Qamchuqa Formation Research Articles

Cretaceous Limestone Dolomitization and Argument of Its Mg2+ Sources: Exampling the Bekhme and Qamchuqa Formations in the Zagros Collision Belt

This study unveils new considerations regarding the dolomitization of the Bekhme and Qamchuqa formations (BQFs), two reefal Cretaceous units in the Iraqi Zagros collisional belt. Previous studies proposed the dolomitization of these formations due to the ascent of Mg-rich hydrothermal solutions through deep faults but lacked substantial supporting evidence. This paper present new considerations suggesting that the dolomitization of the BQFs resulted from the Cretaceous environmental conditions and basin paleogeographic setting of the platform on which these formations were deposited. To justify this consideration, seven proofs presented. First is the occurrence of dolomite as vast layers extending tens of kilometers laterally and bounded between limestone beds, which resemble a strata-bound occurrence. Second is the absence of vertical selective dolomitization such as, hydrothermal mineralization, vertical dolomite dykes, hydrothermal vents, tubes, or zones. Third is the barrenness of most of the fault surfaces and their surrounding rocks with selective dolomitization. Fourth is the sharp boundary between the dolomite and limestone layers, indicating a sudden environmental change from lagoon to reef or forereef. Fifth is the record of dolomitization in the sediments reworked by bioturbation, evident in thalassinoides burrows. Sixth is the succession of BQFs underlain by limestone and green marl devoid of dolomitization and hydrothermal upward movement. Seventh is the contradictory notion of hydrothermal dolomitization among the most recent study published in the Science journal which atributed dolomitization to normal temperate on earth surface. In the present study, the source of the Mg is argued and its presence is attributed to the warmth of the Arabian platform (plate) near the equator during the Cretaceous period. Another source is the connection of the Arabian platform with the Neo-Tethys Sea, which was the locus of Mg-rich mafic volcanism in the form of arcs and mid-oceanic ridge topography, which supplied a voluminous amount of Mg to the Arabian carbonate platform through ocean currents.

Petrophysical Properties of the Upper Qamchuqa Formation in the Jambur Oil Field

The Qamchaq Formation makes up the upper Cretaceous reservoir of the Jambur oil field and is responsible for most of the hydrocarbon production in this complicated carbonate reservoir. The petrophysical characteristics of the rocks and fluids differ in various sections of the region. The first step in constructing an acceptable geological model is to identify reservoir characteristics, geological features, lithological characteristics, and hydrocarbon zones to accurately forecast future reservoir performance during the development phase. The goal of this paper is to describe the petrophysical properties and composition of the upper Qamachq formation based on an analysis of a set of conventional well log data using Techlog 2018 software to make assessment integration easier by offering a variety of functions for processing data and showing results. According to the study, the lithofacies vary from northwest to southeast. The lithology in the northwest is limestone to dolomite; basinal Balambo facies replace it in the southeast of the structure. More parameter estimates include 9% matrix porosity, 51% water saturation, and a net-to-gross ratio of 20%, indicating beneficial petrophysical characteristics in the northwest of the structure that contribute significantly to production, as opposed to the southwest region, which has poor physical characteristics. The permeability derived from log data was inaccurate since the Wyllie-Rose formula's permeability coefficient was designed for sandstone and would not be acceptable for carbonate rock; furthermore, the Coates formula has underestimated the permeability because the permeability coefficient needs to be improved by matching it to the core information for each well.

Reservoir Characterization of the Upper Part of Qamchuqa Formation from Miran and Bazian Oilfields in Kurdistan Region, NE Iraq

Reservoir characterization of the upper part of Qamchuqa Formation at the wells of Miran West-2 (MW-2) and Bazian-1 (BN-1) is studied. This formation typically has low shale content at the BN-1 well. At the same time, in the MW-2 well, the middle part of the studied formation is dominated by shaly and shale intervals, possibly affected by the Sarmord and Balambo depositional environments. Although the upper part of Qamchuqa Formation is mainly composed of dolomite with minor dolomitic limestone, marl and shale are occasionally present. Furthermore, porosity values are commonly less than 15% in both wells; nevertheless, there are a few intervals where porosity significantly increases. The formation at the BN-1 well has a higher porosity than the MW-2 well. Moreover, the secondary porosity is relatively low as 4.0% at the MW-2 well, while in the well of BN-1, it ranges between < 4.0% and 7.5%. The measured permeability of the formation suggests good permeability. According to the shale volume, porosity, and permeability, the upper part of Qamchuqa Formation is subdivided into three reservoir units. RU 1 at the MW-2 well and RU 2 at the BN-1 well have the most substantial reservoir properties. However, the lowest reservoir quality appears within RU 1 of the BN-1 well and RU 2 at the well of MW-2. Additionally, residual hydrocarbons constitute an extensive fraction of the pore spaces, while tiny portions of the moveable one can be discovered along all reservoir units of the formation. Finally, considering the hydrocarbon movability of the MW-2 well, the upper part of Qamchuqa Formation is defined by primarily movable oils in RU 1 and 2. In contrast, moveable oils are detected in almost all of the reservoir units of the BN-1 well.

Article Review/ The Tectonic Evolution of Erbil Area (Ne Iraq) as a Part of the Northeastern Margin of the Arabian-Nubian Plate Throughout Albian-Early Eocene

The Albian-Early Eocene tectonic evolution of the Zagros Foreland Basin of the High Folded Zone in the Iraqi Kurdistan region has been studied based on the recent foreland basin system concept. This study showed that during the cretaceous (Albian – Cenomanian) there was a geodynamic shift from a passive margin to a foreland basin system phase, not to an active margin phase as mentioned in the previous studies. The advance of the continental margin of the Arabian-Nubian Plate (ANP) toward the subduction zone imposed a tectonic load leading to the form of a flexural wave. The consequences of the last tectonic event were reflected by the continuous deposition of the Balambo Formation. in a foredeep depozone. This happened concomitantly with a flexural emergence of the continental shelf further to the west forming a forebulge depozone represented by the deposition of reefal facies of the Qamchuqa Formation. These geodynamic changes are considered here to represent the Megasequence boundary between the Tectonic Megasequence (TMS) of AP8 and AP9. The last sequence of the passive margin was the Qamchuqa Formation Which is called the Pre-Orogenic Carbonate Platform and was separated from the Bekhme Formation by regional unconformity (Megasequence boundary). The latter is represented by the Lower Sequence of the foreland basin system, which is called the Syn-Orogenic Carbonate Platform (SCP). During the Middle Campanian, the Zagros foreland basin started with the underfilled stage, and it was entirely clear by the end of the Cretaceous comprising a broad threefold subdivision of depositional realms that translated into three stratigraphic units known as trinity underfilled units of foreland basin system. The lower carbonate unit, the pelagic and hemipelagic unit, and the upper flysch clastic unit are represented by Bekhme, Shiranish, and Tanjero Formations respectively. All of these units were superimposed during basin depocenter migration and became younger toward the southwest in front of progressing the orogenic wedge toward the Arabian Craton. During the late Maastrichtian to Paleocene – Early Eocene, the Zagros foreland basin underwent a transition from underfill to fill the stage. Deep exhumation of the orogenic wedge and ophiolite assemblage had supplied the clastic sediment of the Kolosh Formation into the basin covering the foredeep and most of the forebulge and backbulge depozones.

Microfacies and Depositional Model of the Shuaiba Formation (Lower Cretaceous), in Selected Wells, Southern Iraq

The Shuaiba Formation (Aptian age) is an important formation due to its wide extent in Iraq and Arabian Gulf. In northern Iraq, it is called Qamchuqa Formation and has an important role in contracting the Arabian plate. The study focused on several wells, which are: ZB-290, WQ1-353, RU-358, R-624, and R-5 from several selected fields, such as Zubair, Rumaila, and West Qurna in southern Iraq. The purpose of the study is to determine the sedimentary and paleontological components of the Shuaiba Formation. The lithology of the Shuaiba Formation consists of very fine crystalline massive limestone that gradually converts to chalky limestone with a large percentage of dolomites, especially in the middle part of the formation. The thickness of the studied formation is about 50 – 110 meters and its main microfacies are two types, which are carbonate and dolomite. The carbonate is subdivided into five secondary types, which are burrowed bioclastic lime mudstone, planktonic foraminiferal lime mudstone, larger foraminifera wackestone, algal wackestone and mixed planktonic, and benthonic Foraminifera wackestone, in addition, to dolostone microfacies. The effect of the diagenesis in the formation is distinguished and most of these processes are destructive, such as dissolution and stylolite. The first depositional stage of the investigated area began with sea level rise following the deposition of the Zubair Formation from still stand. Shuaiba Formation deposited within the ramp setting as the water level rose. During the late Aptian, tectonic and sea levels were the active factors that controlled the deposition of the formation. According to data collected from microfacies and diagenesis processes, the Shuaiba Formation has several depositional environments, which are from the shallowest: restricted, open marine (inner ramp), mid ramp, and finally outer ramp. Generally, toward the upper sequence, the formation reflects deep deposits and then starts to be less deep until it is a shallow basin (Nahr Umr).

Evaluation of Cretaceous-Tertiary Limestone for Building and Dimension Stones in Erbil, Kurdistan Region of Iraq

In Kurdistan NE of Iraq extensive beddings of well bedded carbonate rocks deposited within Tertiary- Cretaceous age. For this purpose various studies of petrographic, physical, mechanical, and chemical properties for building construction were carried out. Appearance of rocks was measured in the field by thickness of the beddings, joints, fractures, and brightness. The petrographic study achived under transmitted light microscope for diagenesis, weathering, allochems, and matrix. Measuring specific gravity, density, water absorption, moisture content, porosity, and saturation coefficient to qualify the rock according to its physical properties, whereas measuring compressive strength of the rocks were determined for qualifying the mechanical properties, the XRF test for determining the oxides and durability tests for qualifying their chemical properties. Eleven samples selected from Qamchuqa Formation in Binabawi anticline, Aqra-Bekhme Formation in Shakrok anticline, Shiranish Formation in Pirat anticline, Shiranish Formation in Harir anticline, Shiranish Formation in Safin anticline, Shiranish Formation in Shakrok anticline, Pila Spi Formation in Pirmam anticline, Khurmala Formation in Bina Bawi anticline, Fatha Formation in Kori syncline, Anah Formation in South Qara Chugh anticline, and Euphrates Formation in North Qara Chugh anticline. The results in terms of economic demand for building and dimension stones showed that samples of Shiranish Formation from Pirat, Safin, Harir, and Shakrok anticline are highly recommended as dimension stone and building stone, while samples of Qamchuqa, Aqra-Bekhme, Pilaspi, Khurmala, and Euphrates Formations are accepted but not recommended as dimension stone and dimension stone, samples of Fatha and Anah Formations are not accepted as dimension stone, but accepted as building stones as an insulator.

Stratigraphic Sequence and Diagenetic Effects of the Upper Qamchuqa Formation in Khabaz and Kirkuk Oil Fields, Northern Iraq

The Upper Qamchuqa Formation was deposited in Zagros foreland basin in the north of Iraq during the Late Albian age. Two boreholes from Kirkuk oil field (K-229) and Khabaz oil field (Kz-4) are selected in the current study, where 100 samples of cores and cutting were used to determine diagenetic evolution of the Upper Qamchuqa Formation. Five major sub-environments can be diagnosed within the Upper Qamchuqa sequence, they are: shallow-open marine environment, semi-restricted marine environment, restricted marine environment, shoal and deep outer ramp environment. The diagenesis process are contain the physical or chemical variations in sedimentary rocks and sediments that happen after the deposition, where many diagenetic process effect on the Upper Qamchuqa Formation which are: Micritization, Cementation with three types (blocky, drusy,and syntaxial calcite overgrowth cement ), Dolomitization with three types too (scattered, Pervasive coarsely ,and saddle dolomite), neomorphism, recrystallization, silicification, dissolution and compaction (mechanical and chemical). There are four sedimentary cycles: cycle A extends from the upper part of the underlying Upper Sarmord Formation (TST) to the shallow open marine facies (HST) of the lower part of Lower Qamchuqa in k-229 which ended with shoal facies, cycle B on the other hand, shows a grain dominated facies where the carbonates buildup kept pace with the still relative sea level (keep up) during high stand which deposited under semi-restricted and restricted successively, cycle C shows a marked variation in thickness within the sections (K-229 and Kz-4); it is greatest thickness was noticed at k-229 where its lower part is mostly mud dominated in Kz-4, and cycle D shows a distinct variation in facies change from grain-rich to mud-poor lithology of restricted to semi-restricted facies in the East (k-229) to predominantly restricted marine conditions at the central area (Kz-4).

Cementation Exponent Estimates and their Impact on Oil Initially in Place Calculations : A Case Study from Lower Qamchuqa Formation in the Bai Hassan Oilfield, Northern Iraq

The effect of Cementation Exponent has been investigated on the calculated water and hydrocarbon saturations and the estimated oil initially in place. The Aptian Lower Qamchuqa (Shua'iba) Formation from the well BH-96, Bai Hassan Oilfield, is used as a case study. Four different values of Cementation Exponent were applied in calculating water saturation using the Archie equation. The static value of 2 commonly used for carbonate reservoirs was one of the cases used to calculate an average of 68% water saturation. In the second case, the value of 1.81 is used for m based on the average m values obtained through testing 22 core samples in the laboratory. The average of 60.5% Sw was calculated for the studied part of the Lower Qamchuqa Formation in this case. The Pickett plot method was used as a third case, and 1.65 was estimated as the m value through which the average of 54% Sw was calculated. In the fourth case, variable values of m were used for the different depth intervals from which core samples were tested in the laboratory. In this case, the calculated average water saturation was equal to 60%. The upper part of the studied section was generally of low porosity and high water saturation, whereas the middle and the lower parts contained hydrocarbons with different saturations. Using shale content, porosity, permeability, and water saturation cutoffs for the four different cases, the net to gross pay ratios were calculated. The ratios ranged between 56.5% in the case of using the 1.65 value of m and 47.6% in the case of using variable core tested m values, and accordingly, the difference of about 4 m in net thickness is expected to be underestimated or overestimated, respectively, when is calculated.

Biostratigraphy and Chronostratigraphy of Late Jurassic – Early Cretaceous in Selected Areas in Kurdistan Region, Northern Iraq

The biostratigraphy and chronostratigraphy of Late Jurassic–Early Cretaceous (Tithonian–Aptian) successions at three outcrops in the Kurdistan Region, northern and northeastern Iraq (Amadia, Gara, and Barsarin sections) are studied depending on ammonite, planktic, and benthic foraminiferal contents. The studied formations: Chia Gara, Sarmord, and Qamchuqa, are recorded in all studied localities, while Garagu and Balambo formations are exposed at some studied localities. Age determination of the Chia Gara Formation relied on the ammonite fauna. The ammonites investigated are the major assemblage fauna of the Durangites Zone, which corresponds to the Late Tithonian. The detailed planktic foraminiferal investigation in Balambo Formation permits the recognition of five well-defined zones, these are Favusella hoterivica Interval Zone, Hedbergella sigali Interval Zone, Globigerinelloides ferreolensis Interval Zone, Globigerinelloides blowi Interval Zone, and Globigerinelloides algeriana Taxon Range Zone (part), which reveal a Late Valanginian to Late Aptian age. The stratigraphic distribution of the benthic foraminifera shows three zones, these are Everticyclammina kelleri Assemblage Zone, Pseudocyclammina lituus Assemblage Zone, and Palorbitolina lenticularis Taxon Range Zone, the 1st and 2nd zones were recognized in the Sarmord Formation at Amadia section, which extends in age from late Valanginian to Hauterivian. While the 3rd zone is recorded from Qamchuqa Formation at the Gara section representing the Early Aptian age.

Sedimentological evidences for subaerial exposure in the upper surface of Qamchuqa Formation, Bekhme area, northern Iraq

The study deals with the upper contact of Qamchuqa Formation with the overlying Bekhme area of northern Iraq. This surface is characterized by presence of autobreccia bed including angular grains of (0.05_30cm in size) and composed of dolomite with disseminated black dolomite fragments which may indicates their subaerial exposure.
 Cementing materials filled the fractures and pores surrounding the breccias mostly are composed of saddle dolomite with dolomite crystal up to 3cm size that were formed late diageneticly by hydrothermal solution.

Lateral growth of Safeen anticline as deduced from drainage analysis, Iraqi Kurdistan region

Safeen anticline is one of the largest anticlines in the Iraqi Kurdistan Region (IKR), with NW – SE trend. The anticline shows clear lateral growth as deduced from different anomalous drainage patterns and forms, besides different geomorphological forms, which are indicative of lateral growth. Among those forms are water gaps, wind gaps, abandoned alluvial fans, and different shapes of valleys. Two hanging synclines exist on both sides of the anticline forming unique geomorphological and structural forms in IKR. The anticline is developed in the High Folded Zone (HFZ) of Iraq. It is part of the Zagros Fold–Thrust Belt (ZFTB), with the exposed rocks of the Qamchuqa Formation (Early Cretaceous), which consists mainly of limestone and dolostone, which are the oldest rocks in the core of the anticline. Two main streams named Shaqlawa and Kori dissect the anticline from the northern and southern sides. We have explained their trends and abnormal courses. We have used geological maps and high-resolution satellite images to interpret geomorphological forms and to confirm the lateral growth of the anticline. A field investigation was carried out to check and confirm the interpreted data; accordingly, we identified the anticline's lateral growth based on the interpreted geomorphological and structural forms.

The Impact of Hydrothermal Fluids on Porosity Enhancement and Hydrocarbon Migration in Qamchuqa Formation, Lower Cretaceous, Kirkuk Oil Company

The Lower Cretaceous reservoir core samples from the upper part of Qamchuqa Formation, Baba Dome, Kirkuk Oil Company, show evidence for multistage episodes of dolomitization and a complex diagenetic history. Optical microscope reveals muti-phase of diagenesis: an early stage of diagenesis and its alteration, later, by evaporated seawater under near-surface setting conditions, followed by different event of dolomitization. The stylolite microstructures postdate anhydrite and early matrix dolomite crystals (DI) and predated the coarse rhombohedral (DII) and saddle dolomite crystals (SD), which were formed under a deep burial realm. High-resolution data from stable isotopes integrated with intensive optical observation, ImageJ software, and litho-log are utilized to establish a qualified methods for mapping a better image of hydrothermal diagenesis under subsurface conditions. These methods revealed different types of dolomites, mostly focused on fractures and void spaces, and the paragenetic sequence shows the complex history of diagenetic carbonate rocks hosted in the limestone of Qamchuqa Formation. The sequence is started from older to younger as follow: Micritization, early anhydrite mineral formation, early dolomite, stylolization, rhombohedral dolomite, and saddle dolomite crystals. The early dolomite phase is usually corroded by hydrocarbon phase, and, geometrically, the hydrocarbon phase is overgrown by the early dolomite. Therefore, the dolomitizing fluids enhanced the porosity system and had positive impact on the hydrocarbon movement. This phase of dolomite and anhydrite formation were associated with the first groups of δ18OVPDB and δ13CVPDB data, a narrow range of oxygen values, and inverse Js of Lohmann curve fits towards the near-surface and shallow diagenetic settings. Detailed optical microscope and supportive data from oxygen-carbon isotopes of saddle dolomite confirm the presence of hot fluids under subsurface condition. The latter data were supported by light δ18OVPDB and constant heavy δ13CVPDB, which indicates a hot fluid possibly circulated in deep burial conditions, and this is channeled along the fracture and pore spaces, consistent with hydrocarbon migration. These pore spaces influenced by leaching were hydrocarbon migrations associated with hot fluids under deep sitting conditions. However, a remarkable part of pristine microfacies of host limestone was preserved. In summary, this study will add a new understanding and insight into the origin, genesis, and timing of these dolomites and their direct connection to hydrocarbon exploration and development in most reservoir oil rocks, which are exposed to hydrothermal fluids. Additionally, the study adds new data on hydrothermal fluids in subsurface conditions, whereas most of the previous reported work has mostly focused on exposed rock.

Adopted Factorial and New In-Situ Micro-Designs for Stimulation of Matrix Acidizing of Carbonate Reservoir Rocks

Matrix acidizing has been developed in the petroleum industry for improving petroleum well productivity and minimizing near-wellbore damage. Mud acid (HF: HCl) has gained attractiveness in improving the porosity and permeability of reservoir formation. However, there are several challenges facing the use of mud acid, comprising its corrosive nature, high pH value, formation of precipitates, high reaction rate and quick consumption. Therefore, different acids have been developed to solve these problems, including organic-HF or HCl acids. Some of these acid combinations proved their effectiveness in being alternatives to mud acid in reservoir rock acidizing. The current research deals with a new acid combination based on Hydrochloric–Oxalic acids for acidizing carbonate core samples recovered from Qamchuqa Formation in Kirkuk oilfield, northern Iraq. A new in-situ micro-model adopted laboratory technique is utilized to study the microscale alteration and evolution of pore spaces, dissolved grains and identification of matrix acidizing characteristics. The in-situ micro-model is based on the injection of an identical dose of different concentrations of the new acid combination into thin section samples under an optical light microscope. The adopted procedure aims to provide unique and rapid information regarding the potential for texture and porosity modification that can be caused by the acidizing stimulation procedure. In connection, solubility tests for the untreated and treated reservoir core samples and the density of the combined acids after treatment are conducted based on designed experiments using response surface methodology (RSM). The effect of acid concentration [12% HCl: Oxalic acid (3.8–8.8%)] and acidizing temperature (from ambient to 78.8 °C) on the solubility percentage of the samples and percentage increase in the combined acid density after acidizing were optimized and modeled. The obtained results confirm that the optimum dissolution of the core samples took place using 12% HCl:3.2% Oxalic acid with an optimum solubility (%) of the carbonate core rock of 53.78% at 21.7 °C, while the optimum increase in density (%) of the combined acids was 1.54% at 78.3 °C. The promising results could be employed for matrix acidizing of carbonate reservoir rocks for other oilfields.

Evaluation of Limestone from Cretaceous to Tertiary age in Kurdistan Region of Iraq for Heavy Duty Road Pavement

Aggregates have an important role in the development and quality of Hot Mix Asphalt pavement, Engineers prefer using different types of acidic aggregates as a dominant road pavement mixture. This study is focused on using a basic aggregate, for this purpose limestone is used as a replacement to sandstone and gravel in the Hot Mix Asphalt for base and binder course, due to its rough, tough, durable and stable properties, that adheres well with the binder due to its hydrophobic properties. A petrographic study and chemical analysis by XRF method was carried out for better determining the mineralogical and chemical contents. Los Angeles Abrasion test carried out for measuring abrasion of the limestone aggregates in Kurdistan Region Iraq from Cretaceous-Tertiary age in different sources of the Shiranish Formation in Pirat, Harir, and Safin, Aqra-Bekhme in Shakrok, the Pila Spi Formation in Pirmam, Khurmala Formation in Safin, the Euphrates Formation in North Qarachugh, and the Qamchuqa Formation in Bana Bawi, while the only last four formations selected for Marshal test depending on wear <45% according to Iraqi SORB, 2003 standards. The soundness test results showed that the selected four samples are within the required specifications. The aggregate-asphalt mixture molds were prepared with the optimum binder content of 4.7%, for the Marshall stability test, which revealed that all the selected four samples are suitable as a heavy-duty pavestone for the base and binder course, with BQ and Pm showed optimum stability results.

Magnitudes and orientations of present-day in-situ stresses in the Kurdistan region of Iraq: Insights into combined strike-slip and reverse faulting stress regimes

The study area is in the Kurdistan Region of Iraq, including the northwestern extension of the Zagros suture zone, where present-day stress data derived from actual measurements is rare. The magnitudes and orientations of principal in-situ stresses were determined using well logging data. The deepest drilled formation in this study was the Albian upper Qamchuqa Formation in northeastern Iraq, which is a carbonate hydrocarbon reservoir. In the present study, several wireline logs including borehole image logs, conventional wireline logs, and six-arm caliper logs for two vertical wells provided detailed borehole breakout and drilling-induced tensile fracture (DITF) data between depths of 1600 and 2240 m. Two oil wells (wells A and B) were evaluated, and in well A, several breakouts occurred in eight distinct zones. Below the depth of 1600 m, 26 pairs of breakouts with considerable length were observed. The standard deviation of breakout azimuths was 11°, and the mean azimuth of the breakouts was N162°E. Using breakout and DITF data, the orientations of the maximum and minimum horizontal stresses (SH and Sh) were determined, and the results were validated by six-arm caliper measurements and lithological evaluation from wireline log data. The mean azimuth of maximum horizontal in-situ stress was N72°E, which showed relative consistency with the NE–SW to E–W direction of tectonic movement and previous studies in the nearby Zagros suture zone. Ultimately, the magnitudes of the three principal in-situ stresses were determined by two methods: poroelastic strain theory and breakout analysis. The stress regime below the depth of 1600 m was a reverse faulting stress regime, and above this depth, it likely changed to a strike-slip faulting stress regime. The determined stress regime was consistent with the nature and dynamics of the tectonic plate movement of the Arabian and Eurasian (Iranian) plates. Consequently, results suggest that the pattern of present-day tectonic stress is controlled mainly by the collision between the Arabian and Eurasian plates.

Geodiversity of Smaquli area as a potential geopark in Kurdistan region, Iraq

This research aims to spotlight abiotic elements of geodiversity in the Smaquli area and value and use as geoconservation through potential geopark. Smaquli area, situated in the southeastern part of Safen anticline, north of Iraq Kurdistan region, has a rich and diverse geological and geomorphological heritage, making it an interesting area for this study. This study aims to present the geodiversity of the Smaqule site as an opportunity to carry out future sustainable socio-economic activities in the geopark. The study includes fieldwork on the area's stratigraphy, structural geology, and geomorphology. Tectonically, the study area lay within the High Folded Zone of the Unstable Shelf of Iraq and was affected by the collision of Arabia-Eurasia Plates which started before 23–25 Ma in northern Zagros. The exposed rock unit formations in the Smaqule area range in age from Cretaceous to Paleogene. The oldest outcrop rock unit is the Qamchuqa Formation. Stratigraphy of the study area includes Qamchuqa, Bekhme, Shiranish, Tanjero, Kolosh, Gercus, and Pila Spi Formations. The study area is a mountainous area with different heights ranging from valleys to high ridges; this is due to structural controlling topography and differential erosion of the structures in the area and their different lithology of the rocks. Many geomorphological landforms are studied in the area, such as ridges, longitudinal and transverse valleys, Sulfur springs, caves, faults, drainage patterns, Badland, and an elongate lake. These features are very attractive landscapes for tourism and balneotherapy. This study highlights the area's geological significance to add to its known cultural value, local products, and tangible and intangible heritage. The study area is suitable for investment by the national and international tourism, creating employment opportunities for local people, and leading to socio-economic development. The Geosites Assessment Model (GAM) has been applied in this study to quantify the geotourism potential in the four geosites within the study area.

Reservoir Characterization of Lower Qamchuqa (Shu'aiba) Formation from the Well BH-86, Bai- Hassan Oil field, Northern Iraq

The reservoir characterization of Lower Qamchuqa (Shu'aiba) Formation (Aptian) is studied at the well BH-86 of Bai- Hassan Oilfield in Kirkuk area, Northern Iraq. The lithological study (of 91 thin sections) revealed that the formation consists of shaly limestone, a thin bed of marl within the limestone, and dolomitic limestone. Four petrographic microfacies were noticed Lime mudstone microfacies, Dolomudstone microfacies, Lime wackestone microfacies, subdivided into benthonic foraminifera lime wackestone submicrofacies and bioclasts lime wackestone submicrofacies, and the last microfacies is the Lime packstone microfacies, which is subdivided into pelloidal lime packstone submicrofacies and Orbitolina lime packstone microfacies. Shale content is calculated from the gamma-ry log, showing that the formation is mainly of low shale content (less than 35%). The porosity determined from sonic, density, and neutron logs reflect that the range between <1 and 15% and in some intervals about 6% is secondary porosity type. The estimated permeability ranges between <0.01 and 2.0mD, reflecting low permeability. The formation is subdivided into six reservoir units according to the shale content, average porosity, and permeability. The unit RU-5 has the best reservoir properties among the identified units with an average shale content of about 3.15%, about 6.2% porosity, and about 1.75mD average permeability. On the other hand, the least reservoir property is noticed in the unit RU-1 with average 9.48% shale content, 3.64% porosity, and 0.5mD average permeability. The research indicates that the fractures contribute to the flow within the Lower Qamchuqa Formation. Fluids flow through the formation in four unique Hydraulic Flow Units (HFU). Only about 8% of the gross 146m of the formation is expected to have the required reservoir properties for oil production and about 68% for gas production. The actual productive thickness for oil is only about 2.8% of the gross thickness of the studied section, and it’s more than 50% of the gross thickness for gas.

Unconformity and Paleokarst in the Lower Part of the Qamchuqa Formation; An Example from the Arabian Carbonate Platform in the Zagros Belt NE Iraq

Northeastern Arabian Plate Margin is now part of the Zagros Collisional belt and extends nearly parallel to the Iraq-Iran border. The margin comprised, during the Early Cretaceous, of the Arabian Carbonate Platform which is poorly explored. This margin consists of thick carbonate succession and separates the Neo-Tethys Ocean (present Sanandaj-Sirjan Zone) from the Arabian Plate interior. The carbonate succession, as the Qamchuqa and Balambo formations, consists of more than 600 m of dolomite and reefal limestone. The present study focused on records and discussions of evidence of unconformity and paleokarst (UaPK) inside the Arabian platform in northeast Iraq. The study recorded this evidence inside the lower part of the Qamchuqa Formation and the pieces of evidence include limestone conglomerate, plaeo-solution cavities, erosional surfaces, widespread coarse and fine grain detrital limestones, hardground, extensive burrows of Thalassiniodes, and mineralization. The solution cavities shaped a complex network, developed inside fine-grain limestone and filled with yellow to brown ooid and detrital limestones. Most of these features are observable over more than 500 km2 in the Sulaymaniyah and traceable inside gorges and valley sides. Toward the north and northeast of the studied area, the unconformity changes to correlative conformity in the Neo-Tethys basin of the studied area where the sediments consist of laminated and graded detrital limestone (packstone-wackstone) and are deposited as a thick succession of calciturbidite that stratigraphically designated as the Balambo Formation. The result of the present study debates the previously claimed unconformities and uncovers many processes and features of the Northeastern Arabian Carbonate Platform Margin. Additionally, it reveals tectonic and paleogeographic settings of the Arabian Plate Margin that have application in searches for oil and better reconsideration of the geologic setting of the Zagros Belt in the future.

Industrial Assessment of Limestone beds of the Qamchuqa Formation for Cement Industry, Kurdistan Region, North Iraq

The Qamchuqa Formation is widely exposed in Kurdistan Region (IKR); north of Iraq. The formation along with the Bekhme Formation form the bulk of the main mountains (anticlines) in the IKR. Among those anticlines is the Ranya anticline, which has a NW – SE trend, where the Qamchuqa Formations has a thickness of about 700 m. The main lithological facies of the formation are limestone, dolomitic limestone and dolomite. We have sampled the uppermost 89 meters of the northeastern limb, by collecting 10 samples of different sampling intervals that range from (3 – 12) m. The ten rock samples were tested by an XRF to measure the concentration of the oxides at each sample. The XRF results showed that the 10 rock samples are limestone with different percentages of oxides. The weighted averages of the oxides in the collected samples have been calculated, and the results showed that the limestone beds along the studied section in the upper part of the Qamchuqa Formations are suitable for the cement industry. The average concentration of CaO and MgO is 55.13 % and 0.26 %, respectively.

Suitability of the Carbonate Rocks of the Bekhme Formation for Cement Industry, Hareer Mountain, North Iraq, Kurdistan Region

The main lithological composition of different formations in the Iraqi Kurdistan Region is the carbonate rocks; some of those rocks are suitable for cement production; such as Qamchuqa Bekhme, Sinjar, Pila Spi and Anah formations. However, the six existing cement plants in are using limestone beds, five of those plants are using limestone from the Sinjar Formation, and one plant is using limestone from the Anah Formation. Recently, performed research works confirmed that the limestone beds within the Qamchuqa, Bekhme and Pila Spi formations are very suitable for cement production. The current research work deals with studying the exposed limestone beds within the Bekhme Formation at Hareer Mountain in the central part of IKR to check their suitability for the cement industry. Accordingly, we collected 12 rock samples from a section within the Bekhme Formation at an almost constant sampling interval (5 m); however, for two samples the sampling interval was 6 and 8 m (sample No. 2 and 12, respectively). Each sample represents a channel sample for the concerned sampling interval to be representative for the thickness of the sampled interval. The total thickness of the sampled section is 64 m with a covered interval of 30 m, totaling up to 94 m. The collected 12 samples were prepared at the laboratory of the University of Kurdistan Hewler and were subjected to XRF test at Mass Cement Plant (Sulaimaniyah) to check the concentration of certain oxides that are used in the Iraqi Standard for cement production. The acquired concentrations of the main oxides (CaO, MgO, Al2O3, Fe2O3, Na2O, K2O, SO3), and Cl and L.O.I. at each sample were changed to weighted averages and the results were compared with the Iraqi standards for cement industry. The result was the sampled rocks are excellent for cement production.