(475h) Boiling Points of Hydrocarbons in Nanoporous Media at High Pressures Using Differential Scanning Calorimetry Measurements

The United States produced close to 11 million barrels of oil per day in the first three months in 2019. A significant portion of this oil comes from tight oil plays in the Permian basin and other shale plays. Imaging and characterization studies have shown that the pore sizes in rocks from tight oil plays are of the order of 5-10 nanometers. It is known that fluid properties are different in such small pores. The purpose of this paper is to measure boiling points of hydrocarbons at pressures higher than atmospheric in materials that consist of pores of similar sizes and compare them to bulk boiling points.

Two silica based mesoporous materials with internal average pore size of about 4 nm were first synthesized. SBA-15 has ordered hexagonal pores while SBA-16 is characterized by ordered cubic pores. Boiling points of heptane and toluene were measured in these materials using a high-pressure differential scanning calorimetry instrument. Boiling points were also measured in the bulk and with sand (with no internal pore structure) for comparison. Boiling points were measured at 1, 7 and 13 bar pressures.

The boiling points were higher at all of the pressures studied, and for all the fluids for SBA-15 and SBA-16 in comparison to the bulk and sand measurements. It was thus possible to generate vapor-pressure curves under confinement for the fluids studied in this paper.