Measurement of streaming potential coupling coefficient in sandstones saturated with natural and artificial brines at high selenity

We report experimental measurements of the streaming potential coupling coefficient in sandstones saturated with NaCl-dominated artificial and natural brines up to 5.5 M (321.4 g L−1 of NaCl; electrical conductivity of 23 S m−1). We find that the magnitude of the coupling coefficient decreases with increasing brine salinity, as observed in previous experimental studies and predicted by models of the electrical double layer. However, the magnitude of the coupling coefficient remains greater than zero up to the saturated brine salinity. The magnitude of the zeta potential we interpret from our measurements also decreases with increasing brine salinity in the low-salinity domain (0.4 M). We hypothesize that the constant value of zeta potential observed at high salinity reflects the maximum packing of counterions in the diffuse part of the electrical double layer. Our hypothesis predicts that the zeta potential becomes independent of brine salinity when the diffuse layer thickness is similar to the diameter of the hydrated counterion. This prediction is confirmed by our experimental data and also by published measurements on alumina in KCl brine. At high salinity (>0.4 M), values of the streaming potential coupling coefficient and the corresponding zeta potential are the same within experimental error regardless of sample mineralogy and texture and the composition of the brine

Foam stability performance enhanced with rice husk ash nanoparticles

The objective is to study the effectiveness of using nano-sized rice husk ash (nano-RHA) as an additive to stabilize normal gas generated surfactant foam used in enhanced oil recovery. To decrease the size of the RHA into nano range, planetary ball mill was used in both dry grinding and wet grinding. Different surfactants including anionic and non-ionic were used to study the polydispersity index of the dispersion and the hydrodynamic diameter using dynamic light scattering in dilute suspension. Besides, the nano-RHA was characterized using FESEM, EDX, XRD and the change in specific area after grinding process was studied using BET. The foamability of different surfactants were then studied using minor concentration of nano-RHA. Next, the concentration of the nano-RHA was varied from 0.1wt% to 0.9wt% in normal gas bulk foam stability test using the suitable surfactant, the texture of foam was observed as well. Moreover, the effect of oil on bulk foam was also studied. Finally, the result was compared using pure silica nanoparticles as the foam addictive at the same variation of concentrations. Dispersion stability tests showed that both anionic and non-ionic surfactants can be used to disperse nano-RHA in water. Furthermore, in the presence of 0.9wt% of nano-RHA concentration, the bulk foam stability test results revealed that the sodium dodecyl sulfate bulk foam half-life increased by 17.9% without the presence of oil, and gave an increment of 20.7% half-life in the presence of oil. Therefore, the study showed a potential of utilizing nano-RHA in stabilizing bulk foam

Development of low liquid fuel Burnera

Recently, most of the gas turbine combustion research and development involves in lowering the emissions emitted from the combustor. Emission causes adverse affect to the world and mankind especially. Main concern of the present work is to reduce the NOx emission since the CO emission could be reduced through homogeneous mixing of fuel and air. Homogeneous mixing of fuel and air is also needed in order to reduce NOx emission. A liquid fuel burner system with radial air swirler vane angle of 30o, 40o, 50o and 60o has been investigated using 163mm inside diameter combustor. Orifice plates with three different sizes of 20mm, 25mm and 30mm were inserted at the back plate of swirler outlet. All tests were conducted using diesel as fuel. Fuel was injected at two different positions, i.e. at upstream and downstream of the swirler outlet using central fuel injector with single fuel nozzle pointing axially outwards. Experiment has been carried out to compare the three emissions NOx, CO and SO2. NOx reduction of about 53 percent was achieved for orifice plate of 20mm with downstream injection compared to orifice plate of 20mm with upstream injection. CO2 and SO2 was reduced about 26 percent and 56 percent respectively for the same configuration. This comparison was taken using swirler vane angle of 60o. The overall study shows that larger swirler vane angle produces lower emission results compared to the smaller ones. Smaller orifice plates produce better emission reduction. Meanwhile, downstream injection position significantly decreases the emission levels compared to upstream injection position. Combination of smallest orifice plate and largest swirler vane angle with downstream injection produce widest and shortest flame length

Potential of polymeric surfactant in stabilizing carbon dioxide foam for enhanced oil recovery

This study investigates the stability of carbon dioxide (CO2) foam generated from water, gas and formulation of Alpha-Olefin Sulfonate (AOS), Betaines and different types of polymeric surfactant. The effects of different types of crude oil on foam stability were also analyzed. It was found that a higher concentration of surfactant provided more stable foam while a finer texture of foam bubbles were observed with addition of Betaines. The addition of Poly(ethylene glycol) dimethyl ether showed the best result as the foam did not degenerate as rapidly as the other polymeric surfactants. The presence of crude oil also affected the foam stability as it went into a steep decline

Laboratory experiment based permeability reduction estimation for enhanced oil recovery

Formation damage is an unwanted operational problem-taking place through several phases of oil reservoir life. The permeability reduction is a key indicator for the formation damage. Suitable assessment of permeability reduction is critical for hydrocarbon recovery. As oil production reach tertiary recovery stage in many fields, formation damage critical evaluation is needed to avoid additional operational cost and technical feasibility concern. The interaction between reservoir minerals and chemical injection practices is not fully understood. Also, clay mineral presence is highly sensitive to the chemicals, while adsorption phenomena can also occur. The degree of permeability reduction cannot be generalized for core/field scales; therefore investigating the permeability reduction in core scale is important before field-scale assessment. Therefore, this study investigates the permeability reduction after chemicals injection under low flow rate in sand-quartz cores and in the presence of kaolinite. Artificial sandpacks were used to control the sand-kaolinite mixture percentage. The permeability was measured before and after each flood by pressure drop calculation. The study showed that the seawater flood has the highest reduction in permeability followed by polymer and surfactants. Also, the results showed a strong effect of surfactant nature and molecular weight on the adsorption process and consequently the permeability reduction. The study provides an insight for the effect of chemicals on cores physical properties

The brink of oil and gas energy: a great loss?

There are many persistent local and international conflicts in oil producing countries due to power struggles among the leaders, to have a total control on oil and gas supplies, etc. These conflicts have disrupted the oil and gas production and supplies which at one point saw the world?s oil price hit an all time high of US$147.27 on 11 July 2008. The high oil price was due to escalated demand than supply, and in reality there is no shortage of conventional oil and gas resources. In fact, the Earth has nearly 1.688 trillion barrels of proven crude oil, which will last 53.3 years at current rates of extraction. The problem lies in produceability and accessibility to those resources. Currently the oil and gas industry is facing a very challenging period with the world?s oil price has dropped sharply from above US$100 per barrel to US$50 per barrel as of 5 November 2015 due to the slowing demand from China, the United States of America, Japan, and Europe. As a result, many local and international oil companies and service companies have released or terminated their technical staff. Oil companies have to reduce their production cost or break-even dollar value per barrel in order to survive in this difficult time. On the other hand, this difficult environment will not stop the Department of Petroleum Engineering from offering the same number of places for the Bachelor Degree in Petroleum Engineering programme to Malaysian and international students. Via the accredited programme and UTM Professional Skills Certificate, those petroleum students are prepared for local and global markets

Utilization of whey protein isolate as CO2 foam stabilizer for enhanced oil recovery

Understanding the fundamental aspects of foaming properties will influence its generation and stabilization at different concentrations of the critical aggregation concentration (CAC), foam volume stability, foam height, salinity influences, and crude oil CO2-foam stability. Carbon-Dioxide based enhanced oil recovery techniques are widely employed to extract additional oil from the reservoir. The adsorption of protein at the interfaces produces extremely viscoelastic layers with high viscosity. This research aims to investigate whether whey protein isolate (WPI) is a foaming agent that can be used to improve oil recovery. WPI lowers the interfaces’ surface tension, which also has a propensity to disclose and stabilize the interface by forming a viscoelastic network and directing to high surface moduli. Comparatively, the surface tension is lowered by sodium dodecyl sulfate (SDS) surfactants than the WPI, but they do not produce a high modulus interface. WPI is demonstrated to be a greater foam stabilizer in oil and various salt conditions than SDS foam. Adding sodium chloride (NaCl) increased the half-life and volume of foam more on WPI foam compared to SDS foam. SDS foamability and foam consistency decreased dramatically at 2 wt% of NaCl concentration and above while WPI foam increased. The crude oil affected both foams, but WPI foam has not been affected as much as the SDS foam due to its high strength compared to traditional foams. The study shows that WPI reduced interfacial tension from 38 to 11 mN/m and reduced surface tension (72.3 to 48 mN/m). It was low enough and can be used as a substitute for a foaming agent to enhance the recovery of oil

Experimental analysis on the formation of CO-NO-HC in swirling flow combustion chamber

The main purpose of this paper is to evaluate the production of CO-NO-HC emissions while varying the swirl angle of curve vane radial swirler. Swirling flow generates central recirculation region (CRZ) which is necessary for flame stability and enhances fuel air mixing. Therefore designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion inside burner system. Four radial curved vane swirlers with 30o, 40o, 50o and 60o vane angles corresponding to swirl numbers of 0.366, 0.630, 0.978 and 1.427 respectively were used in this experiment to measure the vane angles effect on emission production in the combustion chamber. Emission measurements were conducted at 5 axial distances from the burner throat, and at 5 locations along the radius starting the central axis at each section. It was found that at the core near the throat, CO and HC concentrations are low due to high available O2 and high fuel mixing rate producing efficient combustion. This is due to the high shear region created the high swirl flow

Numerical analysis of effect of preheat and swirl of inlet air on temperature profile in canister burner

The main purpose of this paper is to study the Computational Fluid Dynamics (CFD) prediction on temperature distribution inside the canister burner with inlet air pre-heating of 100K and 250K while varying the swirl angle of the radial swirler. Air swirler adds sufficient swirling to the inlet flow to generate central recirculation region (CRZ) which is necessary for flame stability and fuel air mixing enhancement. Therefore, designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion with low pressure losses. A liquid fuel burner system with different radial air swirler with 280 mm inside diameter combustor of 1000 mm length has been investigated. Analysis were carried out using four different radial air swirlers having 30°, 40°, 50° and 60° vane angles. The flow behavior was investigated numerically using CFD solver Ansys Fluent. This study has provided characteristic insight into the distribution of temperature inside the combustion chamber. Results show that with the inlet air preheat before the combustion, the temperature distribution inside the canister would stabilize early into the chamber with higher swirl number (SN) compared without inlet air preheat. As for the inlet air preheat, the main effects are the resulting temperatures in the canister are higher, but there is a smaller hot-spot in the flame. This means that the temperature profile in the chamber is well distributed

LABORATORY EXPERIMENT BASED PERMEABILITY REDUCTION ESTIMATION FOR ENHANCED OIL RECOVERY

Formation damage is an unwanted operational problem-taking place through several phases of oil reservoir life. The permeability reduction is a key indicator for the formation damage. Suitable assessment of permeability reduction is critical for hydrocarbon recovery. As oil production reach tertiary recovery stage in many fields, formation damage critical evaluation is needed to avoid additional operational cost and technical feasibility concern. The interaction between reservoir minerals and chemical injection practices is not fully understood. Also, clay mineral presence is highly sensitive to the chemicals, while adsorption phenomena can also occur. The degree of permeability reduction cannot be generalized for core/field scales; therefore investigating the permeability reduction in core scale is important before field-scale assessment. Therefore, this study investigates the permeability reduction after chemicals injection under low flow rate in sand-quartz cores and in the presence of kaolinite. Artificial sandpacks were used to control the sand-kaolinite mixture percentage. The permeability was measured before and after each flood by pressure drop calculation. The study showed that the seawater flood has the highest reduction in permeability followed by polymer and surfactants. Also, the results showed a strong effect of surfactant nature and molecular weight on the adsorption process and consequently the permeability reduction. The study provides an insight for the effect of chemicals on cores physical properties