Study of subsurface structures using seismic reflection data for Kalar–Khanaqin area/Kurdistan region, Iraq (original) (raw)
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Geophysical Seismic Reflection Method Application to Detect Subsurface Faults and Structures between Nuhr Bin Umr and Zubair Oil Fields, Southern Iraq, 2020
Eighteen seismic lines were chosen to completely cover the area located southern east of Iraq, in order to study the actual subsurface structural variations of the Rumaila, Zubair and Qotnia Formations, as well as the present of faults. Three seismic reflectors were identified on the selected seismic sections by making direct correlation between synthetic seismograms of the wells (A, B, C, D, E, F and G) and the seismic sections passing through these wells. Two of these reflectors represent lower and middle Cretaceous; they represent tops of Rumaila and Zubair respectively, whereas the third one which represents upper Jurassic is the top of Qotnia. These reflectors have good reflectivity and continuity along all studied seismic sections. A general bedding inclination towards the northern east regional direction, NW-SE structural sedal between the obtained Nuhr Bin Umr and Zubair structures and three subsurface deep normal faults trending NW-SE and SW dips were noticed at all levels in the investigated area.
—this research is a reflection seismic study (structural and stratigraphic) of a 268.7 km 2 area located in the central Iraq within the Karbala province (Kifl area). The study area was interpreted by using 3-D seismic data from the Oil Exploration Company. Synthetic traces are prepared by using available data of the four wells (Kf-1), (Kf-2), (Kf-3) and (Kf-4), in order to define and picking the reflector on seismic section, These reflector are: (NahrUmr, Shuaiba, Zubair and Ratawi Formations) which are deposited during the lower Cretaceous age. Faults were picked using instantaneous phase attribute of seismic section across 3D seismic volume of the studied reflectors. The study area affected by a major fault and minor normal faults, Two fault system has been observed in the study area; the major normal fault of (NW-SE) trending, this trending conform with Najd fault system in Iraq, and minor normal faults of (NE-SW)trending, with a small displacement are influenceing the studied reflectors. The time slices were studied across 3D seismic volume of the studied reflector, they proved the presence the structural anticline at lower cretaceous reflection level. Time, velocity and depth maps are prepared depending on the structural interpretation of the picked reflectors, the structural interpretation of these reflectors shows a structural anticline extending in NW-SE trend and plunges to the southeast, and the general dip towards the east. Using seismic attribute techniques including (instantaneous frequency, RMS amplitude maps and reflection strength section), these attributes showed decreasing in frequency, amplitude and strength values. These reflect rocks of low velocity and indicate the presence of hydrocarbon accumulation area. The study of seismic facies of the picked reflectors distinction parallel seismic configuration. The results show the Zubair and NahrUmr facies are clastic depositional system deposited on delta platform, Zubair represents delta platform facies consisting of shallow-water, high-energy marine (delta sandstone, channel-fill sandstones).Pinch out is picked and interpreted by using cosine instantaneous phase attributes, these phenomena can be regarded as Pinch out stratigraphical traps. It's the main factor to explain the difference in thickness of the oil column between well Kf-4 and well Kf-1. Mound and Flat spot phenomenon has been observed within Zubair reflector by using the seismic composite attributes (Band pass filter on an instantaneous phase attributes, as mound stratigraphic traps and flat spot which is represent of Direct Hydrocarbon Indicators (DHI) that refers to the presence of hydrocarbons. Where the use of this techniques has helped to identify the (DHI) for hydrocarbon accumulation and have not been previously identified.Finally 3D seismic model for Kifl field show the extension of structural anticline and its plunge and the distribution of hydrocarbons accumulations in the Kifl field.
Africa Journal of Geosciences (AJG), 2019
The Muglad Basin stretches southeast (south west Republic of Sudan) has a petroleum system which is herein regarded as a geological system that includes the petroleum source rocks and all related geological elements and processes which are necessary for hydrocarbon accumulation and preservation. This study was undertaken to delineate the detailed structural features affecting the Bentiu reservoir in Neem Field by using 6(2D) seismic reflection data. Data interpretation was facilitated by using the PetrelTM, modelling software. To define how structures were formed, it is usual to map a range of marker horizons above and below the target based on well-to-seismic data. Therefore, top Aradeiba (seal), top Bentiu (reservoir) and top Abu-Gabra (source) have been picked to define the detail structures which affecting the Bentiu reservoir in Neem field, Muglad Basin. Generate depth maps for reservoirs formations by generating velocity models and use the models in time to depth conversion. The time and depth structural maps show that top Aradeiba, top Bentiu and top Abu-Gabra Formation is generally dipping to the north direction. Many extensional normal faults can be also noticed on both time and depth structural maps, which are dipping to the north; the change in the degree of colours on the both sides of each fault gives an indication on the dip direction of fault plane as well as the upthrown and downthrown sides, corresponding to alternating NW and/or NNW-oriented grabens and horsts. The results of this study help to identify potential structural traps for hydrocarbons and hence will aid regional exploration.
Article, 2022
The current study aims to detect subsurface geologic features using 3D dense sampling seismic data in the Fatha Formation, in the Chia Surkh area, Kurdistan Region,Iraq. A3D cube seismic data covering 75 Km 2 were used to image the Fatha Formation subsurface geologic structures. The seismic data and appropriate information were gathered from Pet Oil Company with the permission of the Ministry of Natural Resources of the Kurdistan Region, Iraq. A cube of seismic data was used to image the three units of the Fatha Formation. In this study, forty seismic sections with the direction of NE-SW and 30 crossline sections of NW-SE direction were used. The map shows the existence of several features such as a three-way dip closure elongated NW-SE and extended through the whole study area. The reflector three of the Fatha isochron map shows TWT ranging from 890 ms to 1720 ms. The depth map of Fatha unit 1 Formation, shows depth with seismic reference datum ranging from 838 m to 2334 m. The study concluded the existence of several structural features; a major anticline trending with Zagros belt trend, and three longitudinal systematic reverse faults on the southwest side of the anticline, leading to the possibility for which the area is considered as a prospective oil reservoir, might work as a good trap, an anticline, evaporites work as a seal and limestone rocks as a reservoir.
Iraqi Geological Journal, 2020
For the last two decades, the District of Al-Refaei, southern Iraq, experienced several small to moderate size earthquakes that seem to be clustered in a relatively small area. The initial locations of these earthquakes from the available local and international bulletins show scattered events without any clear structural patterns. A seven-elements seismic array was installed for the period 2014 to 2018 to monitor this activity. Each element of the array consists of three-component Geospace GS11d high-frequency (4.5 Hz) geophone, a solar system power source, and telemetry communications system to transmit data to a central recording station. During the period of monitoring, the array recorded more than 56 earthquakes having a range of magnitude between 1.5 ML to 4.7 mb. Large number of the low magnitude earthquakes were not detected by other monitoring agencies; however, they were recorded by the array. Fifty-six of the most clearly recorded earthquakes were screened for relocation ...
Reflection Seismology technique (Seismic Survey) is widely used around the world to produce a detailed analogue image of subsurface geological structures. This information is used by petroleum experts to accurately plan the location of oil wells. Seismic survey sections and corresponding well logs exhibit different variables like acoustic impedance of rock, seismic velocity, rock density, porosity, time and depth that can be manipulated in GIS to infer a subsurface model for stratigraphic as well as structural interpretations. In recent years, GIS has emerged as a powerful analytical tool for subsurface mapping and analysis. Petroleum exploration is a map intensive process that requires the powerful capabilities of GIS. Purpose of this research is integration of Geographical Information System with Seismic Surveys for Structural and Stratigraphic Interpretation of subsurface Geology and locating Petroleum Prospects. In this research work, GIS has been used to investigate subsurface geological structures and stratigraphy to carefully analyze the capabilities of GIS for finding new petroleum prospects in active thrust belt of Meyal, Potwar region, Pakistan. Acquisition of two-dip and three-strike seismic lines is along with well log data, followed by spatial seismic data processing, development of geophysical data management interface, interpolation of shot point data, trend surface analysis and Geostatis-tical analysis using GIS. Subsurface zones of high, low or null probability of petroleum accumulation were then, mapped. Finally, GIS based maps were developed. Geospatial tomography GIS model inferred that study area is structurally deformed and exhibits excessive geological faults, and structural traps. With GIS-tomography interpretation of section 97-MYL-08, a potential oil bearing zone (popup anticline), bounded by two thrust faults was observed at almost 3.6 Km depth in Meyal area How to cite this paper: Fayyaz Z. Fayyaz et al. 1346 with average density of about 2.6 gm/cm 3. Thrust fault recognized from sharp dis-continuity in GIS based survey raster was encountered at 2.9 Km depth. Structure contour map was developed. It depicted that Chorgali formation (dolomitic limestone) at 3.68 Km depth was proven to be reservoir rock in study area. GIS has proved to be a powerful and efficient subsurface modeling and analytical tool and it should be integrated with survey based studies for exploration of oil and gas and investigation of subsurface geological structures.
Seismic Data Interpretation and Fault Mapping in Badin Area, Sindh, Pakistan
Sindh University Research Journal, 2014
The purpose of this research is to study structural variations of subsurface using seismic and well log data of Badin area. 2D seismic reflection data of ten lines after correlation with five wells of the area reveal that extensive structural and depositional changes have occurred as a result of major & minor tectonic events. Seismic interpretation confirms Horst & Graben geometry in the studied area. Grabens are main areas for generation of hydrocarbons. Primary structuring is defined by structural style at Middle Sand level. Compensating faults are increased at shallower level (Top Lower Goru) due to variation in rock mechanics and applied forces. The variable throw at different levels describes structural evolution through the geological time. Contour maps in two way time and depth domain show faults having northwest to southeast trend in the studied area. Seismic and well data is used to establish stratigraphic correlations of different wells in Lower Indus Basin and also to elu...