Author: Xinan LiuPublisher:
ISBN:
Category : Surface active agents
Languages : en
Pages : 460
Book Description
An Experimental Investigation of Effects of Surfactants on Spilling Breakers
Author: Xinan LiuPublisher:
ISBN:
Category : Surface active agents
Languages : en
Pages : 460
Book Description
Experimental Investigation of the Effect of Surfactants on CHF and MHF
Author: Joshua M. BorsariDissertation Abstracts International
Author: Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 674
Book Description
Experimental Investigation of Viscous Forces During Surfactant Flooding of Fractured Carbonate Cores
Author: Jose Ernesto Parra PerezPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The objective of this research was to investigate the effects of viscous forces on the oil recovery during surfactant flooding of fractured carbonate cores, specifically, to test the effects of using surfactants that form viscous microemulsions in-situ. The hypothesis was that a viscous microemulsion flowing inside a fracture can induce transverse pressure gradients that increase fluid crossflow between the fracture and the matrix, thus, enhancing the rate of surfactant imbibition and thereby the oil recovery. Previous experimentalists assumed the small viscous forces were not important for oil recovery from naturally fractured reservoirs (NFRs) since the pressure gradients that can be established are very modest due to the presence of the highly conductive fractures. Hence, the most common approach for studying surfactants for oil recovery from NFRs is to perform static imbibition experiments that do not provide data on the very important viscous and pressure forces. This is the first experimental study of the effect of viscous forces on the performance of surfactant floods of fractured carbonate cores under dynamic conditions. The effects of viscous forces on the oil recovery during surfactant flooding of fractured carbonate cores were tested by conducting a series of ultralow interfacial tension (IFT) surfactant floods using fractured Silurian Dolomite and Texas Cream Limestone cores. The viscosity of the surfactant solution was increased by adding polymer to the surfactant solution or by changing the salinity of the aqueous surfactant solution, which affects the in-situ microemulsion viscosity. The fractured cores had an extreme permeability contrast between the fracture and the matrix (ranging from 2500 to 90,000) so as to represent typical conditions encountered in most naturally fractured reservoirs. Also, non-fractured corefloods were performed in cores of each rock type for comparison with the results from the fractured corefloods. In all the experiments, the more viscous surfactants solutions achieved the greater oil recovery from the fractured carbonate cores which contradicts conventional wisdom. A new approach for surfactant flooding of naturally fractured reservoirs is presented. The new approach consists of using a surfactant solution that achieves ultralow IFT and that forms a viscous microemulsion. A viscous microemulsion can serve as a mobility control agent analogous to mobility control with foams or polymer but with far less complexity and cost. The oil recovery from the fractured carbonate cores was greater for the surfactant floods with the higher microemulsions, thus, it is expected that using viscous microemulsion can enhance the oil recovery from naturally fractured reservoirs.
American Doctoral Dissertations
Author: Publisher:
ISBN:
Category : Dissertation abstracts
Languages : en
Pages : 776
Book Description
The Wind-driven Air-sea Interface
Author: M. L. BannerPublisher:
ISBN:
Category : Ocean waves
Languages : en
Pages : 478
Book Description
Experimental Study of Transitional Behaviour of Soluble Surfactants and Effect of Molecular Shape
Author: Mark W. D. GrattanInvestigation of the Effects of Surfactants on Dewatering Efficiency
Author: Josephine SumMulti-scale Investigations of the Impact of Surfactant Structure on Oil Recovery from Natural Porous Media
Author: Vahideh MirchiPublisher:
ISBN: 9780438886384
Category : Enhanced oil recovery
Languages : en
Pages : 181
Book Description
This study aims at establishing structure-function relationships relevant to surfactant-based enhanced oil recovery (EOR) under different wettability conditions. We present the results of an extensive, multi-scale experimental study designed to probe the effects of surfactant molecular structure on oil displacement in sandstone and carbonate rock samples. Initially a new framework was developed to methodically characterize the effect of surfactants on fundamental parameters governing fluid displacement in brine/oil/tight rock systems at reservoir conditions. For that, we present a detailed methodology for measuring the interfacial properties of these systems, including rock substrate preparation, thin needle utilization, fluid pre-equilibration, in-line density measurements, all of which are critically important due to surfactant partitioning in brine and oil phases. The experimental framework was first validated with simple ultra-low IFT systems using the rising/captive bubble technique, then the effect of pressure, temperature, surfactant concentration, and brine chemistry on IFT and CA were investigated in a systematic manner. Subsequently, the framework was used to examine the effect of hydrophobic and hydrophilic chain lengths of polyoxyethylenated nonionic surfactants on dynamic interfacial properties in porous media. It included comprehensive experimental examination of phase behavior, cloud point temperature, dynamic interfacial tension, dynamic contact angle, and spontaneous and forced imbibitions at ambient and reservoir conditions. This resulted in development of a new insight that relates the speed by which surfactants reduce interfacial tension to oil-brine displacement efficiency. This relationship was reconfirmed by examining pore-fluid occupancies generated through surfactant imbibition in micromodels. In order to directly study pore-level fluid distributions as a function of surfactant structure, a state-of-the-art X-ray micro-CT scanner integrated with a miniature core-flooding apparatus was deployed to generate three-dimensional pore-fluid occupancy maps at the pore scale. The core-flooding results revealed that there is an additional set of factors besides pore geometry, rock surface wettability, fluid-fluid interfacial tension, and fluids’ viscosities, densities, and flow rates that directly contributes to the distribution of fluids at the pore scale. We demonstrate that under similar rock and fluid properties, interfacial repulsive and attractive interactions, caused by the adsorption of surface-active chemicals on fluid-fluid interfaces, can significantly alter pore-scale fluid occupancies. Oil cluster analyses along with three-dimensional (3D) visualization of fluid distributions indicate that using the nonionic surfactant with large head instead of the anionic surfactant with small head results in the breaking up of the large and medium oil clusters into smaller and scattered ones. We propose a mechanism relating the stability of oil-brine interface to surfactant structure that is responsible for the break-up and/or coalescence of oil clusters inside the pore space. The suggested mechanism is confirmed by the micro-CT images and associated oil cluster analyses. This phenomenon affects the competition between the frequency of displacement mechanisms causing variations in remaining oil saturations. Using the same microtomography technique, we developed a significantly-improved understanding of pore-level displacement mechanisms during low-salinity surfactant flooding in oil-wet carbonates. In this contribution, in-situ fluid distribution maps, in-situ contact angles, and thicknesses of wetting oil layers were investigated under different brine salinities in the presence and absence of a cationic surfactant at elevated pressure and temperature conditions. The investigation revealed that enhanced oil production during low-salinity surfactant waterflooding is caused by several factors such as a rapid alteration of in-situ contact angles toward neutral-wet state, layer thinning of the oil phase, and an increase in the contribution of small-sized pores to the total oil production. The wettability reversal was more profound when the surfactant injection was succeeding a low-salinity waterflooding. The insights gained in this work using different surfactant molecular structures, rock types, brine salinities, and wettability conditions have direct implications for the design of more effective surfactant-based EOR projects.
Gas Transfer at Water Surfaces
Author: M. A. DonelanPublisher: American Geophysical Union
ISBN:
Category : Science
Languages : en
Pages : 410
Book Description
The book discusses the complex phenomena of gas transfer processes within the sciences of fluid dynamics and biogeochemistry. It covers: 1.) Effects of surface waves and turbulence on gas transfer. 2.) Effects of buoyancy and surfactants on gas transfer. 3.) Gas gransfer in strong turbulent flows. 4.) Remote sensing for large-scale gas transfer. 5.) gas transfer by aeration.