جستجوی مقالات مرتبط با کلیدواژه « asmari reservoir » در نشریات گروه « زمین شناسی »

The evaluation of hydrodynamic characteristics can be a useful tool to understand the field behavior and production efficiency. The present study is an attempt to clarify hydrodynamic flow in the Asmari reservoir of the Rage Safid oil field. Water oil contact (WOC) depth is 200m lesser in northern flank than southern part. The results indicated that the aquifer potentiometric surface is tilted. The Piper and Composition diagrams are showing the mixing process of two water types including Cl-Na type with higher TDI and calcic-magnesic bicarbonate type with lower TDI in the reservoir water. The first one is sourced from salt horizons of Gachsaran Formation and the second one is from limestone-dolomitic parts of the Asmari Formation. This result is also verified by TDI to depth plot. Hydrodynamic maps and fluids trends are showing a continuous flow from NE to W-SW of the field. This flow is relatively strong in western and south western part. Generally, production index and pressure data indicate a suitable condition in southern –southwestern part of the field. By considering fluid flux from NE to W-SW it is strictly proposed to focus drilling program in the western part and the water injection program in the north eastern part of the field.

Fluid inclusions provide valuable evidence of the formation temperature of minerals, the pressure on their formation environment, the fluids densities that make up the minerals, and the chemical composition of the mineralizing fluids. This data can be used to interpret temperature history, maturity, determination of diagenetic environment, cementation timing, and hydrocarbon migration related to burial history.

In this study, the cores of Asmari reservoir of 7 wells from Ahvaz field (AZ) were used. After checking the appearance characteristics of the samples, 19 double-polished sections with a thickness of 200 to 300 micrometers were prepared. In order to perform microthermometric analysis, at first, all samples were placed in acetone for 24 hours. In the following, after separating the double polished samples from the slide, in order to completely remove the surface contamination, the samples were placed in an ultrasonic device for five minutes in distilled water. After the initial investigation of the occurrence of fluids inclusions in the studied samples, regardless of the size of the fluids involved, 54 intermediate loads of fluids were selected to conduct microthermometric studies. All microthermometric data were obtained using cooling and heating operations on the involved fluids using a Linkam THMSG 600 model stage placed on an Olympus microscope. In addition, in order to determine the amount of UV reflection in the Petroleum Inclusions in the study, the UV light source model U-RFL-T placed on the Olympus microscope was used. After performing microthermometric operations on the fluid’s inclusions, the selected samples were selected for Raman laser spectroscopy analysis to accurately determine the liquid and vapor phases of the Petroleum Inclusions. It should be noted that Raman laser spectroscopy analyzes were performed on microthermometric analyzed samples. All measurements were made using a LABRAM model Raman spectrometer (ISA Jobin Yvon) available in the Fluid inclusions Laboratory of Montanuniversitat University.

Petrographic studies All the samples were subjected to petrography study, which is in terms of the types of single-phase gas, single-phase liquid, two-phase liquid-rich (oil) intermediates. In these samples, hydrocarbon materials can be seen scattered and filling fractures. In terms of origin, it can be seen in different and varied types, primary and secondary false. Microthermometric studies Microthermometry was performed on 54 fluids inclusions. The homogenization temperature of fluid inclusions is between 50 and 362 degrees Celsius. The samples of the Asmari reservoir show the melting temperature of the last ice crystal between -22 and 13.9. The degree of salinity is calculated to be 0.16 to 35% by weight equivalent to table salt. API study In the samples selected from the Asmari reservoir in Ahvaz field, 54 fluid inclusions were identified. These fluid inclusions emitted the following fluorescence spectrum under UV light. The frequency of reflective color is related to green with a value of 55%, which is in the range of 30-40 API degrees, and the value of 40% belongs to blue color, which indicates the range of API degree 40. -50 and only 5% of these colors belong to the yellow color, which indicates the API degree in the range of 20-30. Therefore, in the samples of the Asmari reservoir, the green color with a frequency of 55% has a density of 0.82 to 0.74 g/cm3, which generally indicates oil with a light density. Also, in the second category of these samples, the abundance of fluorescent reflective color, blue color with an abundance of 40%, with a density of less than 0.74 g/cm3, is considered an extremely light oil. Finally, the lowest reflective color abundance of Asmari reservoir samples is yellow with 5% density of 0.9 to 0.82 g/cm3, it is considered a medium density oil. Raman spectroscopy The calculation of liquid phase salinity in petroleum inclusions cargoes using the Raman laser spectroscopy method is dependent on the geometric shape of the spectrum obtained from the liquid phase present in the petroleum inclusions. According to the Cauchy-Lorentz scattering, the Raman spectrum for pure water shows three peaks at cm-13220, cm-13433 and cm-13617. In the samples that were analyzed by Raman spectroscopy, they indicate hydrocarbon compounds in the fluid inclusions.

Based on the petrographic studies conducted on 19 samples (54 fluid inclusions) according to their diversity (primary, secondary), it indicates and confirms the different compositions of the activity of different phases of Asmari reservoir charging. Based on the data obtained from the microthermometric studies, the physicochemical properties of the reservoir, including the last ice melting temperature, homogenization temperature, and salinity of the reservoir were determined. Based on the physicochemical properties of the Asmari reservoir, it shows two temperature ranges, which can be concluded that this reservoir was charged during two phases in two different time periods. One of the reasons confirming this conclusion can be mentioned that the oil of this reservoir has two origins. Also, based on the composition of the phases in the fluid inclusions (two-phase, three-phase with oil, etc.), it is possible to predict the path of charging the reservoir.

The most important reason for studying any oil reservoir is the more efficient use of the production parts of the reservoir and the first step in identifying the reservoir is its zoning. Zoning is determined based on lithological changes by combining production data and petrophysical logs in each reservoir. In order to improve and accelerate the zoning of oil reservoirs, like other branches of science, the use of software has become common in recent years. One of the most powerful of these software's is Cyclolog. The science of using this software is cyclostratigraphy, which can be used to separate reservoir zones based on sedimentary cycles and their knowledge. Cyclolog software with the help of petrophysical logs taken from the wellbore and especially gamma diagram (GR) allows subsurface matching and preparation of matching charts in selected wells. In this study, in the three oil fields studied (Karanj, Paranj and Parsi) using cyclolog software, a total of seven positive timelines (Pb3000, Pb2000, Pb1500, Pb1000, Pb500, Pb400, and Pb300) as well as five negative timelines (Nb4000, Nb3000, Nb2000, Nb1000, and Nb500) were detected. Accordingly, the Pb1500 timeline is the separator and the boundary of the Chattian and Aquitanian peaks, which in the wells of all three studied fields almost cross the boundary of reservoir zones 3 and 4. The Nb4000, Nb3000, and Nb2000 timelines are also Chattian age. The Nb3000 timeline in Karanj oil field has crossed the boundaries of zones 4 and 5 in most of the wells due to calibration with biometric evidence (biostratigraphy) and indicates the top of the formation. The age of the Nb500 timeline is Burdigalian and passes through the middle of their reservoir zone 1 in the study area. The boundary between the Aquitanian and Burdigalian peaks is defined by the Nb1000 timeline. This timeline crosses the boundaries of zones 1 and 2 in all three fields studied.

Permeability is one of the most important petrophysical parameters that play a key role in the discussion of production and development of hydrocarbon fields. In this study, first, the magnetic resonance log in Asmari reservoir was evaluated and permeability was calculated using two conventional methods, free fluid model (Coates) and Schlumberger model or mean T2 (SDR). Then, by constructing a simple model of artificial neural network and also combining it with Imperialist competition optimization (ANN-ICA) and particle swarm (ANN-PSO) algorithms, the permeability was estimated. Finally, the results were compared by comparing the estimated COATES permeability and SDR permeability with the actual value, and the estimation accuracy was compared in terms of total squared error and correlation coefficient. The results of this study showed an increase in the accuracy of permeability estimation using a combination of optimization algorithms with artificial neural network. The results of this method can be used as a powerful method to obtain other petrophysical parameters.

Understanding of oil and gas reservoirs is great help in maximizing hydrocarbon recovery. In the study of the characteristics of oil structures, the analysis of the 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 petrolium geologists. Since the most of Iran's reservoirs are carbonate type, investigation and analysis fractures, 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 illustrator 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 illustrator and then drilling and production problems in Asmari reservoir were evaluated and 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, analysis of Asmari reservoir fractures and how to expand these fractures in the reservoir By using mud loss modeling, interpretation of the FMI illustrator and the effect of these fractures was on the porosity and permeability of the reservoir. In this study, it has been determined that, fractures analysis in wells very good matching with drilling mud loss maps with rock basement faults at the has anticline of the Asmari reservoir.

Marun oilfield is located in the middle part of Dezful Embayment and is situated along the Aghajari، Ahvaz and Ramin anticline. Given the important role of fracture characteristics for improving production، so the aim of this research is to investigate the density pattern of fracture in Asmari formation in Marun oilfield. For this purpose، results of image log، core data، graphic well log، methods of inscribed circle analysis and curvature changes geometry of anticline were analyzed. Asmari formation is the main reservoir rock in Marun oilfield that divided into five zones. Limestone and dolomite are the main lithology of zones 1، 2 and 3 which has a high density of fractures (especially in zones with 90% dolomite). Also there is less fracture density (micro fracture) in the 4 and 5 Asmari zone due to an increase of shale and marl layers and due to less break ablity has a less distribution of fractures. The result show that there are a good conformity existed between the results of inscribed circle analysis، image log، core data، curvature and the presence of fractures in Marun anticline. The data indicate that highest density of fracture density concentrates in the southern limb in the central region of anticline and also in the north limb in the northeast region of the anticline. So، finally using these parameters، it is recommended that further development and production wells be drilled in the north eastern part of the oil filed as well as center part of southern flank of the anticline.