基于瞬态分析的PDG数据处理方法与应用

PDG Data Processing Method Based on Transient Analysis and Its Application

永置式井下仪表能够对井筒内和砂面的压力、温度等数据进行长期监测。通过PDG压力和温度瞬态分析,可以得到近井筒乃至油藏的信息。然而,原始PDG数据常含有大量噪声、异常点和多个瞬态过程,不能直接用于数据分析和解释。在对多个油田PDG数据处理和分析的基础上,提出了基于瞬态分析的PDG数据处理方法,包括鉴于现场数据所含异常点和噪声类型不同的问题,提出针对性的异常点消除和降噪方法;对常用降噪效果评价方式不便于优选降噪参数和降噪结果的问题,提出了考虑数据光滑性要求的新的降噪效果综合评价指标;将移动窗口技术与压力导数法相结合进行断点识别和瞬态提取;并以瞬态作为数据精简的基础,有效保护瞬态数据和断点。经现场PDG数据的处理结果证实,上述处理方法是有效的,为后续的PDG数据瞬态分析提供了可靠的数据保障。

The permanent downhole instrument(PDG) can monitor the pressure and temperature in wellbore and sand surface for a long time.The information near the wellbore and even the reservoir can be obtained through the transient analysis of PDG pressure and temperature data.However,the original PDG data often contain a lot of noise,outliers and multiple transient processes,which can not be directly used for data analysis and interpretation.A PDG data processing method based on transient analysis is proposed based on the analysis and processing of PDG data from several oilfields:In view of the different abnormal points and noise types in the field data,the corresponding abnormal point elimination and noise reduction methods are proposed;In order to solve the problem that it is not convenient to optimize the noise reduction parameters and results by commonly used noise reduction evaluation methods,a new comprehensive evaluation index of noise reduction effect considering the requirement of data smoothness is proposed;The moving window technique is combined with pressure derivative method for identification of breakpoints and extraction of transient state,and transient data and breakpoints are effectively protected taking transient state as the basis of data compaction.The processing results of field PDG data show that the above-mentioned processing method is effective and provide reliable data guarantee for the subsequent transient analysis of PDG data.