Structural Study of Faihaa Oil Field in Basra South of Iraq

This study used structural contour maps to carry out the geometrical analysis for Faihaa structure in Basra southern Iraq. The study used row data of well logs and structural maps while Softwares were Didger 4, Stereonet v.11 and Petrel 2017 Faihaa Oil Field is located at an eastern part of the Mesopotamian Zone within the Zubair Subzone, characterized by subsurface geological structures covered by Quaternary sediments. These structures are oriented in the NW-SE direction in the eastern part of the band and the N-S direction in the southern region, and some in the direction NE-SW. The Faihaa Oil Field shows that is an Anticline structure. The average dip value of an axial surface is 89.7° while the plunge of hinge line between 4–4.2 in North-West direction referred to that Faihaa Structure is upright and gentle fold. Based on the Thickness ratio and axial angle, the Faihaa Structure is thickened Fold. The eastern limb of the fold is longer than the western limb, so Faihaa Oil Field is an asymmetrical structure. The difference in dimensions (5<Length / Width < 2) confirmed the brachy fold of the Faihaa structure.

Development of 1D-Synthetic Geomechanical Well Logs for Applications Related to Reservoir Geomechanics in Buzurgan Oil Field

Knowledge of the distribution of the rock mechanical properties along the depth of the wells is an important task for many applications related to reservoir geomechanics. Such these applications are wellbore stability analysis, hydraulic fracturing, reservoir compaction and subsidence, sand production, and fault reactivation. A major challenge with determining the rock mechanical properties is that they are not directly measured at the wellbore. They can be only sampled at well location using rock testing. Furthermore, the core analysis provides discrete data measurements for specific depth as well as it is often available only for a few wells in a field of interest. This study presents a methodology to generate synthetic-geomechanical well logs for the production section of the Buzurgan oil field, located in the south of Iraq, using an artificial neural network. An issue with the area of study is that shear wave velocities and pore pressure measurements in some wells are missing or incomplete possibly for cost and time-saving purposes. The unavailability of these data can potentially create inaccuracies in reservoir characterization n and production management. To overcome these challenges, this study presents two developed models for estimating the shear wave velocity and pore pressure using ANN techniques. The input parameters are conventional well logs including compressional wave, bulk density, and gamma-ray. Also, this study presents a construction of 1-D mechanical earth model for the production section of Buzurgan oil field which can be used for optimizing the selected mud weights with less wellbore problems (less nonproductive time. The results showed that artificial neural network is a powerful tool in determining the shear wave velocity and formation pore pressure using conventional well logs. The constructed 1D MEM revealed a high matching between the predicted wellbore instabilities and the actual wellbore failures that were observed by the caliper log. The majority of borehole enlargements can be attributed to the formation shear failures due to an inadequate selection of mud weights while drilling. Hence, this study presents optimum mud weights (1.3 to 1.35 g/cc) that can be used to drill new wells in the Buzurgan oil field with less expected drilling problems.

Assessment of Clay Deposits Quality from East of Erbil, Kurdistan Region, Iraq for some Ceramic Industries

For the assessment of clay deposits for brick manufacturing, seven clay samples from different locations were collected by channel sampling method from Injana, Mukdadiyah, Bai Hassan formations and Quaternary deposits in Bestana village, the study area is located east of Erbil city (NE Iraq). For ceramic manufacturing, the quality of clay should be measured according to some physical properties. The mineralogical and geochemical study revealed by using X-ray diffraction and chemical characteristics, which represented that all clay samples containing; kaolinite, smectite, illite, and chlorite with some mixed clay and non-clay mineral quartz, calcite, dolomite, and feldspar. The physical properties of clay samples including grain size analysis and Atterberg limits showed that the raw materials contain clay in high proportion, silt in medium proportion, and sand in minor proportion. Plasticity index of the studied samples showed that they are moderately plastic to plastic range. The geochemical analysis of the studied samples showed that the clay raw materials are composed mainly of silica and alumina, which act as refractory material in the ceramic industry. In addition to that, there are different proportions of calcium, iron oxides, magnesium, potassium, and sodium, which are flux oxides.

Updating Subsurface Image of Khashim Al-Ahmer Gas Field Using the Interpretation for Anisotropic Velocity Model North-Eastern Iraq

This research deals with structural interpretation of Khashim Al-Ahmer Gas Field North-Eastern Iraq in Diyala Province, using the interpretation of inhomogeneous velocity data. The specific target in this field is the gaseous Jeribe reservoir representing the L. Miocene-Tertiary period. A very thick layer of evaporates Al-Fatha Formation is overlap the Jeribe Formation in the gas field and play as a sealed bed and transition zone for faults movement as a thrust fault. The thrust fault with gas content negatively affected the seismic energy, causing a high attenuation below the level of Al-Fatha Formation in the dome of the Khashm Al-Ahmer structure. Using the interval velocities derived from the sonic logs of five surrounding wells that represent the inhomogeneous behavior of the seismic wave velocity within the rock layers, a model of the velocity behavior in the field was built and the extent of the Jeribe gas reservoir was reconstructed according to the new velocities interpretation data.

Biostratigraphy and Facies Analysis of Upper Valanginian-Upper Hauterivian (Sarmord Formation) in Maten Anticline, Northern Iraq

Biostratigraphical and sedimentological study of the Sarmord Formation (Upper Valanginian - Upper Hauterivian) at the southern limb of Maten anticline is conducted within a well-exposed section. The formation is composed of marl, marly limestone, limestone, and dolostone, which yielded moderately diversified benthonic foraminiferal fauna, green algae, echinoderms, gastropods and some bioclast. The stratigraphic distribution of the benthonic species permits the recognition of two well-defined biozones. These are Everticyclammina kelleri Assemblage Zone, which represents the Late Valanginian age and Pseudocyclammina lituus Assemblage Zone, indicating Hauterivian age. These larger benthonic foraminiferal biozones are correlated with other zonal schemes inside and outside of Iraq, which indicates that the age of the Sarmord Formation in Maten anticline extends from Late Valanginian to Late Hauterivian age. The Sarmord Formation in the studied section is composed of limestone, dolomite, marl and conglomerate lithofacies types. Limestone lithofacies is represented by lime wackestone microfacies. According to the characteristic features of these facies, the depositional environments extend from tidal flat to shallow open marine environments.

Geotechnical Properties Study of Soil Bank Slopes for Shatt Al-Hilla, Middle of Iraq

The central regions of Babylon Governorate, located on the Shatt Al-Hilla, suffer from problems as the collapse and erosion of its banks, increase in sedimentation in the river, which reduces the river flow efficiency and forms meanders in the river. After the reconnaissance visit to determine the meandering sites. A detailed study of the area was carried out by drilling 6 test boreholes representing three areas (Ancient Babylon, Bata-Bridge, and Al-Khusrweya), two wells on both sides of the meander at a depth of 10m for each borehole to know soil properties, bearing capacity and consolidation, and its effect on the engineering construction. Soil samples have been taken to carry out geotechnical tests. also conducted a study of banks stability for three stations, where the cross-section was monitored by the M9 device and the height of the banks from both sides by the LEVEL device, using the Geo-Studio-2021 program with soil properties and by using Bishop method the safety factor was extracted for the three stations for erosion-prone areas. it was 3.44 in Ancient Babylon, Bata-Bridge was 1.7 and Al-Khusrweya was 1.6 Under natural conditions, the average river flow level reaches it in year respectively are 27.88, 27.74, 27.33 m, above sea level. Where all the stations were safe unless the water level increased or decreased. Also, the research reached a determination of the allowable bearing capacity reaches it before the landslide.

Shakrook Anticline, a Very Complicated Structural Form, North Iraq, Kurdistan Region

The Shakrook anticline has very a complicated structural form, this is attributed to three thrust faults, and the presence of four anticlinal axes with the main anticlinal body. The most northwest existing anticline is called in the current study the Sisawa anticline, the main two anticlines are called the Shakrook East and Shakrook West, whereas the fourth one is called the Biluk anticline it is developed along the southwestern limb of the Shakrook East anticline. The exposed rocks in the Shakrook anticline range from Upper Jurassic to the Paleogene age. The bulk of the main Shakrook anticline is formed by the Bekhme Formation (Upper Cretaceous age), whereas the bulk of the Sisawa anticline is formed of the Shiranish Formation (Upper Cretaceous age) with Paleogene and Neogene aged rocks. Geological maps and high-quality satellite images were used to elucidate the complex structural form of the Shakrook anticline. The updated geological map is quite different from those existing geological maps. A field investigation was carried out to check the interpreted data and to implement photography to the interested structural and geomorphological forms. Different geomorphological forms also were interpreted; they all refer to the lateral growth of the Shakrook anticline.

Determination of Safe Mud Weight Window in Rumaila Oilfield, Southern Iraq

The oil and gas industry, wellbore instability plays an important role in financial losses and stops the operations while the drilling which leads to extra time known as non-productive time. In this work, a comprehensive study was carried out to realize the nature of the instability problems of the wellbore in Rumaila oilfield to improve the well design. The study goal is to develop a geomechanical model in one dimension by utilizing Schlumberger Techlog (Version 2015) software. Open hole wireline measurements were needed to develop the model. The model calibrating and validating with core laboratory tests (triaxial test), well test (Mini-frac test), repeated formation test. Mohr-Coulomb, Mogi-Coulomb, and Modified Lade are the three failure criteria which utilized to analyze the borehole breakouts and to determine the minimum mud weight needed for a stable wellbore wall. For more accuracy of the geomechanical model, the predicted profile of the borehole instability is compared with the actual failure of the borehole that is recorded by caliper log. The results of the analysis showed that the Mogi-Coulomb criteria are closer to the true well failure compared with the other two criteria and considered as the better criteria in predicting the rock failure in the Rumaila oilfield. The wellbore instability analysis revealed that the vertical and low deviated wells (less than 40º) is safer and more stable. While, the horizontal and directional wells should be drilled longitudinally to the direction of the minimum horizontal stresses at a range between 140º–150º North West-South East and the mud weight recommended is increased to 10.5 ppg to avoid most of instabilities problems. The results contribute in development plan of the wells nearby the studied area and decreasing NPT and cost.

Sequence Stratigraphy of the Fatha Formation in Shaqlawa Area, Northern Iraq

A surface section of the Fatha Formation (Middle Miocene) was studied in the Shaqlawa area, Erbil, Northern Iraq. It consists of siliciclastic silt, evaporates, and carbonates in a mixed siliciclastic silt composition. The Fatha Formation in the study area can be divided into two members of variable thickness based on rocky differences. Depositional settings ranged from shallow open-marine and restricted-hypersaline to supratidal and continental (sabkha, fluvio-deltaic, and exposure). It is bounded below by a type one sequence boundary above the Eocene Pila Spi Formation and marked by conglomerates. The upper sequence boundary with the Injana Formation is conformable. Thirteen sedimentary facies were distinguished in the Fatha Formation within the Shaqlawa region of northern Iraq and include sandstone to mudstone, wavy bedded sandstone to mudstone, Flaser bedded sandstone to mudstone, Marl, sandstone, cross lamination sandstone, Trough cross bedded sandstone, Planar cross bedded sandstone, marly limestone lithofacies, bioclastic grainstone to packstone microfacies, bioclastic lime mudstone to wackestone microfacies, lime mudstone-wackestone microfacies, and gypsum lithofacies. The depositional environment of the formation was inferred based on the facies association concepts. The succession formation can be divided into several third-order cycles, which reflect fluctuations in the relative sea-level rise. High-frequency cycles of transgressive System Tract and Highstand System tract. Fundamental to the evolution of the sequence, in this case, is the local tectonic component.

Concentration, Distribution, and Potential Sources of Heavy Metals in Households Dust in Al-Fallujah, Iraq

Household dust pollution with heavy metals attracted the attention of researchers and environmental managers due to the risk of the health of these metals. The study aims are to determine heavy metals concentrations (Cd, Cr, Cu, Ni, Pb, Zn), their spatial distribution, and their potential sources in the household dust of Al-Fallujah City, Iraq. The dust was sampled from 50 houses. The heavy metals levels in the dust were measured using the atomic absorption spectrophotometry method. The mean concentration of heavy metal was ordered as following: Zn (292.85 mg/kg) > Cr (289.45 mg/kg) > Ni (105.72 mg/kg) > Pb (75.57 mg/kg) > Cu (65.03 mg/kg) > Cd (14.77 mg/kg). The mean concentration of these metals exceeded the reference values. The areal distribution of the reported heavy metals showed specific and non-specific patterns indicating point and non-point pollution sources. The heavy metals potential sources in house dust in the study area were characterized using correlation, Principle components and cluster analyses. The potential sources for Cd, Cu and Pb were interior and exterior sources, while the Ni and Cr were derived from internal sources. This study provides the environmental protection managers and decision-makers with important information about heavy metals concentrations and their sources in indoor environments.