جستجوی مقالات مرتبط با کلیدواژه "south pars field" در نشریات گروه "زمین شناسی"

Dariyan formation which is one of the oil reservoirs in the south pars field, has been studied in wells SPO-1, SPO-2, SPO-3 from this field. Six hydraulic flow units (HFU) were identified by flow zone indicator (FZI) for reservoir facies, including HFU-A, HFU-B, HFU-C, HFU-D, HFU-E and HFU-F. Comparison between these hydraulic flow units indicate HFU-A and HFU-B with very Low reservoir quality, HFU-C with low reservoir quality, HFU-D with medium reservoir quality and HFU-E and HFU-F with high reservoir quality which reveal good correspond with facies texture and diagenetic specifications. Also, based on studies, four rock types were identified. Rock type 1 includes flow unites mostly with very low reservoir quality (B, C), and flow unites with medium (D) and flow unites with high reservoir quality (E, F) are lesser. Rock type 2 is nearly semblable to rock type 1 albeit, flow unites with medium (D) and high (E) reservoir quality are more and flow unites with very low and low reservoir quality are less than rock type 1. Rock type 3 is more liaise to flow unites with high reservoir quality (E, F) and less with medium reservoir quality (D). Rock type 4 is only related with flow unite with high reservoir quality (F).

Dariyan formation is one of the oil reservoirs in the south pars field. This formation has been studied in wells SPO-1, SPO -2 and Spo-3. Thickness of Dariyan formation in mentioned wells are 109, 113 and 114 meters respectively. Based on the studies of thin sections the Dariyan formation of three above mentioned wells, nine carbonate and one detrital facies have been identified within four facies associations including tidal flat (Mudstone), lagoon (Bioclast mudstone to wackstone, Bioclast peloid wackstone to packstone, Bioclast peloid packstone to grainstone, Algal boundstone), Mid ramp (Echinoid mollusk wackstone to packstone, Orbitolina wackstone to packstone, Framestone, Floatstone) and outer ramp (Shale). Facies studies indicate that Dariyan formation has been deposited in a homoclinal ramp.The Dariyan formation has been affected by four diagenetic stages, including marine, meteoric, burial and uplift. The most important identified diagenetic processes are micritization, bioturbation, geopetal, physical and chemical compaction, cementation, neomorphism, replacement, dissolution, fracturing and filling. Among the all diagenesis process, dissolution and fracturing are the major processes improving reservoir quality. In Contrary, physical compaction and especially cementation are the main processes reducing reservoir quality. Dissolution process with generating secondary porosity consists of vuggy and moldic, has important effect on increasing of porosity. Most of the dissolution features have been produced during the meteoric diagenesis and less through burial diagenesis. Dissolution process with develop the vuggy pores caused to connect them in some case and also affected on fractures , stylolites and previous diagenetic cements in upper and lower members of Daryian formation which eventually has been increased permeability and reservoir quality. Also, Fracturing, the main other diagenetic process with connect the some individual vuggy and moldic pores together has effective role to increase the permeability and reservoir quality in upper and lower parts of Dariyan formation.

The south pars gas field is on of the southwestern fields of iran in zagros sedimentary basing and consists of two kangan and dalan reservoirs. the Kangan and Dalan formations belong to Dehram Group and are the most important gas reservoirs in Persian Gulf area. Petrophysical characteristics in the studied well were evaluated by the data of the well logs and Probabilistic method was used for petrophysical by Geolog 6.6 software. for an accurate evaluations, the necessary corrections were applied on logs by considering the places of wash out, environment effects, gas and shale effects. After that, the lithology of the Kangan and Dalan formations were determined by using of cross plot of neutron – density. Analysis of wire line data shows that the formation is basically limeston and in some part it is dolomite. on the based of Lithology, shale volume, presence of evaporate sediments and porosity, the Kangan formation has been zoned to and, and the Dalan formation has been zoned to and. The results show that the zone of the Kangan formation and the zone of the Dalan formation have on apporiate reservoir in terms of gas saturation level, porosity and lithology as results porosity (PHIE) and water saturation (SWE) were obtained 9/45%, 9/7% for kangan and 8/65%, 8/2% for Dalan formation in average, respectively.

Nowadays, wavelet analysis has many applications to identify and analyze the transient boundaries and waves, such as image borders and earthquake waves. Detection of discontinuities in the sedimentary sequences and identifying the boundaries of sequence stratigraphic surfaces are one of those applications. In this study, wavelet analysis was used to analyze wirline logs data, such as GR, NPHI, RHOB, RHOZ, THOR / URAN and multimin data such as anhydrite percentage volume, in which the data vary in sequence boundaries. Different types of sequence boundaries impact on different types of logs. The wireline logs are affected by structural and lithological changes; thus, we cannot identify those boundaries using a kind of correlation coefficients. In this study, a combination of coefficients for the wireline logs is used. This combination offers a good way to automatically determine the borders fairly accurate. The best results are obtained from the coefficients combination of GR, NPHI, RHOB (RHOZ) logs and the anhydrite percentage volume multimin, and also, the coefficients combination of GR, NPHI, RHOB (RHOZ) logs and thorium to uranium ratio (THOR / URAN) graphs. Comparison between the results of this study in Kangan and Dalan formations of South Pars gas field with the other proved methods show the capability of this technique in combination of data.

The Early Triassic Kangan Formation is the main reservoir in the Persian Gulf. In this studyreservoir rock types were recognized according to lithology, rock fabric, geometry andamount of porosity. Therefore, 7 reservoir rock types were determined: - Anhydrite without reservoir quality, - limy– dolomite with mud dominated fabric without reservoir quality, - limy– dolomite with mud dominated fabric and an average reservoir quality, -limy– dolomite with mud dominated fabric and good reservoir quality, - dolomite with crystalline fabric and low reservoir quality, - limestone with grain dominated fabric with an average reservoir quality and - dolomite with crystaline fabric with a good reservoir quality.Based on petrophysical logs(Gamma ray, sonic, neutron & density), 5 reservoir units and 6non – reservoir units were identified. Reservoir units are mainly formed of porous grain dominated limestone, crystalline dolomite and mud dominated fabric dolomite, and non –reservoir units include anhydrite and limy dolomite without porosity. Petrophysical and petrographical studies indicate that moldic, intercrystaline and interparticle porosities are the most effective porosities in the reservoir units of this formation, whereas others like vuggy, fracture and intraparticle porosities have minor role in reservoir quality.

Determination of different facies is one of the important and basic tasks of geological engineering characterization of reservoir rocks well logs and core data. Our objective is to identify and determine different facies of the South Pars Field using RBF and PNN neural networks in order to perform static and dynamic simulation. These networks are utilized to identify facies of the South Pars Field for the first time in Iran. In this study, we use different parameters of mentioned networks such as ‘spread’ and ‘goal numbers’ to improve networks operation. In this regards, the optimum values of these two parameters were 0.01-10 and 0.02-0.04 respectively. The results show that the RBF and PNN neural networks are robust means to determine and model the facies of the South Pars Field in Iran.