Laboratory measurements of solubility and swelling factor for CO₂/Brine and CO₂/heavy oil binary systems under low‐medium pressure and temperature

Abstract

An extensive experimental study was performed to investigate the effect of various parameters such as temperature, pressure, and crude oil API gravity on the fluid interactions in the binary systems of brine-CO 2 and two heavy oil-CO 2 systems. The solubility of CO 2 in 20 000 ppm brine solution was measured at various experimental conditions. The solubility of CO 2 and swelling factor, due to the CO 2 dissolution, of two heavy crude oil samples (type-I: 8API ¼ 20.44 and type-II: 8API ¼ 15.49) were experimentally measured at various operating conditions.Results showed that the solubility of CO 2 in heavy oil increased when the experimental pressure increased, and when the experimental temperature decreased. At a constant pressure of P exp ¼ 3.44 MPa, the solubility of the CO 2 was measured to be 10.13, 5.72 g CO 2 /100 g oil in the type-I crude oil when the temperature increased from T ¼ 21 to 45 8C. Increasing the experimental pressure from P exp ¼ 1.38 MPa to 3.44 MPa at a constant temperature of T ¼ 21 8C increased the solubility of the CO 2 from 2.37 to 7.84 g CO 2 /100 g oil in the type-II crude oil. The reduction in the oil API gravity had an adverse effect on the CO 2 solubility. At a temperature of T ¼ 21 8C and a pressure of P exp ¼ 3.44 MPa, the CO 2 solubility decreased from $10.13 in the type-I oil to 7.84 g CO 2 /100 g oil in the type-II oil. The measured values of the swelling factor showed that the type-I and type-II crude oils could exhibit a maximum swelling factor of 1.079 and 1.052 at a temperature of T ¼ 21 8C and a pressure of P exp ¼ 3.44 MPa.

Volumetric Swelling of Bakken Crude Oil with Carbon Dioxide and Hydrocarbon Gases at 110 °C and Pressures of up to 34.5 Megapascals

“…In addition, carbon dioxide dissolves into the bulk water, which increases the water's acidity and ionic strength, factors that can affect the volumetric swelling of crude oil, as reported in "carbonated water" studies. 51,56,59,62,64 The volume increase of the oil-dominated phase with injected carbon dioxide is enhanced by having water in the cell at higher pressures, results that are consistent with the carbonated water observations of Nowrouzi et al 51 and Huang et al 63 Water also affects the shape of the oil expansion behavior. With no water present, oil swelling with carbon dioxide increases to its MMP of 17.5 MPa, then a drop in the volume of the oil-dominated phase is observed with increasing pressures as more oil hydrocarbons dissolve into the upper gas-dominated phase.…”

“…22 MPa. Both continuous oil swelling with carbon dioxide (with no plateau around MMP) and discontinuous oil swelling (where the oil-dominated phase increases in volume up to MMP, then shows no increase or even a drop in oil volume as pressure is increased to around the MMP, and then shows renewed swelling at higher pressures) have been reported. ,,,, Differences in the oil swelling profiles occur because the type of oil swelling behavior is influenced by the oil composition, injected gas, temperature, and the presence or absence of water. ,− ,,,,,,,, …”

“…All experiments were conducted at typical Bakken field conditions of 110 °C and pressures of up to 34.5 MPa (5000 psi). A variety of approaches have been used to determine crude oil swelling that can be categorized by those using a variable-volume cell − and those using a fixed-volume cell (most often by a “pendant drop” approach). − In the present work, volumetric swelling of the Bakken crude oil was performed using a tall and narrow fixed-volume high-pressure cell similar to the apparatus reported by Ren and Scurto and Tsau et al The use of this tall narrow cell allows simpler measurements of the changes in oil volume during gas injection than using the “pendant drop” methods that must measure the volume of the rounded “drop-shaped” oil sample. The cell used in the present work (“G” in Figure ) is rated at 34.5 MPA (5000 psi) and has an 8 mL internal volume and a 12- × 95 mm viewing window (Model TXT-11, Inferno Manufacturing Corporation, Shreveport, LA).…”

“…injected gas, temperature, and the presence or absence of water. 43,[45][46][47]49,50,52,54,59,61,63,66 Most oil swelling studies have focused on the use of carbon dioxide, and there is a lack of comparative experimental data for carbon dioxide and hydrocarbon gases. However, Yang and Gu 52 have reported a comparison of swelling behavior for a heavy oil at 24 °C using carbon dioxide, methane, ethane, and propane at fairly low pressures (up to supply tank pressures for each gas).…”

Long‐term CO2 sequestration mechanisms and influence of injection mode in Zhujiang Formation of Pearl River Mouth Basin

“…During this period, the pressure near the wellbore was also higher under a higher CO 2 injection flow rate, resulting in more dissolved CO 2 and thus more mineralized CO 2 . 65,66 However, after 5,000 years, compared with other cases, the proportion of dissolved CO 2 in Case 5 with the highest flow rate was the largest (which is 20.14%). Meanwhile, the proportion of mineralized CO 2 in Case 3 with the lowest flow rate was the maximum (which is 80.88%).…”