East Baghdad Oil Field Research Articles

Prediction of shear wave velocity in three sedimentary rocks in East Baghdad oilfield using multiple regression analysis

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 ( ) 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.

Using the Conventional Method to Estimate Water Saturation of Khasib Formation in East Baghdad Oil Field Central Area

The water saturation level may change due to geological changes or human intervention, like earthquakes, excavation, injection, or extraction of fluids from underground reservoirs. This work helps the reader understand how to use electrical logging to acquire a suitable water saturation value in resistivity and dielectric studies. In the East Baghdad field, two wells that were drilled into the Khasib Formation had their petrophysical parameters assessed using IP software. This allowed for the determination of water saturation using the available well logs, including neutron, density, SP, sonic, gamma ray, and resistivity logs for wells EB-25, and EB-29. The limestone section in the Khasib formation represents calcite, the main mineral found. We counted the amount of shale in each well using gamma-ray logs. The porosity at the reservoir unit was determined using a sonic log. Archie's equation and resistivity data are also used to compute fluid saturation. Taking m=n=2, a=1, x=1.76, and Rw=0.033 for Khasib formation. The link between Archie's and Raiga's coefficients, a, m, n, and x, is primarily the basis for this discussion. There is high agreement when this equation is used. In clean formations (non-shaly). this formula can be regarded as a reliable indicator of water saturation in situations where porosity techniques other than acoustic logs are unavailable. It's important to note that this equation provides accurate and realistic answers for rocks with transit times between 40 and 150 As/ft. Porosity knowledge is not required for such an assessment.

Identifying the high potential zones for hydraulic fracture propagation / Eastern Baghdad field

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.

Microfacies Analysis and diagenesis process of Hartha Formation East Baghdad oilfield, center Iraq

Microfacies Analysis and diagenesis process of Hartha Formation East Baghdad oilfield, center Iraq

The Influence of Drilling Process on the Neighboring Soils: A Cause Study in the East Baghdad Oil Field

The study aims to determine the concentrations of major oxides and trace elements in the soil of East Baghdad oil field. Twenty-five soil samples were collected, 24 samples from the East Baghdad oil field and one sample was taken from Diyala governorate, far away from pollution resources (BA). The samples were analysed using X-ray fluorescence (XRF), and the result showed that SiO2 and CaO are the most abundant, followed by other oxides (Na2O, Al2O3, Fe2O3, MgO, K2O, TiO2) with a high percentage of LOI. Trace elements showed that the average values of (Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, V, Zn ) were above the international limits of the soil except for the Fe element within the international limits. High concentrations of trace elements were observed in all soil samples, exceeding the international standard limits in soil. The values of the trace elements suggest that oil industries, oil drilling and extraction operations, and human activities are the most important cause of increasing concentrations of trace elements in the soil of the study area.

Converting of Waste Crude Oil of East Baghdad Oil Field into Light Hydrocarbons Using Thermal Cracking Technology

East Baghdad oil field produces a lot of quantities of waste crude oil due to drilling and production processes activities. This waste is caused a negative impact on the environment and human health. In the present investigation, the collected waste crude oil of API= 13 was converted into light hydrocarbons via a thermal cracking reaction. The thermal cracking process was achieved in a batch reactor at temperatures ranging between 350-450°C in absence of oxygen. At each temperature, the reaction pressures varied between (1-6) kg/cm2. Moreover, a continuous stirring of the reaction mixture inside the reactor was continued during the course of the thermal cracking process at a velocity of 96 rpm. The best yield of produced liquid hydrocarbon, gases, and coke at optimum conditions was 77.56 wt.%, 9.3 wt.%, and 13.14 wt.%, respectively. Actually, this process regards cheap, and simple with a high rate of liquid hydrocarbon production as well as environmentally beneficial.

Radioactivity in the Southern East Baghdad Oilfield from the Reservoir to the Surface Environment

Naturally occurring radioactivity was evaluated in the reservoir rock, surface soil samples, and oil production waste at the East Baghdad South (EBS) Oil Field. The radioactivity of uranium-238 (and radium-226), thorium-232, and potassium-40 were calculated in core samples from four geological formations: Al-Zubair, Al-Khasib, Tanuma, and Hartha Formations, which represent the oil reservoirs in the study area in addition to the natural GR and SGR logs for the oil well in EBS were calculated. The radioactivity of the above-mentioned nuclides was also measured for surface soil samples and waste samples from the site of the oil production industry at the EBS oilfield. The measurements included all the stages of oil production from the collection of crude oil from the wells stage to the storage of the manufactured oil. It also included measurements of radioactivity in samples for some sites outside the industry and near the oil wells in the region. Total radioactivity was measured in count/second and the exposure dose rates were also measured at all the above sites. Relatively high concentrations of uranium-238 and radium-226 were found in rock core samples of some geological units within the oil reservoir formations which will certainly move with the oil to the surface and collect with waste (such as sludge) when oil is produced. Although, some sites have higher Ra-226, Th-232, and K-40, in the sludge samples and oily soil, such as in the 1st separator stage, water separation (Desalter) stage, and near the waste pit, these locations are acceptable if they are compared with other oilfields worldwide. The gamma absorbed doses calculated inside the EBS oil industry were higher than the global average of (59) nGy/h where Ra-226 is the main contributor in these doses, on the other hand, external hazard index (Hex) values less than unity so they are acceptable according to UNSCEAR. Radiation dose values in some places in the study area exceed the values recommended by ICRP, UNSCEAR, and IAEA (1 mSv/y) for the public but less than the values recommended for workers (20 mSv/y). generally, the site of EBS- oilfield does not show radioactive contamination or significant radioactive hazards, as it is a new facility, and safety instructions are still strictly applied, and the removal of waste immediately before its spread by the activity of the workers in the facility.

Well Logs Analysis and Petrophysical Properties of Shiranish Formation in the East Baghdad Oil Field, Central Iraq

The objective of this study is to characterize of the petrophysical properties of Shiransih Formation in East Baghdad oilfield. The analysis involves both of examination of Well Log data obtained from specific wells, namely EB-86, EB-84, EBSK-10-4, EBSK8-2, and EBSK-5-4. The Gamma Ray Log is utilized to quantify volume of shale within the formation, while Porosity Logs, including Density Log, Neutron Log, and Sonic Log, are employed to determine effective porosity and index secondary porosity. Water saturation, movable hydrocarbon, and residual hydrocarbon are calculated using Resistivity logs (LLd, MSFL, and ILD). Additionally, a cross-plot analysis is performed utilizing Density Log and Neutron Log to determine the lithology of the Shiransih Formation.

Well Logs Analysis and Reservoir Evaluation of Hartha Formation in the East Baghdad oil field central Iraq

This study objective of ascertaining various petrophysical properties, which encompass volume shale, porosity, and water saturation. Well logging assumes a pivotal role in the comprehensive evaluation of reservoirs by providing measurements that can be effectively correlated with the volume fraction and composition of hydrocarbons within porous geological formations.In the course of this research, the quantification of shale volume was achieved through the utilization of gamma-ray logs, while the determination of effective porosity was facilitated by employing porosity logs, including the density log, neutron log, and sonic or acoustic log. The Hartha Formation has been stratified into distinct reservoir units based on their petrophysical characteristics. The interpretation of the findings involved the direct examination of well log readings, complemented by the application of well-established relationships and profiles to discern the critical lithological and petrophysical attributes inherent to the Hartha Formation. The selected wells from the East Baghdad oilfield, namely EB-93, EB-97, EB-51, and EB-42.

Studying of Shale Instability Problems with Treatment in Tanuma and Zubair Formations of East Baghdad Oilfield

Shale problems are the most common problems during the drilling process including sloughing shales and swelling clays. To minimize these problems, drilling fluid can be used to solve it. Wellbore stability analysis is critical to minimizing Non Productive Time and drilling costs in the East Baghdad Oilfield. Tanuma and Zubair formations are challenging formations due to shale-fluid chemical interaction. The present study aims to investigate the properties of shale samples and develop drilling muds through laboratory tests. The shale's physical attributes were analyzed using a stereomicroscope and scanning electron microscope to figure out its structures. Cation exchange capacity and capillary suction timer were also conducted to analyze the shale reactivity and select the shale inhibitors. Based on these tests, four drilling muds with unique additives were formulated, and their efficacy was verified using the linear swelling meter and the hot rolling experiments. The results showed a consistent and immediate interaction between the shale and various drilling fluids. A comparison was made between the first and second muds for Tanumah and Zubair formations, it was discovered that water-based muds1 exhibited greater swelling than water-based muds2, where swelling ratios for Tanuma shale units were 6.1% for water-based muds1 and 3% for water-based muds2. In comparison, for Zubair shale units, they were 3.01% and 1.53%, respectively. It is recommended to add 7% KCl to Tanuma mud and 3% KCl to Zubair mud as optimum additives with polypeptide hydration suppressants for inhibiting shale swelling and reducing its risk. This study's findings can contribute to the development of drilling muds that address shale instability concerns and thus minimize drilling expenditures.

Microfacies Analysis and Diagenesis Processes Development for Khasib Formation of East Baghdad Oil field, Iraq

Microfacies Analysis and Diagenesis Processes Development for Khasib Formation of East Baghdad Oil field, Iraq

2D and 3D Modeling of Rock Mechanical Properties of Khasib Formation in East Baghdad Oil Field

Knowing the distribution of the mechanical rock properties and the far field stresses for the field of interest is an important task for many applications concerning reservoir geomechanics, including wellbore instability analysis, hydraulic fracturing, sand production, reservoir compaction, and subsidence. A major challenge with determining the rock's mechanical properties is that they cannot be directly measured at the borehole. Furthermore, the recovered carbonate core samples for performing measurements are limited and they provide discrete data for specific depths. The purpose of this study is to build 2D and 3D geomechanical models of the Khasib reservoir in the East Baghdad oil field/ Central area. TECHLOG.2015.3 software was used to build the 1D-MEM while Petrel E&P 2018.2 software was used to build the 3D distributions of rock mechanical properties. The Khasib formation has nine units (from K1 to K9). The current results support the evidence that the horizontal stresses are somewhat similar for all layers in the vertical case, but their distribution varies horizontally due to the changes in pore pressures. The pore pressure increases vertically, but its distribution within one layer is different due to the production from different wells. Elastic and strength characteristics of rock, including Young modulus, Poisson ratio, and unconfined compressive strength (UCS), have the same behavior, the highest value of the parameters appeared in the surface layer (K1). This layer is more stiff than other layers that have high porosities and high permeability. The internal friction angle for all formations ranges between 38o-40o, which gives a good harmonization with the limestone friction angle. The 3D distribution of the rock's mechanical properties revealed the carbonate heterogeneity because of its marine depositional environment and complex diagenetic processes. The findings of this study can be used for future geomechanical applications in the East Baghdad oil field including wellbore stability analysis, fault reactivation, and CO2 sequestration.

Radiological Effects Assessment in East Baghdad Oil Field, Southern Area

Radiological assessment for the East Baghdad oilfield-southern part was conducted in the current study. 10 samples (scale, soil, sludge, water, and oil) from the different stages of oil production were collected. 232Th, 226Ra, and 40K in the samples were analyzed with 40% efficiency for Gamma spectrometry. system based on HPGe. The findings indicated that the examined sites exhibit comparatively lower levels of NORM contamination, in contrast to other global oilfields. Nevertheless, certain areas, particularly those within separation stages, demonstrate relatively elevated NORM concentrations exceeding the global average in soil and sludge. The maximum value of 226Ra, 232Th, was found in sludge sample the findings indicated that over 70% of the sampled locations exhibited concentrations of Norm that surpassed the worldwide average values. The highest exposure dose rate readings within the study areas reached 0.13 µSv/h, which exceeds the worldwide dose rate of 58 nGy/h as reported by UNSCEAR. Radiation exposure dose and hazard indices were calculated using the concentrations of 232Th,226Ra and 40K within samples. Indeed, the indices encompass various factors, these metrics provide a comprehensive understanding of the radiation exposure and associated risks. The study indicated that the relatively more contaminated stages within the oil production stages are the 1st separation stage, desalter stage and the waste pit stage where the higher concentrations of 226Ra, 232Th and exposure rates are recorded. Generally, the site exposes dose rate within an acceptable rate. Generally, the values of all hazard indices indicate that samples of some locations have values higher than the values recommended by UNSCEAR and ICRP.

Biostratigraphy of the Mauddud Formation from selected Boreholes, central Iraq

The Mauddud Formation was one of the important and widespread Lower Cretaceous period formations in Iraq. It has been studied in three wells (EB. 55, EB. 58, and EB. 59) within the East Baghdad Oil Field, Baghdad, central Iraq. 280 thin sections were studied by microscope to determine fauna, the formation composed of limestone and dolomitized limestone in some parts which tends to be marl in some parts, forty species and genus of benthic foraminifera have been identified beside algae and other fossils, three biozones have been identified in the range which is: Orbitolina qatarica range zone (Late Albian), Orbitolina sefini range zone (Late Albian – Early Cenomanian) and Orbitolina concava range zone (Early Cenomanian), The age of the Mauddud Formation was determined using these three biozones, and it was then suggested that the formation was Late Albian–Early Cenomanian based on careful comparison and correlation with foraminifera species found locally and globally.

Reservoir Characteristics for Khasib Formation in selected wells of East Baghdad Oil field, Iraq

Four subsurface sections and electrical, porosity logs, and gamma-ray logs of the Khasib Formation (age Late Turonian-Lower Coniacian) were studied to identify reservoir characteristics and to evaluate the reservoir properties of the Khasib reservoir units in the East Baghdad oilfield. The lithology of the formation is limestone throughout the whole sequence in all studied wells EB-83, EB-87, EB-92, and EB94. It is bounded conformably from the top by Tanuma Formation and has a conformable lower contact with Kifl Formation. The lower and upper boundaries of the formation were determined using well log analysis, and the formation was divided into three main rock units (Kh1, Kh2, and Kh3), depending on the porosity logs. The porosity was calculated using acoustic or sonic, neutron, and density logs. The effective porosity (average 0.0 - 0.32 %) is the predominant porosity in the formation and to less extent; the secondary porosity. The volume of shale is very low (average 0.0 - 0.13 %), indicating limestone is the main rock of the Khasib Formation. The study of the reservoir water (average 0.11- 1.0%) and hydrocarbon saturations (average 0.0 - 0.88 %) showed that the formation contains varying proportions and quantities of water and hydrocarbons suspended in the wall void, and hydrocarbons capable of being produced. The lithological study reflected that the predominant lithic formation is limestone. It was found that Kh 2 unit is the best oil reservoir unit in all selected wells in terms of porosity, water saturation, diagenesis processes, and microfacies analysis.

Distribution and Evaluation of Lead and Cadmium in Some Soils Surrounding East Baghdad Oil Field

Soil acts as a last sink for elements that people release into the environment through a range of activities due to its physiochemical characteristics. These substances, whether are organic or mineral pollutants, accumulate in the soil and constitute a significant risk to the ecosystem in general because they mess with the chemical and physical equilibrium of the soil, get into the food chain, and eventually get to people. When pollutant concentrations during the bioaccumulated process exceed the global standards for what is regarded as a contaminant in water, air, and soil. Nine soil samples were collected from different sites and two samples from each site at two depths (0-20 and 20-40 cm) to determine if there were any differences in element concentrations at each depth near the East Baghdad oil field in Iraq in February 2022 and analyzed to determine the impacts of industrialization and pollutants related to urbanization. When the grain sizes of the soil samples were analysed, the predominated size fractions were Loam + Clay Loam. The trace elements analysis using atomic absorption spectrometry for the examined soil samples showed levels of Pb and Cd within the global average. The physicochemical characteristic of soil samples was examined. The pH of soil samples from the study area ranged from 7.24 to 7.87, with a mean value of 7.631, indicating that the soil is slightly alkaline.

Evaluation of Vanadium Contamination in Some Soils of the East Baghdad Oil Field

Since oil is the primary source of vanadium in the environment and crude oil has a correspondingly high percentage of vanadium. Vanadium is crucial as a sign of oil contamination. Twenty soil samples were taken from various locations surrounding the East Baghdad oil field in Iraq during February 2022 and then analyzed to determine the effects of industrialization along with urbanization-related pollutants. The soil samples were analyzed using spectrophotometry analysis. In soil samples taken from the research area, vanadium concentrations range from (0.26 to 1.2 ppm). The contamination (CF), geoaccumulation (Igeo) and Enrichment factors (EF) indicated that all the soil samples are uncontaminated.

Sedimentology and geochemistry of Zubair Formation sandstone reservoir, East Baghdad Oilfield, central Iraq

Two wells (EB10 and EB92) within the East Baghdad Oilfields in central Iraq were chosen to study the Zubair Formation sandstones. The Zubair sandstones mostly consist of quartz (84–97.5%), feldspar (0–2.9%), and heavy minerals (0.1–1%) with a few rock fragments. The most common binding materials are silica, carbonate, and ferruginous cements. As a result, matrix makes up less than 10% of the rock. The sandstones are mineralogically and texturally mature quartz arenites. Heavy minerals were classified into four major groups. The opaque, ultrastable (zircon, tourmaline, rutile), metastable (pyroxene, amphibole, garnet, epidote), and mica (muscovite, biotite, chlorite) groups are among these as well. These minerals' features revealed that they are mostly of mature passive continental margin, acidic igneous, and regional metamorphic origin. The Arabian Shield is thought to be the origin of the Zubair sediments, which were deposited under humid or tropical conditions. Zubair Formation sandstones are medium to very fine and well to moderately well sorted sediments. Sedimentary structures and grain-size parameters propose that the Zubair sandstones formed in a mixed fluvial, beach, and shallow marine environment. Sandstone geochemistry has been investigated in order to infer provenance and tectonic settings by subjecting them to whole rock geochemistry (major oxides, trace). The results show that the major oxides of the Zubair sandstones vary only slightly with depth. In comparison to PAAS and UCC values, SiO2 is enriched, while Al2O3, CaO, MgO, Na2O, and K2O are depleted. The geochemical indices of the sediments clearly imply that they were deposited in a humid, non-marine environment.

Diagenetic Features and Porosity Development for Hartha Formation in the Balad and East Baghdad Oil Fields, Central Iraq

The Hartha Formation (age Late Campanian – Early Maastrichtian) is considered an important oil reservoir in Iraq. The petrography and the diagenetic features were determined based on the analyses of 430 thin sections from selected wells within Balad and East Baghdad oil fields, Ba-2, Ba-3, EB-53, Eb-56 and EB-102. The most important and common diagenesis processes that affect Hartha Formation include Cementation, Neomorphsim, Micrtitization, Dolomitization, Compaction, Dissolution, and Authigenic minerals. This diagenesis deformation on Hartha Formation has overall accentuated the reservoir quality heterogeneity. The reservoir quality evolution is affected by destruction by grain compaction mechanical and chemical (stylolitization) causing decreases in porosity and permeability. The porosity is continuous through stylolite and is affected by dissolution precedes between the stylolite walls. The permeability decreased due to cementation. These processes led to seven proximately heterogeneity units in the Hartha Formation, characterized by a decrease in their porosity as barrier units of the Balad Oil Field. While in the East Baghdad oil field the effective porosity units appeared with less thickness of the barrier unit. The reservoir quality enhancement has resulted from dissolution, recrystallization, and partial dolomitization appeared alternately with the barrier unit in the upper part of Hartha Formation of Balad and Baghdad Oil Fields.

Aging Effect on Rock Wettability Alteration

One of the factors controlling fluid distribution in porous media is wettability, which is ranging from water-wet to oil wet. Wettability could be changed due to the long-time contact with hydrocarbon liquids. Wettability alteration resulting from the aging of core samples in hydrocarbon liquids becomes a widely used technique. The aging of Core samples from different locations in different types of liquids had been studied. The aging periods used in these studies range from hours to 110 days. In this work, synthetic core samples were aged for a period ranging from 205 to 824 days into two different hydrocarbon liquids (heavy crude from the East Baghdad oil field and gas oil). Results show that long time aging periods dramatically alter wettability; also, heavy crude oil alters wettability higher than that of light hydrocarbon.