Iraqi Journal of Chemical and Petroleum Engineering

Given the significant differences in gas accumulation modes, coal reservoir characteristics, and gas preservation conditions for ultra-deep coalbed methane (vertical depth > 3000 m, measured depth > 5000 m), their production characteristics, flowback patterns, and flow phase classifications also vary greatly. Additionally, there are limitations in the production technologies applicable to deep reservoirs. To explore the relationship between the production characteristics of deep coalbed methane and medium-shallow coalbed methane, as well as to investigate suitable technologies for deep coalbed methane, this paper uses Well Q1 as an example and conducts research and analysis based on reservoir engineering theory. It is believed that in the vertical section of Well Q1(The depth is generally less than 3000m), the flow pattern transitions from bubbly flow to slug flow in the early stage, and with reduced water production, it is predicted to transition from transitional flow to annular flow in the later stage. In the inclined section (The depth is generally between 3000 and 4000m), slug flow predominates most of the time, while in the horizontal section (The depth is generally greater than 4000m), the flow evolves from elongated bubble flow to slug flow in the early stage, from elongated bubble flow to stratified smooth flow in the middle stage, and remains in the stratified smooth flow zone in the later stage. Furthermore, it is proposed that the insertion depth of Well Q1 should be correlated with the well deviation angle, gas production rate, and water production rate. From the perspective of gas-water ratio optimisation and energy efficiency, there should be an optimal timing for tubing insertion.

Carbon dioxide geological storage gives tremendous promise for mitigating anthropogenic carbon emissions. CO2 hydrate has been given rising attention due to its potential in carbon geo-sequestration projects. The effect of silica nanoparticles (SiNPs) on the kinetics of CO2 hydrate formation was systematically studied at 3.5 MPa and 280 K. Pure (bare) and surface-modified (hybrid) SiNPs were separately characterized and used in this study. The effect of bare and hybrid SiNPs concentrations on the induction time of CO2 hydrate formation was investigated. A high-pressure, high-temperature stainless steel vessel was used as a hydrate reactor, and pressure-temperature data were continuously recorded to follow the hydrate formation process. Results revealed that the SiNPs significantly impact the kinetics of CO2 hydrate formation. The increase of Hybrid SiNPs concentration (>0.03 wt% hybrid SiNPs), significantly reduces the induction time and thus accelerates the rapid formation of CO2 hydrate. In contrast, bare SiNPs showed a lower effect on CO2 hydrate formation. Further, the increase of bare SiNPs (e.g., >0.07 wt% bare SiNPs) can tend to eliminate the effect of NPs on induction time. Thus, surface-modified SINPs can significantly enhance CO2 hydrate formation when formulated correctly.

Development of a mature oil reservoir blocks strategy in optimizing hydrocarbon production from mature oil fields. Using dynamic modeling techniques together with subsurface interpretations that were based on sharply adjacent well data, the study has presented new development well placements. Production data studies, pressure surveys, and detailed subsurface studies will be integrated to improve the understanding of the reservoir behavior to predict reservoir performance. The key findings indicate high increments in oil production on account of the implementation of new development wells. The current research provides not only empirical evidence supporting the efficacy of strategic drilling but also lends a structured workflow applicable for similar mature oil fields, thus providing practical means for increasing production and improvement in field life. Opportunities that deliver high value yet have limited associated risks and costs are typically characterized in general by short payout periods and reinvestment of savings. Unlocking residual potential from low-productivity or shut-in wells, maximizing asset value, and using information to drive decisions on optimizing is an asset development strategy. These strategies can only be effectively implemented if inter-disciplinary teams work together to ensure that data is comprehensively analyzed and all solutions are formulated in line with these analyses.
This work discusses the efficiency of developing non non-drained oil reservoir blocks strategy in optimizing hydrocarbon production from mature oil fields. Using dynamic modeling techniques together with subsurface interpretations that were based on sharply adjacent well data, the study has presented new development well placements. The study of the Abu Rudeis oil field has laid the foundation for long-term optimization, integrating production data, pressure surveys, and geological studies into a comprehensive reservoir management strategy. The interdisciplinary approach ensured well-informed and targeted decisions, resulting in enhanced hydrocarbon recovery and improved field performance. Results from the three-dimensional grid that captured heterogeneity in the reservoir, the assignment of reservoir properties like porosity and permeability, and fluids distribution helped to leverage data-driven strategies and advanced technology, the field's sustainability and efficiency have been significantly improved, providing a strong foundation for future optimization efforts.

Recently, one of the most crucial objectives for the petroleum refining industries is producing clean or eco-friendly fuel. The world demands clean diesel utilizing simple processes under safe conditions (i.e., moderate operating conditions). For this purpose, an oscillatory helical baffled reactor (OHBR) was designed to improve the oxidative desulfurization (ODS) process, which is achieved here by converting sulfur compounds found in diesel fuel using a new homemade nanocatalyst. First, the homemade catalyst support, γ-alumina nanoparticles, was prepared using precipitation technology. The γ-Al2O3 was then used to design the synthetic nanocatalyst made of iron oxide using the IWI technology with 5% Fe2O3. A good distribution of the metal oxides has maintained a good surface area (SA) and pore volume (PV), resulting in high activity. The ODS of sulfur compounds and the performance of the modified nano-catalyst at different safe reaction conditions (frequency of oscillation from 0-2 Hz, amplitude of oscillation from 2-8 mm, reaction temperature from 50-80 oC and residence time only 9 min) were evaluated in the new designed OHBR. The best removal of sulfur was 73.23% at an oscillation frequency of 2 Hz, oscillation amplitude of 8 mm, and oxidation reaction of 80 oC with a residence time of 9 min under constant pressure. A kinetic model related to the sulfur oxidation from real diesel fuel by the ODS process in the OHBR was also investigated in this manuscript to estimate the best kinetic parameters of the relevant reactions in the first order.

The present study is conducted to investigate the adsorption desulfurization process for eliminating sulfur from a simulated fuel within a sulfur content range similar to what exists in typical naphtha streams. The model oil, n-hexane, was sulfurized with dibenzothiophene (DBT), which is the most complex form of sulfur constituents in fuels. Corncob, a natural biomass waste material, was utilized to accomplish the adsorption remedy of sulfur.
The carbonization process took place at 500 °C. FTIR, SEM, XRD, AFM, and BET-surface area facilitated a comprehensive characterization of carbonized corncob (CC) adsorbent. The results showed that the corncob sample has homogeneous surfaces and relatively analogous active positions. The CC adsorbent was utilized to adsorb sulfur in its DBT configuration from the sulfurized fuel (n-hexane). Certain adsorption factors of temperature, contacting time, and adsorbent dosage were examined to select the most appropriate adsorption conditions. After that, the chosen conditions were employed to adsorb various sulfur concentrations. For the same initial concentration of sulfur of 400 ppm, the removal attained 75% at favorable parameters of 60°C, 30 min, and 3g L-1, respectively. The efficiency of sulfur removal was substantially augmented with the reduction of the initial sulfur content. Thus, it attained more than 79 % when the original concentration of sulfur in the n-hexane was maintained in the range of 100 ppm. The results perfectly coincided with the Langmuir model of adsorption isotherms. The thermodynamics of the desulfurization adsorption process reflected that the adsorption is associated with an endothermic event. The estimated standard enthalpy changes were 6.34 kJ mol-1. The adsorption was spontaneous over the employed temperature range of 30 – 60°C.

Stimulation plays a crucial role in the oil and gas industry, particularly in the acidizing process. Thus, the development of acidification processes is essential for improving the productivity index and enhancing the physical properties of reservoirs. This research investigates the effect of Tin oxide (SnO2) and Titanium dioxide (TiO2) nanomaterials on the surface properties in acidic media of hydrochloric acid (HCl) at various acid and nanomaterials concentrations, as well as their impact on the wettability of carbonate rocks. To achieve this, surface tension, contact angle, and zeta-potential were measured using various instruments. The findings show that SnO2 and TiO2, at a concentration of 1000 ppm, significantly reduce surface tension to 34.69 and 43.44 mN/m, respectively, while maintaining stability with zeta potential values up to 51.27 and 49.17 mV, respectively. These results exceed the generally accepted stability threshold of around ±30 mV, indicating a strong electrostatic repulsion that prevents agglomeration and ensures prolonged suspension stability. Additionally, the findings show a substantial decrease in contact angles, from 95.17° to 16.32° with SnO2 and from 98.48° to 25.26° with TiO2. This shift indicates a transition from non-wetting to a more wetting condition, which is crucial because it reflects an increased affinity of the acid solution for the carbonate rock surfaces. This results in promoting better acid distribution and enhancing rock dissolution. In conclusion, both SnO2 and TiO2 reveal excellent performance as surfactants in the stimulation process, presenting substantial benefits for the acidizing process in the oil and gas industry.

With increasing population and development, the resources of fossil fuels decreased, leading to the need to find alternative sources of energy. Furthermore, the use of fossil fuels is accompanied by several downsides including environmental fatality associated with toxic gas emissions from diesel engines and continuous increase of the price of diesel fuel. Biodiesel is one of the most important types of renewable energy that replaces the fossil fuel requirement (mineral diesel) and maintains eco-friendly sustainability. Calcium is an essential plant nutrient as it plays an important role in the formation of plant cell walls and membranes. Therefore, the fallen leaves of mango tree can be utilized to produce nano calcium oxide and serve as a highly effective catalyst in the transesterification process for biodiesel production. The green approach of mango leaves extract is more cost-effective, nontoxic, and environmentally friendly compared to other ways such as chemical and physical procedures. Transesterification reaction was conducted at fixed parameters of 65 ℃ reaction temperature, 3 wt.% catalyst concentration, 1.5 h reaction time, and 50% alcohol to oil weight ratio. The effects of several other parameters on the transesterification reaction were studied such as the volume of the reaction mixture, mixing speed, FFA% content, and methanol/ethanol weight ratio. The study found that methanol is more effective than ethanol as alcohol in transesterification reaction, and the FFA% has a slight effect on the catalyst to 1.8% FFA. The produced biodiesel was characterized by GC-MS and FT-IR analysis which indicate the presence of esters. The physical and fuel characteristics of the produced biodiesel were measured; it had a viscosity of 3.708 mm2/s, a density of 0.88869 g/cm3, and a flash point of 108 °C.

Elastic parameters are essential for understanding the behavior of materials under stress, including their tendency for deformation and failure. Elastic modulus is a key parameter, which can be determined using static and dynamic methods. Dynamic methods involve analyzing properties from well logging such as density and wave velocity (compressional and shear waves), while static techniques quantify properties in a laboratory setting. While static techniques are the most accurate, they are also expensive and time consuming. However, there are correlations available to estimate static modules from dynamic modules, although many are specific to certain formations and not applicable to different rock types. In this paper, a new correlation was developed for predicting the static Young's modulus for carbonate formations in the Rumaila Oil Field based on dynamic modulus. Data from 4803 points in an 8.5 in hole size section between 1980 m and 2711 m depth were collected. The results showed that the new correlation accurately predicted the static Young's modulus of carbonate formation, a correlation coefficient (RSQ) of 97%, and an average absolute error of 8.15%. The new correlation provides a continuous profile of static Young's modulus with depth and ultimately leads to reduce the cost of estimating elastic properties in carbonate formations in the Rumaila Oil Field.

A comparative study for two nanoscale semiconductors (TiO2 and WO3) was conducted as heterogeneous photocatalysts to degrade about 50 ppm of Congo red dye in an aqueous solution. The reaction was carried out in a batch reactor placed in a dark box and equipped with an air pump. The dye solution and 0.2 g/L of the catalyst were mixed, firstly, in a dark environment to monitor the amount of adsorbed dye, then the ultraviolet light was turned on with two different powers (15 and 30 W) to study the photocatalytic degradation reactions. The results showed that TiO2 had higher photocatalytic activity to degrade the dye. The CRD removal values for TiO2 and WO3 were 99.67 and 72.16 %, respectively, using 15 W, and the UV power did not have a significant effect on redox reactions according to the observations and the electrical energy consumption. The reaction kinetics study showed that the results obtained followed a first-order kinetics model. A mathematical model was developed based on the recycle ratio approach to study the effects of the recycle ratio and space-time on the Congo red dye removal through the different types of reactors. The simulated results showed that the ideal plug flow reactor performance gave the highest removal in less space-time than the recycle plug flow reactors. The recorded reactor performance decreased with the increasing recycling ratio, and the worst reactor performance was reported for the mixed-flow reactor.

Hydrocarbon estimation is a vital step for formation evaluation and development plans, significantly impacting the decision-making process. Well logs data from 40 wells in the Nasiriyah oilfield was utilised to characterise the Mishrif formation and construct a 3D static model. This model illustrates the spatial distribution of petrophysical properties and calculates the Original Oil in Place volume (OOIP) using a volumetric approach.
The model incorporates water saturation, effective porosity, permeability, and a 2D structural, which is discretized by 317130 grids. These petrophysical properties are populated in 3D dimensions using the geostatistical method SGS. At the same time, the difference in depths of OWC is captured and represented by three regions of initialization for accurate characterization of the reservoir. The geological modeling identified unit MB1 as the main reservoir in the Mishrif formation, characterized by an average porosity of 21.5%, permeability up to 500 md, and water saturation of 27%. However, unit MB2 exhibits similar petrophysical properties but with significantly higher water saturation above 70%, making it a water-bearing zone. The total OOIP volume for the studied reservoir was calculated to be 8535 MMSTB, mainly accumulated in units MB1 and MB2. Unit MB1 holds approximately 73% of the total oil in place, establishing it as the major reservoir in the Mishrif formation, while unit MB2 contains the remaining 27%.

The development of new, cleaner technologies is presently receiving a lot of attention to capture pollutant CO2 gas. 13X zeolite is one of the most popular adsorbents employed for this purpose. Batch and continuous fluidized beds were used to examine the adsorption capacity. Isothermal and kinetic models for the batch were determined at 1–5 bar and 298 K and 303 K pressure range and temperatures, respectively. The Langmuir model fitted the process with qm = 4.01 mmol/g and a correlation R2 = 0.986. Pseudo-first order was also fitted with a correlation of R2 = 0.997. The impact of the inlet CO2 concentration (5%, 10%, and 14%), the bed heights varied between (5, 15, 25) cm, with a flow rate range of (6, 10, 14) L/min at temperature 298 K and pressure of 0.5 bar (gauge pressure), was investigated by utilizing the area under the breakthrough curve in a continuous fluidized bed experiment. Lower flow rate (6 l/m), bed height (25 cm), and higher CO2 initial concentration (14%) achieved the best results.

The region of Kirkuk and its surrounding areas, including (Baba, Jambour, Qara Chuq, Qaiyarah, Demir Dagh, Bai Hassan, Taq Taq, Makhul, Gilabat as well as southern Mosul and the cities of Erbil and Sulymania, are known as one of the oldest discovered oil fields in northern Iraq. This area presents a significant opportunity for further organic geochemical analysis to describe maturation zones and estimate economically generated hydrocarbons with particular reference to the Sargelu formation, to enhance hydrocarbons productivity. To assess the potential of these oil fields, it is essential to perform correlation, comparisons, and geochemical analyses of the data collected from exploration wells in the surrounding area. This approach provides key information and evidence related to the source rock precursors, maturation indices, and other physical properties. The depth of samples in this study ranges from 5,125 ft (1,562 m) to 10,866 ft (3,312 m). Notably, about 20% of these samples demonstrate Total Organic Carbon (TOC) values higher than 4%, with Rock-Eval Hydrogen indices (HI) between 100 and 600, corresponding to Tmax values within the oil generative window. The proven TOC value that has been measured is 16%, while the recorded HI value is 442, and the Tmax value of 439°C. The oil and gas accumulations of the Cretaceous and Tertiary in the Mesopotamian Basin and Zagros fold belt are overlying mature Jurassic source rocks, emphasizing the importance of vertical migrat
ion in hydrocarbon generation. Terpane and Sterane biomarker distributions as well as stable carbon isotope values were determined for oils in the region and potential Sargelu source rock extracts in order to determine dependable oil-to-source rock correlations. The remarkable API gravity, sulfur content, and biomarker ratio provide valuable insights into the source and maturity of various reservoirs. The high sulfur content and wide range of API gravity, from extra heavy to light, are achieved within the range of 8.5–43.3 API.

There is a growing imperative to extract oil not only through primary and secondary means but also via tertiary recovery methods to meet the escalating global energy demands. Consequently, Enhanced Oil Recovery (EOR) is slated to increase significance in the oil industry in the coming years. The amalgamation of low salinity water (LSW) with chemicals to augment oil recovery has gained substantial traction in recent years owing to its demonstrated effectiveness. In this study, a systematic investigation utilizing contact angle measurements to elucidate the underlying mechanisms was undertaken. The results reveal that the contact angle (CA) demonstrated the effectiveness of the combined fluid in altering the wettability from oil-wet to water-wet. The stability of the ionic liquid C12PYCL under reservoir conditions was indicated by thermogravimetric analysis (TGA) and UV-visible spectroscopy. Following the injection of LSW for secondary recovery, core flooding tests were conducted for two different concentrations of the ionic liquid. This resulted in additional oil recoveries of 17% and 19.7% OOIP respectively, at a flow rate of 0.667 cm3/min. At the higher concentration of the ionic liquid, core flooding tests were conducted across a range of flow rates (0.334, 1, and 1.375) cm3/min, resulting in additional recoveries of 5%, 10.5%, and 8.2% OOIP. This study stands as one of the pioneering investigations in the southern oil fields of Iraq, exploring the potential of enhanced oil recovery across varying flow rates using a hybrid solution comprising LSW and ionic liquid.

The assessment of petroleum characteristics through well log analysis has always been essential for identifying and evaluating hydrocarbon-bearing zones. This study presents a comprehensive re-evaluation and correction of five well log data sets from Khasib formation which is the primary reservoir in the East Baghdad oil field (10 kilometers east of Baghdad City). The corrected data sets were utilized to calculate key parameters, including water saturation, porosity, lithology, and shale volume. Lithology was determined using M-N cross-plots and neutron-density analysis, which showed that the Khasib formation mainly consists of limestone, with calcite as main mineral components and minor amounts of dolomite. Shale volume was assessed using both single and dual shale indicators. The three main logs of porosity neutron, density, and sonic logs were used for computing the porosity. Then, Archie equation was employed to determine water saturation. To verify the accuracy of the computation, a comparison between the results and the available core data was conducted, which indicated that porosity values ranged from 0.143 to 0.212, while water saturation varied from 0.643 to 0.951. In addition, core samples and geological reports confirmed that Khasib formation was clean with minimal shale content.

Theobromine, theophylline, and caffeine retention times in a C18 HPLC column (stationary phase) were investigated as a function of mobile phase flow rate, mobile phase composition, and column temperature. When the mobile phase flow rate increased from 0.1 to 1 mL/min and the methanol concentration increased from 5 to 30%, the retention time and peak width of these three compounds were found to be reduced. While there was a small influence of increasing the mobile phase flow rate on the resolution, decreasing the methanol concentration in the mobile phase considerably reduced the resolution. In addition, the mobile phase flow rate and composition were determined to have a more significant impact than the column temperature. According to the findings, theobromine, theophylline, and caffeine were most effectively separated by liquid chromatography at a flow rate of 0.5 mL/min with a mobile phase methanol concentration of 15%.

Hydrocarbons play a substantial role in the energy industry; however, maintaining a steady and optimal production rate in deviated wells remains a significant challenge, especially due to flow bottlenecks that reduce output efficiency. This study focuses on identifying and resolving production constraints in a deviated well located in the TK oil field in North Iraq with a total measured depth of 9639.5 ft. The true vertical depth is at 8137 ft. at an inclination angle of 39.90o. The well failed to meet the pre-evaluated rate of 1044 STB/D based on the current conditions. To accomplish the optimum rate, the deviated well S17 is subjected to nodal analysis and various possible alterations in the well geometry and production system. The nodal analysis through the Inflow Performance Relationship and Vertical Lift Performance characteristics is addressed utilizing IPM suites Prosper to replicate the flow in the tubing through integrated correlations, the fluid behavior, and the phase envelope. The saturation pressure is tuned with the correlations in the PVTp program. Different scenarios were set, such as the change in wellhead pressure, tubing internal diameter, reservoir pressure, skin factor, and the introduction of artificial lift. Following the simulation, as referred to previously, the detailed analysis of the variables provides an exhaustive insight for the field operators. The key finding of this well is that reducing skin factor and alongside the use of Electrical submersible pump (ESP) installation, significantly enhance production feasibility and the well will be able to produce when the reservoir pressure drops to 1500 psi These results provide actionable insides for field operators to improve production performance in similar well conditions.