porosity

Open Access Article

1 - Reservoir zonation using discrimination of effective and ineffective porosity method in one of the SW Iranian oil Fields; a special look at resistivity logs
جواد هنرمند ژیلا رضائیان دلوئی ارسلان زینل زاده

Abstract In this paper, core samples from Upper carbonates (Miocene age) of the Asmari Formation in one of the SW Iranian oil fields were studied in macro and microscopic scale. Subsequently, results from core and thin section studies compared with core porosity and pe More

Abstract In this paper, core samples from Upper carbonates (Miocene age) of the Asmari Formation in one of the SW Iranian oil fields were studied in macro and microscopic scale. Subsequently, results from core and thin section studies compared with core porosity and permeability and petrophysical wireline logs, especially resistivity logs. Due to texture variation (mudstone to grainstone) and diagenetic events (dolomitization, dissolution, calcite and anhydrite cementation), porosity type and percentage changed in wide range in this formation. This study showed that resistivity logs could be used as an effective tool to distinct effective and ineffective-bearing zones. High permeability intervals have relatively high deep resistivity and high separation between deep and shallow resistivity logs, whereas non-reservoir intervals have low resistivity and very low separation between deep and shallow resistivity. Based on this study, studied carbonate interval of the Asmari Formation was divided into 13 zones. Using separation of deep and shallow resistivity logs, flow zones could be correlated throughout the studied field Manuscript profile

Open Access Article

2 - Comparsion of the result of FMS image log and thin sections data in one field of Kopedagh Basin
زهرا شمشیری فریدون سحابی غلامحسین نوروزی حسین معماریان

20.1001.1.22518738.1392.3.5.4.4

Abstruct Survey and study of porosity and the form and the size of that in oil and gas reservoirs are important due to its key role in reservoir quality and productivity. In this paper, unlike conventional methods of using cores to recogn More

Abstruct Survey and study of porosity and the form and the size of that in oil and gas reservoirs are important due to its key role in reservoir quality and productivity. In this paper, unlike conventional methods of using cores to recognize the geometry and morphology of porosity, FMS image log and thin section of cutting from drilling are used .after determining the over all dimension of the porosity shown as black patches and spots by FMS log, the shape and the size of the porosity was studied in the form of petrological study,based on thin sections from Mzdouran reservoir formation(lower Jurassic) in one of the gas fields in the East of Kopedagh basin. Tracing and comparing of the results of the two methods show a good correlation for determining the type and geometry of porosity .Data fusion of FMS log data with petrological studies of thin sections of cutting from drilling has advantages the most important of which is the possibility of replacement of core with FMS log and thin sections in order to determining the geometry of porosity. Manuscript profile

Open Access Article

3 - Application of Kuster and Toksoz equations in inverse modeling technique to estimate the percentages of pore types in carbonate rocks
اصغر نادری مصطفی حیدری ایرج مداحی ناصر کشاورز فرج خواه

20.1001.1.22518738.1391.2.3.1.0

The most prominent parameter of seismic studies is seismic wave velocity. This parameter is influenced by different factors such as rock properties (Compaction, age, Lithology, Porosity, Pore Shape and etc), fluid properties (Viscosity, Density, fluid type, Saturation) More

The most prominent parameter of seismic studies is seismic wave velocity. This parameter is influenced by different factors such as rock properties (Compaction, age, Lithology, Porosity, Pore Shape and etc), fluid properties (Viscosity, Density, fluid type, Saturation) and environment (Stress history, Depositional environment, production history, temperature, pressure, etc). Therefore, by identification, study and investigation of the relationship between seismic velocity and these parameters, properties of rock, fluid and environment from seismic data can be inferred. The main factors affecting these parameters are the porosity and pore ambiences. Many studies have been conducted to obtain and understand these relations. Most of the theoretical equations haven’t considered changes in seismic properties from pores. Therefore, the seismic inversion, AVO and pore volume calculated based on these equations, include much uncertainties. One of the equations that consider several factors such as porosity, pore type, mineralogy and pore fluid is provided by Kuster and Toksoz. In this study, using this equation and inverse modeling technique, geometry and pore type and percentage of any type of pore shape in 3 wells penetrated one Irainain hydrocarbon reservoir were estimated. In this reservoir, Spherical and Disk shape have the highest percentage. Manuscript profile

Open Access Article

4 - Petrophysical evaluation and determination of reservoir rock types in the Ghar member,the Abouzar oilfield, Persian Gulf.
مهرناز نصیری محمدرضا رجلی نوده

20.1001.1.22518738.1391.2.3.3.2

This study is aimed at petrophysical evaluation of the Ghar reservoir using Multimin method by Geolog software in five wells from the Abouzar oilfield. For this purpose, well log data comprising of neutron, density, sonic, gamma, resistivity and photoelectric absorption More

This study is aimed at petrophysical evaluation of the Ghar reservoir using Multimin method by Geolog software in five wells from the Abouzar oilfield. For this purpose, well log data comprising of neutron, density, sonic, gamma, resistivity and photoelectric absorption were utilized and their analysis lead to determination of quantitative petrophysical properties such as porosity, volume of shale, water, oil saturation and qualitative parameters including lithology and clay mineral types. The analyses revealed that three zones could be identified in the Ghar reservoir. Meanwhile, there are three shaly interlayers within the Ghar foemation. By application of the cutoff values on oil in place (OIP), petrophysical properties were determined zone by zone and based on Net to Gross ratio (N/G) high reservoir quality zone was identified. Finally by using clustering algorithm, reservoir rock types were identified based upon six properties including density, neutron, gamma ray, volume of shale, water saturation and effective porosity. The facies were introduced on the basis of their priority in reservoir quality so that there is an agreement between petrophysical evaluation results and electrofacies. General lithology of the reservoir in composed of upper loose sands and consolidated sand in the lower part. The lower sands are consolidated by the calcite cement. Overall, the volume of clay minerals in the lower part is less than that of upper part. However, productive zones were separated by a thin shaly layer. The clay minerals type in the shaly layer differs from those present in the reservoir rocks. Total and effective porosity are almost identical which is due to low volume of shale. Manuscript profile

Open Access Article

5 - Secondary porosity index effect on improving approaches permeability estimation from petrophysical logs utilizing artificial intelligent
سجاد کاظم شیرودی مرتضی خانیان

20.1001.1.22518738.1391.2.3.5.4

Abstract Permeability estimation using core data and petrophysical logs is a conventional approach which bears high uncertainty especially in carbonate reservoir characterization. In essence, the problem consists not only due to coring expenses rate, but also ambig More

Abstract Permeability estimation using core data and petrophysical logs is a conventional approach which bears high uncertainty especially in carbonate reservoir characterization. In essence, the problem consists not only due to coring expenses rate, but also ambiguity in finding proper explicit log correlation to core data. Moreover, utilizing the correlated formula in wells without core data can pose errors. In this research the permeability was estimated from conventional petrophysical logs and it was calibrated with permeability obtained from core lab experiments. Applied intelligent systems are the matter of this research for permeability values estimation. To construct permeability estimation model, three techniques have been applied including conventional ANN, the Gonzalez, and Hambalek fuzzy logic techniques. These methods were applied in two wells drilled in Surmeh reservoir in Balal field to establish ANN and to derive a relation between core and well. The models were applied in control well in order to check the reliability and capability of models to estimate representative permeability value. The result showed however three foresaid techniques for permeability estimation were successful the secondary porosity distributed the correlation due to its reduction effect on permeability so that they were not interconnected. Therefore this effect was omitted using secondary porosity index in which the permeability estimation were improved and were estimated close to core value. Manuscript profile

Open Access Article

6 - Simulation of porosity and permeability reservoir parameters by using Co-Sequential Gaussian Simulation method in one of the oil field in the South West of Iran
Bahareh Fereidooni Mohammad Mokhtari

20.1001.1.22518738.1396.7.13.3.7

Three-dimensional study of petrophysical parameters of hydrocarbon reservoirs such as porosity and permeability is considered as an efficient and effective tool for comprehensive study of reservoirs as well as reservoir management. In this study, which was carried out o More

Three-dimensional study of petrophysical parameters of hydrocarbon reservoirs such as porosity and permeability is considered as an efficient and effective tool for comprehensive study of reservoirs as well as reservoir management. In this study, which was carried out on one of the oil fields in the southwest of Iran, the aim is to simulate the petrophysical parameters of effective porosity and permeability by using Co-Sequential Gaussian Simulation in part of Khatiyah reservoir. With this simulation, a three-dimensional model of petrophysical reservoir parameters can be presented which is important for simulating fluid flow and identifying areas that are prone with higher reservoir quality. For this purpose, effective porosity and permeability logs of seven wells with 3D seismic data and seismic inversion results have been used. After reservoir gridding and creating a structural model, up scaled petrophysical data has entered to model and its own cell. For three-dimensional distribution of effective porosity parameter, due to the correlation of effective porosity and acoustic impedance attribute of seismic inversion, 3D seismic data and up scaled effective porosity logs as the initial data and acoustic impedance attribute of seismic inversion as secondary data have entered in Sequential Gaussian Simulation. In order to simulate permeability, due to the good correlation between effective porosity simulation model and permeability log, simulated porosity as a secondary data and up scaled permeability and 3D seismic data as secondary data have been used. The results of validation indicate the accuracy of the present study and the efficiency of Sequential Gaussian Simulation method in effective porosity and permeability modeling in this reservoir. Manuscript profile

Open Access Article

7 - Study the role of drilling mud loss modeling and FMI log in determining Asmari reservoir fractures in one of the oil fields in Southwest Iran
Kioumars Taheri Mohammad Reza Rasaei Abbas Ashjaei

20.1001.1.22518738.1396.7.14.1.7

Understanding of oil and gas reservoirs is of great help in maximizing hydrocarbon recovery. In the study of the characteristics of oil structures, the study of fractures of reservoir rock in the stages of production and development of the field is very necessary. Nowad More

Understanding of oil and gas reservoirs is of great help in maximizing hydrocarbon recovery. In the study of the characteristics of oil structures, the study of fractures of reservoir rock in the stages of production and development of the field is very necessary. Nowadays, the use of mud loss modeling and image logs in helping accomplish this task is of great assistance to oil geologists. Since the most of Iran's reservoirs are carbonate kind, investigating and identifying fractures, the degree of fissures opening and porosity distribution in the Asmari reservoir field of study, It is one of the most effective factors in the production of hydrocarbons from this field. One of the best ways to identify and interpret geology in the well, using of the FMI image log is, which can create high quality images from the well. With the help of the images provided, can determine the types of fractures, porosity, the distribution of diagenetic porous spaces and the estimation of permeability trend. In this article, first, structure and Functionality of the FMI image log and then drilling and production problems were evaluated in Asmari reservoir. In the following, the functional role of the log in interpreting and determining the degree of fissures opening, porosity distribution and permeability level in 8 wells in Asmari reservoir, has been evaluated. In this study, identification of Asmari reservoir fractures and how to expand these fractures in the reservoir By using mud loss modeling, interpretation of the FMI image log and the effect of these fractures was on the porosity and permeability of the reservoir. In this study, it has been determined that, fractures identified in wells very good matching with drilling mud loss maps with rock basement faults at the has anticline of the Asmari reservoir. Manuscript profile

Open Access Article

8 - Effect of sequential pressure on petrophysical properties of carbonate reservoir rocks
Ali Moradzadeh yaser Salimidelshad Ezatollah Kazemzadeh abbas Majdi

20.1001.1.22518738.1397.8.15.2.7

Today, oil industry significantly relies on the precise determination of rock reservoir properties, which reduces the costs and risks of production planning. The reservoir rock always is compacted by pressure drop of the reservoir, which rises effective stress, reservoi More

Today, oil industry significantly relies on the precise determination of rock reservoir properties, which reduces the costs and risks of production planning. The reservoir rock always is compacted by pressure drop of the reservoir, which rises effective stress, reservoir compaction and alterations of reservoir properties. As these pressure variations can considerably affect petrophysical properties, in this study, several carbonate reservoir rock samples with different fabric and porosity type (according to CT scan and Archie classification analysis) subjected to cyclic and short-term loading from 600 to 6000 psi. Their petrophysical and compressive properties including pore volume, permeability and compressibility were measured using CMS-300 apparatus. Moreover, structural analysis and heterogeneity of core samples were analyzed by CT scan images. By performing this study, it will be possible to identify the value of the hysteresis effect on the reservoir rock samples as a result of increasing and decreasing of the pressure during cyclic loading. The obtained results show that, pore volume and permeability are both decreased due to loading, whereas reduction of the permeability is several times than the pore volume ones. Moreover, this reduction of pore volume is less severe in vuggy porous samples that shows the effect of heterogeneity and porosity type on hysteresis. Also, the results obtained from the behavior of the reservoir rock under various pressure conditions can provide a suitable design for gas injection studies to enhance oil recovery and also natural gas storage. Manuscript profile

Open Access Article

9 - Comparison of the function of conventional neural networks for estimating porosity in one of the southeastern Iranian oil fields
Farshad Toffighi parviz armani Ali Chehrazi َAndisheh Alimoradi

20.1001.1.22518738.1399.10.20.1.0

In the oil industry, artificial intelligence is used to identify relationships, optimize, estimate and classify porosity. One of the most important steps in evaluating the petrophysical parameters of the reservoir is to identify the porosity properties. The main purpose More

In the oil industry, artificial intelligence is used to identify relationships, optimize, estimate and classify porosity. One of the most important steps in evaluating the petrophysical parameters of the reservoir is to identify the porosity properties. The main purpose of this study is to compare the accuracy and generalizability of three multilayer feed neural networks (MLFNs), radius base function networks (RBFNs) and probabilistic neural networks (PNNs) to estimate porosity using seismic properties. In this regard, geological data of 7 wells were evaluated from an offshore oil field in Hindijan in the northwest of the Persian Gulf basin. Acoustic impedance was estimated using model-based inversion method and then the mentioned neural networks were designed using optimal seismic properties and evaluated by stepwise regression method. Finally, it became clear that the MLFN model did not work well for estimating porosity. PNN has the best performance accuracy in porosity interpolation, but RBFN generalizability is better. Manuscript profile

Open Access Article

10 - Petrographical factor and Petrophysical parameter: An approach to reservoir evaluation of the Sarvak formation in NW, of the Persian Gulf
Alireza Bashari

20.1001.1.22518738.1401.12.24.4.5

Sarvak formation is a major oil reservoir in the Persian Gulf. Various nomenclature of the Sarvak formation were applied by different operative oil companies In the northern part of the Persian Gulf. The aim at this study is to harmonize stratigraphical nomenclatu More

Sarvak formation is a major oil reservoir in the Persian Gulf. Various nomenclature of the Sarvak formation were applied by different operative oil companies In the northern part of the Persian Gulf. The aim at this study is to harmonize stratigraphical nomenclature in this district , as well as to study the reservoir qualities and to asses hydrocarbon accumulations in this area. By using different petrophysical data and integration with geological factor, resulted in revealing three stratigraphy members ( Mishrif, Ahmadi and Mauddud), as well as reservoir qualities variations , in this district. By applying, available petrophsical data, and integration with geological information, various 3D geological maps, ( porosity, water & oil saturation maps etc…) were made. Preliminary assessment of the reservoir potential of the Bahregansar & Hendijan Fields shows , Sarvak formation in these two fields, have a good reservoir qualities, but other part of this district has poor reservoir qualities. This study shows , having high portions of clay mineral in the Sarvak reservoir along with lack of suitable cap rock and poor reservoir qualities , diminished reservoir potentials in this district. Manuscript profile

Open Access Article

11 - Identification of gas in carbonate rock using wavelet transform
Hassan Omrani Hashem omrani

Gas can be diagnosed in clean sand rock by petrophysical log. It is not easy to determine the gas in carbonate rock by petrophysical log. The R.F.T. tool is used to determine the gas in carbonate rock. The fluid density in the rock is determined by calculating the press More

Gas can be diagnosed in clean sand rock by petrophysical log. It is not easy to determine the gas in carbonate rock by petrophysical log. The R.F.T. tool is used to determine the gas in carbonate rock. The fluid density in the rock is determined by calculating the pressure difference related to depth. The R.F.T. tool has some disadvantages, such as being expensive, taking much time to run, and rock having a neutron porosity of about 15%, and sometimes the R.F.T. tool is stuck in well. This study applies the wavelet transformation, a recent advance in signal analysis technique, to detect reservoir rock fluid. The porosity and water saturation are denoised using the "demy" mother wavelet. At last, the pore hydrocarbon saturation, porosity denoise by the "demy" wavelet, pore volume plot and R.F.T. tool are plotted together in one figure to identify the kind of fluid in sand and carbonate rocks. Manuscript profile

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