We conducted an initial high-power CSEM (controlled-source electromagnetic method) survey in a coastal salt-flat area in the broader area of Half Moon Bay, in the southern part of Dammam Peninsula in the eastern province of Saudi Arabia. The primary purpose of this work was to verify the technology, but we were also able to detect and characterize potential economic brines in the study area. For a high-quality data acquisition, several transmitter–receiver configurations, different acquisition parameters, and passive and active EM data were collected, evaluated, processed, and interpreted to characterize the subsurface. The long-offset EM (LOTEM) and the focused-source EM (FSEM) were the optimum configurations due to the high-quality of the collected data. This is a starting point for using the CSEM method towards the O&G, geothermal, CO2 sequestration, groundwater, lithium brine, and other natural resources’ exploration and exploitation in the Gulf countries.

Nitrate (NO3−) represents one of the major groundwater constituents with increasing distribution and concentration in the Kingdom of Saudi Arabia. This study aimed to determine potential sources of nitrate in the Early to Late Cretaceous Wasia aquifer system at the Al Kharj area (Central Saudi Arabia) by an integrative approach using groundwater geochemistry, nitrate isotopes (15N–NO3 and 18O–NO3), and tritium (3H) measurements. The lowest saline groundwater samples (TDS = 1400–2000 mg/L) from the peripheral zone were representative for pristine groundwater from the Wasia aquifer with nitrate concentrations below 20 mg/L and low 18O–NO3 ratios (8.7–20.6‰) but enriched 15N–NO3 values (up to 10.8‰). In contrast, 11 out of 34 analyzed water samples from irrigation wells and cattle watering wells exceeded the World Health Organization (WHO) drinking water guideline value for nitrate of 50 mg/L with maximum concentrations of up to 395 mg/L. Nitrate fertilizers and atmospheric deposition are the main sources of nitrate in groundwater in the eastern and northern sections of the study area. The combination of elevated salinities (4940–7330 mg/L), NO3 (111–395 mg/L), boron (516–1430 μg/L), and enriched 18O–NO3 (21.7–25.8‰) ratios with depleted 15N–NO3 (5.7–7.6‰) confirm the local influx of evaporated irrigation water with remnants of dissolved fertilizer into the Wasia groundwater system. There was no evidence for the influx of animal or human wastes from adjacent dairy, poultry, and housing infrastructures. Tritium concentrations below the detection limit of 0.8 TU for most borehole samples implied the absence of recent natural recharge. The estimated annual average N influx of 3.34 to 6.67 kg/ha to the Wasia aquifer requires a combination of atmospheric deposition and anthropogenic sources (mainly nitrate fertilizers) to increase the nitrogen content of the Wasia aquifer.

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The purpose of this study is to describe and model a modern fluvial channel that cut gently dipping alluvial plain (in eastern Sudan) and changes its morphology from upstream to downstream. Ultimately this study explores the spatial variability in geomorphological characters of this channel with the topography of the alluvial plain and how such variability controls channel connectivity and reservoir architecture. The workflow of this study integrates remote sensing, reservoir modeling, and fluid flow simulation. Satellite images (8 panels of a 160-km fluvial channel) provide means to capture channel morphology (width, sinuosity, and amalgamation), and were used to produce realistic two-dimensional (2D) geo-cellular models. Stacked on top of each other from upstream to downstream, the 2D models provide a three-dimensional (3D) geo-cellular model that simulates the horizontal variability in the channel morphology vertically. Within this 3D model, fluvial channels were assigned to clean sandstone facies (relatively higher porosity and permeability), and flood plains were assigned to mudstone facies (relatively lower porosity and permeability). Systematic penetration of the 3D models by 27 pseudo wells shows a low chance of penetrating the channel sandstone by these wells―only 8 out of the 27 pseudo wells (∼ 30%) penetrate the channel sandstones. The opportunity of penetrating channel sandstone increases toward the upstream area (lower zones in the 3D models), where the channel has a wider width and low sinuosity. The penetrated thickness also increases toward the upstream area. These trends affect the oil's flow properties, which is presumed to fill the channel sandstone in the 3D model. Modeling and understanding such horizontal channel variability provide perspectives into the nature and controls on complex architecture patterns of fluvial reservoirs in rift basins.

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