List of Articles Sequence stratigraphy

• Open Access Article
  • Abstract Page
  • Full-Text
  
  1 - Determination of the sequence stratigraphy boundaries by combining the wavelet analysis of wire line data - case study in South Pars field
  علي  خوبياري دکتر اسماعیل کلانتری  Charchi  Keshavarzi
  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 su More

  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. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  2 - Microfacies, Sedimentary Environment and Sequence Stratigraphy of the Qom Formation, Deh Namak, Northwest of Garmsar
  Jahanbakhsh Daneshian  Asadi Mehmandosti yousef ramezani
  Deh Namak section is exposed along the most northern point of the Qom Formation, where the Central Iran zone and Alborz zone come together. The study of microfacies, sedimentary environments and sequence stratigraphic features of the Qom Formation in this area can h More

  Deh Namak section is exposed along the most northern point of the Qom Formation, where the Central Iran zone and Alborz zone come together. The study of microfacies, sedimentary environments and sequence stratigraphic features of the Qom Formation in this area can help to understand the situation of the Qom sedimentary basin in the northern part, bordering the Alborz zone. 166 samples of the Qom Formation in Deh Namak section in the northwest of Garmsar are investigated. Microfacies analysis of these sedimentary rocks indicates that according to sedimentary environment they consist of nine microfacies belonging to four facies belts including tidal flat, agoon, shoal/reef sediments and slope of platform. Due to the absence of the gravitational and turbidity sediments and abundance of reef/shoal sediments, a rimmed carbonate shelf depositional environment is suggested in which more sediments were precipitated in shallow water. In this model, deep facies of the basin did not spread and the deepest facies belong to the slope. Also, sequence stratigraphic studies show that the Deh Namak section is composed of four sedimentary sequences of third- order, two types II and one type I sequence boundaries were recognized in this formation. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  3 - Sequence Stratigraphy of Oligo-Miocene deposits at Ahmadi anticline, southeast of Shiraz
  Jahanbakhsh Daneshian Mohsen Yaghoobi Alireza Tahmasbi Sarvestani
  The sequence stratigraphic studies can be of great help in understanding and analysis of sedimentary basins. For this purpose, Oligo-Miocene sediments (Razak and Asmari formations) at the Tang-e-Abdi section (southern flank of Ahmadi anticline) located in Fars province More

  The sequence stratigraphic studies can be of great help in understanding and analysis of sedimentary basins. For this purpose, Oligo-Miocene sediments (Razak and Asmari formations) at the Tang-e-Abdi section (southern flank of Ahmadi anticline) located in Fars province was selected and investigated. The Asmari Formation overlies paraconformably on the Jahrum Formation, and it is overlain by the Razak Formation. The lithologic column of this section includes a succession of the Jahrum (10m), Asmari (35m) and Razak (172.5m) formations, and consists mainly of limestone, argillaceous limestone, marl, sandstone, conglomerate, shale and dolomitic deposits. Totally, 84 samples were investigated, and their age is suggested as Late Eocene for the Jahrum Formation to Rupelian for the Asmari sediments, and Rupelian to Aquitanian for the Razak Formation based on the benthic foraminiferal stratigraphic distribution. The microfacies studies were led to recognition of four facies belts including tidal flat, lagoon, sand shoals and open marine. According to field & laboratory studies, four sequences and sequence boundaries were recognized. Two sequence boundaries are of type one and the other two are of type II sequence boundaries. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  4 - The application of Normalized Cumulative Gamma Deviation Log (NCGDL) in sequence stratigraphic analysis and correlation, a case study from the Sarvak Formation, Abadan Plain, SW, Iran
  A. Asaadi A. Imandoust J.  Honarmand ایرج عبدالهی فرد O.R. Salmian
  20.1001.1.17357128.1401.16.63.2.3
  Identification of key sequence stratigraphic surfaces is an essential task in geological evaluation of hydrocarbon reservoirs. The Sarvak Formation with Late Albian-Early Turonian age constitute the important reservoir unit in the Abadan Plain region, SW Iran. This stud More

  Identification of key sequence stratigraphic surfaces is an essential task in geological evaluation of hydrocarbon reservoirs. The Sarvak Formation with Late Albian-Early Turonian age constitute the important reservoir unit in the Abadan Plain region, SW Iran. This study investigates the application of Normalized Cumulative Gamma Deviation Log (NCGDC) to discriminate and correlate key sequence stratigraphic surfaces in six wells in a giant oil field in the Abadan Plain. To achieve this goal, identified key stratigraphic surfaces from core and thin sections were compared with interpretation of NCGDC method. From sequence stratigraphic point of view and based on the results from geological studies, the Sarvak Formation has been sub-divided into four third-order sequences which are described and interpreted. Two main disconformity surfaces, considered as sequence boundaries, are characterized by features of karstification, dissolution-collapse brecciation, and development of paleosol horizons. Generally, positive surfaces correspond to maximum flooding surfaces and negative surfaces occur at sequence boundary. Comparison of the results shows that, the identified sequence by NCGDC method can be effectively used for discrimination and correlation of sequences in different carbonate and siliciclastic reservoirs in the field scale. Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  5 - The history of deposition and post-deposition and their effects on the reservoir quality of Asmari Formation in Ahvaz oilfield
  Akbar Heidari Milad Faraji Narges Shokri
  The carbonate interval of the Asmari formation along with sandstone deposits were deposited in most areas of the Zagros sedimentary Basin, including the Ahvaz area, in Oligo-Miocene. In this study, the effects of depositional and post-depositional environments on the re More

  The carbonate interval of the Asmari formation along with sandstone deposits were deposited in most areas of the Zagros sedimentary Basin, including the Ahvaz area, in Oligo-Miocene. In this study, the effects of depositional and post-depositional environments on the reservoir quality of zone A7 of the Asmari Formation in well No. 4 in Ahvaz oil field were studied. The study of the sequences of the Asmari Formation in this section led to the identification of 11 carbonate facies, one evaporite facies, one mixed carbonate-siliciclastic facies, and one siliciclastic facies. Sedimentary environments of tidal zone, lagoon, coral reef and open sea were introduced for the depositional environment of identified facies. Due to the absence of sudden changes, it seems that the studied deposits were deposited in a ramp-type carbonate platform that was influenced by siliciclastic sediments from the Zagros river systems. The immature sedimentary texture of the sandstone facies indicates the proximity of the origin of the quartz sources to the carbonate basin. Among the diagenetic processes that have affected the examined sequences, the following processes can be mentioned: micritization, cementation, neomorphism, physical and chemical compaction, dissolution, fracture development and filling, dolomitization, and anhydritization. These diagenetic processes occurred in post-depositional marine, meteoric and burial diagenetic environments. Many fractures were filled with petroleum, which indicates that fractures, along with dolomitization, chemical compaction, and fenestral pores, are among the most important post-sedimentation complications to increase reservoir quality. While cementation and anhydritization resulted in reducing the reservoir quality by closing the pore spaces . Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  6 - Reservoir quality evaluation of the Asmari Formation in the framework of sequence stratigraphy in one of the Iranian SW oilfield
  Ebrahim Sfidari A. Hakymi-Zanuz
  The Oligo-Miocene Asmari Formation forms the main reservoir rock of many Dezful Embayment fields. Microfacies analysis, diagenetic features, and sequence stratigraphic evaluation of the Asmari Formation were carried out based on the petrographic investigation, petrophys More

  The Oligo-Miocene Asmari Formation forms the main reservoir rock of many Dezful Embayment fields. Microfacies analysis, diagenetic features, and sequence stratigraphic evaluation of the Asmari Formation were carried out based on the petrographic investigation, petrophysical logs, and core measurement porosity and permeability data. Petrographic analyses led to the identification of twelve microfacies indicating five subenvironments including tidal flat, lagoon, barrier (belonging to inner ramp), middle ramp, and outer ramp, all of which are representing a homoclinal ramp. Tidal flat, lagoonal, and barrier microfacies are mostly present in the upper parts of the Asmari Formation, while middle and outer ramp microfacies were largely developed in the middle part. Cementation, compaction, dolomitization, dissolution, and fracturing are the main diagenetic processes in this formation. Compaction and cementation have negatively affected reservoir quality while fracturing, dolomitization, and dissolution contributed to reservoir quality enhancement. The sequence stratigraphic studies represent three 3rd order sequences of early Aquitanian, late Aquitanian, and early Burdigalian age based on the main features of microfaces, their depositional environments, and shallowing and deepening-upward trends. Microfacies of the Transgressive System Tract (TST) have been affected by compaction, dissolution (moldic), cementation, and slightly dolomitization in the middle to outer ramp parts. The Highstand System Tract in the inner ramp part has been affected by dolomitization, dissolution, and fracturing close to the sequence boundaries, and has a better reservoir quality than the Transgressive System Tract. Manuscript profile