With the development of complex and unconventional reservoirs, oil and gas exploration becomes increasingly difficult. Highly deviated wells/horizontal wells are widely used. The electromagnetic propagation logging while drilling (LWD) is more effective in complex geological environment detection owing to geological orientation and real-time formation evaluation. However, its operating frequency is generally at the MHz level. Traditional acquisition techniques require an analogue to digital converter with high sampling rates, which will introduce complex circuit structures and increase sampling costs. The undersampling technology has overcome these disadvantages. The difficulties in the undersampling technology include the selection of an undersampling frequency and the acquisition of a signal correction coefficient. The range of undersampling frequencies and a correction coefficient has been developed to process the electromagnetic propagation LWD measurements in this paper. The range of undersampling frequency ensures the validity of the sampled data. The correction coefficient ensures that different frequency signals use the same undersampling frequency to obtain the same frequency recovery signal. The correctness of these parameters is verified by simulation and field data examples. The range of undersampling frequency and a correction coefficient has been applied, improving the data stability and providing reliable technical support for the exploration and development of unconventional oil and gas.

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基于欠采样技术的随钻电磁传播测井数据采集方法

随着复杂、非常规油气藏的开发，油气勘探难度越来越大。大斜度井/水平井被广泛使用。电磁传播随钻测井（LWD）由于地质定向和实时地层评价，在复杂地质环境检测中更加有效。但是，它的工作频率一般在MHz级别。传统的采集技术需要具有高采样率的模数转换器，这将引入复杂的电路结构并增加采样成本。欠采样技术克服了这些缺点。欠采样技术的难点包括欠采样频率的选择和信号校正系数的获取。本文开发了欠采样频率范围和校正系数来处理电磁传播 LWD 测量。欠采样频率的范围保证了采样数据的有效性。校正系数保证不同频率信号使用相同的欠采样频率得到相同的频率恢复信号。通过仿真和现场数据实例验证了这些参数的正确性。应用了欠采样频率范围和修正系数，提高了数据稳定性，为非常规油气勘探开发提供了可靠的技术支持。欠采样频率的范围保证了采样数据的有效性。校正系数保证不同频率信号使用相同的欠采样频率得到相同的频率恢复信号。通过仿真和现场数据实例验证了这些参数的正确性。应用了欠采样频率范围和修正系数，提高了数据稳定性，为非常规油气勘探开发提供了可靠的技术支持。欠采样频率的范围保证了采样数据的有效性。校正系数保证不同频率信号使用相同的欠采样频率得到相同的频率恢复信号。通过仿真和现场数据实例验证了这些参数的正确性。应用了欠采样频率范围和修正系数，提高了数据稳定性，为非常规油气勘探开发提供了可靠的技术支持。