DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

Technical Report · Tue Jul 01 04:00:00 EDT 2003

DOI:https://doi.org/10.2172/820956· OSTI ID:820956

Mohanty, Kishore K

There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. We have conducted adsorption, phase behavior, interfacial tension (IFT) and wettability studies. Addition of Na{sub 2}CO{sub 3} decreases IFT with a minimum at about 0.2 M. Addition of surfactant decreases IFT further. In the absence of surfactant the minerals are oil-wet after aging with crude oil. Addition of surfactant solution decreases the contact angle to intermediate-wet for many surfactants and water-wet for one surfactant. Addition of Na{sub 2}CO{sub 3} decreases anionic surfactant adsorption on calcite surface. Plans for the next quarter include conducting core adsorption, phase behavior, wettability and mobilization studies.

• Research Organization: University of Houston (US)
• Sponsoring Organization: (US)
• DOE Contract Number: FC26-02NT15322
• OSTI ID: 820956
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
ADSORPTION
AGING
CALCITE
CARBONATES
ENHANCED RECOVERY
FRACTURED RESERVOIRS
FRACTURES
PETROLEUM
SANDSTONES
SOLUBILITY
SURFACTANTS
WATERFLOODING
WETTABILITY