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Research on an Lost Circulation Zone Location Method Based on Transient Pressure Wave
ACS Omega ( IF 3.7 ) Pub Date : 2021-09-22 , DOI: 10.1021/acsomega.1c04359 Ruida Zhang 1 , Zhongxi Zhu 1 , Chaofei Wang 2 , Zhigang Guan 3
ACS Omega ( IF 3.7 ) Pub Date : 2021-09-22 , DOI: 10.1021/acsomega.1c04359 Ruida Zhang 1 , Zhongxi Zhu 1 , Chaofei Wang 2 , Zhigang Guan 3
Affiliation
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Accurately identifying the location of loss zone after lost circulation is the key to subsequent plugging operation. In view of the difficulty of identifying the location of lost circulation zone, a method of identifying the location of loss zone by transient pressure wave signal is proposed. When lost circulation occurs, transient back pressure is applied to the wellhead at the surface choke manifold to produce transient pressure wave. The transient pressure wave propagates downward from the wellhead. The propagation process of transient pressure wave in an annulus system is analyzed, and the position of loss zone is determined according to the change of pressure signal at the choke manifold. Based on the simulation of this method, relevant experiments are also carried out. Aiming at the problem of excessive noise of the pressure wave signal collected in the experiment, variational modal decomposition (VMD) is used to decompose the signal into multiple band-limited intrinsic mode function (BIMF) components. Combined with a Hilbert spectrum, the time–frequency characteristics and energy distribution of each BIMF component are analyzed in turn. The main frequency component is selected to reconstruct the signal to achieve the denoising effect. On this basis, a wavelet modulus maxima method is used to decompose the denoised signal, extract the characteristic points of the signal, identify the loss circulation information in the signal, and then identify the thief zone position by a time–domain method. Through experimental verification, the existence of loss zone will affect the change trend of pressure wave; a VMD–wavelet modulus maxima algorithm can effectively remove the noise of the pressure wave signal and locate the pressure change point. The experimental recognition error range of this method is 0.10–9.22%, which has certain guiding significance for field application.
中文翻译：
基于瞬态压力波的漏失环流区定位方法研究
漏失后准确识别漏失区位置是后续封堵作业的关键。针对井漏区位置识别困难的问题，提出了一种利用瞬态压力波信号识别井漏区位置的方法。当发生漏失时，在地面节流管汇处向井口施加瞬态背压以产生瞬态压力波。瞬态压力波从井口向下传播。分析了瞬态压力波在环空系统中的传播过程，根据节流管汇压力信号的变化确定了损失区的位置。在对该方法进行仿真的基础上，还进行了相关实验。针对实验采集的压力波信号噪声过大的问题，采用变分模态分解（VMD）将信号分解为多个带限本征模态函数（BIMF）分量。结合希尔伯特谱，依次分析各BIMF分量的时频特性和能量分布。选取主频分量对信号进行重构，达到去噪效果。在此基础上，利用小波模极大值法对去噪信号进行分解，提取信号特征点，识别信号中的环损信息，进而通过时域方法识别窃贼区位置。通过实验验证，损失区的存在会影响压力波的变化趋势；一种VMD-小波模极大值算法可以有效去除压力波信号中的噪声，定位压力变化点。该方法的实验识别误差范围为0.10-9.22%，对现场应用具有一定的指导意义。
更新日期：2021-10-06
中文翻译：
基于瞬态压力波的漏失环流区定位方法研究
漏失后准确识别漏失区位置是后续封堵作业的关键。针对井漏区位置识别困难的问题，提出了一种利用瞬态压力波信号识别井漏区位置的方法。当发生漏失时，在地面节流管汇处向井口施加瞬态背压以产生瞬态压力波。瞬态压力波从井口向下传播。分析了瞬态压力波在环空系统中的传播过程，根据节流管汇压力信号的变化确定了损失区的位置。在对该方法进行仿真的基础上，还进行了相关实验。针对实验采集的压力波信号噪声过大的问题，采用变分模态分解（VMD）将信号分解为多个带限本征模态函数（BIMF）分量。结合希尔伯特谱，依次分析各BIMF分量的时频特性和能量分布。选取主频分量对信号进行重构，达到去噪效果。在此基础上，利用小波模极大值法对去噪信号进行分解，提取信号特征点，识别信号中的环损信息，进而通过时域方法识别窃贼区位置。通过实验验证，损失区的存在会影响压力波的变化趋势；一种VMD-小波模极大值算法可以有效去除压力波信号中的噪声，定位压力变化点。该方法的实验识别误差范围为0.10-9.22%，对现场应用具有一定的指导意义。
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