电容式阵列持水仪CAT在海外油田高含水直井中进行产液剖面测量的适用性分析

Application of Capacitive Array Holdup Tool(CAT)in the survey of production profile in Sudan Oilfield

在产液剖面测量中,常用的流体识别定量计算方法为电容式持水率计CWH以及流体密度仪器,但只在直井和含水较低(0-48%)的情况下,持水率计CWH和密度仪器的测量精度较高,能够达到理想的测量效果,如果是稠油井,密度仪器分辨油水的能力也将大大降低。当前苏丹油田的大部分生产井含水都高达80%以上,超出CWH的测量范围,且有些为稠油井,所以常规含水仪器很难达到区分油水的目的。Sondex公司的MAPS系列仪器中的电容式阵列持水仪(CAT),具有阵列安装的12个电容传感器,同时测量靠近套管周围流体的电容,从而通过产生的精确的截面图来成像显示油水的分布以及含量,含水测量范围为0-100%,能够达到在高含水油井中进行产业剖面测量的目的。但是CAT仪器通常在大斜度井或者水平井中才能够得到更精确的测量数据,在直井中是否能得到较好的测量效果还有待确认。本文通过对CAT仪器测量原理的介绍以及直井中CAT计算结果与CWH计算结果的对比,分析了高含水直井中CAT仪器的适用性。从几口井的测量结果显示,能够半定量进行含水计算,大致判断产出剖面,与单CWH仪器相比能够得到较好的测量效果。

For the production profile survey job,capacitance water holdup(CWH)of Sondex company are always be used to measure and calculate the water content of the production layer in Sudan Oilfield.CWH has high accuracy and it can achieve perfect measuring results on the condition of straight well and low water saturation.However,CWH would not be suitable in the case of deviation or horizontal wells and high water saturation.On the one hand,the fluid in the deviation well or horizontal well will be stratified flow due to the gravity separation of the oil and water,so the position of the CWH sensor will affect the measurement results directly and cause a large error.On the other hand,the effective measurement range of water cut of CWH is limited and the water phase becomes continuous in the production profile with high water cut.The resolution of CWH is greatly reduced and the desired results cannot be obtained.The tool has an array of 12 capacitance sensors,each sensor of the array measures the capacitance of the surrounding fluid close to the well casing.Thus,the accurate cross-sectional map is used to show the distribution and content of oil and water,which has achieved good application results in Sudan.