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The time-depth conversion process is a significant task in seismic interpretation to establish the link between geophysical information in the time domain and geological information in the depth domain at/away from well locations. Selecting the suitable velocity model for time-depth conversion to generate an accurate depth map is difficult if the accuracy of these models is unknown. In the current study, the cross-validation technique is used as a tool to diagnose and evaluate the performance of time-depth conversion at/away from well controls to predict the depth of Top Hartha and Zubair reservoirs using the dataset of East Baghdad Oil Field. To test this technique, four common velocity model approaches used for time-depth conversion with different scenarios of velocity parameters (initial velocity V0 and depth gradient (K)) were applied to produce ten velocity models (1–10). According to the gradient variation of velocity with depth, check shot analysis, the velocity models (1–10) include three key velocities layer-cakes: Layer 1 (Middle Miocene-Upper Cretaceous), Layer 2 (Upper Cretaceous), and Layer 3 (Lower Cretaceous) with 18 horizons from Middle Miocene down to Lower Cretaceous. The cross-validation analysis reveals that the velocity model with a variable surface initial velocity and constant depth gradient (Model 9) was the most accurate with fewer mistie between actual and predicted depth. Consequently, this model is used to construct the depth map of the Hartha and Zubair reservoirs. Finally, this study progresses a workflow that can be applied to the region with any geological setting to investigate time-depth conversion uncertainty. [ABSTRACT FROM AUTHOR]

The current study aims to assess the groundwater quality in the Wana area, Northwest of Mosul. Water samples were collected from 18 selected wells within the study area during the dry season of October 2020 and the wet season of April 2021. Field and laboratory measurements including electrical conductivity (EC), TDS, pH, Total hardness, and major and some minor ions analyses were performed following standard methods. The results revealed a wide variation of EC values ranging from 0.66 to 5.09 ds⋅m-1 . All wells have hard water due to the presence of gypsum and carbonate rocks. The water quality index (WQI) values showed that wells drilled in the Fatha Formation and wells of mixed water from both the Fatha Formation and the Quaternary sediments provide low-quality drinking water. Wells that only penetrate the Quaternary sediments yield good-quality drinking water. According to the irrigation WQI, the Fatha Formation wells produce low-quality irrigation water, and the water quality of wells drilled in Quaternary sediments or that penetrate both the Fatha Formation and Quaternary sediments (mixed water) ranges from excellent to acceptable for irrigation purposes. [ABSTRACT FROM AUTHOR]

The depth conversion process is a significant task in seismic interpretation to hstlbatse the link between the seismic data in the time domain and the drilled wells in tehdepth domain. To promote the exploration and development of tehSubba oilfield, more accurate depth conversion is required. In this paper, three approaches of depth conversions: Models 1, 2, and 3 are applied from the simplest to the most complex on Nahr Umr Reservoir in Suba oilfield. This is to obtain the best approach, lehsstvt s ahss itst with the actual depth at well locations and good inter/extrapolation between or away from well controls. The results of these approaches, together with the uncertainty analysis provide a reliable velocity model and more accurate predicted depth that reduced the ambiguity of the subsurface. The uncertainty analysis reveals that Model 3 is considered a more practical and most accurate approach because it gives a minimized standard deviation value of 14 with less residual and error values. The uncertainty of the depth conversion and the standard deviation values is raised towards the eastern part of the field due to an increase in the dipping depth in this region that affects the depth conversion results. [ABSTRACT FROM AUTHOR]