有保护时隙的高效PPM钻井液脉冲信号编码  

New PPM Coding with Protection Time Slots for Optimizing the Drilling Fluid Pulse Signal for High Energy Efficiency

作　　者：胡永建 HU Yongjian(CNPC Engineering Technology R&D Compcmy Limited,Beijing,102206,China)

机构地区：[1]中国石油集团工程技术研究院有限公司,北京102206

出　　处：《石油钻探技术》2018年第6期118-122,共5页Petroleum Drilling Techniques

基　　金：国家科技重大专项"深井高速信息传输钻杆技术与配套装备研究"(编号:2016ZX05020-005-001)部分研究内容

摘　　要：为了提高井下数据的传输速率,降低电池能耗和脉冲发生器动作频次,需要研究并选择具有高编码效率和节电效率的钻井液脉冲信号编码方法。为此,选择具有较高节电效率的脉冲位置调制(PPM)编码方法,分别计算了有不同数量保护时隙的多脉冲位置调制(MPPM)与差分脉冲位置调制(DPPM)的编码效率和节电效率。计算结果表明:MPPM的编码效率随着待编码信息位数增加而升高,而DPPM编码信息位数可以取定值来实现组合编码;在待编码信息位数较少的情况下,DPPM编码、译码算法更易实现,有更高的编码效率及节电效率,在保护时隙数量为2时,DPPM编码效率可达46.2%,节电效率可达84.6%。研究结果表明,有保护时隙的DPPM编码具有较高的编码效率及节电效率,其编码映射方法更简单,是适合钻井液脉冲信号的高效编码方法。In order to improve the transmission rate of downhole data and increase battery life and the frequency of drilling fluid pulser action,it is necessary to study and select the drilling fluid pulse signal coding method with high coding efficiency and energy saving efficiency.The coding efficiency and energy saving efficiency of multi-pulse position modulation(MPPM)and differential pulse position modulation(DPPM)with different number of protection time slot are calculated by high efficient pulse position modulation coding(PPM)methods.By comparing the calculation results of MPPM and DPPM,it is found that the coding efficiency of MPPM increases with the number of information and DPPM has the fixed information digits number to implement combinatorial coding.In the case that the number of bits of information to be encoded is small,DPPM has fewer bits of information to be encoded,and its encoding and decoding algorithms are easier to implement.Further,it has higher encoding and power saving efficiency.When the number of protection time slot is2,the coding efficiency of DPPM can reach46.2%and the energy saving efficiency can reach84.6%.The research results show that DPPM coding with a protection time slot has high coding and energy saving efficiency,as its coding mapping method is simpler.It is an efficient coding method suitable for applying to the drilling fluid pulse signal.

关 键 词：钻井液 脉冲信号 脉冲位置调制 编码效率 节电效率 保护时隙 

分 类 号：TE927[石油与天然气工程—石油机械设备]