摘要
研究井眼环境因素对钻柱中声波传播的影响规律不仅是实现井下信息声波传输技术的基础,也关系到井下信息声波传输技术载波的选取及中继装置的设计安装。为此,设计了用于测试声波在钻柱信道中传输及衰减特性的试验装置,开展了井壁性质、井眼内循环介质对声波传播的影响试验,分析了钻柱与井壁的接触状态及循环介质对钻柱声传播的影响规律。结果表明:①井眼环境主要影响声波在钻柱中的衰减,基本不影响通阻带分布规律;②随着井壁硬度的增加,声波衰减减小;③随着钻柱与井壁支撑点的增加,声波衰减加剧,但通阻带的位置和宽度变化不明显;④液体循环状态下的声波辨识效果弱于液体静止状态,有液体存在的声波辨识效果弱于气体状态。在井下信息声波传输系统载波选择及中继器位置确定过程中,应该充分考虑井眼环境引起的声波衰减,而基本不用担心其引起的频带变化。
Identifying the influence of borehole environment on acoustic propagation in drill string serves as a basis in downhole-infor- mation acoustic transmission technologies, and is also related to carrier wave selection of such technologies and design and installa- tion of relay units. In this paper, test units were designed to test the transmission and attenuation characteristics of acoustic waves in drill string channels. Then, tests were performed in terms of the influence of borehole wall natures and circulated medium in the borehole on acoustic propagation. Moreover, analysis was further carried out on the influence laws of drill string and borehole wall contacting state and circulated medium on drill string acoustic propagation. The following conclusions are finally reached. First, bore- hole environment has much effect on the attenuation of acoustic waves in drill strings, but little effect on the distribution rules of passbands and stopbands. Second, acoustic attenuation reduces with the increase of borehole wall hardness. Third, with the increase of contact points between drill strings and borehole wails, acoustic waves attenuate sharply, but passbands and stopbands present no obvious change in locations and widths. And fourth, the acoustic identification effect at the state of liquid circulating is less than that of liquid in a still state, and that in the situations with liquid is less than that with gas. When the carrier waves of downhole-informa- tion acoustic transmission systems are selected and the locations of repeaters are confirmed, much attention should be paid to acous- tic wave attenuation caused by borehole environment, instead of the frequency band change.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2015年第12期58-63,共6页
Natural Gas Industry
基金
"十二五"国家高技术研究发展计划(863计划)项目"低压易漏地层钻井关键技术及装备"(编号:2012AA091601)
国家自然科学基金青年科学基金项目"钻柱信道内多源激励声信号的特性表征与识别检测"(编号:51404285)
中国博士后科学基金面上资助项目"井下随钻信息声传输系统研制与应用研究"(编号:2014M551985)
关键词
声波传播
影响规律
井眼环境
传输效果
钻柱信道
衰减特性
井下信息
Acoustic propagation
Influence law
Borehole environment
Transmission effect
Drill string channel
Attenuation char- acteristics
Downhole information
