جستجوی مقالات مرتبط با کلیدواژه « مخزن سروک » در نشریات گروه « زمین شناسی »

In this study, electrofacies analysis has been done using MRGC (Multi-resolution graph-based clustering) method to be used in static modeling. Then, the resulting facies was modeled and compared together by applying different geostatistical stochastic algorithms in Petrel software. Two electrofacies classes including reservoir and non-reservoir facies were determined which were used for facies modeling. Seismic data was also applied for seismic facies construction and also to construct trend maps for appropriate facies distribution. In order to investigate the effect of five applied different geostatistical algorithms used in facies modeling on porosity distribution, the constructed facies models were used for porosity modeling. According to this study, the uncertainty of electrofacies modeling without applying seismic data increases which in turn reduces the accuracy of porosity models. In addition, electrofacies modeling considering the sequential indicator simulation (SIS) algorithm and applying the seismic trend maps, enhance the accuracy of the porosity model. Moreover, construction the of seismic facies is considered the best method for facies modeling to be used for porosity modeling due to the high correlation coefficient between acoustic impedance and porosity.

The use of hydraulic flow units as a method to determine the quality of the reservoir and also the use in the zoning of hydrocarbon reservoirs has a very high role in the development of reservoirs. The most reliable data in the discussion of reservoir study are obtained from the core, which due to the high cost of core retrieval, there is a small amount of this data in each field, however, the data from the core may Can play a decisive role in the study of the reservoir. In the present study, core porosity and permeability data were investigated and 6 hydraulic flow units (HFU) were identified using the regional flow index method, which were separated based on reservoir quality. Then 6 electrofacies were determined using petrophysical logs by self-organized method. The conformity of the electrofacies and the designated hydraulic flow units indicated a good convergence between them and an increase in reservoir quality from unit 1 to unit 6. The results of this study can be used as input for the construction of field facies models in the modeling process and locating new wells.

Reservoir characterization and the identification of the main factors controlling the quality of the reservoir has an important contribution to providing a real image of reservoir properties. The Sarvak Formation is one of the most important reservoir rocks in the Zagros sedimentary basin and the studied well is divided into three core facies based on layering, texture, fossils, and sedimentary structure. In this study, first, using the porosity and permeability data of a well in this formation, hydraulic flow units were determined based on the flow zone indicator and then compared with the results of thin sections studies, effective factors on the quality of each flow unit were identified. The results of determining the hydraulic flow units based on the flow zone indicator indicate the existence of four flow units A, B, C, and D in Sarvak Formation, which increase the reservoir quality from units A to D, respectively. Then, the electrofacies of Sarvak Formation were determined using well log data which resulted in five electrofacies. By comparing electrofacies with flow units and the results of microscopic section studies, it was observed that Sarvak Formation has a high heterogeneity in the studied well due to various diagenetic processes such as dissolution, cementation, and dolomitization that using the concept of flow units and electrofacies and comparing with the results of microscopic section studies, it is possible to separate different parts of this reservoir that have the same flow characteristics and generalize the results to non-core wells in the study field.

Until now, many researchers have used organic geochemistry to increase exploration efficiency by accounting for many variables, including source rock quality and richness, thermal maturity, and the timing of generation-migration-accumulation relative to trap formation. The Sarvak and Mishrif Formation is one of the main Cretaceous carbonate promising reservoirs in the Abadan Plain and Mesopotamian Basin. Considering limited studies describing the Abadan plain petroleum system and lack of oil-oil correlation between Sarvak and Mishrif oil reservoirs, in this study, initially the quantity, quality and maturity of organic matter in candidate source rocks were investigated and then the geochemical properties of Sarvak oils were evaluated. Finally correlation study was performed on Sarvak and Mishrif oils.

Two oil samples in the Cretaceous Sarvak Formation from the west of Abadan Plain oil fields have been analyzed using Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS). In addition, twenty cutting samples from candidate source rocks in the area from the lower Cretaceous and the upper Jurassic have been studied for source rock analysis.

The final interpretations of rock evaluation data for candidate source rocks in Abadan plain are as follows:Garau formation has good to excellent potential for hydrocarbon generation (mostly oil and less gas).Fahliyan formation has poor to fair potential to generate hydrocarbons. Although it is mature but the organic richness of the rocks are not enough and have generated relatively low amounts of hydrocarbons.Gadvan formation is evaluated as having poor potential source rocks and no oil could have been generated from these clastic rocks.Kazhdumi formation evaluated as fair to very good potential source rock, but being thermally immature and no hydrocarbon could have been generated from this rock.The biomarker analysis shows that Sarvak oils have been sourced from mature carbonate rocks containing Kerogen type II and were deposited in a low salinity environment. Also, based on C28 and C29 steranes and ETR, Sarvak oils were generated from Jurassic source rocks. According to biomarker and source rock studies, Sargelu and Garau formations were introduced as main source rocks in the west of Abadan plain, which generated Sarvak oils in maturity levels of early to middle oil window. On the other hand, biomarker data of five Mishrif oils from Iraqi oil fields (taken from released paper) were collected to compare them with Sarvak oil biomarkers.

The observations have been suggesting excellent correlations between Sarvak and Mishrif oil biomarkers, so according to close proximity of oil fields and rock evaluation data similarities, all generation levels, migration and accumulation of hydrocarbons in Sarvak and Mishrif reservoir located in the west of Abadan Plain and Mesopotamian basin respectively, are similar to each other. Finally, Sargelu and Garau formations generated hydrocarbons and are likely to have charged upper traps such as Sarvak reservoir, probably during Miocene, along faults and fractures.

Depositional facies and diagenetic features are usually understood by their detailed petrographic studies and core or outcrop description. This study focuses on identification and interpretation of depositional and diagenetic facies from log facies concept in the Sarvak reservoir of a giant oil fields of the Abadan Plain, SW Iran. In order to achieve this, three step approach is used. Firstly core description and thin section study were carried out to determine sedimentary and diagenetic processes in one studied key well with 265 m core and 760 thin-sections. Facies analysis led to the recognition of 12 microfacies representing six facies belts, which are lagoon, shoal, rudist biostrome, slope, proximal and distal open marine. According to the results, it seem that studied interval have been deposited in a carbonate shelf platform. Diagenetic processes include micritization, bioturbation, recrystallization, cementation, dissolution, compaction and fracturing have been affected the Sarvak reservoir after deposition. In this study we introduced diagenetic facies as a method for effective comparison between diagenetic alterations and log facies distribution. Three diagenetic facies were recognized that coincide with intervals with low cementation and dissolution (facies 1), high dissolution (facies 2) and high cementation (facies 3). Secondly, five log facies were identified by hierarchical clustering method. The number of clusters were determined based on dendrogram tree and geological heterogeneity. Comparing the results of log facies distribution with depositional and diagenetic changes, show a good agreement between geological and petrophysical heterogeneity. Finally, identification of depositional facies belts and diagenetic facies after calibration of log facies with this geological properties, were carried out in un-cored wells by log facies approach. The presented approach in this study is effective in highlighting main depositional and diagenetic heterogeneity of the Sarvak reservoir in studied field.

In this study, 8 crude oil samples of the Sarvak (5 samples) and Fahliyan (3 samples) reservoirs from one of the main oilfields of the Abadan Plain was assessed geochemically by Liquid Chromatography, Gas Chromatography (GC) and Gas Chromatography Mass Spectrometry (GC-MS) techniques. Types of crude oils of the Sarvak reservoir are Paraffinic Naphtenic and Aromatic Intermediate and are Paraffinic type for the Fahliyan reservoir crude oils. Biomarker ratios of saturate fractions such as variation of Pr/nC17 and Ph/nC18 ratios and Pr/Ph versus C27/C29 (20R) Sterane diagram indicate formation of source rock in reducing marine environment for both oil reservoirs. Furthermore, high amount of C29 Sterane in compare to C27 and C28 Steranes show that organic matter of source rock was formed in marine environment with terrestrial kerogen input. High amount C29 Hopane versus C30 Hopane, variation C27 (Dia/Dia䗨) Steranes versus Pr/(Pr), low amount of Diasteranes versus Steranes and variation Sterane/Hopane versus C27/C29 Steranes show carbonate- shale lithology for source rock of studied oils. Depending on high amount of resin, scattering of normal alkanes, high values of Pr/nC17 and Ph/nC18 and higher UCM in compare to other samples, K11 and K15 samples of the Fahliyan reservoir and B5 sample of the Sarvak reservoir demonstrate slight to moderate biodegradation while B19 sample show very slight biodegradation. According to variation of Pr/nC17 vs. Ph/nC18, C29 Sterane 20S/(20S�) vs. C32 Hopane 22S/(22S�), C29 Sterane 20S/(20S�) vs. C29 Sterane αββ/(αββααα) samples from both reservoirs denote early oil window formation. Samples from the Fahliyan reservoir have high thermal maturity in compare to the Sarvak reservoir samples.

The position of the oil-water contact (OWC) and improving the understanding of tilted OWC in fields, helping to explain risk analysis and development drilling. Oil-water contact has been defined in all wells of Civand (Sirri C) field utilizing petrophysical logs and confirmed using RFT data. Tilted oil-water contact has been established and presented in the field after provided isovalue map of OWC and using well correlation map in different direction. The oil-water contact has been tilted close to 0.5 degrees westward. Hydrodynamic flow and its direction was defined Based on calculated potentiometric surface in the studied wells and potentiometric and isosalinity maps. The results show that oil-water contact tilting has been associated to hydrodynamic flow in Sarvak (Mishrif) aquifer in east-west direction.