TY - THES

T1 - Emulsions and Wettability Observations in Powdered Rock

AU - Wimmer, Christian

N1 - embargoed until 03-09-2020

PY - 2019

Y1 - 2019

N2 - Designing EOR methods like low salinity waterflooding, requires an accurate assessment of the wettability of the oil-water-reservoir rock system and a vast understanding of the mechanisms that define this property. Wettability tests by optical contact angle measurement on the rock surface or as a function of displacement properties within an intact core are common, but undamaged cores can be hard to retrieve. The possibility of determining the wettability from sedimentation tests of fine powder gathered by crushing rocks, is examined experimentally. Crushed Eagle Ford Rock, Bentonite, Illite, Kaolinite and Silica Flour are rained on polar and non-polar interfaces and their residence time is recorded on video and analyzed in Matlab. Varying the salinity and the pH-value of the brine and the chemical composition of the hydrocarbon phase influences the residence time of the particles at the interfaces. Pickering emulsions are investigated in theory and experimentally. Although surfactant-based emulsions are the industry standard in many EOR applications, the interest in nanoparticles serving as emulsifiers increased recently, due to their simplicity and resistance to coalescence. In a series of tests, they are formed by shaking vials containing the same particles used in the sedimentation tests. The observed emulsion type depends on the wettability of the particle. Water-wet particles form oil-in-water emulsions. Conversely, oil-wet particles form emulsions consisting of water droplets in oil. The droplet size of the dispersed phase and the stability of the emulsion is influenced by the salinity of the brine. The sedimentation and emulsion tests are complemented by a series of imbibition tests, in which water imbibes kerosene-saturated pastes of different particles. The associated capillary forces cause fines migration and compaction leaving behind desiccation cracks. Imbibition and desiccation crack highlight water-preference, in other words water-wet mineral surfaces.

AB - Designing EOR methods like low salinity waterflooding, requires an accurate assessment of the wettability of the oil-water-reservoir rock system and a vast understanding of the mechanisms that define this property. Wettability tests by optical contact angle measurement on the rock surface or as a function of displacement properties within an intact core are common, but undamaged cores can be hard to retrieve. The possibility of determining the wettability from sedimentation tests of fine powder gathered by crushing rocks, is examined experimentally. Crushed Eagle Ford Rock, Bentonite, Illite, Kaolinite and Silica Flour are rained on polar and non-polar interfaces and their residence time is recorded on video and analyzed in Matlab. Varying the salinity and the pH-value of the brine and the chemical composition of the hydrocarbon phase influences the residence time of the particles at the interfaces. Pickering emulsions are investigated in theory and experimentally. Although surfactant-based emulsions are the industry standard in many EOR applications, the interest in nanoparticles serving as emulsifiers increased recently, due to their simplicity and resistance to coalescence. In a series of tests, they are formed by shaking vials containing the same particles used in the sedimentation tests. The observed emulsion type depends on the wettability of the particle. Water-wet particles form oil-in-water emulsions. Conversely, oil-wet particles form emulsions consisting of water droplets in oil. The droplet size of the dispersed phase and the stability of the emulsion is influenced by the salinity of the brine. The sedimentation and emulsion tests are complemented by a series of imbibition tests, in which water imbibes kerosene-saturated pastes of different particles. The associated capillary forces cause fines migration and compaction leaving behind desiccation cracks. Imbibition and desiccation crack highlight water-preference, in other words water-wet mineral surfaces.

KW - Wettability

KW - EOR

KW - Pickering emulsion

KW - imbibition

KW - desiccation crack

KW - Benetzung

KW - Tertiäre Ölgewinnung

KW - Pickering-Emulsion

KW - Trocknungsrisse

M3 - Master's Thesis

ER -