Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
The influence of temperature and pressure on precipitation and subsequent scale formation of barium and strontium sulphates during enhanced oil recovery processes
Submission Author:
Levy Bertoletti , PR
Co-Authors:
Levy Bertoletti, Jefferson Lima Andrade, Vinicius Gustavo Poletto , Fernando Cesar De Lai, Silvio L. M. Junqueira, Luciano Rossi, Andre Leibsohn Martins
Presenter: Levy Bertoletti
doi://10.26678/ABCM.COBEM2021.COB2021-1757
Abstract
One of the most important problems in oil industries today is flow assurance. Keeping the oil reservoir at high pressure to maximize production output and to avoid scale formation is the challenge. Injected water usually comes from seawater due to practicability, low investment and ease of operation in relation to other fluids. Formation or connate water is the one trapped in the interstices of sedimentary rock of reservoirs. It presents considerable concentrations of alkaline and alkaline earth metals, such as barium (Ba2+), strontium (Sr2+) and calcium (Ca2+). As the injection water has a high concentration of sulphate ions (SO42-), formation and precipitation of inorganic compounds may occur due to its incompatibility when mixed with the formation water. Temperature and pressure also strongly influence precipitation, especially when it leads to supersaturation. Therefore, it is essential to understand the process that takes the precipitated particles to an eventual adhesion to the pipeline walls, a process so-called scale formation. In addition to causing stoppages on the production line, scaling requires the use of specific equipment that can reach values in the order of millions of dollars. Also, there is the need for improvements in the techniques of preventing and removing the scales. In the present work, a methodology that has already been used successfully to predict precipitation and calcium carbonate scale is applied to barium and strontium sulphates. For a given salt solubilization capacity, the proposed model predicts precipitation and subsequent formation of barium and strontium sulphates scaling using thermodynamic equations of pressure, temperature, and concentration. For a pressure ranging from 1 bar to 100 bar and temperature from 0°C to 100°C, compared to other models and software, the approach presented proves to be a good choice; for barium sulphate values vary from 0.01% to 0.1%, for strontium sulphate values vary from 0.13% to 0.62%.
Keywords
Enhanced oil recovery, Inorganic scale, Thermodynamics, Sulphates
