Iraqi Journal of Oil and Gas Research

The reliable prediction of asphaltene precipitation is critical for mitigating operational challenges in oil production, yet existing thermodynamic models face persistent limitations due to the complex composition and self-association behavior of asphaltenes. This study evaluates two dominant modeling frameworks: solubility-based approaches, which treat asphaltenes as dissolved macromolecules, and colloidal stability-based models, which conceptualize asphaltenes as suspended particles stabilized by resin interactions. Solubility models, including Flory-Huggins’s theory and cubic equations of state, correlate precipitation with solubility parameters and Gibbs free energy changes, but are constrained by assumptions of molecular homogeneity and reliance on ill-defined critical properties. Colloidal models, such as micellization theory, link precipitation to resin depletion and micelle destabilization.
Statistical Associating Fluid Theory (SAFT) models, particularly the Perturbed-Chain (PC-SAFT) variant, bridge two modeling approaches by incorporating molecular-specific parameters—such as segment size, interaction energy, and chain length—to describe complex behaviors like molecular size variations and clustering in fluids. While SAFT models offer strong predictive accuracy, their reliance on carefully calibrated inputs and computational complexity highlights a trade-off between scientific rigor and practical application. Experimental studies demonstrate that no single model reliably predicts asphaltene precipitation across all crude oil types, underscoring the need for hybrid methods.
This article critically reviews model-based predictions in the context of asphaltene behavior, addressing their necessity, strengths, and limitations. It investigates the most widely adopted models in both academic literature and industrial software, analyzing the underlying reasons for their prevalence. Furthermore, the study explores the similarities and differences among existing models and their classification criteria.

The Gullfaks field constitutes one of the largest hydrocarbon deposits in Norway. It is divided into several geological formations: Cook, Statfjord, Lunde and the Brent group. It’s consists of several reservoirs, two of which are the subject of this paper: Tarbert and Ness reservior. This paper aim to re-pressurize the reservoir of the Gullfaks field through the implementation of a secondary oil recovery method by flooding the reservoir with water. Many methods have been employed for the estimation of hydrocarbons and the enhancement of oil recovery (EOR). This study utilises the water flooding method to optimized oil recovery in the Gullfak field. Based on data from the Gullfaks field provided by company X for security reason, a 3-dimension static model of the reservoir, created using Petrel, revealed a volume of 459 119 496,855 bbls of oil and 206 274 915 000 cf of gas. Subsequently, a 3-dimension dynamic model was constructed through Eclipse simulation to predict a 20-year operation (2000-2020) of water injection into the reservoir over 20 years (2000-2020). The results indicated an oil recovery factor of 28.8%, representing a 19.7% increase over the primary recovery of 9.1%. Similarly, the gas recovery factor was determined to be 36.1%, representing a 24.6% increase over the primary recovery of 11.5%. This exponential increase in gas and oil production has led to economic growth, indicating that this method enhanced high quality production in comparison to other oil recovery techniques.

The Crude oil is typically produced as a complex mixture containing saline water, leading to the formation of water-in-oil emulsions during fluid transport through pipelines and valves. These emulsions are further stabilized by natural components in crude oil, such as asphaltenes, resins, waxes, and suspended solids. The presence of water negatively affects crude oil production by increasing transportation costs and accelerating pipeline corrosion. To reduce reliance on chemical demulsifiers in oil processing, this study provides a comprehensive review of low-frequency ultrasound as an environmentally friendly alternative technique. The review discusses emulsion stabilization and destabilization mechanisms, with a focus on chemical, biological, membrane, electro-radiation, and microwave methods, in comparison with ultrasound-assisted separation. The findings highlight that low-frequency ultrasound has the potential to significantly improve emulsion breakdown efficiency while minimizing the environmental impact of conventional chemical treatments. This approach offers a promising pathway toward sustainable crude oil processing and enhanced operational efficiency.

The oil and gas sector is one of the most capital-intensive and risk-prone industries, requiring advanced practices project management to ensure successful delivery. In recent years, digital technologies and sustainability, digital twins, and environmental, social, and governance (ESG) principles have become central to project governance.
The existing paper presents a systematic literature review of number of peer-reviewed publications from 2014 to 2024, examining the evolution of project management strategies in oil and gas megaprojects. With an emphasis on the Iraqi environment, the current paper uses a qualitative-analytical technique to synthesize recent developments in oil and gas project management. It identifies three dominant trends: the hybridization of management frameworks, the increasing in adoption of digital platforms, and the integration of ESG performance indicators.
The findings also highlight persistent challenges in developing regions, including institutional immaturity, inconsistent ESG application, and failed digital transitions. The main conclusion provided from the study that Iraq's oil and gas project management has structural problems, particularly when it comes to integrating modern methods and digital tools into a challenging institutional structure. Final, paper is recommending maturity-based models, context-specific ESG scorecards, and structured digital roadmaps to improve project outcomes.

With global energy demand on the rise, natural gas continues to hold a crucial role in meeting the world’s energy needs. This growing reliance also brings practical challenges, one of the most important being the contamination of pipelines with black powder. Reducing these pollutants, which threaten pipeline integrity and transmission efficiency, is critical to ensure sustainable gas supplies and maintain system performance. The study aims to investigate the effect of chemical treatments with zinc chloride (ZnCl2) and sodium nitrate (NaNO3) on the composition of black powder taken from an Iraqi gas pipeline. Samples were treated with solutions at concentrations of 5, 7, and 10% for each component and inspected using X-ray fluorescence (XRF) to evaluate their effect. The results demonstrated that ZnCl₂ reduced iron oxide (Fe2O3) content by about 32%, while NaNO3 achieved a slight reduction in Fe2O3. Treatment with ZnCl₂ successfully reduced iron content but introduced secondary contaminants, while NaNO₃ achieved a cleaner, though less intense, effect. This suggests that chemical treatments can significantly alter the composition of black powder and improve pipeline maintenance strategies.

This research investigates the factors influencing the mechanical behavior of rock in geothermal reservoirs, also examining the role of working fluid in extracting heat from geothermal systems. Geothermal reservoirs involve several processes: thermal, hydraulic, mechanical and chemical. Thermal, hydraulic, and mechanical processes can lead to the generation of stresses and related changes in the structural properties of the rock, which will impact the heat extraction performance and the overall stability of the geothermal reservoir. Choice of working fluid, such as water or carbon dioxide, would affect the performance of heat extraction - but, more importantly, alter the mechanical and structural behavior of the rock. Some studies have shown that supercritical carbon dioxide can enhance heat extraction efficiency due to its combination of thermal and chemical properties, thereby minimizing environmental impacts. This working fluid alters rock mechanical properties through chemical reactions, including dissolution and precipitation, which can also impact rock integrity and permeability. Through examinations of laboratory data and existing models from previous studies, this research will conclude the central importance of managing the factors that affect the mechanical and structural behavior of the rock and ensuring optimal operational conditions for the sustainable performance of geothermal systems. This research demonstrated that effectively managing factors affecting rock properties and changes in their condition can optimize stability in geothermal reservoirs and improve energy output. Finally, this study provides suggestions for improving the performance of geothermal systems under different operating conditions.

The transportation of heavy crude oil faces various obstacles because its thick composition creates both operational challenges and financial obstacles. The research examines the process of decreasing Iraqi heavy crude oil thickness by mixing light hydrocarbons which originate from the East Baghdad field. Researchers conducted experiments on kerosene and toluene and naphtha by using three different solvents under controlled temperature conditions of 21 and 40 and 62 degrees Celsius with mixing time durations of 30 and 60 minutes at concentrations ranging from 5 to 20 percent volume/volume. A capillary viscometer operating under ASTM D445 standards served as the measurement tool for viscosity assessments by the researchers. The study demonstrates that both solvent selection and solvent quantity along with process temperature and mixing duration determine the efficiency of viscosity reduction. Among the tested solvents naphtha emerged as the superior dilution agent because it decreased the concentration by 60% when used at 20% v/v while toluene and kerosene delivered lower yet substantial effects. The combined effects of solvent selection with operational parameters demonstrate that field optimization stands as a critical factor. The research delivers functional proof through data which enhances heavy crude pipeline transport efficiency and cost savings and encourages further investigation about economic evaluations alongside environmental impacts.