The aim of the current study is to determine the elastic properties of carbonate rocks using ultrasonic method. Forty rock samples of Anah formation were collected at different depths from four wells drilled at the study area . The relationship between wave velocities and elastic properties of rocks was defined. Regression analyses to define these relations were applied. The results indicate that the elastic properties of the rocks show a linear relationship with both P- and S-wave velocities. The best relationship was obtained between both Young's modulus and Shear modulus with Vs in the determination of the coefficient ( R2 ), with values of 0.91 and 0.94, respectively. Bulk modulus and Lame’s constant were better correlated with Vp than with Vs in the determination of R2,with values of 0.92 and 0.83, respectively. Poisson’s ratio showed a good correlation using the ratio of Vp/Vs in the determination of R2, with a value of 0.81. The main output of this study shows that the ultrasonic method is a useful tool for the prediction of the elastic dynamic properties of sample rocks and that it can be used as an economical , simple and non- destructive method, especially for engineering purposes.
Three-dimensional seismic reflection study was conducted for the Eastern Baghdad oil field which is located in the middle part of Iraq within Al-Madaaen province that belong to Baghdad governarate, South of Diyala River , this field includes two southern parts (S1 and S2), the study area was about 781.905 km 2 for the upper Cretaceous age, synthetic seismogram was generated from data of EB-5 and EB-1 wells. Saadi reflector was picked and identified to determine the Hartha Formation. The seismic sections and time slice maps confirmed that the upper Cretaceous age was affected by faults and the indicators of faults ended within Hartha Formation and continue to the deeper formations with increasing intensity. The attribute section was applied on time slice and shows that the area was affected by normal fault parallel to the structure of the field trends (NW-SE). Time, velocity and depth maps of Hartha reflector depending on data from wells (EB-1, EB-2, EB-6, EB-30, EB-52, EB-54) the maps show the structural picture of East Baghdad structural nose opened toward NW and trending (NW-SE) that confirmed by 3D volume which prepared for the studied area. DHI was identified as flat spot, dim spot and sag , when applying attributes like (instantaneous phase and Instantaneous Frequency) has been proved the absence of hydrocarbons in EB-15 well on other hand found in adjacent wells such as EB-2 and EB-5 because of facies changes and not structural change. A scaling facies change was identified at (inline 40910 and inline 47960) , Mound (inline 48310), as well as the work of the Isochron map, which was used to find Isopach and a suitable site for drilling wells.
The aim of the current research is to use the ultrasonic wave velocity for assessment of rock competence for pre-foundation study at engineering site near Rawa city. Thirty seven (37) rock samples were gathered from different depths of well drilled at the site. Both compressional and shear waves velocity (Vp and Vs) were measured in the laboratory. To assess the competency of rocks as foundation materials, some geotechnical properties include Poisson’s ratio(σ), Effective angle of internal friction (ϕ), Material index(Im), and Coefficient of lateral earth pressure at rest (Ko) were calculated. The results of the study showed that the first layer characterized by incompetent to fairly competent materials, the second layer (Anah Formation) composed of alternation of the moderately competent (limestone) with thin incompetent (fractured coralline limestone) rocks, while the third layer (Baba Formation) which composed of dolamatic limestone characterized by good competent rocks. Depending on above mentioned results, the third layer (Baba Formation) is more suitable as foundation rocks for constructions purposes at the investigated site. The results also confirm that the ultrasonic wave velocity is effective method in evaluating the geotechnical properties of rock in pre-construction works.
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