWD prototype and supporting control and processing software were developed.The prototype was tested several times in Well YL-x of the Yuanba Gas Field in Sichuan,and the fault-free operation duration for one run reached 120.0 h,and the total operation time reached 234.0 h.The maximum measured depth exceeded 3 000.00 m,and the measured and transmitted downhole temperature data generally conformed to the ground temperature distribution law;the well inclination was in consistence with the wire-logging inclination.The study showed that MMWD technology could solve the problem of limited measured depth of EM-MWD technology,and had accurate and reliable measurement results,which provided a new high-efficiency MWD method for gas drilling.