成像测井解释评价方法及其地质应用

Interpretation and evaluation methods of image logs and their geological applications

为了系统梳理成像测井解释评价存在的问题并拓展其在地质与工程领域中的应用范围,首先回顾了成像测井采集系列的发展历程及资料处理步骤与解释流程,然后提出了“四个层次”为约束(图像直接解释、常规测井约束、岩心约束以及地质理论约束)的成像测井精细解释方法。成像测井相模式可划分出具有地质意义的块状、条带状、线状、斑状、杂乱、递变模式和对称沟槽状模式七大类。成像测井可用于岩心定向、地层产状获取、裂缝评价、断层性质分析、地应力方向判别、沉积特征拾取以及古水流方向判别等领域中。通过阿尔奇公式反算,成像测井数据矩阵可以生成孔隙度频谱以及视地层水电阻率谱,并可分别运用于储层质量评价以及流体性质识别。成像测井切片处理可凸显沉积纹层等信息,可实现细粒沉积岩纹层结构拾取及非常规油气储层高分辨率测井评价。Poro Tex图像结构分析技术可用于拾取孔洞缝等储集空间特征,并定量计算孔隙度和裂缝孔隙度等参数,因此被广泛运用至非均质性较强的碳酸盐岩储层测井综合评价工作中。研究成果可规避成像测井解释中的误区同时可扩展成像测井应用领域。

[Significance]To systematically address problems related to the interpretation and evaluation of image logs and expand their application range in geology and engineering fields,firstly,the development history,data processing steps and interpretation process of image log acquisition series are reviewed,and then fine interpretation methods for image logs,constrained by"four levels"(direct interpretation of images,conventional logging constraints,core constraints and geological theory constraints),are proposed in this paper.[Progress]The image log facies models can be divided into seven categories:massive,banded,cross-stratified,spotted,convoluted,graded and symmetrical groove modes.Image logs can be used for core orientation,formation attitude acquisition,fracture evaluation,fault property analysis,in situ stress direction discrimination,sedimentary characteristic pickup,palaeocurrent direction discrimination,etc.Through the inverse calculation of Archie′s formula,the image log data matrix can generate porosity spectra and apparent formation water resistivity spectra,which can be used for reservoir quality evaluation and fluid property identification,respectively.Slab images can reveal information such as sedimentary laminae,fine-grained sediment lamina textures can be identified,and high-resolution logging can be used to evaluate unconventional oil and gas reservoirs.Poro Tex image structure analysis technology can be used to identify the characteristics of reservoir spaces such as pores and fractures and to quantitatively calculate parameters such as porosity and fracture porosity.Therefore,it is widely used in comprehensive logging evaluations of highly heterogeneous carbonate reservoirs.[Conclusions and Prospects]These research results can help us to avoid misunderstandings in image logs interpretation and expand the application field of image logs.