pH Measurements in Aqueous CO₂Solutions under High Pressure and Temperature

Abstract

In order to determine the acidity of corrosive media prevailing in oil and gas wells where 00 2 corrosion is encountered, a pH meter has been built which enables pH measurements under pressures from 0.1 up to 100 MPa. The usual physical chemistry of calcocarbonic equilibria is also presented in a new form which better emphasizes the influence of the partial pressure of CO2 as the controlling variable in the system. According to both theoretical and experimental results, the pH of a production water depends as much upon its alkalinity as upon the level of the 002 partial pressure. The effect of calcareous saturation or supersaturation is also emphasized. It is then shown through a survey of production waters that their acidity under well conditions is much weaker than is commonly assumed. This stands for both 00 2 corrosion and sulfide stress cracking.( '>Trade marks.

CO2 Corrosion in the Region Between the Static and Turbulent Flow Regimes

“…There is a wide variety of models for understanding the CO 2 corrosion of carbon steel 2,3,4,5,6,7 . It is known that the CO 2 effect is associated with the increased amount of hydrogen developed in the cathode and with the formation of an iron carbonate film as a corrosion product on the steel surface.…”

Propuesta Para La Mejora De Las Facilidades De Producción Del Campo A

“…Consecuentemente, hay una clara necesidad de caracterizar la química de la solución con respecto a la disolución del CO 2 donde la acidificación resultante dependerá también de la composición del agua y de su capacidad buffer (Crolet & Bonis, 1983). …”

Application limits of stainless steels in the petroleum industry

“…For conventional oilfield applications, the following parameters must be known: l Service temperature and pressure l Maximum stress level l Chloride content of carried fluid l Process contaminants (e.g., oxygen) l Added chemicals, especially acids l H 2 S and CO 2 partial pressures Another important parameter is pH, which is difficult to determine in situ, but can be estimated based upon the above data, since in an aqueous solution it is controlled essentially by the acid gases CO 2 and H 2 S. An extensive discussion on the matter is provided by Crolet and Bonis [1,2].…”