Solubility of Barite up to 250 °C and 1500 bar in up to 6 m NaCl Solution

Abstract

The ultrahigh temperature (150–200 °C), pressure (1000–1500 bar), and TDS (over 300 000 mg/L) encountered in oil and gas production from deepwater pose significant challenges to scaling prediction and control. An apparatus has been built to test scale formation at temperature up to 250 °C and pressure to 1700 bar (24 000 psi). The study expands the current knowledge of Barite (BaSO4) solubility to the condition of high temperature, pressure, and ionic strength. By fitting Pitzer’s model to experimental solubility data, this study also provides a feasible approach to assess the temperature and pressure dependence of virial coefficients in the Pitzer’s equations of ion activity coefficients through measurement of mineral solubility. The prediction of Barite solubility made by the Brine Chemistry Consortium software ScaleSoftPitzer (SSP) that has incorporated the newly developed coefficients is consistent with experimental measurement.

Improvement of Thermodynamic Modeling of Calcium Carbonate and Calcium Sulfates at High Temperature and High Pressure in Mixed Electrolytes

“…Scale prediction and control need good understanding of the thermodynamic and kinetic properties of common minerals over such temperature, pressure, and TDS ranges Shi et al 2012). However, Figure 1 shows that the typical temperature, pressure and TDS ranges of existing thermodynamic data (i.e.…”

“…Such brine water mixture and temperature and pressure changes will lead to a great potential for scale formation which will cost millions of dollars per year. In the past, in order to solve the scale problem, many researchers have focused on properties of common minerals including barite (BaSO 4 ), calcite (CaCO 3 ), calcium sulfates (CaSO 4 · nH 2 O, anhydrite (n = 0), hemihydrate (n = 0.5), or gypsum (n = 2)), celestite (SrSO 4 ), halite (NaCl), silica or silicate, siderite (FeCO 3 ), sulfides (FeS, FeS 2 , PbS, CaS, and ZnS), and dolomite (CaMg(CO 3 ) 2 ) (Blount and Dickson 1969;Blount and Dickson 1973;Pitzer et al 1984;Johnson and Tomson 1991;Kaasa 1998;Duan and Li 2008;Lu et al 2010;Okocha and Sorbie 2010;Kan and Tomson 2012;Shi et al 2012;Shi et al 2013). However, the thermodynamic properties of most minerals, especially at HTHP in complex electrolytes solutions, have not been thoroughly analyzed.…”

“…Solubility measurement at high temperature and high pressure 3.1. Apparatus and chemicals Shi et al (2012Shi et al ( , 2013 have designed a novel apparatus for solubility measurement of minerals at high temperature (up to 250 o C) and pressure (up to 24000 psi), and measured the solubility of barite and calcite (Shi et al 2012;Shi et al 2013). As is shown in Figure 11 and Figure 12, the solids (gypsum, 99.998% trace metals basis, Sigma-Aldrich; anhydrite, 99%, Acros Organics) were packed in a stainless steel column (SS316, High Pressure Equipment Company, packed porosity is 50%; for gypsum, the total volume is 9 mL, and for anhydrite, the total volume is 24 mL) with 0.2 µm filter at the end of it, and it is enclosed in the oven within which the temperature can be kept Compared with the apparatus designed by Dickson et al (1963), this novel apparatus has several advantages.…”

Thermodynamic Model Improvements for Common Minerals at High Temperature, High Pressure and High TDS with Mixed Salts

“…In this paper, K sp, BaSO4 values are obtained by regression of high temperature-high pressure data reported by Helgeson and others as those used in SOLMINEQ.88 (Kharaka et al, 1989). The comparisons of these data from various resources can be seen in our previous paper (Shi et al, 2012).…”

“…Scale prediction in such conditions relies on a thorough understanding of the thermodynamic and kinetic properties of common mineral salt precipitation at such ranges of temperature, pressure and TDS (Shi et al, 2012). For instance, scale prediction requires precise values of both equilibrium constants (including solubility product of the minerals, K sp , and other association constants for complexes, if applicable) and activity coefficients at different temperature, pressure and brine composition.…”