Figure 15- - uploaded by Ahmed Al-Banna
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Showing 3D velocity cube (as segy format) in depth domain designed by conversion the 3D geometrical model to the velocity inverted from the gravity spectral slices.
Source publication
A new derivative applied to the old gravity Bouguer map (served in 1940 s and 1950s), taking regional study area covered the mid and south of Iraq. The gravity anomaly reflects a density contrast variation; therefore it is possible to use gravity inversion to the density and velocity model through layers (615m, 1100m, 1910m, 2750m and 5290m), the d...
Citations
... The density and velocity values within the all-grid profiles have been interpolated to put available data over the entire 3D model. Determination and stochastic techniques are able for the deployment of continual properties, as a part of the geometric modeling processing, thus pre-set system variables may be used to create the estimated density and velocity models (Al-Banna and Al-Karadaghi, 2018). Every cell in the model will obtain a numeric value that fits the specific system variable. ...
The gravity method is a measurement of relatively noticeable variations in the Earth’s gravitational field caused by lateral variations in rock's density. In the current research, a new technique is applied on the previous Bouguer map of gravity surveys (conducted from 1940–1950) of the last century, by selecting certain areas in the South-Western desert of Iraqi-territory within the provinces' administrative boundary of Najaf and Anbar. Depending on the theory of gravity inversion where gravity values could be reflected to density-contrast variations with the depths; so, gravity data inversion can be utilized to calculate the models of density and velocity from four selected depth-slices 9.63 Km, 1.1 Km, 0.682 Km and 0.407 Km. The depths were selected using the power spectrum analysis technique of gravity data. Gravity data are inverted based on gravitational anomalies for each depth slice or level and the extracted equivalent depth data from available wells using a connection curve between densities and velocities, which were mostly compatible with Nafe and Drake's standard curve. The inverted gravity data images highlight the behavior of anomalies/structures in the model and domain of density/velocity, which can be utilized in the processing of the recorded seismic data and time to depth conversion, in parallel with available well's data information within the intended study area of South-Western Iraq.
... It can be measured by the seismic characteristics of time and amplitude, frequency attenuation, or combinations of those parameters [6]. Several studies have concluded that the use of seismic elements is a good tool for calculating the seismic properties of a region [7], [8] [9]. Most geophysical methods that can penetrate to a sufficient depth lack the precision to complete drilling effectively. ...
... Where P-velocity analysis precision, X-maximum offset length, F p -effective domain frequency and domain frequency and V-average square root velocity [7]. The analysis result by KLSeis is shown in Figure 7. ...
... It also decreases the data frequency. The formula of the relation between the NMO distortion and maximum offset is shown below [7]. ...
The current study includes preparing a geometric proposal of the main parameters that must be worked within a seismic reflection survey to prepare a three-dimensional subsurface image. This image represents the Siba oil field located in Basra, southern Iraq. The results were based on two options for selecting these approved elements to create a three-dimensional image of the Mishrif, Zubair and Yamama formations as well as the Jurassic and Permian Khuff and the pre-Khuff reservoir area. The first option is represented in the geometry in option-1 is 12 lines, 6 shots, and 216 chs. The receiver density is 66.67 receivers / km 2 , so the shot density is the same. Total shots are 21000, which is the same number of receiving points. The survey area (in km 2) and full fold area (in km 2) are 317and 328, respectively. However, the second option in the geometry are16 lines, 16 shots, and 208 chs. Receiver density and shot density are 50, while the total shots are 16200 and the total receiving points are 16000; with survey area and full folded area are 198 and 198 km 2. The aim of the current study is to characterize the structure and reservoir quality of Yamama and Zubair intervals and to image potential exploration targets such as the Mishrif, Jurassic, Permian Kuff and Pre Khuff formations. The present study succeeded in preparing the geometric proposal and getting at a subsurface image of the reservoir in three dimensions.
