2018-07-21T03:46:29Z
http://jpst.ripi.ir/?_action=export&rf=summon&issue=91
Journal of Petroleum Science and Technology
JPST
2251-659X
2251-659X
2017
7
2
Enhanced Gas Recovery with Carbon Dioxide Sequestration in a Water-drive Gas Condensate Reservoir: a Case Study in a Real Gas Field
Hossein
Zangeneh
Mohammad Amin
Safarzadeh
Gas reservoirs usually have high recovery due to high mobility and low residual gas saturation, although some of them producing under water-drive mechanism have low recovery efficiency. Encroachment of water into these reservoirs traps considerable amount of gas and increases the maximum residual gas saturation, which results in the reduction of gas and condensate production. Generally, the recoveries of water-drive gas reservoirs vary between 35-75%, whereas depletion-drive reservoirs exhibit recoveries near 85%. In this work, a method was proposed for reducing water encroachment, sweeping reservoir gas content effectively, and enhancing the hydrocarbon recovery consequently. To this end, a condensate gas reservoir model, located in the south of Iran, was chosen to study the process. The injection was performed above the bottom-up aquifer from two horizontal wells, and the base gas was produced by four vertical wells. Three cases of inactive aquifer (Case I), active aquifer (Case II), and active aquifer with CO2 injection (Case III) were studied subsequently. The proposed gas-gas displacement method increases the recovery of reservoir especially the recovery of heavier components composing the main part of the condensate. Moreover, the injection of a huge volume of CO2 without significant CO2 production can be interesting from an environmental point of view and can be considered as a CO2 sequestration process.
Water-drive
Gas Condensate Reservoir
carbon dioxide
Enhanced Gas Recovery
Sequestration
2017
06
20
3
11
http://jpst.ripi.ir/article_743_13a3be1f44472e9064124ba68863c333.pdf
Journal of Petroleum Science and Technology
JPST
2251-659X
2251-659X
2017
7
2
An Investigation of Asphaltene Deposition Mechanisms During Natural Depletion Process by a Two Phase Modeling Using Genetic Algorithm Technique
Sepideh
Kashefi
Mohammad Nader
Lotfollahi
Abbass
Shahrabadi
In this work, the natural depletion process in sandstone and carbonate cores was modeled to investigate the asphaltene deposition mechanisms. A new permeability reduction correlation was proposed based on the Minssieux model that considers a combination of surface deposition, pore throat plugging, and filtration cake mechanisms. The results showed that the filtration cake is a dominant asphaltene deposition mechanism during natural depletion process in both core samples. Therefore, a modified model was proposed with adding formation of filtration cake mechanism due to pore filling to the Wang and Civan deposition model. The absolute average deviation (AAD (%)) for permeability reduction between the results of the three models (including new correlation, the modified model, and Wang and Civan model) and the experimental data were calculated and reported. These values for the three models were 3.28, 2.67, and 4.83% for sandstone core and 3.01, 2.58, and 4.69% for carbonate core respectively. The results showed that the modified model proposed in this study presented good performance for asphaltene deposition prediction
Natural Depletion
Asphaltene Deposition
Modeling
Filtration Cake
2017
06
20
12
20
http://jpst.ripi.ir/article_744_1fff6cb197408cb4da451b4804becb75.pdf
Journal of Petroleum Science and Technology
JPST
2251-659X
2251-659X
2017
7
2
A Study on the Adsorption and Catalytic Oxidation of Asphaltene onto Nanoparticles
Alireza
Solaimany nazar
Fatemeh
Amin
The use of nanoparticles, including metal oxide surfaces, as asphaltene adsorbents is a potential method of removing and/or upgrading asphaltenes. The adsorption of two asphaltene types, extracted from two types of Iranian crude oil, onto nanoparticles (TiO2, SiO2, and Al2O3) are assessed and the thermal behavior of the adsorbed asphaltenes is examined under an oxidizing atmosphere through thermogravimetric and differential scanning calorimetry (TG/DSC) analyses. The extracted asphaltenes are characterized through the X-ray diffraction technique, and adsorption isotherms are measured through UV-Vis spectrophotometry of the asphaltene-toluene model solutions. The isotherm data of all the nanoparticles are adequately fitted by the Langmuir model, indicating that asphaltenes form monolayer coverage on solids surface sites. The adsorption capacities of asphaltenes onto the metal oxides follow the order of Al2O3> TiO2> SiO2. The results indicate that asphaltene with high aromaticity has more adsorption affinity, indicating the effect of the chemical structural of the asphaltenes. The results of asphaltene oxidation tests reveal that the presence of nanoparticles leads to a decrease in oxidation temperature (~100 °C) and activation energy. The effects of nanoparticles on asphaltene oxidation are catalytic.
Asphaltene
Nanoparticles
Adsorption Isotherm
Catalytic Oxidation
2017
06
20
21
29
http://jpst.ripi.ir/article_745_7a854b9369440ee4718c04b05d30ebcc.pdf
Journal of Petroleum Science and Technology
JPST
2251-659X
2251-659X
2017
7
2
Implication of an Integrated Approach to the Determination of Water Saturation in a Carbonate Gas Reservoir Located in the Persian Gulf
Marzieh
Neyzan Hosseini
Ezatallah
Kazemzadeh
Ehsan
Sobhani
Bita
Arbab
Water saturation determination is one of the most important tasks in reservoir studies to predict oil and gas in place needed to be calculated with more accuracy. The estimation of this important reservoir parameter is commonly determined by various well logs data and by applying some correlations that may not be so accurate in some real practical cases, especially for carbonate reservoirs. Since laboratory core analysis data have a high accuracy, in this study, it is attempted to use core and geological core description data to present an improved method to determine an optimized cementation factor (m) and a saturation exponent (n) in order to evaluate water saturation within carbonate reservoirs compared to default values (m=2, n=2, a=1) in a carbonate gas reservoir located in the Persian Gulf. Based on integrating core petrography and velocity deviation log (VDL), core samples were classified based on the type of porosity and geology description, and then by employing log-log plots of formation resistivity factor (FRF) versus porosity and formation resistivity index (FRI) versus water saturation, saturation parameters (m,n) were determined for each classification. Utilizing default and optimized values of saturation parameters, water saturation logs were obtained through different conductivity models by employing Multi min algorithm. Then, optimized water saturation was compared to core data. Error analysis showed that water saturation data resulted in optimized saturation parameters having a lower average error of 0.08 compared to the default ones with an average error of 0.14, and based on cumulative histogram, optimized water saturation data are in good agreement with the trend of core water saturation.
Water saturation
Saturation Parameters
Petrography
Velocity Deviation Log
2017
06
20
30
42
http://jpst.ripi.ir/article_746_2bbf0dbd6f75270ecc97226cca33fb29.pdf
Journal of Petroleum Science and Technology
JPST
2251-659X
2251-659X
2017
7
2
Pervaporation (PV) Separation of Methanol/Methyl Tert-butyl Ether Mixtures in Low Permeate Pressure Conditions
Ghasem
Khatinzadeh
Mohammad
Mahdyarfar
Ali
Mehdizadeh
Recently, pervaporation separation processes have gained much attention in the separation of azeotropic and close boiling point organic-organic mixtures due to its high separation efficiency, economy, safety, and energy saving potentials. In this work, the effects of experimental factors such as feed composition and operating temperature on the performance of a commercial poly vinyl alcohol membrane in the separation of methanol/methyl tertiary butyl ether (MTBE) mixtures at low permeate side pressures (1-20 mmHg) were evaluated. Separation factor and methanol flux significantly increased by decreasing permeate side pressure, especially to less than 5 mmHg. Therefore, the reduction of pressure from 20 to 1 mmHg at 45 °C at a feed methanol concentration of 5 wt.% increased methanol flux and separation factor from 248 to 412 g/hm2 and 73 to 211 respectively. In addition, the results indicate that by increasing feed temperature and methanol concentration in the feed, methanol flux is increased, while separation factor dropped.
Pervaporation
Separation
Permeate Pressure
MTBE
Methanol
2017
06
20
43
48
http://jpst.ripi.ir/article_747_bf0eaa313e61458f0428c4c04337c585.pdf
Journal of Petroleum Science and Technology
JPST
2251-659X
2251-659X
2017
7
2
Research on Chaos Characteristic of Crack Evolution in Coal-rock Fracturing
wanchun
zhao
dan
zhao
tingting
wang
dongfeng
jiang
Precisely describing the formation and evolution rules of coal-rock fracturing crack have great value on reservoir fracturing improvement and highly efficient mining of coal bed methane well. In this paper, a non-linear dynamic method is used to study crack damage evolution behavior of coal-rock fracturing. Considering distribution characteristics of natural cracks in coal-rock, and based on damage mechanics, a mathematical model on stress around the tip of coal-rock fracturing crack and crack evolution is developed. Micro-crack amounts, circumferential stress, and axial stress at the crack tip of coal-rock fracturing crack evolution process are used as characteristic indicators to describe crack evolutionary. C-C method is chosen to reconstruct the phase space of coal-rock fracturing crack evolution. Correlation dimension, Lyapunov index, and Kolmogorov entropy are introduced as chaos characteristic quantities of crack evolution system, and the process of coal-rock fracturing crack damage evolution could be calculated and described. Coal-rock mass of Zhangchen mining area in Heilongjiang, China was used as a research object, and the results show that as the radial stress increases, the Kolmogorov entropy and the degree of chaos decrease; also, as the circumferential stress increases, the Kolmogorov entropy increases, and a higher degree of chaos is obtained; increasing the number of micro-cracks evolution raises Kolmogorov entropy up to a critical value, and then the Kolmogorov entropy drops, which means the chaotic degree decreases. The results calculated show that crack formation is a damage evolution process which has chaos characteristics. Finally, we provided a new way for further research on coal-rock fracturing crack evolution regularities.
Coal-rock Fracturing
Crack Evolutionary
Chaos Characteristic
Nonlinear Dynamics
Zhangchen Mining Area
2017
06
20
49
61
http://jpst.ripi.ir/article_748_597e80d3f93f685d671ebbb447ac08b5.pdf
Journal of Petroleum Science and Technology
JPST
2251-659X
2251-659X
2017
7
2
Reduction of Reservoir Fluid Equilibrium Calculation for Peng-Robinson EOS with Zero Interaction Coefficients
Mehdi
Assareh
For some of the EOS models the dimension of equilibrium problem can be reduced. Stability and difficulties in implementation are among the problems of flash calculation. In this work, a new reduction technique is presented to prepare a reduced number of equilibrium equations. Afterwards, a number of appropriate solution variables are selected for the prepared equation system to solve the equations in an efficient numerical scheme. All the derivatives and solution procedures for the new reduced flash calculation framework were prepared based on Peng-Robinson equation of state. One reservoir oil sample and one gas condensate sample were selected from published literature to evaluate the proposed method for the calculations of reservoir fluids equilibrium. The equilibrium calculations with the proposed reduction technique were compared to full flash calculations. The reduced formulation implementation is simple and straightforward as it is derived from full flash fugacity equality criteria. The presented technique not only reduces the number of equations, and hence simplifies flash problem, but also presents a comparable convergence behavior and offers the same solution system for different reservoir fluid types. The results, demonstrates the proposed method performance and the accuracy for modeling with complex equilibrium calculations like compositional reservoir simulation when there are many components available in the mixture fluid description.
Reduction
Flash calculation
Reservoir Fluids
Peng-Robinson
Cubic Equation of States
2017
06
20
62
76
http://jpst.ripi.ir/article_749_4eea257147134a41f605b1d0b445e639.pdf
Journal of Petroleum Science and Technology
JPST
2251-659X
2251-659X
2017
7
2
Static Modeling of Oil Field Mineral Scales: Software Development
Mohammad
Parvazdavani
Behjat
Kari Payhan
Mahmood
Dinmohammad
seyed Ali
Mousavi Dehghani
Mineral scale deposition in near wellbore regions of injection wells is one of the main challengeable issues during the water injection process, which magnifies the importance of robust models in predicting the amount of mineral scale deposition such as calcium sulfate. One of the main challenges of CaSO4 scale is in carbonated reservoirs, in which sensitive behavior is observed in related to the contribution of both calcium and sulfate ions in carbonated and sulfated scale reactions. This defect is mirror of wrong procedure and value in the estimation of first kind/value of precipitant contributed in scale deposition reactions (ions competition) as well as inconsistent temperature/pressure dependent coefficients of prediction model. The objective of this study is to develop a model that can accurately predict the formation and amount of CaSO4 scale as the dominant scale in multicomponent aqueous systems by three major tools, namely utilization the best temperature- and pressure-dependent thermodynamic interactive ion coefficients (MSE Model: Pitzer), developing our fine-tuned iterative mathematical solver, and verification of the results of the model by accurate experimental data. The results showed that at the optimum value of precipitant (10%) in scale deposition reactions and by defining the best temperature- and pressure-dependent coefficients, we can attain the best accuracy in the prediction of CaSO4 scale deposited amount (less than 0.06% as a relative error compared to 36% overestimation and 22% underestimation in commercial software). The output of this study is developed software leading to the more accurate prediction of the amount of promising scales in near wellbore regions or pipelines.
CaSO4 Scale
Laboratory Static Jar Tests
Iterative Mathematical Solver
Pitzer Thermodynamic Model
Ions Binary Interactive Coefficient
2017
06
20
77
90
http://jpst.ripi.ir/article_750_f5c6c3789c0a3b390150d80208cb8476.pdf