Estimation of gas/liquid and oil/water interface levels in an oil/water/gas separator based on pressure measurements and regression modelling

Abstract

Gravity separators are widely used for separation of gas/oil/water/sand from both offshore and onshore oil production facilities. Estimation of the gas/liquid and oil/water interface levels in gravity separators have been a concern since these parameters are important for reliable operation. Most of the instruments on the market today do not provide reliable measurements of both gas/liquid and oil/water interface levels. The few instruments that do provide reliable measurements are however based on radioactive principles. Nevertheless these radioactive instruments possess a strong health, safety and environmental risk. An alternative inexpensive, environmentally friendly, accurate and cost effective way for gas/liquid and oil/water interface level estimation based on pressure measurement is presented. The root mean squared error of prediction (RMSEP) for gas/liquid and oil/water interface level estimation from traversing a pressure sensor based on partial least square regression (PLS-R) were 14.5 mm and 17.7 mm respectively. A comparison of results from models based on PLS-R and ordinary least square regression (OLS-R) techniques proved that the RMSEP from the PLS-R technique was better in estimating the oil/water interface level but in the case of gas/liquid interface level estimation the OLS-R technique was slightly better. It was concluded that the PLS-R technique provided a better overall result and is recommended  Corresponding author: e-mail: benjamin.k.arvoh@hit.no, Tel: +47 35575134, Telefax: +47 35575001 3 when pressure measurements in combination with multivariate data analysis is applied for gas/liquid and oil/water interface level estimations in gravity separators.

Liquid level gauge based in plastic optical fiber

“…This requirement is not only an individual company requirement, to control the company production efficiency and gains, but also a legal imposition to estimate fiscal taxes [1]. Usually, the liquid level in the container is measured by traditional technologies, such as differential pressure level meters, radar, magnetostrictive, or magnetic float technologies [2,3]. However, some limitation may apply, since such methods are electronic and the sensing system is often exposed to combustible liquids or accumulated flammable vaporous environments.…”

Estimation of the Filling Distribution and Height Levels Inside an Insulated Pressure Vessel by Guided Elastic Wave Attenuation Tomography

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A Continuous Liquid-Level Sensor for Fuel Tanks Based on Surface Plasmon Resonance

“…However, when the tank contains fuel and water, other methods have been proposed to detect the water content in the tank and to measure the levels of the water and fuel in the tank. These methods are based on acoustics [ 8 ], microwave reflection [ 1 ], reflectometry [ 9 , 10 ], electrode arrays [ 11 ], magnetic floats [ 12 ], pressure sensors [ 13 , 14 ], and capacitance sensors [ 15 ]. All these methods have advantages and disadvantages [ 16 , 17 ].…”