Muhammad A. Manan

Experimental study of the influence of silica nanoparticles on the bulk stability of SDS-foam in the presence of oil

ABSTRACT The influence of silica nanoparticles on the bulk stability of SDS-foam in the presence of oil was investigated in this study using KRÜSS dynamic foam analyzer. The bulk foam static stability was evaluated from half-decay time, liquid drainage, bubble size distribution, and change in total height and volume of the generated foams with respect to time. Results clearly showed that foam stability in the presence of oil mainly depends on the viscosity and density of the oil. Foam stability increased with the addition of silica nanoparticles due to the aggregation of the nanoparticles at the thin lamellae of the foam, which prevents spreading of the oil at the gas–liquid interface. Moreover, optimum foam stability was obtained with the modified nanosilica–SDS mixtures, while slower liquid drainage from the foam did not generally result in high foam stability. GRAPHICAL ABSTRACT

Calcium Carbonate Production through Direct Mineral Carbon Dioxide Sequestration

Mineral carbon dioxide sequestration provides a leakage free and permanent method of CO2 disposal to produce environmentally benign and stable solid carbonates. FGD gypsum as a source of calcium was proposed as the potential feedstock in this study. The purpose of this laboratory study was to investigate the effects of reaction parameters such as CO2 pressure, reaction temperature, particle size, and ammonia solution concentration on calcium carbonate purity through Merseburg process. Increasing the reaction temperature as well as the pressure was very effective in improving the calcium carbonate purity. High purity calcium carbonate was produced when reaction temperature and CO2 was increased to 400 °C and 70 bar, resulting in 93% and 94% purity, respectively. Experimental results showed that reducing particle size was also effective in enhancing the calcium carbonate purity in which the smallest particles produced higher purity calcium carbonates rather than larger particles. The role of ammonia solution on calcium carbonate purity was found to be beneficial in improving the calcium carbonate purity in which increasing the ammonia solution increased calcium carbonate purity significantly in all experiments.

Mechanistic study of nanoparticles–surfactant foam flow in etched glass micro-models

ABSTRACT This study was conducted in order to identify the pore-level mechanisms controlling the nanoparticles–surfactant foams flow process and residual oil mobilization in etched glass micro-models. The dominant mechanism of foam propagation and residual oil mobilization in water-wet system was identified as lamellae division and emulsification of oil, respectively. There was inter-bubble trapping of oil and water, lamellae detaching and collapsing of SDS-foam in the presence of oil in water-wet system and in oil-wet system. The dominant mechanisms of nanoparticles–surfactant foam flow and residual oil mobilization in oil-wet system were the generation of pore spanning continuous gas foam. The identified mechanisms were independent of pore geometry. The SiO2-SDS and Al2O3-SDS foams propagate successfully in water-wet and oil-wet systems; foam coalescence was prevented during film stretching due to the adsorption and accumulation of the nanoparticles at the gas–liquid interface of the foam, which increased the films’ interfacial viscoelasticity. GRAPHICAL ABSTRACT

Rheological properties of surface-modified nanoparticles-stabilized CO2 foam

Abstract This study investigates the rheological properties of surface-modified nanoparticles-stabilized CO2 foam in porous media for enhanced oil recovery (EOR) applications. Due to the foam pseudo-plastic behavior, the foam apparent viscosity was estimated based on the power law constitutive model. The results show that foam exhibit shear-thinning behavior. The presence of surface-modified silica nanoparticles enhanced the foam bulk apparent viscosity by 15%. Foam apparent viscosity in the capillary porous media was four times higher than that in capillary viscometer, and foam apparent viscosity increased as porous media permeability increases. The high apparent viscosity of the surface-modified nanoparticles-stabilized foam could result in effective fluid diversion and pore blocking processes and enhance their potential applications in heterogeneous reservoir. Graphical Abstract

Influence of Silicon Oxide and Aluminum Oxide Nanoparticles on Air and CO2 Foams Stability in Presence and Absence of Oil

One of the major issues in foam application for enhanced oil recovery (EOR) is the foam stability in presence and absence of oil. In this study, a systematic experimental study of the bulk and bubble scale stability of air and CO2 foams stabilised by sodium dodecyl sulphate (SDS) and nanoparticles were conducted. Foam-oil interactions were further study in etched glass micromodel in order to investigate and compare the foam performance at static and dynamic conditions. Influence of nanoparticles hydrophobicity and oil types on foam behaviors were assessed. Static bulk and bubble-scale experiments were conducted with KRUSS dynamic foam analyser while the flow characteristics experiments were conducted in etched glass porous medium. Results show that the foam half-life increased while the size of generated bubbles decreased with the presence of nanoparticles in the surfactant solution. Successful propagation of nanoparticles-SDS foam through capillary snap-off and lamellae division was observed in presence of oil in the porous medium. Foam stability decreases with decreasing oil viscosity and density. Except for hydrophobic aluminum oxide nanoparticles with contact angle of 118.19°, the static and dynamic stability of the air and CO2 foams increased with increasing nanoparticles hydrophobicity. The addition of nanoparticles into the surfactant solution considerably improved foam stability due to the adsorption and aggregation of the nanoparticles at the thin lamellae and plateau border. This prevents liquid drainage and film thinning by increasing film elasticity and film strength from 23.2 µm to 136µm. It can be concluded from this study, that stable air and CO2 foams can be generated with nanoparticles- surfactant mixed systems in absence and presence of oil with favourable nanoparticles hydrophobicity.

The Application of Pressure Drop Through a Horizontal Well Correlation to Oil Well Production Performance.

From the petroleum engineering standpoint, pressure drop through a horizontal wellbore is very small and is negligible in predicting the production performance. However, not much research has been done to study this phenomenon and more importantly to prove the above assumption. This paper discuss the application of published pressure drop through a horizontal well correlation in the prediction of horizontal oil-well production performance. The correlation relates two-phase pressure drop along the hole to the fluid inflow from the reservoir. This correlation together with friction and hydrostatic effects were used to determine the total pressure drop from the wellhead to the well tip. The calculations by iteratively solving pressure drop along pipe equations with reservoir flow equations was done with the aid of computer program. The study proves that pressure drop is very important in predicting the inflow rate distribution along well bores especially when using small perforated rough pipes and dealing with long horizontal wellbores. References and illustrations at end of the paper INTRODUCTION Many researchers argued that multiphase flow pressure drop along horizontal oil-well can be ignored when predicting well production performance. Some of these arguments were supported by calculation of pressure drop due to pipe wall friction. This, however is not true. Fluid inflow through the perforation causes flow disturbance and momentum change along the hole, thus creating additional pressure drop (See Fig. 1). This pressure drop may affect the calculation of inflow rate distribution along the hole especially in long low drawdown wells and high permeability reservoirs. The inflow rate distribution calculation is very important when dealing with thin oil rims with underline water or/and overlying gas, where possible coning problems might occur at the highest inflow rate section. Controlling the optimum oil production rate and designing appropriate completion should be done to avoid premature water or gas breakthrough. The early study on this subject was made by Dikken1• He developed simple analytical models for single phase flow in well bores and steady state fluid flow in the reservoirs. These two models were solved simultaneously to give solutions for cases of infinite or fmite well length. The results of the study are quite interesting. It shows that the calculation of pressure drop along the horizontal hole is very 2 AZMI M. ARSHAD, MUHAMMAD A. MANAN & ABDUL R. ISMAIL SPE 28801 important especially in calculating inflow rate and production performance. The study was then followed by several others.2-7 Only correlations by Asheim et al. 8 and Arshad et al. 9 were found in literatures where simple and direct correlation describing the effect of fluid inflow through the perforation on the pressure drop along the pipe were developed. However, no application of the correlations was introduced. The focus of this study was on the use of these correlations to calculate well performance behavior. The correlations was combined with the two phase frictional effect along the pipe and coupled with the reservoir flows. Pressure drop and flow behavior along the well and the relationship between the pressure drop and the fluid inflow from the reservoir were studied. PRESSURE DROP BY FLUID INFLOW Conceptually, fluid inflow through the perforations may affect the pressure drop along the wellbore by: (a) Disturbing the boundary layer at the pipe Wall, thus altering the wall friction.8 (b) Disturbing the pipe flow pattern, thus changing the flow frictional effect, and (c) Consuming pressure energy to accelerate the inflow streams up to the average pipe flow velocity.8 Asheim et ale Correlation Asheim et al. correlation was produced from combined theoretical and experimental studies on single phase wellbore flow with fluid inflow effects due to perforations. They proposed a new flow resistance correlation combining the effect of wall friction and external fluid inflow through perforations. The external fluid inflow pressure drop correlation itself can be described by: where PI VI qi Q liquid density (kg/m3) liquid flow velocity in the pipe (mls) liquid inflow rate per length unit (m3/s/m) liquid pipe flow rate (m3/s) Arshad et ale Correlation Arshad et al. correlation is the results of two phase experimental studies and mathematical modeling. One inch inside diameter PVC pipe was used to study the effect of single and multiple perforations on pressure drop along the pipe. Eighty-one sets of data points were analyzed from the experiment that was used air and water as two phase fluids. The study proves that the effect of multiple perforations can be neglected to calculate the pressure drop. However, the volume of in situ two phase inflow rates entering the pipe controls the amount of pressure drop. The correlation developed is given by: where Ap Vg Pg qg cross-sectional area of the pipe (m2) gas flow velocity in the pipe (mls) gas density (kg/m3) gas inflow rate per length unit (rft3/s/m) In horizontal pipe flow, the difference between the velocity of liquid and gas through the pipe is very small. For that reason, the terms liquid and gas velocities can be replaced by single term named average mixture velocity. The equation then can be modified to: where Vm average mixture flow velocity of gas and liquid in the pipe (mls)