Seismic stratigraphy study of the East Razzaza in Jurassic- Cretaceous succession- Central Iraq

This study is deal with seismic structural and stratigraphic interpretation that applied on the East Razzaza (central of Iraq) area, by using 2D seismic data from Oil Exploration Company. Three main seismic reflectors were picked. These reflectors are Zubair, Yamama and Gotnia Formations, which were used to define petrophysical well logs and synthetic seismograms , that are calculated from sonic-logs of the wells of East Baghdad-1 (Eb-1) and West Kifl-1(Wk-1) by Geoframe program, to interpret the Yamama basin and the boundaries of the basin (Zubair and Gotnia Formations), and suggest a stratigraphic model for the study area. Structural maps are prepared for each reflector in addition to analyze stratigraphic features on the seismic sections to obtain the location and direction of the sedimentary basin and shoreline. It is concluded that the basin lies in the east and south east of the area. Seismic stratigraphic interpretation of the area approves the presence of some stratigraphic features in the studied formations. Some distributary buildup mound and carbonate platform are determined. Yamama Formation is interpreted to represent a carbonate platform, and it is divided into three sequences; they represent progradational seismic facies (sigmoid). Maximum flooding surface (MFS) is recognized on top of Yamama Formation and system tracts are determined on the basis of seismic and log data. Seismic attributes technique was used to predict the physical properties distribution of Yamama Formation succession

3D Reservoir Study for Yamama Formation in Nasirya Oil field in Southern of Iraq

Nasriya oil field is located at the Southern part of Iraq, this field is a giant and prolific, so it take a special are from the Oil Exploration Company for development purposes by using 3D seismic reflection. The primary objective of this thesis is to obtain reservoir properties and enhance the method of getting precise information about subsurface reservoir characterizations by improving the estimation of petrophysical properties (effective porosity, P-wave, water saturation and poisson's ratio). There are five wells in the study area penetrated the required reservoirs within Yammam Formation. The Synthetic seismogram of Nasriya wells were created to conduct well tie with seismic data. These well tie was very good matching with seismic section using best average statistical wavelet. Five main horizons were picked from the reflectors by using synthetic seismogram for wells then converted to structural maps in depth domain by using average velocity of five wells. By using petrel program TWT maps have been constructed from the picked horizons, Average velocity maps calculated from the wells velocities survey data and the sonic log information and Depth maps construction was drawn using Direct time-depth conversion and the general trend of these map was NW-SE. The model of low frequency was created from the low frequency contents from well data and the five main horizons were picked. The seismic inversion technique was performed on post-stack three dimensions (3D) seismic data in Nasriya oil field

Structural and Stratigraphic 3D Seismic Study of NahrUmr and Zubair Formations in Kifl oil field _ center of Iraq

This research is a reflection seismic study (structural and stratigraphic) of a 268.7 km2 area located in the central Iraq within the Karbala province (Kifl area). The study area was interpreted by using 3-D seismic data from 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 piking 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 faults system has been observed in the study area; the major normal fault of (NW-SE) trending and minor normal faults of (NE-SW) trending, with a small displacement are influenced 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 south east, 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 shows the Zubair and NahrUmrfacies 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 are 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 bass filter on an instantaneousphase 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