Ordovician Platform, Slope, and Basin Facies in Subsurface of Southern North America: ABSTRACT
0
Citation
0
Reference
10
Related Paper
Abstract:
Ordovician carbonates of the Nashville dome and Ozark dome regions have long been considered typical shelf deposits. In the subsurface to the south, in the Black Warrior basin, Mississippi Embayment, and Arkoma basin, these shelf carbonate units changed facies. The most significant change is the occurrence of a thick limestone unit characterized by a faunal and floral assemblage of Nuia, Girvanella (isolated long strands), Sphaerocodium, a delicate stacked-chambered organism (.algal), and sponge spicules and sponge mudstone clumps. In ascending order, the complete Ordovician sequence consists of: a lower dolostone, the Nuia-sponge limestone, a dolostone, and a limestone. The upper part of this four-fold sequence changes character westward into the Arkoma basin. The lower two units maintain their character for long distances along depositional strike and occur in parts of the Appalachians as far north as Newfoundland, and on the opposite side of the continent in Nevada. The Nuia-sponge assemblage is a distinctive petrographic marker and seems to be a persistent Ordovician rock and fossil assemblage of widespread occurrence. In Nevada, it occurs on the surface where it is associated with slump and slide features that suggest that it is an outer shelf or upper slope deposit. Coeval carbonates in themore » Ouachita Mountains are different and show indications of being deep water (basinal). Biostratigraphic evidence indicates that the succession in the subsurface is continuous; the regional Lower Ordovician-Middle Ordovician unconformity is absent. The Lower Ordovician-Middle Ordovician boundary falls near the top of the Nuia-sponge mudstone unit and not at the top of the underlying thick dolostone unit.« lessBuilding a rock-type (facies) model is critical in the process of constructing the geological model.The facies model utilizes the facies obtained from the different characterization methods to represent the structure and the geology of the studied reservoir. Therefore, the importance of building a 3D rock-type model is to distribute the petrophysical properties depending on the rock facies to reflect the actual distribution and achieve a realistic model.Khasib formation in Amara oil field is mainly composed of limestone and exhibits a high degree of heterogeneities in its petrophysical and geological features, showing a complicated porosity-permeability relationship. Hence, the formation should be characterized by facies with specific property relationships and use these facies to build an accurate rock-type model to represent the geological rock modeling for this carbonate formation.The Rock-Type model for Khasib formation has been constructed using the facies obtained from flow zone indicator and cluster analysis characterization methods, these facies were distributed with the PETREL software by applying the sequential indicator simulation (SIS) algorithm.The 3D Rock- type model establishes that a different rock type characterized each unit within Khasib formation; the reservoir units (KH11, KH12, and KH2) were characterized by the presence of RT-1, RT-2,andRT-3, which represent the best, good, and intermediate reservoir quality rocks, respectively. The best rock type RT-1 with the best reservoir petrophysical properties was only noticed in unit KH2. The non-reservoir units (Khasib, Base KH11, Base KH12, and Base KH2) were characterized by RT-4 and RT-5, which reflect the bad rock quality with non-reservoir properties.
Petrophysics
Petroleum reservoir
Cite
Citations (10)
The Hulusimpang Formation is located in the Bukit Barisan strip and is part of the Woyla terrane associated with Cretaceous volcanic arcs. Research on the Lampung formation, especially the Hulusimpang Formation, is still a little researched. This research was conducted to determine the facies, facies association and depositional environment of the Hulusimpang Formation. The study of facies analysis uses a measured stratigraphic cross section and divides the rock into several facies and facies associations. The facies analysis data was taken from Pekon Way Manak, Sukaagung, Sukamara, Tanggamus Regency. The Hulusimpang Formation consists of seven facies, namely tuff facies (F1), claystone facies (F2), siltstone facies (F3), black siltstone facies (F4), sandstone facies (F5), limestone facies (F6), mudstone facies (F7) . The facies found were grouped into four facies associations, namely channel facies association (AF1) and levee facies association (AF2), creverse splay facies association (AF3), and exposure facies association (AF4). AF1 consists of F1, AF2 consists of F2, F3, F4, F5, AF3 consists of F6, and AF4 consists of F7. Based on the facies association found in the Hulusimpang Formation, it indicates that the depositional environment is Fluvial-Shallow Sea.
Siltstone
Cite
Citations (0)
There are two sets of sands chang811 and chang831 in the chang81 reservoirs in the Maling oilfield of Ordos basin.The sand body is thin,associated with the large thick change in horizontal.Based on seismic forward modeling,we use the technique of waveform classification and frequency-divisional to interpret the seismic facies,and classify the distribution of chang811 and chang831 seismic facies.By means of comparing the seismic facies with sedimentary microfacies of single well,we setup the correlation between seismic facies and sedimentary facies.We draw the distribution and horizontal change of sandstone and predict the distribution of reservoir.The desired result has been used successfully in this region.
Seismic attribute
Cite
Citations (0)
The rostroconch mollusc Eopteria aiteneria sp. nov. is described from the Late Ordovician Angrensor Formation of north-eastern Central Kazakhstan; it is the first and only known representative of this group from the Ordovician of central Asia. By the beginning of the Late Ordovician Eopteria and the family Eopteriidae were on the verge of extinction and the new Kazakhstan species represents the youngest preserved record of the family in the Ordovician. It is likely that the group found a refuge in the diverse, but rather conservative, faunal assemblage of the Hiberno-Salairian type associated with Late Ordovician carbonate algal build-ups and mud mounds which spread widely during the late Caradoc to mid Ashgill across Kazakhstanian volcanic island arcs and microplates.
Cite
Citations (6)
Abstract In the development of conventional oil and gas projects, inter-well sandstone prediction and facies evolution provide benefit by reducing the number of wells drilled, optimizing well location and maximizing the performance of the wells. However, several particularly thorny issues were encountered in our study. Multi-bedded thin sandstone reservoirs were vertically stacked with thin coal seams. The main sedimentary facies of sandstones in areal and vertical directions varied quickly. This paper summarizes one multidisciplinary integration methodology to predict the distribution of inter- well sandstone and sedimentary facies in the South Sumatra Basin in Indonesia. To overcome the aforementioned disadvantages, this method included the following steps. First, it made use of multidisciplinary knowledge including mineralogy, sedimentology, lithology, geology, petrophysics and geophysics based on cores, well logs, and seismic data of various source data. Second, sequence strata division and correlation were studied with eleven target layers in order to describe this multi-stack reservoir. Then sedimentary facies system including braided channel and braided delta were identified based on reliable data from sedimentary structure of lithology, facies sequence, Formation Micro scanner Image data (FMI), and sedimentary characteristics of core samples such as: rock color, lithological features, mineral composition, and rock sedimentary structure. Fourth, a sandstone identification assessment standard was established to improve the precision of the reservoir prediction. Fifth, logging data and sedimentary facies were used to establish the facies log patterns. Favorable reservoir facies in strata were outlined based on the study of properties of sedimentary facies. Sixth, a four step procedure including seismic data partitioning, seismic attribute analysis, normalized seismic attributes of three compartments and sandstone thickness calculation was used to identify sandstone inter-well distribution. Seventh, multidisciplinary integration was used to understand facies and facies evolution to arrive at favourable facies and properties distribution which could then be used for geomodel building. This methodology constitutes a systematic and effective way to delineate the distribution of sandstones and sedimentary evolution for future well planning.
Lithology
Petrophysics
Cite
Citations (0)
The Ordovician is one of the longest and geologically most active periods in Phanerozoic history. The unique Ordovician biodiversifications established modern marine ecosystems, whereas the first plants originated on land. The two volumes cover all key topics on Ordovician research and provide a review of Ordovician successions across the globe.
Cite
Citations (1)
The Ordovician is one of the longest and geologically most active periods in Phanerozoic history. The unique Ordovician biodiversifications established modern marine ecosystems, whereas the first plants originated on land. The two volumes cover all key topics on Ordovician research and provide a review of Ordovician successions across the globe.
Cite
Citations (1)