Journal of Petroleum Research & Studies

Rock extraction is a particularly major step for the preparation of rock samples for core analysis, it can be performed by many traditional techniques like Soxhlet, centrifuge, and flooding system. In this study, a new technique was suggested for core cleaning by microwave. New experiments were conducted as part of this research project, focusing on the cleaning of several types of core plugs under different conditions such as temperature and solvent volume. Additionally, the goal was to extract hydrocarbons from naturally saturated reservoir rocks that had been prepared for standard testing. These findings were then compared with the conventional method of cleaning samples using an organic solvent, specifically toluene.
The experiments successfully employed microwave technology for the cleaning process, effectively optimizing key variables including time, temperature, energy, and solvent quantity. The operational duration was set at 3 hours per day, using 20 ml of solvent, following numerous trials and iterations. This method allowed for the extraction of crude oil from 36 plug samples while achieving complete cleanliness of the rocks. Conducting porosity tests before and after the cleaning procedures showed the absence of any damage to the rock samples. Notably, there was an observed alteration in granular size within an acceptable range of 0.02 to 0.6. Further analyses were conducted, including gas chromatography and infrared analysis, both of which indicated that microwaves had no adverse effect on the crude oil extracted. Conclusively, the use of microwaves in the cleaning of rocks appears as a harmless, economically viable, environmentally friendly technique. The feasibility of this method was proved at the laboratory level, showcasing its potential for wider application.

Geomechanical problems are the most important problems that happen in the Zubair oil field; treating these problems requires a lot of time (Non-Productive Time) and thus increases the cost of drilling the well. Wellbore instability, subsidence, reservoir compaction, casing smash, pipe damage, and well kick is the main geomechanical problems facing the drilling process in the Mishrif formation, Zubair oilfield. The main goals of this study are to estimate the changes in stresses and subsequent subsidence values for this field during the production and injection periods. These estimation values, many problems can be avoided, thus increasing the drilling efficiency.
This study is to introduce the one way coupling between the reservoir model and geomechanical model using the finite element method. The finite element technique in CMG 2018 program was used to estimate the stress states during the production or injection operations in this field of interest.
The results of the 3D finite element model showed that the effective vertical stress rises by 32 psi during production while the effective horizontal stress increases by 16 psi. This may be explained by the fact that variations in pore pressure have little or no impact on the total vertical stress generated by weight. The results of this study demonstrated that the finite element method is a conservative method for coupling reservoir geomechanics and fluid flow. Subsidence values were 6.096 mm in the north part of the Al-Hammar dome, while at the center the subsidence was -5.1816 mm. Shuaiba dome has negative subsidence which is about -9.75 mm. It is important to note that the positive results subsidence signify the pore volume compacting, which may have an impact on the permeability and porosity of the reservoir petrophysics. As a result of a negative subsidence deformation, different failures including well casing damage, wellbore failure, and pipe smashing, are expected. Based on these results, production can cause an increase in the differential stress, which leads to rock shear failure and in injection cases, increasing pore pressure can cause a tensile rock failure.

Maximizing the net present value (NPV) of oil field development is heavily dependent on optimizing well placement. The traditional approach entails the use of expert intuition to design well configurations and locations, followed by economic analysis and reservoir simulation to determine the most effective plan. However, this approach often proves inadequate due to the complexity and nonlinearity of reservoirs. In recent years, computational techniques have been developed to optimize well placement by defining decision variables (such as well coordinates), objective functions (such as NPV or cumulative oil production), and constraints. This paper presents a study on the use of genetic algorithms for well placement optimization, a type of stochastic optimization technique that has proven effective in solving various problems. The results of the study show significant improvements in NPV when using genetic algorithms compared to traditional methods, particularly for problems with numerous decision variables. The findings suggest that genetic algorithms are a promising tool for optimizing well placement in oil field development, improving NPV, and reducing the risk of project failure.

Rock Strength Properties (Internal Friction Angle ????, Unconfined Compressive Strength UCS, Cohesion C_o, Tensile Strength T_o) are considered the significant parameters of geomechanics modeling affecting the rock failure criteria. Various researchers have developed rock strength for specific lithology to estimate high-accuracy value estimation without a core. Previous analyses did not account for the formation's numerous lithologies and interbedded layers. The main aim of the present study is to select which the suitable correlation to predict these properties for hole depth of formation without separating the lithology by using data from three wells along ten formations (Tanuma, Khasib, Mishrif, Rumaila, Ahmady, Maudud, Nahr Umr, Shuaiba and Zubair). The results revealed, after calibration with core test, that the Young’s Modulus correlations are the best to predict UCS with RMSE equal to (53.23 psi). Furthermore, the result showed using the static Young Modulus as an input parameter in predicting UCS gives closer result to the laboratory test than using a sonic log. In this study, it was found that many of the previous equations were developed for only one type of rock and tend to generalize poorly to the broader database. This study further offers a more precise prediction of rock strength, hence improving the forecasting of operational strategies and the planning of hydraulic fracturing locations in oil well development. This is particularly beneficial in cases when geomechanical analysis must be conducted in the absence of core samples. Finally, the formation's strength and stability surrounding the wellbore may be inferred from the projected continuous rock mechanical profile.

CO2-water mass transfer was studied in a multi-orifice oscillatory baffled column (OBC) operated in a semi-batch system (batch liquid phase and continuous gas phase). The effect of column configurations, oscillation conditions and gas flow rates, on CO2 concentration ratio (C/Co) in the gas phase, CO2 concentration in water (g/l) and mass flux (g/m2.min) were examined. The experiments were conducted over a wide range of oscillation condition expressed by modified oscillatory Reynolds number (〖Re〗_o^'= 0-1450) and aeration rate, volume of gas per volume of liquid per minute, (vvm = 0-1). The inlet gas stream consists of 15% v/v CO2 (the rest is N2) used to simulate the emission of flue gas streams in industries. The results showed that the mass transfer enhancement increased with oscillation (frequency and amplitude) due to the improved mixing in the OBC. The OBC showed a higher enhancement in CO2-water mass transfer than that obtained with a bubble column (BC) (smooth column without baffles and oscillation), and baffled column (without oscillation). The maximum enhancement of CO2 mass flux achieved in the OBC was 10-fold over the BC at 〖Re〗_o^' = 1449 and vvm=0.8.

This study focuses on the hydrodesulfurization process of two different types of feedstocks: low and high-sulfur-content gasoil. The objective is to remove sulfur using a commercial Co-Mo/γ-Al2O3 catalyst obtained from the Daura refinery. The catalyst underwent various characterization tests, including BET surface area, crush strength, and composition tests using atomic absorption. Similarly, the feedstocks were also characterized before the evaluation process. The study explored the impact of temperature, LHSV (Liquid Hourly Space Velocity), and pressure as operating conditions for gasoil hydrodesulfurization (HDS) using the commercial catalyst Co-Mo/γ-Al2O3 in a pilot hydrotreating unit located at the petroleum research & development centre. The findings indicated that decreasing LHSV led to an increase in sulfur removal. Furthermore, increasing the temperature showed a general trend of increased sulfur removal for both high and low sulfur gasoil feedstocks. These trends were observed within the optimal operating conditions of LHSV 1 hr-1, 375oC temperature, 35 bar pressure, and a ratio of 200 cm3 of hydrogen gas to 200 cm3 of hydrocarbon. These results shed new light on the potential of this catalyst for effectively treating heavier fuels containing complex sulfur compounds.

Oil produced from Qubbat Baba in the Kirkuk oil field -North Oil Company (NOC) requires pre-treatment at the refinery due to water, mineral salts, and sediments. The water contains soluble mineral salts like sodium, calcium, and magnesium chlorides. Failure to treat the crude oil can result in operational problems, such as equipment scaling, corrosion, fouling, and catalyst poisoning in the hydrotreating unit. The study focuses on corrosion in wet oil treatment equipment especially crude oil horizontal separators (process vessels). Corrosion in the internal chamber resulted from two factors: firstly, scale deposition occurred on the surface of Galvalume (GAIII) anodes (passivation phenomenon) during oil-water separation at elevated temperatures (60°C). Secondly, the existing cathodic protection system was inadequate for the crude oil's specifications and the current field's operating conditions for separators. The XRD and XRF chemical analysis revealed that a significant portion of these deposits consisted of Al2O3 and ZnO. Based on the provided reasons, the researchers suggested a new design for the Sacrificial Anode Cathodic Protection system (SACP) using MATLAB Simulink software.

The aim of this work is to measure and analyze corrosion problems in storage tanks to find solutions. ASTM A283-C specimens are used for studying the corrosion rate of tank bottoms by two factors of crude oil: the first is salt content, and the other is sulfur percentage. Also, some specimens were coated with a special epoxy to determine the efficiency of corrosion resistance. The specimens immersed in crude oil with a high sulfur content suffered from a high corrosion rate. The maximum corrosion rates of every specimen were calculated, which at the sulfur percentage (5.4399 wt%) as corrosive medium were equal (2.49395 mm/year). While the other specimens for salt content did not suffer from any significant corrosion during the immersion period (six months), the coated specimens with epoxy were not affected by any corrosion.

This work is related to reducing the impact of incident solar radiation on the internal thermal conditions of the LPG tank. An experimental study was carried out to test the effectiveness of using new thermal insulation layer for liquefied petroleum gas (LPG) tanks to reduce the absorbed heat during the summer season in Baghdad. Semi-spherical perlite particles of size (0.1861 to 1.604 mm) were mixed homogeneously with the resin coating is used as the heat insulating layer. Two identical thermally insulated and non-insulated LPG tanks are tested to indicate the effect of the adopted thermal insulation under different operating conditions. The two tanks were field tested with LPG volumetric filling ratio of (80%, 70%, 50%, 20%) and exposed to the same environmental conditions.
Experimental results indicated that the coating significantly reduced the increase in temperature and pressure in the tanks, thus ensuring effective protection for the tanks. Where the results showed that the approved thermal coating prevented an increase in temperature and pressure in the insulated tank by (18.6%, 25%), respectively, compared to the non-insulated tank in July 2022. The data obtained confirmed the improvement in the safety of LPG storage, meaning that the thermal coating It is an effective way to improve the storage and transportation of liquefied gas in hot summer days.

Kalina cycle is a thermodynamic power cycle uses any waste heat source (low temperature source) to generate electrical power or cooling. Many versions of Kalina cycle exist. In this paper a regenerative Kalina version is designed and constructed. The cycle consists of the following main components: heat recovery vapor generator (HRVG), separator, turbine, condenser, throttling valve, mixer (absorber), heat exchanger and pump. The heat exchanger is used to heat the working fluid coming from the pump before entering the HRVG by the hot saturated liquid (weak solution) coming from the separator. The cycle uses aqua ammonia mixture as the working fluid with different ammonia concentrations. The effect of many operating conditions on cycle performance is studied such as ammonia (NH3) mass fraction (range from 0.85-0.89), low pressure (range from 2-4 bar), and maximum pressure (range from 20-40 bar). The dryness fraction (DF) at separator entrance is kept at 0.3. The results show that the highest thermal efficiency obtained is 12.9% at Pmax=35 bar, Pmin=2 bar, and x=0.85. The highest value of the net power is 0.367 kW at x=0.89 at turbine inlet pressure of Pmax=20 bar. The highest value of exergy efficiency is 28.5% at Pmax=35 bar, Pmin=2 bar. It is noticed that the highest exergy destruction is in the heat recovery vapor generator (HRVG) which is about 48% due to high temperature heat exchange process and low mass flow rate. The exergy destruction is larger at Pmax=35 and x=0.89 than the exergy destruction at Pmax=20 bar and x=0.89.