Iraqi Journal of Chemical and Petroleum Engineering

The identification studies of rock and reservoir characteristics are essential for evaluating the efficiency of a reservoir by analyzing the types of rock and pores. In this study, Nuclear Magnetic Resonance (NMR) for six wells was utilized to identify the rock and reservoir characteristics of the Mishrif formation in the South of the Zubair Field, specifically the Rafdyia and Safwan domes, as well as the west flank. Specific correlations were utilized to describe the classification of rocks, estimate pore throat radius, and recognize possible flow intervals. The results revealed that the Mishrif Formation mainly consists of limestone, dolomite, and shale. The Safwan dome consists mainly of pack-wackestone, wackestone, and mudstone, while the Rafdyia dome is a mixture of packstone, grainstone, and wackestone with some shoal and rudist bioherm facies. The west flank is characterized by pack-wackestone, wackestone, and mudstone. These results were further supported by core analysis. Pore throat types in the Safwan dome range from Micropores to Nanopores, while the Rafdyia dome is dominated by Megapores, Macropores, and Mesopores. The back-shoal facies overwhelm the packstone microfacies. The west flank of the Mishrif Formation in the Zubair Field is mesoporous and micropores. Flow units were identified in the Safwan and Rafdyia domes, as well as the west flank. The Safwan dome has fifteen flow units in the north and seven in the south, while the Rafdyia dome has ten flow units in both the north and south regions, with five flow units on the west flank of the Zubair Field.

In the context of oil and gas extraction, a dead well refers to a well that has ceased to produce hydrocarbons. The major problems that account for this are: the reservoir has been depleted, the pressure has dropped too low to allow for extraction, or there are technical issues such as blockages or equipment failure. The main objective of this paper is to analyze the performance of a dead well called K88 (for confidential reasons) activated by the progressive cavity pump (PCP) in order to improve and maximize the oil flow rate produced. The completion, reservoir, production pressure, volume, and temperature (PVT) data are processed under Excel and Prosper software by using nodal analysis, sensitive analysis, economic analysis, and decline curve methods to obtain the results. The results showed that well K88 activated by the PCP has an oil flow rate of 1600.9 STB/day. The optimization makes it possible to obtain a net oil flow rate of 2005 STB/day associated with a head pressure of 45 psig. According to the economic calculation results, a gain in production is noticed during 10 years of production and a return on investment at the latest 39 days of production.

Phenol is one of the worst-damaging organic pollutants, and it produces a variety of very poisonous organic intermediates, thus it is important to find efficient ways to eliminate it. One of the promising techniques is sonoelectrochemical processing. However, the type of electrodes, removal efficiency, and process cost are the biggest challenges. The main goal of the present study is to investigate the removal of phenol by a sonoelectrochemical process with different anodes, such as graphite, stainless steel, and titanium. The best anode performance was optimized by using the Taguchi approach with an L16 orthogonal array. the degradation of phenol sonoelectrochemically was investigated with three process parameters: current density (CD) (25, 50, 75, and 100 mA/cm2), time (1, 2, 3, 4 h), and phenol concentration (100, and 200 mg/l). Signal-to-noise (S/N) ratio and analysis of variance (ANOVA) were utilized to examine the impact of each factor. The optimal conditions for phenol removal were 100 mA/cm2, 100 mg/l of phenol, and 4 hours of electrolysis. Under optimal operating conditions, the phenol removal efficiency was 80.99%. The CD was the most influential factor on phenol elimination effectiveness, while the phenol concentration had the least impact.

Globally, oil production has steadily increased which causes a rise in the coproduction of oil and water emulsions. These emulsions pose significant challenges in transportation and the oil refinery industry, causing high-pressure drops and corrosion problems due to chlorides in the water. Despite advancements in renewable energy, crude oil remains a primary energy source. The crude oil industry faces numerous challenges, including cost emulsion issues. This study developed a corn oil bio-demulsifier (MFK). A unique demulsifier was tested using FTIR, GC-MS, and TGA. Using the bottle test method, the produced demulsifier MFK was tested with Basrah oil and East Baghdad S1 oil. The emulsion-breaking processes have been studied under several factors, such as settling time, dosage, temperature, pH, water content, and mixing time after demulsifier addition. At 2000 ppm Basrah oil, water separation efficiency reached 75%. For East Baghdad S1 oil, the highest separation result was 43.3% at 4000ppm, after 5 h of settling time at 70°C, with a 30/70 water-to-oil ratio. When studying the pH, the best water separation rate was 86.5% at a pH of 10. The best water content was 92% when the water-to-oil ratio was 50/50, and the best demulsifier mixing time with the emulsion was 2 min with a separation rate of 74.5%. When mixing was increased, undesirable results occurred. This study demonstrated that biodemulsifiers may replace conventional biodemulsifiers in early units while reducing environmental and economic impacts with further study and development.

The accurate determination of reservoir lithology remains a challenge in petroleum engineering. There are some conventional techniques available to determine the lithology. However, the application of those techniques has been long and complex. So, the main goal of this study is to simplify the identification of reservoir lithology. This paper presents a Pattern Recognition Approach (PRA) to identify the reservoir lithology simply and accurately. It is type of artificial neural network. Four wells from the Camaal Field were chosen to develop this approach. Around 32400 data points from the previous wells were digitized. The PRA approach used depth, gamma ray, lithology, sonic, neutron, and density logs as inputs. The model classifies lithology into permeable and impermeable rocks, further categorizing them into clastic and carbonate rocks, and subsequently into specific types into sand, sandstone, dolomite and limestone. The results show that the proposed approach provides a suitable prediction of lithology with higher accuracy compared with actual lithology. The model demonstrates high accuracy rates in identifying various lithologies, with overall accuracies of 76.2% for permeable/impermeable rocks, 94.9 for clastic/carbonate rocks, 86.2% for sand/sandstone, and 92.8% for dolomite/limestone.

In this study, lead ions were removed from simulated wastewater by batch adsorptive filtration. A three-dimensional printed water filtration was designed using a blender and successfully synthesized from a PLA spool and a 3d printer machine. The filter surface was treated with NaOH solution to hydrolyze the polyester group in PLA. After that, α-Fe2O3 was prepared by the coprecipitation method and coated on the filter through doping and drying. α-Fe2O3 was characterized by X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), and Brunauer-Emmet-teller (BET). The results successfully indicate the synthesis of α-Fe2O3 consisting of 67.3% Fe and 32.7% O2. α-Fe2O3 appeared to have a surface area of 95 m²/g with distinct morphology and functional group. The effect of initial Pb concentration (100-800) ppm and the effect of contact time (5-120) min on the removal process were studied. Lab data was collected, and the adsorption was investigated kinetically. The 3d printed filter system coated by iron oxide showed significant and promised results for wastewater treatment and lead ions removal using this technique. Also, the results showed that the adsorption of Pb ions on the α-Fe2O3 surface fitted with the Langmuir model, with a correlation coefficient (R²) of 98.65%. The kinetic model’s investigations revealed that the pseudo-second-order model was the most fitted model for the process with R² of 99.997%. The highest adsorption saturation capacity was 165.2 mg/g adsorbent.

The mechanical characteristics of rocks such as elasticity (Young's modulus, Poisson's ratio, and unconfined compressive strength) play an essential in sand production analysis, well design, and borehole stability assessment. In this study, the mechanical characteristics of rocks were indirectly estimated using gamma ray, density, and acoustic (compressional and shear) log data from well RU-X in the Rumaila oil field, specifically for the Zubair Formation. These estimated properties were compared to direct measurements obtained from triaxial and uniaxial mechanical tests conducted on well RU-X. The results showed a significant similarity between the indirect estimates and the direct measurements, indicating their reliability for sand production analysis and their valuable contribution to constructing the geomechanical model. Moreover, the static profile of Poisson's ratio was validated using laboratory core test results, demonstrating reasonable agreement. The validation process involved comparing laboratory-derived measurements with actual field measurements in the Zubair Formation. The higher Poisson's ratio observed in the shale was attributed to the slower propagation of acoustic waves, resulting in a good matching with an R2 value of 0.77. On the other hand, the lower Young's modulus in the shaly formations indicated lower resistance to deformation, with a comparative ratio of R²=0.96. Static measurements, which consider various influencing factors, provide a more realistic representation of rock behavior under different conditions. Regarding unconfined compressive strength, the comparative ratio was R²=0.83.

Iron nanoparticles were prepared by using the co-precipitation process, and then used to fabricate magnetic field-responsive hydrogel films. The magnetic nanoparticles' structural, physical-chemical, morphological, and magnetic characteristics and the effect of hydrogel films' coating concentration were studied. The properties of the hydrogel film responsive to the magnetic field were investigated using Fourier analysis spectroscopy infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and a vibration sample magnetometer (VSM). The results indicated that all samples showed good inter-integration of the constituent materials and their functional groups. The hydrogel film samples which were polycrystalline, had broad diffraction peaks and showed constant particle size with nearly spherical particles with rounded edges. The SEM image of the magnetic nanoparticles with and without coating was established for the accumulation of numerous nanoparticles with a 17 nm mean diameter. In addition, the magnetic properties of the magnetic field-sensitive hydrogel films were evident and sufficient for drug delivery to the desired location.

The hydraulic fracturing technique is a widely used technique worldwide, making it interesting to study. This technique was applied for the first time in Iraq on a tight carbonate reservoir in the Halfaya oil field. In this field, the oil production rates, and flowing pressure were low during production periods reflecting a problem for the development plan designed to increase production using a hydraulic fracture technique. Initially, the hydraulic fracture well showed high oil-producing rates, but then, quickly experienced a high decline failing to keep a stable production rate. To address this problem, it is important to describe and analyze the behavior of pilot hydraulic fracturing wells during their production period, study the inflow performance relationship (IPR), and determine the optimum wellhead pressure above the bubble point pressure (Pb) to avoid loss of lifting energy. Furthermore, it identifies the allowable flow rate to keep stable production, investigates the effect of selecting internal tubing size, and reveals a future production procedure for hydraulic fracture wells.
This study reveals that the transient inflow performance relationship observed in the production history of hydraulic fracture well in the tight carbonate reservoir and traditional inflow performance relationship concepts are not applicable. The optimum wellhead pressure for stability in production for Wells w-5 and w-55 is determined to be 750 and 580 psi with optimum rates of 800 and 450 Bbl/D, respectively. The results also showed that producing at a high flow rate may cause a depletion in the fracture potential storage without giving an opportunity for a reservoir to compensate for the produced fluid into fracturing potential storage. The internal tubing size has a passive effect on the hydraulic fracture well, as an increase in size causes an unstable flow zone. Lastly, future production procedures emphasize keeping wellhead pressures stable or increasing them if they drop. This can be accomplished by re-adjusting the choke size according to any changes observed.

Linear alkylbenzene sulphonate (LAS), a surfactant frequently incorporated into detergent formulations, typically ends up in wastewater treatment facilities after use. The present study aims to investigate the efficacy of bacteria isolated from Iraqi wastewater in removing LAS. This strain was identified as Pseudomonas aeruginosa by genetic analysis (16S rRNA). Three LAS concentrations (25, 50, and 100 mg/l) were employed in this investigation, along with three temperatures (30, 35, and 40 oC) and pH values (5, 7, 9). The LAS anionic surfactant demonstrated optimal biodegradation by Pseudomonas aeruginosa at a temperature of 30 °C and at pH levels of 7 and 9, with removal percentages of 93.76% and 90.4%, respectively, at a concentration of 25 mg/l of LAS. The study's findings demonstrated the possibility and importance of using aerobic biodegradation to remove LAS from actual effluents. This bacterium is useful for bioremediation because of its capacity to break down LAS.

Shear wave is a crucial parameter for assessing the wellbore stability, the stress response, and rock deformation. It is essential for constructing the mechanical earth model (MEM) for many applications related to reservoir geomechanics including wellbore stability, sand production, hydraulic fracturing, and fault reactivation. However, shear sonic data is often omitted during the well-logging measurements for cost and saving purposes. To overcome this challenge, recent research has been focused on determining shear wave velocity through the use of core plugs, empirical correlations, artificial intelligence techniques, and multiple regression to quantify and evaluate the mechanical properties of subsurface formations without performing direct measurements at the wellbore. The greatest difference between this study and the literature is to predict the shear wave velocities for three sedimentary rocks based on conventional well logs.
This study has been conducted on datasets of two wells drilled in the East Baghdad oilfield, for which there is a lack of shear wave data. Two formations (Tanuma and Zubair formations) within the production section of this field were conducted to develop new models for determining the shear wave velocity using multiple regression analysis. These two formations primarily consist of three lithologies: limestone, sandstone, and shale. Before the model development, data analysis on the selected data was applied to figure the most influential parameter(s) in determining the shear wave velocity. The results of the developed models are then compared with the previous models in the literature.
The results showed that the multiple regression analysis technique is a powerful technique in determining shear wave velocity with high-performance capacity. The correlation coefficient (R^2) and the root mean square error (RMSE) were 0.84 and 0.092 for limestone, 0.84 and 0.0972 for sandstone, and 0.86 and 0.0796 for shale respectively. Furthermore, the performance of the developed models is well matched to the actual shear wave data rather than the Castagna correlations. The findings of this study are effective in determining shear wave velocity for future applications related to reservoir geomechanics without needing costly well-log or core measurements.

Differential-pressure pipe sticking is one of the main problems that occurs during drilling operations, leading to an increase in the non-productive time (NPT). To address this problem, the industry uses a range of spotting fluids to enable the recovery of a differentially stuck pipe effectively. Thus, any delay in solving this problem can turn into a difficult rescue operation that can eventually lead to the abandonment of the well in extreme conditions. Therefore, it is crucial to choose the appropriate spotting fluid that is suitable for the specific mud composition, as using an unsuitable spotting fluid may result in dangerous conditions. Additionally, other factors can further complicate the process of freeing a stuck pipe. Therefore, for prevention, remediation, and enhancing the recovery of stuck pipes, it is important to understand the root causes of the pipe sticking issue, the conditions that lead to it, and the operational mechanisms of various spotted fluids and their application areas.
This paper studies the challenges of pipe sticking during drilling operations, particularly emphasizing differential pipe sticking, and the role of spotting fluids in releasing pipe sticking. It discusses the testing and evaluation methods used to choose appropriate spotting fluids while rejecting the inferior options, highlighting the benefits and disadvantages.
This study, which was conducted at Well NR-A in the Nahr Umr field in southeastern Iraq, aims to address the problem of differential stuck pipes. By employing a stuck pipe list check table, the mechanism of this problem was diagnosed, resulting in a thorough analysis of the causes of differential stuck pipe and subsequent steps necessary to release the stuck pipe. Finally, recommendations are presented to improve testing and evaluation methods, overcoming the limitations of conventional methods.

This study aims to prepare new compounds and investigate them spectroscopically and biologically against selected types of positive and negative bacteria and fungi to demonstrate their biological effectiveness. The prepared ligand combining formaldehyde, indole, sulfa benzamide, and 2-mercapto benzimidazole, a Mannich base ligand (L) was synthesized. The six metal ions including Cobalt (II), Nickel (II), Copper (II), Palladium (II), Platinum (IV), and gold (III) have interacted with the ligand and formed new complexes. Different spectroscopic methods, including C.H.N.S., FTIR, UV- Range visible, 1HNMR, 13CNMR, mass spectra, magnetic moment, and molar conductivity were used to suggest the new geometry of the complexes. The result from the infrared spectrum showed that the ligand behaves as tridentate with all prepared complexes. Conductivity analysis revealed the electrolytic nature of palladium, platinum, and gold ions complexes and non-electrolytes. The antibacterial activity of the compounds that were produced was tested using an agar-well diffusion procedure towards two strains of gram-positive as well as two strains of gram-negative bacteria and fungi (Staphylococcus, Streptococcus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans) respectively at 0.02M. The standard (∆Eo) and (∆Hfo) of ligand and six complexes were calculated using the program Hyper chem 8.0.7. The research established that complexes are more stable than ligands. Calculated HOMO and LUMO and vibration frequencies using (parametric method 3 (PM3)) to find out the active sites in the ligand showed that they can coordinate and note the extent to which the results of theoretical vibrational frequencies are close to the process when calculating the vibrational frequency of the active aggregates.

The Material Balance Equation is a crucial tool utilized in reservoir studies to evaluate fluids and rock properties at static pressures. The Flowing and Dynamic Material Balance methods offer a significant advantage by avoiding the requirement to shut down wells, as they use flowing pressure instead of static pressure under constant or variable flow rates. The concept of "Dynamic Material Balance" involves converting the bottom hole flowing pressure at any point at any given time to the average reservoir pressure at that point. This allows for the use of classical material balance calculations and the development of classical material balance plots. In this study, the Dynamic Material Balance and Agrawal Type Curve techniques were used to estimate average reservoir pressures, initial hydrocarbon in place, and ultimate oil recovery for a well in the Mishrif reservoir, the main reservoir in the Buzurgan oil field. Many wells in this field experience problems such as high-pressure decline or continuous water production, necessitating ongoing evaluation. While the Dynamic Material Balance method focuses on boundary-dominated flow data, the Agrawal-type curve technique analyzes data from both transient and boundary flow periods. Agarwal decline curves were constructed using relationships of pseudo pressure normalized production, material balance pseudo time, and dimensionless variables in well-test analysis. The results from both methods showed comparable results with an absolute percentage error of (0.738) %, (3.07) %, and 5.7% for oil-in-place, drainage area, and average reservoir pressure, respectively. This strong correlation between the Dynamic Material Balance and Type Curve results indicates their accuracy and reliability.

For a reservoir with high storage capacity and low ability to produce, the serious problem is the sharp reduction in the recorded well productivity within a short period. One solution to this problem is to create hydraulic fractures that increase formation permeability and keep its production at high rates for a sufficient time. The field under study is the East Baghdad oil field of three formations: Saadi, Tanuma, and Khasib. Knowing the geomechanical behavior of these reservoirs has a critical effect on the success of hydraulic fracturing operations. In this study, rock stress magnitude and direction, rock elasticity, rock strength to fracturing initiation, and all these parameters in addition to petrophysical properties will be used to identify whether the hydraulic fracturing operation could be successful or not. An integrated modeling of the studied reservoir is an essential step including 1-D geomechanical evaluation of many formations in order to choose the perfect layer to create hydraulic fracture. Then, a 3-D distribution of geomechanical properties and petrophysical properties was presented to make a perfect selection of these properties. The geomechanical evaluation of the reservoirs under study is supported by experimental evaluation of core samples including Energy Dispersive X-ray spectroscopy (EDS), Scanning Electron Microscopic (SEM) image, and thin section (TS) image. The results show that a reduction in the calculated geomechanical properties in terms of Poisson ratio young modulus and compressive strength are favorable for candidate layer selection. Among the studies of rock mechanical properties, it is also noticed that unconfined compressive strength is a crucial parameter for best layer selection. The suitable depths for fracturing jobs are given in detail in this study using brief data collected from four wells.

A successful synthesis of mesoporous Santa Barbara amorphous (SBA-15) with nanoparticle size was attempted using prepared sodium silicate from Iraqi high silica sand. EO20PO70EO20 copolymer was used as a template at highly acidic conditions (pH < 2). The effect of crystallization temperature of (100, 110, 120, and 130 0C), and crystallization time of (24, 48, 72, and 120 h) on surface properties was studied. The experiments were characterized using XRD, FTIR, AFM, BET, and FESEM. The XRD and FTIR tests represent amorphous SBA-15 without any impurities. Decreasing average particle size distribution increased the surface area, and decreased the porosity (pore volume, and pore size) in all experiments. The texture properties were surface area of 210-756 cm2/g, volume pore of 0.28-0.7 cm3/g, and pore size of 1.94-13.45 nm. The optimum result of surface area was achieved at hydrothermal conditions of 110 0C, and 24 h, while optimum results of pore volume, and pore size were achieved at hydrothermal conditions of 100 0C, and 120 h. Semi-spherical shape of particles appeared at hydrothermal conditions of 120 0C and 24 h. This morphology was transferred to small rods at 130 0C, and to semi-platelets at 120 h.