Asep Permadi | ITB - Institut Teknologi Bandung (original) (raw)

Papers by Asep Permadi

Research paper thumbnail of Swelling Performance of Paraffinic Crude Oil Under Carbon Dioxide Injection

Advances in Geophysics, Tectonics and Petroleum Geosciences

Research paper thumbnail of A New CO2-EOR Methods Screening Model Based on Interdependency Parameters

Applied Sciences

The successful implementation of carbon dioxide-enhanced oil recovery (CO2-EOR) is crucial in inc... more The successful implementation of carbon dioxide-enhanced oil recovery (CO2-EOR) is crucial in increasing oil production and reducing carbon emissions. For this reason, screening criteria are needed for the initial characterization of a suitable CO2-EOR reservoir. The existing screening model treats the screening parameters independently. Therefore, each parameter has its criteria limit and does not relate to the others. However, in reality, several screening parameters are interdependent, so we need a method that treats the interdependent parameters simultaneously. This research develops a new simultaneous screening model using the interdependency of the parameters. Quantitative and actual data were collected from CO2-EOR field documentation worldwide with a comprehensive analysis. A statistical approach with a correlation analysis method was used to determine the interconnected screening parameters. The results were synchronized with the expert domain to match actual physical condi...

Research paper thumbnail of The Effect of Carbonyl and Hydroxyl Compounds Addition on CO2 Injection through Hydrocarbon Extraction Processes

Applied Sciences, 2020

CO2 miscible flooding occurs when injection pressure is higher than the minimum miscibility press... more CO2 miscible flooding occurs when injection pressure is higher than the minimum miscibility pressure (MMP) which can exceed the fracture pressure. Co-solvents are expected to reduce the MMP by interacting with various hydrocarbons that depend on the polarity and intermolecular forces of solvent and oil. However, there are limited studies that have investigated co-solvent performance in CO2 injection through an extraction process based on oil compositional analysis. This paper is aimed at studying the effects of carbonyl and hydroxyl compounds on oil extraction and also the mutual interactions of CO2-oil-carbonyl and -hydroxyl. The experiment is conducted by using VIPS (viscosity, interfacial tension, pressure-volume, and swelling) and gas chromatography (GC) apparatuses. The compositional results from GC are utilized to analyze the performance of co-solvents, which are further classified based on the carbon number and molecular structure of oil. Acetone is a non-associated polar com...

Research paper thumbnail of An Experimental Study of Clay Swelling Phenomenon by Carbonic Acid Injection in Clay Sandstone: Implication for CO2 Injection

Modern Applied Science, 2018

Significant portion of CO2 is dissolved in reservoir brine during CO2-Enhanced Oil Recovery. Diss... more Significant portion of CO2 is dissolved in reservoir brine during CO2-Enhanced Oil Recovery. Dissolved CO2 forms an acidic environment which could modify rock-fluid interaction. One of the phenomena that could happen due to this interaction is clay swelling which may affect enhanced oil recovery performance. Several experiments were conducted in a number of sandstone core samples, i.e. Imbibition test, Core flood test, Conductivity test, and pH measurement. Imbibition test was conducted to evaluate CO2-saturated brine (approached with carbonic acid) performance toward oil recovery during five days measurement compared with brine imbibition performance. Moreover, core flood experiment was run to determine the effect of dissolved CO2 in brine on injection in sandstone. This is simulated by injecting brine (base case) followed by carbonic acid under 68.3 OC. Thus, conductivity and pH of the imbibed fluids (before & after running imbibition test) were measured to justify occurrence of c...

Research paper thumbnail of Pemodelan Sumur “Horizontal Bersegmen” Pada Reservoir Dengan Bottomwater Menggunakan Simulator Numerik

Sebagai akibat operasional pemboran atau terbatasnya informasi reservoir dengan beberapa alasan, ... more Sebagai akibat operasional pemboran atau terbatasnya informasi reservoir dengan beberapa alasan, sumur horizontal kadang menembus daerah dekat WOC, kemudian mendatar, lalu naik mengarah ke puncak formasi, dan kemudian mendatar lagi. Dengan demikian, trayek pemboran mempunyai segmen-segmen mendatar di bawah, miring, dan mendatar di atas (“horizontal bersegmen”). Karena bentuk sumur horizontal yang bersegmen tersebut, maka dalam studi simulasi numerik diperlukan teknik pemakaian grid yang khusus agar dapat menggambarkan aliran menuju lubang sumur (inflow) dengan baik dan benar. Misalnya, berbeda dari pemodelan sumur “horizontal sempurna” dimana perubahan saturasi air terutama terjadi pada arah vertikal, sistem grid untuk pemodelan sumur “horizontal bersegmen” harus dapat menggambarkan perubahan saturasi baik pada arah vertikal maupun arah horizontal. Tulisan ini menyajikan cara implementasi sistem grid yang ada dalam literatur untuk mempelajari perilaku sumur “horizontal bersegmen” de...

Research paper thumbnail of An evaluation of Stones method to determinte pseudo-relative permeability

Research paper thumbnail of Reservoir distribution and quality of Pliocene deposits in eastern offshore area, its implication to deepwater exploration of Tarakan basin, East-Kalimantan

Proc. Indon Petrol. Assoc., 34th Ann. Conv.

Research paper thumbnail of A new integrated HPHT experimental apparatus to measure interfacial tension, swelling factor, and viscosity simultaneously

Journal of Petroleum Exploration and Production Technology, 2022

An experimental apparatus has been designed to investigate interaction among CO2 injection parame... more An experimental apparatus has been designed to investigate interaction among CO2 injection parameters. It is an integrated-closed system of measurement kits that aimed to obtain interfacial tension, swelling factor, and viscosity data simultaneously. The apparatus had been successfully tested to measure properties of dead and live oils mixed with CO2 in high-pressure and high-temperature environment. An experimental study was completed using samples from real fields. Results showed consistency and coherency among the parameters that can be utilized to estimate the minimum miscibility pressure (MMP) graphically. The MMP is taken as the pressure at the intersection between two straight lines.

Research paper thumbnail of The Effect of Carbonyl and Hydroxyl Compounds on Swelling Factor, Interfacial Tension, and Viscosity in CO2 Injection: A Case Study on Aromatic Oils

Processes

A factor influencing the effectiveness of CO2 injection is miscibility. Besides the miscible inje... more A factor influencing the effectiveness of CO2 injection is miscibility. Besides the miscible injection, CO2 may also contribute to oil recovery improvement by immiscible injection through modifying several properties such as oil swelling, viscosity reduction, and the lowering of interfacial tension (IFT). Moreover, CO2 immiscible injection performance is also expected to be improved by adding some solvent. However, there are a lack of studies identifying the roles of solvent in assisting CO2 injection through observing those properties simultaneously. This paper explains the effects of CO2–carbonyl and CO2–hydroxyl compounds mixture injection on those properties, and also the minimum miscibility pressure (MMP) experimentally by using VIPS (refers to viscosity, interfacial tension, pressure–volume, and swelling) apparatus, which has a capability of measuring those properties simultaneously within a closed system. Higher swelling factor, lower viscosity, IFT and MMP are observed from ...

Research paper thumbnail of Ketone Solvent to Reduce the Minimum Miscibility Pressure for CO2 Flooding at the South Sumatra Basin, Indonesia

Processes

This paper experimentally analyzes the chemical additives, i.e., methanol and ethanol, as alcohol... more This paper experimentally analyzes the chemical additives, i.e., methanol and ethanol, as alcohol solvents, and acetone as a ketone solvent, and the temperature influencing the minimum miscibility pressure (MMP) that is essential to design miscible CO2 flooding at an oil field, the South Sumatra basin, Indonesia. The experiments were designed to measure CO2-oil interfacial tension with the vanishing interfacial tension (VIT) method in the ranges up to 3000 psi (208.6 bar) and 300 degrees Celsius. The experiment results show that lower temperatures, larger solvent volumes, and the acetone were effective in reducing MMP. The acetone, an aprotic ketone solvent, reduced MMP more than the methanol and the ethanol in the CO2-oil system. The high temperature was negative to obtain the high CO2 solubility into the oil as well as the lower MMP. The experimental results confirm that the aprotic ketone solvent could be effective in decreasing the MMP for the design of miscible CO2 flooding at ...

Research paper thumbnail of Nonionic Surfactant to Enhance the Performances of Alkaline–Surfactant–Polymer Flooding with a Low Salinity Constraint

Applied Sciences

This paper presents a nonionic surfactant in the anionic surfactant pair (ternary mixture) that i... more This paper presents a nonionic surfactant in the anionic surfactant pair (ternary mixture) that influences the hydrophobicity of the alkaline–surfactant–polymer (ASP) slug within low-salinity formation water, an environment that constrains optimal designs of the salinity gradient and phase types. The hydrophobicity effectively reduced the optimum salinity, but achieving as much by mixing various surfactants has been challenging. We conducted a phase behavior test and a coreflooding test, and the results prove the effectiveness of the nonionic surfactant in enlarging the chemical applicability by making ASP flooding more hydrophobic. The proposed ASP mixture consisted of 0.2 wt% sodium carbonate, 0.25 wt% anionic surfactant pair, and 0.2 wt% nonionic surfactant, and 0.15 wt% hydrolyzed polyacrylamide. The nonionic surfactant decreased the optimum salinity to 1.1 wt% NaCl compared to the 1.7 wt% NaCl of the reference case with heavy alcohol present instead of the nonionic surfactant. ...

Research paper thumbnail of Optimal Design of Alkaline–Surfactant–Polymer Flooding under Low Salinity Environment

Polymers

This paper presents an optimal design of alkaline–surfactant–polymer (ASP) flooding and an experi... more This paper presents an optimal design of alkaline–surfactant–polymer (ASP) flooding and an experimental analysis on the effects of ASP components under low formation salinity, where the assignment of salinity gradients and various phase types are limited. The phase behavior and coreflooding tests confirmed the ASP formula is optimal, i.e., 1 wt % sodium carbonate (Na2CO3) as the alkaline, 1:4 weight ratio for linear alkylbenzene sulfonate (LAS) and dioctyl sulfosuccinate (DOSS) as a surfactant, 5 wt % diethylene glycol monobutyl ether (DGBE) as a co-solvent, and hydrolyzed polyacrylamide (HPAM) as a polymer. The salinity scan was used to determine that the optimum salinity was around 1.25 wt % NaCl and its solubilization ratio was favorable, i.e., approximately 21 mL/mL. The filtration ratio determines the polymer concentrations, i.e., 3000 or 3300 mg/L, with a reduced risk of plugging through pore throats. The coreflooding test confirmed the field applicability of the proposed ASP ...

Research paper thumbnail of Determination and evaluation of minimum miscibility pressure using various methods: experimental, visual observation, and simulation

Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles

This research proposes a simultaneous technique using various methods to yield the most reliable ... more This research proposes a simultaneous technique using various methods to yield the most reliable Minimum Miscibility Pressure (MMP) value. Several methods have been utilized in this study including slim tube test, swelling test, vanishing interfacial tension test, visual observation during swelling test and vanishing interfacial tension test, and simulation. The proposed method may reduce the uncertainty and avoid doubtful MMP. The method can also demonstrate discrepancies among the results. There were two samples used in this study namely Crude Oil AB-5 and Crude Oil AB-4. It showed that for Crude Oil AB-5 the discrepancies among the results from that of the slim tube test were between 3.9% and 10.4% and 0% and 5.9% for the temperature of 60 °C and 66 °C, respectively. The highest discrepancy was shown by the results from the visual observation during vanishing interfacial tension test and the lowest discrepancy was shown by the results from the swelling test. The vanishing interfa...

Research paper thumbnail of Effect of CO2-Oil Contact Time on the Swelling Factor and Viscosity of Paraffinic Oil at Reservoir Temperature

Current Topics in Microbiology and Immunology

Research paper thumbnail of Experimental analysis to design optimum phase type and salinity gradient of Alkaline Surfactant Polymer flooding at low saline reservoir

Journal of Petroleum Science and Engineering

Research paper thumbnail of Robust Decline Curve Analysis

Journal of the Indonesian Mathematical Society, 2012

Empirical decline curve analysis of oil production data gives reasonable answer in hyperbolic typ... more Empirical decline curve analysis of oil production data gives reasonable answer in hyperbolic type curves situations; however the methodology has limitations in fitting real historical production data in present of unusual observations due to the effect of the treatment to the well in order to increase production capacity. The development of robust least squares offers new possibilities in better fitting production data using decline curve analysis by down weighting the unusual observations. This paper proposes a robust least squares fitting lmRobMM approach to estimate the decline rate of daily production data and compares the results with reservoir simulation results. For case study, we use the oil production data at TBA Field West Java. The results demonstrated that the approach is suitable for decline curve fitting and offers a new insight in decline curve analysis in the present of unusual observations.

Research paper thumbnail of Convergence Visualization of Enkf for Linear Dynamical System

One of the popular data assimilation techniques is Ensemble Kalman Filter (EnKF). EnKF is a Monte... more One of the popular data assimilation techniques is Ensemble Kalman Filter (EnKF). EnKF is a Monte Carlo implementation of Kalman Filter for non linear dynamical system where the initial state is generalized using sample, called ensemble, and the state covariance matrix is approximated using sample covariance. To justify the validity of EnKF, it is important to investigate the convergence in probability of the EnKF. For linear dynamic system EnKF converges to Kalman Filter. In this paper, we proposed a statistical quality control chart to visualize the convergence in probability of EnKF and probability limits of the average of state in forecast step and analysis step are calculated using Chebyshev's inequality. Simulation studies show that the variability of the state in forecast step and analysis step will be smaller if the ensemble size becomes infinity and the visualization improves the understanding of EnKF convergence.

Research paper thumbnail of Exploring Decline Curve Residual Modeling using Kalman Filter

International Journal of Applied Mathematics and Statistics

In this paper we propose a new method to capture the fluctuations in decreasing of oil production... more In this paper we propose a new method to capture the fluctuations in decreasing of oil production that was not considered in the Arps model. The proposed method is called as the Decline Curve Residual (DCR) method. The DCR is defined as the difference between production data and the discretized Arps estimate for each corresponding time. The difference will then be modeled by time series model. The Kalman filter will be used to forecast the DCR using a state-space representation that is formed by an appropriate time series model. We also propose a scatter plot of Akaike's Information Criterion (AIC) vs. Sum Square of Errors (SSE) value as a new tool to select the best model. Based on this scatter plot, the best model is selected from the point which gives the shortest distance from AIC and SSE value point to the origin. Based on our data, numerical study shows that the DCR is not stationary in variance. Therefore, we explore this DCR modeling using the autoregressive and moving average (ARMA) and generalized autoregressive conditional heteroscedasticity (GARCH) process. From the scatter plot of AIC vs. SSE value, the result shows that the best model is ARMA(2, 4)-GARCH(2, 1).

Research paper thumbnail of A Comprehensive Investigation of WASP Application in Heavy Oil Using Response Surface Methodology

Steamflood has been performed successfully since the 1950's in several fields worldwide. Alth... more Steamflood has been performed successfully since the 1950's in several fields worldwide. Although being considered successful, it still has problems associated with its mechanism. Due to gravitational effects, steam tends to move towards the upper portion of the reservoir causing the lower section to be poorly drained. In order to overcome this effect, water alternating steam process (WASP) might be a good solution which helps inhibiting the steam from moving upwards while keeping breakthrough-time from increasing. Previous literature study about WASP is scarce, even though this process is complex and sensitive to operating condition. By investigating WASP using response surface methodology, factors governing the steamflooding operations can be evaluated. This paper presents the investigation regarding WASP applications in heavy oil. The reservoir model is ran with several operating conditions to achieve the most realistic interpretation. The operating variables include WASP sta...

Research paper thumbnail of A Success Story in a Plan of Development Study: Increasing Recovery of Sandstone Reservoir by Water Injection in Indonesia Input parameters for reservoir model

Crude oil makes a major contribution to the world economy today. To meet the rising energy consum... more Crude oil makes a major contribution to the world economy today. To meet the rising energy consumption in the world, there is a dire need to produce more crude oil. Hence, attention is being paid to Secondary Recovery for recovering more oil from the existing oil fields. Secondary Recovery refers to techniques, such as gas or water injection. This study presents a success story in a plan of development study: increasing recovery of sandstone reservoir by water injection. The main goal of this study is to predict future performance of a reservoir and find ways and means of optimizing the recovery of some of the hydrocarbon under various operating conditions.

Research paper thumbnail of Swelling Performance of Paraffinic Crude Oil Under Carbon Dioxide Injection

Advances in Geophysics, Tectonics and Petroleum Geosciences

Research paper thumbnail of A New CO2-EOR Methods Screening Model Based on Interdependency Parameters

Applied Sciences

The successful implementation of carbon dioxide-enhanced oil recovery (CO2-EOR) is crucial in inc... more The successful implementation of carbon dioxide-enhanced oil recovery (CO2-EOR) is crucial in increasing oil production and reducing carbon emissions. For this reason, screening criteria are needed for the initial characterization of a suitable CO2-EOR reservoir. The existing screening model treats the screening parameters independently. Therefore, each parameter has its criteria limit and does not relate to the others. However, in reality, several screening parameters are interdependent, so we need a method that treats the interdependent parameters simultaneously. This research develops a new simultaneous screening model using the interdependency of the parameters. Quantitative and actual data were collected from CO2-EOR field documentation worldwide with a comprehensive analysis. A statistical approach with a correlation analysis method was used to determine the interconnected screening parameters. The results were synchronized with the expert domain to match actual physical condi...

Research paper thumbnail of The Effect of Carbonyl and Hydroxyl Compounds Addition on CO2 Injection through Hydrocarbon Extraction Processes

Applied Sciences, 2020

CO2 miscible flooding occurs when injection pressure is higher than the minimum miscibility press... more CO2 miscible flooding occurs when injection pressure is higher than the minimum miscibility pressure (MMP) which can exceed the fracture pressure. Co-solvents are expected to reduce the MMP by interacting with various hydrocarbons that depend on the polarity and intermolecular forces of solvent and oil. However, there are limited studies that have investigated co-solvent performance in CO2 injection through an extraction process based on oil compositional analysis. This paper is aimed at studying the effects of carbonyl and hydroxyl compounds on oil extraction and also the mutual interactions of CO2-oil-carbonyl and -hydroxyl. The experiment is conducted by using VIPS (viscosity, interfacial tension, pressure-volume, and swelling) and gas chromatography (GC) apparatuses. The compositional results from GC are utilized to analyze the performance of co-solvents, which are further classified based on the carbon number and molecular structure of oil. Acetone is a non-associated polar com...

Research paper thumbnail of An Experimental Study of Clay Swelling Phenomenon by Carbonic Acid Injection in Clay Sandstone: Implication for CO2 Injection

Modern Applied Science, 2018

Significant portion of CO2 is dissolved in reservoir brine during CO2-Enhanced Oil Recovery. Diss... more Significant portion of CO2 is dissolved in reservoir brine during CO2-Enhanced Oil Recovery. Dissolved CO2 forms an acidic environment which could modify rock-fluid interaction. One of the phenomena that could happen due to this interaction is clay swelling which may affect enhanced oil recovery performance. Several experiments were conducted in a number of sandstone core samples, i.e. Imbibition test, Core flood test, Conductivity test, and pH measurement. Imbibition test was conducted to evaluate CO2-saturated brine (approached with carbonic acid) performance toward oil recovery during five days measurement compared with brine imbibition performance. Moreover, core flood experiment was run to determine the effect of dissolved CO2 in brine on injection in sandstone. This is simulated by injecting brine (base case) followed by carbonic acid under 68.3 OC. Thus, conductivity and pH of the imbibed fluids (before & after running imbibition test) were measured to justify occurrence of c...

Research paper thumbnail of Pemodelan Sumur “Horizontal Bersegmen” Pada Reservoir Dengan Bottomwater Menggunakan Simulator Numerik

Sebagai akibat operasional pemboran atau terbatasnya informasi reservoir dengan beberapa alasan, ... more Sebagai akibat operasional pemboran atau terbatasnya informasi reservoir dengan beberapa alasan, sumur horizontal kadang menembus daerah dekat WOC, kemudian mendatar, lalu naik mengarah ke puncak formasi, dan kemudian mendatar lagi. Dengan demikian, trayek pemboran mempunyai segmen-segmen mendatar di bawah, miring, dan mendatar di atas (“horizontal bersegmen”). Karena bentuk sumur horizontal yang bersegmen tersebut, maka dalam studi simulasi numerik diperlukan teknik pemakaian grid yang khusus agar dapat menggambarkan aliran menuju lubang sumur (inflow) dengan baik dan benar. Misalnya, berbeda dari pemodelan sumur “horizontal sempurna” dimana perubahan saturasi air terutama terjadi pada arah vertikal, sistem grid untuk pemodelan sumur “horizontal bersegmen” harus dapat menggambarkan perubahan saturasi baik pada arah vertikal maupun arah horizontal. Tulisan ini menyajikan cara implementasi sistem grid yang ada dalam literatur untuk mempelajari perilaku sumur “horizontal bersegmen” de...

Research paper thumbnail of An evaluation of Stones method to determinte pseudo-relative permeability

Research paper thumbnail of Reservoir distribution and quality of Pliocene deposits in eastern offshore area, its implication to deepwater exploration of Tarakan basin, East-Kalimantan

Proc. Indon Petrol. Assoc., 34th Ann. Conv.

Research paper thumbnail of A new integrated HPHT experimental apparatus to measure interfacial tension, swelling factor, and viscosity simultaneously

Journal of Petroleum Exploration and Production Technology, 2022

An experimental apparatus has been designed to investigate interaction among CO2 injection parame... more An experimental apparatus has been designed to investigate interaction among CO2 injection parameters. It is an integrated-closed system of measurement kits that aimed to obtain interfacial tension, swelling factor, and viscosity data simultaneously. The apparatus had been successfully tested to measure properties of dead and live oils mixed with CO2 in high-pressure and high-temperature environment. An experimental study was completed using samples from real fields. Results showed consistency and coherency among the parameters that can be utilized to estimate the minimum miscibility pressure (MMP) graphically. The MMP is taken as the pressure at the intersection between two straight lines.

Research paper thumbnail of The Effect of Carbonyl and Hydroxyl Compounds on Swelling Factor, Interfacial Tension, and Viscosity in CO2 Injection: A Case Study on Aromatic Oils

Processes

A factor influencing the effectiveness of CO2 injection is miscibility. Besides the miscible inje... more A factor influencing the effectiveness of CO2 injection is miscibility. Besides the miscible injection, CO2 may also contribute to oil recovery improvement by immiscible injection through modifying several properties such as oil swelling, viscosity reduction, and the lowering of interfacial tension (IFT). Moreover, CO2 immiscible injection performance is also expected to be improved by adding some solvent. However, there are a lack of studies identifying the roles of solvent in assisting CO2 injection through observing those properties simultaneously. This paper explains the effects of CO2–carbonyl and CO2–hydroxyl compounds mixture injection on those properties, and also the minimum miscibility pressure (MMP) experimentally by using VIPS (refers to viscosity, interfacial tension, pressure–volume, and swelling) apparatus, which has a capability of measuring those properties simultaneously within a closed system. Higher swelling factor, lower viscosity, IFT and MMP are observed from ...

Research paper thumbnail of Ketone Solvent to Reduce the Minimum Miscibility Pressure for CO2 Flooding at the South Sumatra Basin, Indonesia

Processes

This paper experimentally analyzes the chemical additives, i.e., methanol and ethanol, as alcohol... more This paper experimentally analyzes the chemical additives, i.e., methanol and ethanol, as alcohol solvents, and acetone as a ketone solvent, and the temperature influencing the minimum miscibility pressure (MMP) that is essential to design miscible CO2 flooding at an oil field, the South Sumatra basin, Indonesia. The experiments were designed to measure CO2-oil interfacial tension with the vanishing interfacial tension (VIT) method in the ranges up to 3000 psi (208.6 bar) and 300 degrees Celsius. The experiment results show that lower temperatures, larger solvent volumes, and the acetone were effective in reducing MMP. The acetone, an aprotic ketone solvent, reduced MMP more than the methanol and the ethanol in the CO2-oil system. The high temperature was negative to obtain the high CO2 solubility into the oil as well as the lower MMP. The experimental results confirm that the aprotic ketone solvent could be effective in decreasing the MMP for the design of miscible CO2 flooding at ...

Research paper thumbnail of Nonionic Surfactant to Enhance the Performances of Alkaline–Surfactant–Polymer Flooding with a Low Salinity Constraint

Applied Sciences

This paper presents a nonionic surfactant in the anionic surfactant pair (ternary mixture) that i... more This paper presents a nonionic surfactant in the anionic surfactant pair (ternary mixture) that influences the hydrophobicity of the alkaline–surfactant–polymer (ASP) slug within low-salinity formation water, an environment that constrains optimal designs of the salinity gradient and phase types. The hydrophobicity effectively reduced the optimum salinity, but achieving as much by mixing various surfactants has been challenging. We conducted a phase behavior test and a coreflooding test, and the results prove the effectiveness of the nonionic surfactant in enlarging the chemical applicability by making ASP flooding more hydrophobic. The proposed ASP mixture consisted of 0.2 wt% sodium carbonate, 0.25 wt% anionic surfactant pair, and 0.2 wt% nonionic surfactant, and 0.15 wt% hydrolyzed polyacrylamide. The nonionic surfactant decreased the optimum salinity to 1.1 wt% NaCl compared to the 1.7 wt% NaCl of the reference case with heavy alcohol present instead of the nonionic surfactant. ...

Research paper thumbnail of Optimal Design of Alkaline–Surfactant–Polymer Flooding under Low Salinity Environment

Polymers

This paper presents an optimal design of alkaline–surfactant–polymer (ASP) flooding and an experi... more This paper presents an optimal design of alkaline–surfactant–polymer (ASP) flooding and an experimental analysis on the effects of ASP components under low formation salinity, where the assignment of salinity gradients and various phase types are limited. The phase behavior and coreflooding tests confirmed the ASP formula is optimal, i.e., 1 wt % sodium carbonate (Na2CO3) as the alkaline, 1:4 weight ratio for linear alkylbenzene sulfonate (LAS) and dioctyl sulfosuccinate (DOSS) as a surfactant, 5 wt % diethylene glycol monobutyl ether (DGBE) as a co-solvent, and hydrolyzed polyacrylamide (HPAM) as a polymer. The salinity scan was used to determine that the optimum salinity was around 1.25 wt % NaCl and its solubilization ratio was favorable, i.e., approximately 21 mL/mL. The filtration ratio determines the polymer concentrations, i.e., 3000 or 3300 mg/L, with a reduced risk of plugging through pore throats. The coreflooding test confirmed the field applicability of the proposed ASP ...

Research paper thumbnail of Determination and evaluation of minimum miscibility pressure using various methods: experimental, visual observation, and simulation

Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles

This research proposes a simultaneous technique using various methods to yield the most reliable ... more This research proposes a simultaneous technique using various methods to yield the most reliable Minimum Miscibility Pressure (MMP) value. Several methods have been utilized in this study including slim tube test, swelling test, vanishing interfacial tension test, visual observation during swelling test and vanishing interfacial tension test, and simulation. The proposed method may reduce the uncertainty and avoid doubtful MMP. The method can also demonstrate discrepancies among the results. There were two samples used in this study namely Crude Oil AB-5 and Crude Oil AB-4. It showed that for Crude Oil AB-5 the discrepancies among the results from that of the slim tube test were between 3.9% and 10.4% and 0% and 5.9% for the temperature of 60 °C and 66 °C, respectively. The highest discrepancy was shown by the results from the visual observation during vanishing interfacial tension test and the lowest discrepancy was shown by the results from the swelling test. The vanishing interfa...

Research paper thumbnail of Effect of CO2-Oil Contact Time on the Swelling Factor and Viscosity of Paraffinic Oil at Reservoir Temperature

Current Topics in Microbiology and Immunology

Research paper thumbnail of Experimental analysis to design optimum phase type and salinity gradient of Alkaline Surfactant Polymer flooding at low saline reservoir

Journal of Petroleum Science and Engineering

Research paper thumbnail of Robust Decline Curve Analysis

Journal of the Indonesian Mathematical Society, 2012

Empirical decline curve analysis of oil production data gives reasonable answer in hyperbolic typ... more Empirical decline curve analysis of oil production data gives reasonable answer in hyperbolic type curves situations; however the methodology has limitations in fitting real historical production data in present of unusual observations due to the effect of the treatment to the well in order to increase production capacity. The development of robust least squares offers new possibilities in better fitting production data using decline curve analysis by down weighting the unusual observations. This paper proposes a robust least squares fitting lmRobMM approach to estimate the decline rate of daily production data and compares the results with reservoir simulation results. For case study, we use the oil production data at TBA Field West Java. The results demonstrated that the approach is suitable for decline curve fitting and offers a new insight in decline curve analysis in the present of unusual observations.

Research paper thumbnail of Convergence Visualization of Enkf for Linear Dynamical System

One of the popular data assimilation techniques is Ensemble Kalman Filter (EnKF). EnKF is a Monte... more One of the popular data assimilation techniques is Ensemble Kalman Filter (EnKF). EnKF is a Monte Carlo implementation of Kalman Filter for non linear dynamical system where the initial state is generalized using sample, called ensemble, and the state covariance matrix is approximated using sample covariance. To justify the validity of EnKF, it is important to investigate the convergence in probability of the EnKF. For linear dynamic system EnKF converges to Kalman Filter. In this paper, we proposed a statistical quality control chart to visualize the convergence in probability of EnKF and probability limits of the average of state in forecast step and analysis step are calculated using Chebyshev's inequality. Simulation studies show that the variability of the state in forecast step and analysis step will be smaller if the ensemble size becomes infinity and the visualization improves the understanding of EnKF convergence.

Research paper thumbnail of Exploring Decline Curve Residual Modeling using Kalman Filter

International Journal of Applied Mathematics and Statistics

In this paper we propose a new method to capture the fluctuations in decreasing of oil production... more In this paper we propose a new method to capture the fluctuations in decreasing of oil production that was not considered in the Arps model. The proposed method is called as the Decline Curve Residual (DCR) method. The DCR is defined as the difference between production data and the discretized Arps estimate for each corresponding time. The difference will then be modeled by time series model. The Kalman filter will be used to forecast the DCR using a state-space representation that is formed by an appropriate time series model. We also propose a scatter plot of Akaike's Information Criterion (AIC) vs. Sum Square of Errors (SSE) value as a new tool to select the best model. Based on this scatter plot, the best model is selected from the point which gives the shortest distance from AIC and SSE value point to the origin. Based on our data, numerical study shows that the DCR is not stationary in variance. Therefore, we explore this DCR modeling using the autoregressive and moving average (ARMA) and generalized autoregressive conditional heteroscedasticity (GARCH) process. From the scatter plot of AIC vs. SSE value, the result shows that the best model is ARMA(2, 4)-GARCH(2, 1).

Research paper thumbnail of A Comprehensive Investigation of WASP Application in Heavy Oil Using Response Surface Methodology

Steamflood has been performed successfully since the 1950's in several fields worldwide. Alth... more Steamflood has been performed successfully since the 1950's in several fields worldwide. Although being considered successful, it still has problems associated with its mechanism. Due to gravitational effects, steam tends to move towards the upper portion of the reservoir causing the lower section to be poorly drained. In order to overcome this effect, water alternating steam process (WASP) might be a good solution which helps inhibiting the steam from moving upwards while keeping breakthrough-time from increasing. Previous literature study about WASP is scarce, even though this process is complex and sensitive to operating condition. By investigating WASP using response surface methodology, factors governing the steamflooding operations can be evaluated. This paper presents the investigation regarding WASP applications in heavy oil. The reservoir model is ran with several operating conditions to achieve the most realistic interpretation. The operating variables include WASP sta...

Research paper thumbnail of A Success Story in a Plan of Development Study: Increasing Recovery of Sandstone Reservoir by Water Injection in Indonesia Input parameters for reservoir model

Crude oil makes a major contribution to the world economy today. To meet the rising energy consum... more Crude oil makes a major contribution to the world economy today. To meet the rising energy consumption in the world, there is a dire need to produce more crude oil. Hence, attention is being paid to Secondary Recovery for recovering more oil from the existing oil fields. Secondary Recovery refers to techniques, such as gas or water injection. This study presents a success story in a plan of development study: increasing recovery of sandstone reservoir by water injection. The main goal of this study is to predict future performance of a reservoir and find ways and means of optimizing the recovery of some of the hydrocarbon under various operating conditions.