Simulation of surfactant based enhanced oil recovery

Surfactant flooding is an important process for enhanced oil recovery. A substantial amount of remaining oil resides in reservoirs especially in carbonate oil reservoirs that have low primary and water-flood oil recovery. Most of the surfactant flooding studies to date has been performed in water-wet sandstone reservoirs. As a result, the effects of heterogeneity and wettability of carbonates on surfactant flooding efficiency are fairly unknown. The purpose of this simulation study was to determine the effects of wettability and wettability alteration on Dodecylbenzene Sulfonate surfactant flooding in carbonate reservoirs. This study used the multi-phase, multi-component, surfactant flooding simulator called UTCHEM. The base case results showed that additional 27.8% of oil recovered after water-flooding process. Sensitivity analyses of key parameters such as chemical slug size and concentrations, salinity, reservoir heterogeneity and surfactant adsorption were performed to optimize a surfactant design for a mixed-wet dolomite reservoir. The study was then extended to simulating wettability alteration during the field scale surfactant flood. The results of modeling the wettability alteration showed that significant differences in injectivity and oil recovery are caused by the changes in the mobility of the injected fluid. As the use of surfactant flooding spreads into the reservoir especially oil-wet and mixed-wet reservoirs, the importance of surfactant-based wettability alteration will become important

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

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

Performance of surfactant-polymer flooding under the influence of intermittent ultrasonic waves

The main focus of this research is to initiate the use of intermittent vibration in order to save the cost. Mechanical vibrations generated by ultrasonic radiation influence interfacial forces and increase the relative permeability of the phases. In this project, ultrasonic vibration was designed to assist surfactant-polymer (SP) flooding process for more significant effects, as SP flooding is one of EOR methods that is able to maximize both sweep and displacement efficiency. Besides, this work has been designed to understand the mechanics of intermittent ultrasonic vibration in influencing additional recovery of SP flooding, reduction of residual oil saturation, and displacement pattern at pore scale during the flooding process under exposure of ultrasonic waves. To achieve this, experiments consisting of visualization (at pore scale) and displacement experiments were conducted. Ultrasonic power was changed to see the influence on the process. Residual oil saturation at end of the flooding was recorded and snapshots of oil displacement were taken. The outcomes justified that intermittent vibrations can produce and enhance more additional oil recovery of SP flooding compared to the continuous vibration, and the reduction of residual oil saturation, and oil displacement rate highly dependent on the ultrasonic power

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

Experimental investigation of hole cleaning in directional drilling by using nano-enhanced water-based drilling fluids

The authors wish to thank the Ministry of Higher Education, Malaysia and Universiti Teknologi Malaysia for funding this project under grants with cost center and reference numbers of Q.J130000.2646.15J52 (PY/2017/01823), Q.J130000.2546.14H83 (PY2016/06266) and R.J130000.7651.4C195 (PY/2018/03001). We are also grateful to Ainuddin Wahid Endowment Fund for providing the necessary support to accomplish this research. Also, the support from the School of Engineering at the University of Aberdeen UK to complete this work is appreciated.Peer reviewedPostprin

NaOH treated spent bleaching earth

Spent bleaching earth (SBE) was treated with sodium hydroxide (NaOH) and used for the removal of methylene blue (MB). Adsorption test of treated SBE was carried out to evaluate the removal efficiency of MB. It showed that the maximum uptake of MB was at 76.9 mg/g using SBE treated with 3.0 M NaOH which is equivalent to 76% removal of MB. The effect of increasing initial concentration on the removal of MB showed that higher initial concentration leads to higher surface loading which reduces its removal potential. The effect of SBE dosage on the removal of MB pointed to the maximum removal percentage of 95% at 100 mg SBE dosage

Comparative numerical study for polymer alternating gas (PAG) flooding in high permeability condition

Polymers have been used in water alternative gas, to viscosify the water and improve the overall sweep efficiency. The use of polymer alternative gas was successful in increasing the oil production in high permeability zones. However, few practical factors affecting the field applicability have been overlooked. Therefore, this study is aimed at bridging the gap between the possibility of using several EOR such as water flooding, CO2 flooding, water alternative gas, polymer flooding and polymer alternative gas. The research based on progressive comparison considering constant constraint. The numerical simulation STARS-CMG was used to predict the characteristics and behaviour of the fluid in the reservoir. The designed flooding pattern chosen was a single producer-single injection (P-I) scheme in homogeneous high permeable reservoir. The results of oil incremental recovery showed the following order compared to Water flooding < (3%) CO2 flooding < (6.8%) < Water alternative gas (11.6%) Polymer flooding < (15%) Polymer alternative gas. The impact of polymer on enhancing the water alternative gas was mostly noticeable in the reduction of water cut% (83%). The controlled conformance by polymer aided in improving the sweep efficiency as indicated by the uninform U-shape. Moreover, the delayed gas breakthrough was significant and resulted in the lowest gas oil ratio of 5.17E + 04 ft3/bbl. The low gas oil ratio observation is indication of potential capturing of CO2 in the reservoir and thus, good evidence to further implementation of CO2 as green utilization