Improvements in the X-Ray Saturation Technique of Studying Fluid Flow

Abstract

Improvements in the X-ray method of measuring liquid saturation and saturationdistribution are presented. Two identical direct current amplifiers have beenadded to measure continuously the intensities of the X-ray tube output and thebeam which has passed through the core under test. The ratio of theseintensities is automatically recorded on a modified Brown Electronik Recorder.Arrangements have been made to drive the core automatically and in synchronismwith the recorder chart so as to give a continuous curve showing the variationof liquid saturation along the length of the core. By determining the ratio ofthe two X-ray beam intensities simultaneously the measurements are madeessentially independent of small fluctuation in voltage and current supplied tothe tube. This improved technique has been used for investigating the fluiddistribution along the length of cores and core assemblies when one fluid isdisplaced by another. Typical results of these studies are shown.

Introduction

In a previous publication a method was described for measuring the oilsaturation in cores which was based on the absorption of X-rays by the fluidcontent of the core. While that technique is capable of yielding accurateresults, the original apparatus was not especially convenient for determiningthe fluid distribution along the length of a core. This was primarily due tothe slow response of the amplifier and galvanometer and the necessity of makinga point by point survey of the material under investigation. It was, therefore,not only possible for sections of the core having a variable or unusualsaturation distribution to escape observation entirely, but changes in outputof the X-ray generator between readings on the unknown and the monitorintroduced errors in the measurements that could be avoided only by furtherstabilization of the source or by taking a large number of readings.

This paper describes a method and apparatus for recording continuously andautomatically the intensity of the X-ray beam that is transmitted by a core.The variation of saturation with time at a given section of the core may thusbe found, or by scanning the core by driving it in synchronism with therecorder the saturation distribution may readily be determined.

T.P. 2881