渤海油田注水井酸化效果预测评价方法

针对渤海油田注水井酸化低效的问题，以注水井酸化低效最为典型的SZ油田Ⅱ期注水井为例，统计注水井酸化60余井次，采用灰色关联度分析法进行渤海油田注水井酸化影响因素及预测评价方法研究。结果表明，渤海油田注水井酸化曲线类型主要归纳为戒下型、双台阶型、平均型、快速下降型等4种，以戒下型为主。其中，戒下型平均有效期最长，快速下降型平均有效期最短。从影响酸化增注效果的作业参数、储层参数和堵塞程度等因素出发，深入分析了各影响因素对注水井酸化增注效果的重要性等级，明确了注水井酸化增注效果的关键影响因素主要包括酸液类型及溶蚀解堵能力、酸化前视吸水指数、酸化半径、有效厚度、渗透率和孔隙度等，研究建立了酸化有效期、累计增注量预测评价分析模型。研究成果可用作注水井酸化效果事先预判和评价，有助于注水井酸化设计方案优化，延长酸化有效期和增加累计增注量，确保注水井酸化效果，助力渤海油田稳产3000万吨。 

Methods of Predicting and Evaluating Effect of Acidizing Job of Water Injectors in Bohai Oilfield

A study has been conducted in an effort to address the problem of poor acidizing job performed in water projectors in Bohai oilfield. Typical Ⅱ stage projectors with poor acidizing job in Block SZ were selected for studying and data regarding the acidizing job were collected for more than 60 wells/times. Factors affecting the acidizing job quality of the injectors in Bohai oilfield and prediction and evaluation of the job quality were studied using Grey Relational Analysis.The study shows that the acidizing curves of the injectors in Bohai oilfield can be classified mainlyas S-type, double-step-shaped type, average type and rapid-declining type, most of which is the S-type curve. Injectors with S-type curve have the longest time in which the effect of acidizing job remains effective, and injectors with rapid-declining curve have the shortest time in which the effect of acidizing job remains effective. Several factors affecting the effects of augmented acid injection, such as the operational parameters, reservoir data and the blocking of flow channels in the formations, were studied for their importance of affecting the effects of augmented acid injection. The key factors affecting the effects of augmented acid injection were found to be the type of acid and its ability to eroding the blockage, the apparent water injectivity index before acidizing job, acidizing radius, the effective thickness of acidized formation, and the permeability and porosity of formations. A model has been established for predicting and evaluating the effective period of an acidizing job and the cumulative volume of acid solution injected. The study can be used to predict and evaluate the effect of acidizing job and is helpful to the optimization of acidizing program for injectors. By prolonging the effective period of an acidizing job and increasing the cumulative volume of acid solution injected, the effect of an acidizing job can be ensured, contributing to the realization of stabilizing petroleum production at 30 million tons per year in Bohai oilfield.