固井形成的水力封隔系统封隔能力评价方法

Evaluation of Isolation Ability of the Hydraulic Isolating System Formed by Cementing

油、水井固井的主要目的是保护生产管柱和封堵相邻的油、气、水层。固井水泥凝固后形成了一个纵向上的水力封隔系统,影响这个系统水力封隔能力的因素包括系统的缺陷和系统的强度。目前的固井质量评价方法主要检测套管、水泥环胶结情况,没有直接针对固井的目的(层间水力封隔情况)给出评价。在深入分析声波测井方法和水泥环密度测井方法特点的基础上,提出了油、水井固井质量综合评价方法,即利用声波测井和水泥环密度测井资料进行优势互补,解释固井第Ⅰ界面微环、水泥环抗压强度、固井第Ⅱ界面胶结状态,再针对固井的目的,综合以上各参数评价固井形成的水力封隔系统的水力封隔能力。

The most important function of cementing for oil production and water injection well is to protect the production string and achieve zonal hydraulic isolation between adjacent permeable zones. Casing-cement sheath and formation formed a vertical hydraulic isolation system; hydraulic isolation ability of the system formed by cementing mainly depends on defection and strength of the system. Traditional cement evaluation techniques mainly detect cement-to-pipe bonding, instead of completely evaluating the purpose of cementing （zonal hydraulic isolation ability）. Based on analysis of the features of acoustic logging and Gamma-gamma density logging, we give a comprehensive interpretation method of cement bond quality, that is, combining the above two methods to interpret bonding states of two interfaces and compressive strength of cement in order to compensate each other, then, using above-mentioned parameters, we can comprehensively evaluate hydraulic isolation ability of the system for the purpose of cementing.