Sharif Digital Repository

Gas injection is the second largest enhanced oil recovery process being applied in many reservoirs around the world. Simulation of these processes is necessary for implementation, management, and decision making. Relative permeability is one of the most important factors in numerical reservoir simulation. In this study, several core flood experiments are done and the relative permeability in carbon dioxide (CO2) injection is compared with nitrogen (N2) injection. Oil relative permeability in CO 2 injection is found to be higher than in N2 injection, but gas relative permeability in CO2 injection is found to be lower than in N2 injection. Higher oil relative permeability in CO 2 injection... 

In an experimental study, investigation is performed based on the surface-mounted hot-film sensors and surface pressure and rake pressure measurements. The boundary-layer (BL) events such as laminar separation (LS), transition onsets, and variations of the wall shear stress are discussed and compared for both pitching and plunging oscillations for various cases of before, within, and beyond the static stall angle of attack (AOA) conditions. All experiments are conducted in a low-speed wind tunnel. The surface pressures are measured using differential pressure sensors with a range from 0.075 to 1.0 psi and with a maximum error of 0.15% of their full span. In addition, the wake profile behind... 

In an experimental study, investigation is performed based on the surface-mounted hot-film sensors and surface pressure and rake pressure measurements. The boundary-layer (BL) events such as laminar separation (LS), transition onsets, and variations of the wall shear stress are discussed and compared for both pitching and plunging oscillations for various cases of before, within, and beyond the static stall angle of attack (AOA) conditions. All experiments are conducted in a low-speed wind tunnel. The surface pressures are measured using differential pressure sensors with a range from 0.075 to 1.0 psi and with a maximum error of 0.15% of their full span. In addition, the wake profile behind... 

An experimental investigation has been carried out to verify characteristics of pressure fluctuations inside a circular, horizontal and inclined pipeline (90mm inside diameter and 10 m long) carrying two-phase air-water flow in a controlled manner (operating at room temperature and normal pressure). The pressure fluctuation was considered to be due to interaction between the fluid and air bubble compressibility in the pipe. The fluctuating pressure was studied in detail while the flow pattern was mainly slug, wavy or stratified flow. The tests were carried out varying with time, space, water flow rate/air flow rate ratio and pipe inclination. The pressure fluctuations were measured... 

This work aims to discuss the results of wide ranges of laboratory investigations to evaluate the performance of a newly-formulated surfactant for heavy oil reservoirs in order to improve the microscopic sweep efficiency after water flooding processes. In the first part, the specific behavior of the formulated surfactant including its salinity tolerance, interfacial tension, and optimum performance window was determined. Then, the application of surfactant solutions in real sandstone reservoir rocks was assessed for both oil-wet and water-wet cases. Besides, the effect of changing the capillary and viscous forces and interfacial tension on the residual phase saturations were characterized.... 

This work aims to discuss the results of wide ranges of laboratory investigations to evaluate the performance of a newly-formulated surfactant for heavy oil reservoirs in order to improve the microscopic sweep efficiency after water flooding processes. In the first part, the specific behavior of the formulated surfactant including its salinity tolerance, interfacial tension, and optimum performance window was determined. Then, the application of surfactant solutions in real sandstone reservoir rocks was assessed for both oil-wet and water-wet cases. Besides, the effect of changing the capillary and viscous forces and interfacial tension on the residual phase saturations were characterized.... 

The study of air-water, two-phase flows in hydraulic structures such as pressurized flow tunnels, culverts, sewer pipes, junctions, and similar conduits is of great importance for design purposes. Air can be provided by vortices at water intakes, pumping stations, aerators, steep channels, etc. Under certain conditions, air may also be introduced into pressurized intake systems, which may form large bubbles in portions of the pipe. The bubbles may, in turn, cause an unstable slug flow, or other flow patterns, that leads to sever periodic transient pressure. In this paper, an experimental model (a circular and transparent pipeline, 90 mm in ID and 10 m in length) is used to predict pressure... 

In this paper, the impact of three parameters including nanoparticles geometry, particles aggregation and borehole inclination on induced formation damage from water based drilling fluids were investigated by means of experimental studies. Accordingly, we designed a dynamic filtration setup capable to rotate and change well inclination. Nano-based drilling fluids consisting of spherical, cubical and tubular shapes nanoparticles as fluid loss additives were used. Mud cake quality, core permeability impairment and degree of formation damage at various well inclinations were examined. The cluster structure of aggregated particles were determined using fractal theory and applying dynamic light... 

In this paper, the impact of three parameters including nanoparticles geometry, particles aggregation and borehole inclination on induced formation damage from water based drilling fluids were investigated by means of experimental studies. Accordingly, we designed a dynamic filtration setup capable to rotate and change well inclination. Nano-based drilling fluids consisting of spherical, cubical and tubular shapes nanoparticles as fluid loss additives were used. Mud cake quality, core permeability impairment and degree of formation damage at various well inclinations were examined. The cluster structure of aggregated particles were determined using fractal theory and applying dynamic light... 

The present study examined the effect of nanoparticle size and geometry on filter cake buildup during dynamic filtration using experimental and modeling approaches. A dynamic filtration setup was proposed and designed to test cross-flow circulation against a synthetic core at a constant differential pressure. The proposed mathematical model considers the critical deposition boundary of the porous media for particles along with drag, lift, friction, buoyancy, permeate, and electrostatic forces. The comprehensive model response allowed investigation of the aggregation and shape of nanoparticles at different cross-flow inclinations. The drag and lift force coefficients and moment of inertia of... 

The strength of a newly formulated surfactant with an alkali and polymer (AS/ASP) to improve an acidic heavy oil recovery was laboratory evaluated by various flooding experiments. The comparative role of the parameters like chemical nature, surface wettability, salinity, temperature and injection scheme were explored at high temperature and pressure on Berea sandstone rocks. According to the results the anionic surfactant is capable of providing proper oil displacement under high salinity conditions around 15 wt%. Continuous monitoring of differential pressure response and effluents’ state clearly represented the formation of an emulsified oil in high saline solutions with both alkali and... 

Nitrogen has emerged as a suitable alternative to carbon dioxide for injection into hydrocarbon reservoirs worldwide to enhance the recovery of subsurface energy. Nitrogen typically costs less than CO2 and natural gas, and has the added benefit of being widely available and non-corrosive. However, the underlying mechanisms of recovery following N2 injection into fractured reservoirs that make up a large portion of the world's oil and gas reserves are not well understood. Here we present the laboratory results of N2 injection into carbonate rocks acquired from a newly developed oil reservoir in Iran with a huge N2-containing natural gas reservoir nearby. We investigate the effectiveness of N2...