Method to form a barrier in a reservoir with a magnetorheological fluid

The invention relates to a method of winning oil from a source via a bored well, wherein a magnetorheological fluid is introduced into the source via the bored well to re duce the water content of the oil won. Oil drilling is resumed in the presence of a magnetic field, thereby increasing the oil yield and/or decreasing the water content of the drilled oil.Civil Engineering and Geoscience

Method of drilling with magnetorheological fluid

A method of drilling a bore hole into a stratum, wherein via the drill hole drilling fluid is introduced and fed to the drill head. In order to avoid dilution or leak-off of the drilling fluid the same is in accordance with the invention a magnetorheological drilling fluid, and when an undesirable pressure difference occurs between the drilling fluid at the height of the drill head and a fluid present in the stratum surrounding the drill head, a magnetic field is applied. The inventions also provide a permanent solution.Civil Engineering and Geoscience

CT scan study of the leak-off of oil-based drilling fluids into saturated media

Leak-off of oil-based drilling mud into liquid-saturated cores was studied both theoretically and experimentally. First a simple model for the leak-off process was developed extending an earlier analysis of static filtration into unsaturated cores. Then CT scan aided static filtration experiments were performed in dry, brine-saturated and oil-bearing cores, simulating possible reservoir saturation regimes. Formation of external filter cake and internal filtration of solid particles were visualized and leak-off volumes were measured as function of time. At the end of the experiments the formed external filter cake and internal particle deposition were characterized with the aid of an Electron Scanning Microscope. Using drilling fluids containing carbonate particles it was found that leak-off volumes for saturated cores are larger than for unsaturated cores. It was observed further that leak-off volumes increase with particle size, i.e. consistently with a more permeable external filter cake and limited internal filtration. Leak-off volumes decreased when using smaller hematite particles or barite particles having wider particle distribution size.Dorien Frequin, Pavel Bedrikovetsky, Pacelli L.J. Zith

Alkali-surfactant foam improves extraction of oil from porous media

Capillary forces result in the trapping of the oleic phase in porous media even after extensive flushing with brine. Alkali-surfactant-polymer formulations drastically diminish capillary forces, whereas adding polymer to the water phase increases viscous forces, resulting in highly efficient extraction of the residual oil. However, by virtue of its scale, the above process requires a large quantity of chemicals, which poses a threat to the environment. Here, we demonstrate that replacing the polymer with a gas such as nitrogen, flue gas, or carbon dioxide achieves equally superior oil extraction efficiency when using a much smaller amount of chemicals. Mobilized oil is first displaced as a continuous phase (oil-bank) and then as an oil-in-water dispersion. Microflow visualization experiments reveal that dispersed oil spreads at the gas–liquid interface (surfactant solutions) due to the presence of adsorbed surfactant molecules. Our dry-cleaning extraction of hydrocarbons has a wide spectrum of applications and is particularly useful for the production of hydrocarbons from underground formations while mitigating the impact of chemicals on the environment.Petroleum EngineeringWind Energ

Characterization of interfacial effects during reactive transport with MRI methods

The alkoxysilane tetramethylorthosilicate (TMOS) is soluble and chemically stable in oil. Nevertheless, when a mixture of oil and TMOS is brought into contact with water, the compound is transferred from the oil phase into the water phase where it undergoes hydrolysis and, subsequently, the products of the hydrolysis condense into a gel. The coupled mass transfer and gelation processes give rise to an intriguing motion of the interface between the oleic and the aqueous phases. This phenomenon was analyzed in detail both theoretically and experimentally. The theory was developed assuming quasi-static conditions and provides a non-linear second-order boundary value problem, which was treated numerically. The experiments were done using magnetic resonance imaging (MRI) to quantify the fluids in the oil and water phases and capture the interface profiles between the oil and the water phases at time intervals. The mass transfer is complete after several hours. An excellent fit of the theoretical interface profiles to the experimental ones at various times reveals that the interfacial tension increases gradually during the extent of the mass transfer

Self-similar solutions for the foam drainage equation

The travelling wave solutions of the equation for foam drainage in porous media are developed taking into account the mass conservation criterion. The existence of traveling wave solutions is also discussed. Finally, numerical solutions are obtained using a finite difference scheme together with the Van Leer flux limiter, to reduce numerical dispersion. An excellent match is obtained between the analytical and the numerical solutions.Electrical Engineering, Mathematics and Computer Scienc

Method of hardening a fluid mass

The invention relates to a method of hardening a fluid mass in contact with a wall, in a desirable shape. According to the invention, the fluid mass is a magneto-rheological fluid mixture that in addition to at least one hardening component comprises a particulate magnetic component, with minimally 80% of said particles having a particle size of at least 0.0005 mm, and a magnetic field is applied for a length of time that suffices to achieve the desired strength by hardening in the absence of a magnetic field.Civil Engineering and Geoscience

Investigation of certain physical–chemical features of oil recovery by an optimized alkali–surfactant–foam (ASF) system

The objective of this study is to discover a synergistic effect between foam stability in bulk and micro-emulsion phase behaviour to design a high-performance chemical system for an optimized alkaline–surfactant–foam (ASF) flooding for enhanced oil recovery (EOR). The focus is on the interaction of ASF chemical agents with oil in the presence and absence of a naphthenic acid component and in situ soap generation under bulk conditions. To do so, the impact of alkalinity, salinity, interfacial tension (IFT) reduction and in situ soap generation was systematically studied by a comprehensive measurement of (1) micro-emulsion phase behaviour using a glass tube test method, (2) interfacial tension and (3) foam stability analysis. The presented alkali–surfactant (AS) formulation in this study lowered IFT between the oil and aqueous phases from nearly 30 to 10−1–10−3 mN/m. This allows the chemical formulation to create considerably low IFT foam flooding with a higher capillary number than conventional foam for displacing trapped oil from porous media. Bulk foam stability tests demonstrated that the stability of foam diminishes in the presence of oil with large volumes of in situ soap generation. At lower surface tensions (i.e. larger in situ soap generation), the capillary suction at the plateau border is smaller, thus uneven thinning and instabilities of the film might happen, which will cause acceleration of film drainage and lamellae rupture. This observation could also be interpreted by the rapid spreading of oil droplets that have a low surface tension over the lamella. The spreading oil, by augmenting the curvature radius of the bubbles, decreases the surface elasticity and surface viscosity. Furthermore, the results obtained for foam stability in presence of oil were interpreted in terms of phenomenological theories of entering/spreading/bridging coefficients and lamella number.Petroleum Engineerin

Systematic Phase Behaviour Study and Foam Stability Analysis for Optimal Alkaline/Surfactant/Foam Enhanced Oil Recovery

Alkaline-Surfactant-Foam (ASF) flooding is a recently introduced enhanced oil recovery (EOR) method. This paper presents laboratory study of this ASF to better understand its mechanisms. The focus is on the interaction of ASF chemical agents with oil and in the presence and absence of naphthenic component and in-situ soap generation. The impact of alkali, IFT reduction, in-situ soap generation and oil acid number were systematically studied by measurement of phase behaviour, interfacial tension and foam stability. Phase behaviour results indicate the synergistic effect between the generated soap and synthetic surfactant, which gives wider range of optimal salinity in terms of IFT reduction. The novel alkali-surfactant formulation lowered IFT between oil and aqueous phase from nearly 30 mN/m to 10-1 - 10-3 mN/m. This means that chemical formulation can create low tension foam flooding with higher capillary number than conventional foam for displacing oil from porous media. In the foam stability analysis of ASF agent in the presence and absence of oil, several characteristics such as foam volume evolution, foam half decay time, liquid fraction of foam were measured over a wide range of surfactant, alkali, electrolyte and naphthenic acid concentration. Bulk foam stability tests demonstrated that stability of foam diminishes in presence of oil with high in-situ soap generation. The obtained results for foam stability in the presence of oil were successfully interpreted in terms of phenomenological theory of entering/spreading/bridging coefficient, lamella number and pseudo-emulsion film. The discussed method in this paper can be successfully applied to formulate high performance chemical agents for achievement of improved foam flooding according to reservoir fluid condition, i.e. properties of crude oil and formation water.Geoscience & EngineeringCivil Engineering and Geoscience