The Control of Apparent Wettability on the Efficiency of Surfactant Flooding in Tight Carbonate Rocks

Abstract

In this research, a state-of-the-art experimental core flooding setup is used to assess the efficiency of surfactant flooding as an enhanced oil recovery (EOR) technique in tight carbonate rocks. Specifically, we investigate the role of apparent wettability in governing the effectiveness of surfactant flooding. A series of flooding experiments with well-defined boundary conditions were performed on the low permeability core plug samples of Indiana Limestone (calcite-cemented carbonate grainstones). Experiments were conducted on three samples exhibiting differing apparent wetting characteristics: strongly oil-wet, moderately oil-wet and weakly oil-wet. Initially, the oil-saturated core samples were flooded with brine until the residual oil saturation was achieved, with surfactant flooding performed as a tertiary recovery technique. Interestingly, our experimental results reveal that the efficiency of surfactant flooding increases with the degree of oil-wetness of the tight carbonate rocks. The strongly oil-wet core showed the highest recovery, while the weakly oil-wet core manifested the least additional oil recovery associated with surfactant flooding. Moreover, we provided a pore-scale argument that explains the macroscopic role of surfactant flooding in tight carbonate rocks. We hypothesized that at the pore-scale the presence of thin film plays a critical role in controlling the effectiveness of surfactant flooding in the strongly oil-wet tight carbonate rocks. Overall, we believe that our macroscopic study provides novel insight into the dynamics of surfactant flooding in tight carbonate reservoirs and can aid in optimizing the field development plans for oil recovery.

Surrogate Models for Studying the Wettability of Nanoscale Natural Rough Surfaces Using Molecular Dynamics

“…Correspondingly, the investigated surfaces within the rock may be facets resulting from both the initial growth and mechanical or chemical modifications afterward. Due to the simple macroscopic pore structure, this rock type is often used for multiphase flow studies, such as CO 2 injection or oil recovery in conjunction with micro computed tomography (µCT) imaging [8,31,[70][71][72].…”

“…In the energy industry, the consequences of changes in the wettability of natural rocks have an impact on all aspects of fossil fuel production and enhanced oil recovery processes. In sub-surface fluid reservoirs, such as oil reservoirs, CO 2 storage, or energy storage sites, wettability is known to control the flow efficiency and dynamics [6][7][8]. In computational models, aiming to predict this behavior, the wetting behavior is commonly reflected through contact angles [9,10].…”

Estimating of Non-Darcy Flow Coefficient in Artificial Porous Media

“…Single-phase flow experiments in heterogeneous core samples Shachi et al [36] and two-phase flow modeling homogeneous core samples [37] were performed. We have also completed several studies related to foam flow in heterogeneous core samples without the presence of oil [38,39]. We have also created synthetic core samples and a perforation tunnel to conduct single-phase flow experiments and model a peroration tunnel [40][41][42][43].…”

Insights into Enhanced Oil Recovery by Polymer-Viscosity Reducing Surfactant Combination Flooding in Conventional Heavy Oil Reservoir

“…In addition, the high consumption of alkali for the heavy oil with low acid number, which will lead to saltsensitive effect and reduce the viscosity. Thus, due to the existence problems of severe scale formation and disposal of produced emulsions, surfactant-polymer (SP) flooding has gained more interests for enhancing oil recovery in recent years [45][46][47][48][49][50]. In fact, SP flooding pilots have been performed and proven to be efficient in many light oil reservoirs.…”