Analyses and Treatment of Oil Field Formation Water of Upper Assam Basin (India)

Abstract

Formation water constitutes the biggest oil by-product of oil exploration and production industries, which disturbs the ecological balance. In view of the above, this study is an attempt to examine the physical and chemical parameters of formation water and to determine the scaling potential of untreated and treated formation water by Ryznar stability index and Langelier saturation index calculators. Ten samples of crude oil containing more than 70% formation water are collected from the wellheads of ten production wells of the Upper Assam Basin. Analyses of the parameters of the separated formation water from crude oil are found to be outside the permissible range set by the Central Pollution Control Board of India which gives us a clear view that the untreated water cannot be discharged to the environment until proper treatment is done. The formation water samples are treated in a parallel flow hollow fiber membrane module by micro-filtration, ultra-filtration and nano-filtration membranes in sequence. The parameters of the treated samples by nano-filtration are found to be within the range set by the Central Pollution Control Board of India, therefore, it can be disposed of without affecting the environment. The scaling potentials are evaluated by Ryznar stability index and Langelier saturation index calculators of the untreated and treated formation water. The untreated water sample forms heavy scales than the treated ones.