List of articles (by subject) Petroleum Reservoir Geology
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Open Access Article
1 - Modeling Mud Loss in Asmari Formation Using Geostatistics in RMS Software Environment in an Oil Field in Southwestern Iran
Kioumars Taheri Farhad Mohammad TorabStudying lost circulation in Asmari formation is very important because about 25% to 40% of drilling costs is allocated to drilling mud expenses. Considering that Studied oil field encounters severe mud loss in Asmari formation, therefore the purpose of this study is re MoreStudying lost circulation in Asmari formation is very important because about 25% to 40% of drilling costs is allocated to drilling mud expenses. Considering that Studied oil field encounters severe mud loss in Asmari formation, therefore the purpose of this study is recognition of the lost circulation zones and illustrating the mud loss distribution in Asmari formation. The mud loss maps in Asmari field were plotted in RMS software using moving average algorithm method. For this purpose, the data of 363 wells in this oil field was processed after data preparation, for mapping and 3D modeling of 11 different zones in Asmari formation. The data processing includes different stages such as elimination of outliers, normal transformation, drawing the histogram, variography and estimation and modeling. In this research, the geostatistical kriging method was also used for estimation and 3D modeling of mud loss in Asmari formation so that the output of geostatistical modeling method shows the localized and better results. Consequently, by applying and analysis of results, the 2D and 3D models of mud loss in Asmari formation were demonstrated. By simulation and modeling of mud loss and its comparison with reservoir fault modeling and production indexes plots, it was identified that the dominant mud losses are related to fault zone fractures and in minor cases the increasing of mud weight is the reason of mud loss. Applying appropriate operations such as under balance drilling (UBD) and suitable well placement, use of drilling mud with proper mud weight in severe mud loss points, use of NIF and MMH especial drilling muds with lowest formation damage, or a combination of these methods are suggested for mud loss control in critical points of the oil field. Manuscript profile -
Open Access Article
2 - Relation between microfacies, depositional environment and diagenesis with reservoir quality the Jahrum Formation in well no. 11, Golkhary oil field, Zagros basin
Maryam Sinapour Naser ArzaniIn this study the relationship between petrographic studies (microfacies, environment of deposition and diagenesis) and petrophysical data of core analysis in order to identify reservoir quality of the Jahrum Formation in well no. 11 at the Golkhary oil field. The Go MoreIn this study the relationship between petrographic studies (microfacies, environment of deposition and diagenesis) and petrophysical data of core analysis in order to identify reservoir quality of the Jahrum Formation in well no. 11 at the Golkhary oil field. The Golkhary oil field is located at the west of Qatar-Kazerun fault, in between Binak and Nargesi oil fields. The Jahrum Formation consists of limestone, dolomite limestone and dolomite. Petrographical studies accomplish in two parts microfacies studies led to the recognition of 9 microfacies that were deposited in 3 facies belt tidal flat, lagoon and open marine environment. In diagenesis studies the most important factors included bioturbation, micritization, mechanical compaction, secondary porosity, secondary anhydrite cement, calcite burial cement, stylolites and solution seams, replacement dolomite, dolomite cement and hydrocarbon shows. Porosities identified are intercrystalline, intergrain, intrafossil and intragrain, moldic, fracture, solution along stylolite, solution enlarge and shelter. The results of this study shows that Grain supported MF3 (Bioclast Nummulitidae Rotalia wackestone/ packstone/ grainstone) and MF4 (Bioclast Nummulitidae Orbitolites packstone/ grainstone/ floatstone) due to the presence in the environment energetic, micrite absence, lack of widespread cement, presence of effective porosities includes intergrain porosity and intercrystalline porosity identified are reservoir microfacies. Petrophysical data with high levels of permeability and effective porosity between these two microfacies is the confirmation of the results of petrographic studies. Manuscript profile -
Open Access Article
3 - Al Khalij field in Qatar, and extension toward Reshadat Oil Field, in the Persian Gulf
Ali reza BashariAlkhalij field located offshore Qatar , was discovered in 1991 and put into production in 1997. The field is original in many aspects. it is one of the few carbonate reservoir with stratigraphic closure, the oil is being trapped in upper part of a monocline due to a l MoreAlkhalij field located offshore Qatar , was discovered in 1991 and put into production in 1997. The field is original in many aspects. it is one of the few carbonate reservoir with stratigraphic closure, the oil is being trapped in upper part of a monocline due to a lateral variation in reservoir facies. In addition, the reservoir lies within the capillary transition zone and consists of a succession of highly conductive oil bearing layers ( drains) in between matrix layers of poor permeability. High- resolution 3D seismic has revealed additional area developed, which were previously considered to be uneconomic. Resent 4D seimic pilot has given encouraging result to utilize Seismic Technologies to analyse the evolution of the Al Khalij oilfield over time. Studies shows, this field possibly extended toward Reshdat oil field. Manuscript profile -
Open Access Article
4 - A case study of carbonate reservoir permeability determination using NMR log in one of the southwestern fields of Iran
Bahram HabibniaPermeability is one of the most important parameters for characterization of hydrocarbon reservoirs that has a basic role in almost all of the petroleum engineering problems. Determination of reservoir permeability is usually done in core laboratories in a time consumin MorePermeability is one of the most important parameters for characterization of hydrocarbon reservoirs that has a basic role in almost all of the petroleum engineering problems. Determination of reservoir permeability is usually done in core laboratories in a time consuming process. In the well test, the obtained average permeability is related to the drainage area. Due to cost, these two methods are not performed in the all wells, whereas well logging tools are generally performed in all wells. With progress of well logging tools, some researchers tried to estimate permeability from special well logs such as NMR directly. The data obtained from NMR was used as lithology independent data to estimate the water saturation and porosity, and also for analysis of pore space. One of the important parameters obtained from NMR is the transversal relaxation time (T2). In this work, NMR log measurement in a carbonate field was used to estimate the permeability using Timur, SDR and regression models. The results of the methods were compared against core permeability. The results show that SDR method is more accurate with the accuracy of 44.1% and the error of 23.12%. Manuscript profile -
Open Access Article
5 - 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 AshjaeiUnderstanding 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 MoreUnderstanding 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
6 - The impact of microfacies and diagenesis characteristics on the reservoir quality of Asmari Formation in the Gevarzin gas field, Zagros basin, south Iran
Karim Mombani Ahmad YahyaeiAsmari Formation from the Gavarzin gas field have erosional unconformity boundary on marl and pelagic limestones of Pabdeh Formation and gradually change to evaporate cap rock of Gachsaran Formation. Cores studies from the one of wells of Gavarzin field is 183 m in thic MoreAsmari Formation from the Gavarzin gas field have erosional unconformity boundary on marl and pelagic limestones of Pabdeh Formation and gradually change to evaporate cap rock of Gachsaran Formation. Cores studies from the one of wells of Gavarzin field is 183 m in thickness, which includes 1.30 m from the top of Pabdeh, 162.4 m from the Asmari Formation and 19.30 m from the base layers of Gachsaran. Asmari Formation includes alternation of limestone, calcite dolomitic, claystone and shale with green marl. Petrology and facies analysis of the sequence of these formations identified 12 microfacies, a carbonate ramp from deep-sea to sabkha environments and formed in a retrograded sequence. This ramp includes deep environments, open sea, patch reef, bio-, clastic-bars, lagoon and tidal environments, which confirms a changing environment due to rapid facies changes and deposition of evaporative sediments in Gachsaran as a restricted environment. Diagenesis processes are considered as the main factors in carbonate reservoir quality of Gavarzin field. The diagenesis history of the Asmari carbonates of the studied cores is summarized as A) marine phreatic diagenesis, bioturbation, micritization and cementation processes occurred. B) vadose zone diagenesis, where the crystallization, cementation, and dissolution occurred. C) burial diagenesis, comprises compression-induced, pressure dissolution and fracturing are common. The microfacies show a wide varieties of reservoir characteristics and therefore a heterogeneous reservoir has been formed. Micro-fractures, however have strongly influence on the reservoir quality in the section. The simultaneous presence of dissolved spaces and fractures in the reservoir the permeability greatly increased. The best reservoir quality in the Grainstone/Packston facies are coated grains with moldic porosity that were created by the leaching of Ooid-bearing Packston lithology during the diagenesis of atmospheric waters. Manuscript profile -
Open Access Article
7 - Occurrence of heavy crude oil in the Persian Gulf
Ali reza BashariSome of the most prolific petroleum reservoirs with high gravities of oil in the world occured in the Upper Jurassic and Cretaceous carbonate formations in the Persian Gulf area .Most of the reservoirs are composed of pelletal,oolitic ,or bioclastic grai MoreSome of the most prolific petroleum reservoirs with high gravities of oil in the world occured in the Upper Jurassic and Cretaceous carbonate formations in the Persian Gulf area .Most of the reservoirs are composed of pelletal,oolitic ,or bioclastic grainstones and reefal limestone that have high primary porosity and permeability .These reservoirs are sealed either by tight limestone ,massive anhydrite, or by impermeable rocks. The seals are effective throughout most of the Persian Gulf and surrounding areas, Accumulations of heavy oil and natural asphalts on the Iranian side of the Persian Gulf extend NE to SW along the Qatar arch. some of the geological structures which are located along this trend contain heavy oil and natural asphalts within post- Jurassic formations. The major geologic factor which caused accumulations of heavy oil within some geological structures is the Qatar arch. As a result ,some differences appear in lithologic units in two sub-basins northwest and southeast of the Qatar Arch. In general , the occurrence of heavy oil in this trend can be explained as follows; • Fracturing and joints within formation ; • Reduction of thickness of post- Jurassic sediments; • Facies change of Arab reservoirs, cap rock (Hith anhydrite), in some structures from anhydrite to dolomite and also pinchout; The absence of proper environment for the generation of high gravity oil may also be of importance .It should be mentioned that "F" structure (Ferdows), with huge amount of oil in Ratawi and Sulaiy carbonate reservoirs(Lower Cretaceous), is one of the largest heavy oil fields along this trend .The Farsi "B" structure, ( Farzad), with a thick Jahrum formation (Eocene) which has excellent reservoir properties, is filled with natural asphalts. Manuscript profile -
Open Access Article
8 - Laboratory study of alteration in reservoir rock wettability for the prevention of asphaltene sediment formation using metal oxide Nano-particles
abdolhamid ansari Sadegh AmeriOne of the methods of harvesting oil reservoirs is the injection of nanoparticles. Nanoparticles increase oil recovery from reservoirs by changing wettability, reducing surface tension, reducing oil viscosity. Metallic nanoparticles (ceramic nanoparticles) have the high MoreOne of the methods of harvesting oil reservoirs is the injection of nanoparticles. Nanoparticles increase oil recovery from reservoirs by changing wettability, reducing surface tension, reducing oil viscosity. Metallic nanoparticles (ceramic nanoparticles) have the highest application in increasing the absorption of reservoirs. In this research, changes in the contact levels of oil, water, and stone in the presence and absence of metal oxide nanoparticles have been investigated. The change in the rock's wettability has been analyzed in various concentrations of nanoparticles in the aqueous phase and the governing mechanism for changing the rock solidity in two metal oxide nanoparticles is presented. 4 nanoparticles used in this study are TiO2, NiO, Co3O4, Al2O3 The specimens were then measured by the DSA and the angles were measured and it was observed that the maximum gradient of the graph is related to nickel oxide followed by cobalt oxide and then titanium oxide and the lowest slope to aluminum oxide. In this respect, from this point of view, Nano particles are considered as NiO> Co3O4> TiO2> Al2O3, respectively. So the first suggestion is to select the most suitable nanoparticles of metal oxide, NiO, and for the second position Co3O4, the third and fourth choices are TiO and Al2O3, respectively. Manuscript profile -
Open Access Article
9 - An attempt to reservoir characterization of Burgan sand, in the northwest of the Persian Gulf toward Kuwait
Ali reza BashariThe Sand tongues of the Albian Kazhdumi Formation is a major prodactive reservoir in North West part of the Persian Gulf towards Kuwait . High porosity and high permeability of these sandstones together with existence of shale either as source rock or cap rock in MoreThe Sand tongues of the Albian Kazhdumi Formation is a major prodactive reservoir in North West part of the Persian Gulf towards Kuwait . High porosity and high permeability of these sandstones together with existence of shale either as source rock or cap rock in this formation, have provided all conditions needed for hydrocarbon accumulation. A rapid sea level fall in ealry Albian initiated the deposition of Burgan clastic reservoirs over the Shuaiba Carbonates. The lower Burgan Formation was deposited in a lowstand systems tract represented by massive sandstone reservoirs. High frequency sealevel changes have resulted in deposition of shoreface sands and extensive marine shales within an overall fluvial setting. The middle part Burgan was deposited in a transgressive systems tract. The upper part witnessed a relative sealevel fall in a lowstand systems tract with deposition of sand prone facies in estuarine channels. The clastic cycle was terminated by initiation of Mauddud carbonate sedimentations in transgressive systems tract. A combined effect of allocyclic nesting of sequence stratigraphic packages and autocyclic ramp profile were the primary factors controlling the lithofacies association. This Formation has been informally subdivided into: Lower Interval (C) mainly shaly sands, middle Interval (B) clean sands “main reservoir” and upper Interval (A) interbedded shale & sands. Petrographic analysis shows that the reservoir consists of quartz-rich sands, (typically>70%) and feldspar poor (mainly <5%). Nine authigenetic minerals in the Burgan sands have been identified: quartz, calcite, siderite, pyrite, glauconite along with four groups of the clay minerals. XRD analysis of clay fraction indicates the presence of four clay mineral groups in the Burgan reservoirs : kaolin, illite , chlorite and expandible- lattice mixed –layer, illite/ smectite. Manuscript profile -
Open Access Article
10 - Hydrodynamic activity in the Mishrif reservoirs: an approach to characterize Sarvak formation , in eastern part of the Persian Gulf
Ali reza BashariThe hydrodynamic activity and its effects on oil water contact of oil fields in Sirri district ( Eastern Part of the Persian Gulf), has been revealed by drilling and coring of third well of Mishrif reservoir, (SiDA1) on 1976. Discovery of Sirri –D1 ( Dena) i MoreThe hydrodynamic activity and its effects on oil water contact of oil fields in Sirri district ( Eastern Part of the Persian Gulf), has been revealed by drilling and coring of third well of Mishrif reservoir, (SiDA1) on 1976. Discovery of Sirri –D1 ( Dena) in 1972 and SiD-2 confirm existence of oil only 5 meter at the top of structure. Field development started in 1975 and showed the existence of tilted, oil- water contact along fairly south –north direction with slopes up to 12:1000, particulary on the western flank of structure. Slope and direction of water level of Sirri-C ( Sivand) which is close to Sirri-D (Dena) , contain the same slope in both field, at the eastern border of field. The oil –water contact of Sirr- E, (Alvand) field has been constructed with good accuracy and fair probability in 1978. As a result, this modeling was confirm with actual result after full field development of this field on 2002. An entirely original study has been undertaken on residual oil of core, which permitted to characterize various zone as well as modern and fossil interfaces, and proved Hydrodynamic activity in the Mishrif reservoir in western part of Persian Gulf ( Sirri District). This study was carried out, with an approach to combined reservoir characterization , and revealed accuracy of results after full development of these fields. Manuscript profile -
Open Access Article
11 - 3D modeling of rock types using the integration of core, well logs and seismic data in one of the carbonate reservoirs of southwestern Iran.
Mahdi Kheirollahi Golnaz Jozanikohan Reza Mohebian Ali MoradzadehRock typing is the process of assigning reservoir properties to geological facies, and an identified rock type has similar geological and reservoir properties. Due to the importance of identifying and separating rock types in hydrocarbon reservoirs, various methods have MoreRock typing is the process of assigning reservoir properties to geological facies, and an identified rock type has similar geological and reservoir properties. Due to the importance of identifying and separating rock types in hydrocarbon reservoirs, various methods have been proposed and developed today for the determination of rock types. One of the simplest methods is the porosity chart against permeability and cut-off determination, and one of the most important and practical of these methods is to determine rock types by flow zone indicator. In this study, we examine one of the most important hydrocarbon fields in the south of Iran where core, well and seismic data are available for the field studied so that by designing a new workflow and with use of the most important and efficient methods of rock typing, including FZI, porosity, Winland-Pitman index, FZI*, and logarithms of FZI and FZI* we have identified rock types in three dimensions and through the whole field. After the final validation, the correlation coefficient values were more than 83%, 57%, 70%, 70%, 73% and 78% for the methods used, indicating greater accuracy and efficiency of the FZI method for the rock types separation in this field. The partial comparison of the validation results after each method employment also confirms the highest accuracy belongs to the FZI method. As a result, by integrating this method with seismic attributes, the rock types have been separated in four different groups throughout the field in three dimensions. Manuscript profile -
Open Access Article
12 - Integration of petrophysical and Seismic data: an Attempt to Geological model, Ilam reservoir oil field, Sirri District , in the Persian Gulf.
Alireza BashariIlam Formation is deposited at the late Cretaceous (Santonian) in a neritic/pelagic environment. Following the Ilam deposition, a general deepening has occurred and the Gurpi formation (shaly layer) was deposited. Ilam has thickness variation between 75-110m and st MoreIlam Formation is deposited at the late Cretaceous (Santonian) in a neritic/pelagic environment. Following the Ilam deposition, a general deepening has occurred and the Gurpi formation (shaly layer) was deposited. Ilam has thickness variation between 75-110m and structure has created as a result of upward movement of deep seated salt. Ilam reservoir in this field is regarded as a secondary hydrocarbon potential, and since now, no oil has been produced from this horizon. petrophysical and Seismic interpretation has been done for the Ilam reservoir, the geological models (structural and property models) are generated, with both deterministic and stochastic approaches. The seismic attributes as secondary variables, improved the kriging and Sequential Gaussian Simulation (SGS) algorithm results for modeling of Ilam. This study reveals that Water Saturation is generally high, indicating that Ilam reservoir has low hydrocarbon potential, within the five reservoir potential zones, the zone 5 indicated a good original oil in place potential, especially in the western and central parts of the field. Manuscript profile -
Open Access Article
13 - Petrophysical Modeling of Lower Zone of Ratawi Formation, using Neural Network Method in Assimilating Seismic and Geological Well Log Data
Javid Hanachi Alireza BashariEsfandiar field is located at the northern part of the Persian . This field is a single large anticline with Lulu field of Saudi Arabia, with , 20 KM length and 7 KM width. The field was discovered in 1966 by drilling of well E1, on the northern culmination of t MoreEsfandiar field is located at the northern part of the Persian . This field is a single large anticline with Lulu field of Saudi Arabia, with , 20 KM length and 7 KM width. The field was discovered in 1966 by drilling of well E1, on the northern culmination of the field. wells E3 and E2 were drilled at the top of structure in the southern part of the field. DSTs tests results of E1 proved that the top of Lower Ratawi formation contain 15 m oil column. E3 well test result regards as a dry hole DSTs test results of E2 were not conclusive due to inadequate testing plans . E4 Appraisal well contained, 14 m oil column at the Lower Ratawi. Log interpretations results indicated, E2 and E3 wells contains oil in Yamama formation in the southern part of the field which has not been tested properly. Lower Ratawi (Top oil-bearing zone ), Zone 'B' of Lower Ratawi (Oil bearing zone at bottom), Yamama were constructed based on the existing data. Petrophysical and geophysical data has been used for the Lower Ratawi reservoir, as a result the geological models (structural and porosity models), with applying, related software’s and neural network geophysical method are generated . At the conclusion, the recommended plan consists of horizontal drilling wells for oil production in Lower Ratawi in the north of the field has been proposed. Manuscript profile -
Open Access Article
14 - Isotopic and Geochemical comparison of Bangestan and Asmari Oils to determine origination
ashkan Zardashti Morteza Tabaei mahmood memarianiIn order to analyze the geochemical characteristics, the oil samples of the Asmari reservoirs and the Bangistan group in the Kopal field were studied using various geochemical techniques such as asphalting technique, gas chromatography technique, gas chromatography-mass MoreIn order to analyze the geochemical characteristics, the oil samples of the Asmari reservoirs and the Bangistan group in the Kopal field were studied using various geochemical techniques such as asphalting technique, gas chromatography technique, gas chromatography-mass spectrometry technique and carbon isotope measurement technique, were subjected to analysis. the purpose of This research is a comparison of carbon isotope and geochemical properties of Asmara and Bangestan oils in Kopal field to determine their parent rock and origin. Considering the results of the testing technique and analysis of biomakers of the esteranes and terpanes family extracted from saturated cutting, it can be stated that the oils accumulated in the Asmari and Bangestan reservoirs of the Kopal field have the characteristics of oil. are paraffinic, which indicates the existence of light oil with good quality, mature, low viscosity and high sulfur. By placing the ratio of biomarker parameters against carbon 13 isotope and examining the general results of the graphs, it was found that the oil samples of Asmari reservoirs and Bangestan reservoirs in the studied field are from a common generative rock. have been found and have the same characteristics and only slightly differ in maturity, degree of fluidity, and the amount of migration processes between the source rock and the reservoir rock, and similarly, the transformation course of the source rock organic materials has occurred naturally in the Copal field. The values of carbon isotopes in the oils indicate the average maturity of the rocks producing the oils. The graph of the ratio of the aromatic carbon 13 isotope against the saturated carbon 13 isotope showed that both field oil samples The subject of study belongs to marine environments. Manuscript profile -
Open Access Article
15 - Petrographical factor and Petrophysical parameter: An approach to reservoir evaluation of the Sarvak formation in NW, of the Persian Gulf
Alireza BashariSarvak 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 MoreSarvak 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