Wettability alteration and oil recovery by spontaneous imbibition of smart water and surfactants into carbonates

Abstract

Naturally fractured carbonate reservoirs have very low oil recovery efficiency owing to their wettability and tightness of matrix. However, smart water can enhance oil recovery by changing the wettability of the carbonate rock surface from oilwet to water-wet, and the addition of surfactants can also change surface wettability. In the present study, the effects of a solution of modified seawater with some surfactants, namely C 12 TAB, SDS, and TritonX-100 (TX-100), on the wettability of carbonate rock were investigated through contact angle measurements. Oil recovery was studied using spontaneous imbibition tests at 25, 70, and 90 °C, followed by thermal gravity analysis to measure the amount of adsorbed material on the carbonate surface. The results indicated that Ca 2+ , Mg 2+ , and SO 4 2− ions may alter the carbonate rock wettability from oil-wet to water-wet, with further water wettability obtained at higher concentrations of the ions in modified seawater. Removal of NaCl from the imbibing fluid resulted in a reduced contact angle and significantly enhanced oil recovery. Low oil recoveries were obtained with modified seawater at 25 and 70 °C, but once the temperature was increased to 90 °C, the oil recovery in the spontaneous imbibition experiment increased dramatically. Application of smart water with C 12 TAB surfactant at 0.1 wt% changed the contact angle from 161° to 52° and enhanced oil recovery to 72%, while the presence of the anionic surfactant SDS at 0.1 wt% in the smart water increased oil recovery to 64.5%. The TGA analysis results indicated that the adsorbed materials on the carbonate surface were minimal for the solution containing seawater with C 12 TAB at 0.1 wt% (SW + CTAB (0.1 wt%)). Based on the experimental results, a mechanism was proposed for wettability alteration of carbonate rocks using smart water with SDS and C 12 TAB surfactants.

A Data Mining Perspective on the Confluent Ions` Effect for Target Functionality

“…The data used in the present work was obtained from the open literature as well as our own experiments [4,25,[27][28][29][30]. As explained earlier, the data was collected so as to target three main functionalities minimizing permeability impairment (I), minimizing the possibility of scale damage in the field (II), maximizing oil recovery from matrix (III).…”

Probing surface interactions of underwater oleophobic polyelectrolyte multilayers

“…The wettability of solid surface has long been the spotlight of scientific research due to its substantial application in lubrication, waterproofing, antifouling, self-cleaning, and oil/water separation, in relation to industrial engineering applications such as in agricultural pesticide, electric power transmission, detergents, petroleum production, material modification, and biomedicine (Zheng et al 2010;Guo et al 2012;Song et al 2019;Rostami et al 2019;Ehsan et al 2019;Luo et al 2016;Sudha et al 2019;Ahmadi et al 2020). The fundamental theory of wetting is properly expressed by Young's equation (Young 1805), which describes the spontaneous wetting mechanism of a solid surface.…”

Mechanism of Permeability and Oil Recovery during Fracturing in Tight Oil Reservoirs

“…Fern et al [8][9][10][11][12] used nuclear magnetic resonance imaging (MRI) to monitor the self-absorption process of the rock, studied the evolution process of percolation and oil recovery in core samples and found that reverse percolation and absorption only occurred in the first time [13]. Chapman [14] studied the influence of pore shape and throat width on fluid displacement through a microetching model and observed the distribution characteristics of oil and water in pores in the process of infiltration and absorption. However, the microetching model and the nuclear magnetic technology could only study the mechanism of percolation and absorption; hence, the variation characteristics of percolation and absorption could not be quantitatively described.…”