Geothermal gradients in Iraqi Kurdistan deduced from bottom hole temperatures

Abdula, Rzger A.

doi:10.1016/j.ejpe.2016.08.007

Cited by 14 publications

(9 citation statements)

References 3 publications

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“…Second, variations in the present-day geothermal gradient and heat flow have been described in the study area (e.g. Abdula 2016;Hakimi et al 2017), but the approach described is an acceptable simplification in view of the multiple sources of data and variations in data quality.…”

Section: Erosionmentioning

confidence: 99%

Quantifying vertical movements in fold and thrust belts: subsidence, uplift and erosion in Kurdistan, northern Iraq

Tozer¹,

Hertle²,

Petersen³

et al. 2019

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Traditional structural analysis in fold and thrust belts has focused on quantifying horizontal movements. In this paper, the importance of quantifying vertical movements is illustrated using a case study from Kurdistan, northern Iraq. The subsidence history of this area can be determined by analysis of the stratigraphic record from deep exploration wells. A phase of thermal subsidence from Middle Permian to Late Cretaceous (tectonic subsidence 1.8-1.9 km) was followed by flexural subsidence in the Late Cretaceous and Cenozoic (tectonic subsidence >0.6 km) in response to the closure of the Neo-Tethys Ocean. The main phase of continental collision during the Neogene resulted in the development of the Zagros fold and thrust belt; the amount of uplift at individual anticlines can be estimated from their amplitude (up to 3 km), but regional cross-sections indicate that approximately 1 km of additional basement-involved uplift is present NE of the Mountain Front. The timing of basement-involved uplift is interpreted to be coeval with the deposition of a Pliocene-Quaternary growth sequence adjacent to the Mountain Front. The amount of erosion resulting from the uplift can be estimated from vitrinite reflectance and cross-sections; these estimates show a similar pattern, with maximum erosion in the mountains NE of the Mountain Front (>1.5 km) and lesser erosion in the adjacent foreland basin (generally <0.8 km). The results provide a quantitative understanding of subsidence, uplift and erosion, and have been used to define prospective and high-risk areas for petroleum exploration.

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Section: Erosionmentioning

confidence: 99%

Quantifying vertical movements in fold and thrust belts: subsidence, uplift and erosion in Kurdistan, northern Iraq

Tozer¹,

Hertle²,

Petersen³

et al. 2019

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“…Based on palaeontological studies, it has been assigned to the Oxfordian–Kimmeridgian (Abdula, 2016; Alsharhan & Nairn, 2003). The age‐equivalent units to Najmah are the Naokelekan Formation in the Kurdistan region of Iraq and Hanifa/Jubaila formations in Saudi Arabia (Figure 1b; Abdula, 2015; Abdula et al, 2015; Abdula, 2017; Jassim & Buday, 2006). The Gotnia Formation is 30 m thick in eastern areas of the study area and consists of dolomitic breccia.…”

Section: Geological Backgroundmentioning

confidence: 99%

“…Due to their economic interest, these carbonate platforms and intrashelf basin successions have been studied from palaeogeographic and sequence stratigraphy points of view (Al‐Mojel et al, 2018; Hughes, 2004; Sadooni, 1997; Sharland et al, 2001; Ziegler, 2001). However, some intrashelf basins, such as the Sargelu or Gotnia Basin (present Kurdistan Region of northern Iraq) and Hawraman Basin (Hawraman region in NW Iran; Figure 1a), have received less attention, and most studies, specifically in Kurdistan, have been limited to facies analysis and source rock studies (e.g., Kirkuk and Hamrin oilfields; Abdula, 2015, 2017; Abdula, Balaky, Nurmohamadi, & Piroui, 2015; Abdula et al, 2020; Balaky, 2004; Hakimi, Najaf, Abdula, & Mohialdeen, 2018; Jassim & Buday, 2006; Salae, 2001). Predominant carbonates and shales were deposited during the Middle and Late Jurassic in these intrashelf basins (i.e., Sargelu, Najmah, and Gotnia formations in Hawraman Basin in NW Iran; Sargelu, Naokelekan, and Barsarin formations in Sargelu [Gotnia] Basin in the Kurdistan region of Iraq; Figure 1b).…”

Section: Introductionmentioning

confidence: 99%

Palaeogeographic reconstruction and sequence architecture of the middle‐upper Jurassic successions of Hawraman Basin (NW Iran): Implications for tectono‐depositional processes of the northeastern passive margin of the Arabian Plate

2022

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The middle‐upper Jurassic successions (Sargelu, Najmah, and Gotnia formations) of the NW sector of the Zagros Mountain belt are studied to generate a sequence stratigraphic model that helps to understand the Jurassic tectono‐depositional processes and palaeogeographic reconstructions of the northeastern passive margin of the Arabian Plate. The major geological structures observed in northwestern Iran indicate the predominance of an extensional deformation during the Toarcian to Aalenian owing to the eastern Mediterranean rifting. This extensional regime reached its maximum from the Early to Middle Jurassic, causing the fragmentation/drowning of the long‐lived Triassic to Early Jurassic carbonate platform and the development of the Hawraman intrashelf basin (HIB). Associated changes in marine current dynamics, trophic conditions, and degree of substrate oxygenation led to the bloom of oligotypical biota (Bositra limestones) creating unfavourable conditions for the development of other benthic communities (Sargelu Formation). Later, from the Callovian to Oxfordian, changes in carbonate production types (switch from the Bositra filament facies to the stromatolitic‐thrombolitic boundstones) remarkably decreased the dip angle of the depositional profile (Najmah Formation). A second‐order tectono‐eustatic cycle (a major long‐term transgressive/regressive [T/R] cycle) including six minor short‐term T/R facies cycles (TR1–TR6) is identified in the study area. The development of the T/R facies cycles during the Middle Jurassic (TR1–TR3; give‐up sequences; Sargelu Formation) as a result of combined global eustatic transgression and linear subsidence resulted in drowning and backstepping of the platform. In contrast, the short‐term cycles that developed in the upper Jurassic (TR4–TR6; keep‐up sequences; Najmah and Gotnia formations), following a sea‐level fall, resulted in progressive shallowing of the carbonate platform. This study suggests that extensional deformation of the area reached its peak in the transition of the Early to Middle Jurassic, leading to the creation of HIB, but either decreased or played a subordinate role to eustatic sea‐level variations during the deposition of the TR1–TR3 facies cycles (Bajocian‐Callovian). Changes in tectonic regime from an extensional deformation (Early Jurassic) to cooling subsidence (Middle Jurassic), accompanied by a long‐term transgressive sea‐level trend during the Middle Jurassic, were important factors in the development of anoxic trough environments with the deposition of organic‐rich intervals, represented by the TR1–TR3 facies cycles. Tectonic instability (tectonic uplift plus considerable differential subsidence due to the reactivation of faults) in the eastern margin of the Arabian platform during the Late Jurassic led to the development of the TR4–TR6 facies cycles.

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“…These differences can also refer to variation of the overburden rocks, groundwater flow, and conductivity of the rock units. For instance, the study of Abdula [36] on the geothermal gradient in selected wells in the Iraqi Kurdistan, has displayed the different geothermal gradients values. The Geothermal gradient for the studied area is around 17.83 -19.74 C/km [36], which is relatively low compared to that of the Low Folded Zone.…”

Section: Basin Modellingmentioning

confidence: 99%

Source Rock Evaluation and 1-D Basin Modelling Approach for the Sargelu Formation, Atrush-2 Well, Kurdistan Region-Iraq

Akram¹,

Edilbi²,

Mamaseni³

et al. 2021

OJG

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The present study focuses on source rock evaluation of the Sargelu Formation by using core chips of rocks collected from well Atrush-2, Duhok, Kurdistan Region-Iraq. The Rock-Eval pyrolysis and vitrinite reflectance were executed. Subsequently, the selected parameters were used for source rock evaluation and 1-D Basin Modelling calibration. The upper part of the formation mainly comprises argillaceous limestone with low content of organic matter (0.64%-1% TOC). By contrast, the lower part is dominated with shale interval and contains high amounts of TOC values (>4% for 1272-1278 m) reveling good to very good quality source rock. Accordingly, good to very good hydrocarbon generation potential is suggested for this formation. Organic matter of the Sargelu Formation contains type II and mixed-type II-III kerogen. The values of Tmax and vitrinite reflectance (Ro%) demonstrate that the formation is thermally mature and in the oil zone. In order to construct a thermal history of the formation and determine the timing of hydrocarbon maturation and generation, the 1-D basin modelling PetroMod 2019.1 was used in this study. Based on the 1-D Basin modelling simulation and its outputs, about 3500 m of overburden have been eroded at the study area. The present-day heat flow was found to be 30 mW/m 2. The organic matter of Sargelu Formation entered the early oil zone in 64 Ma and reached the main oil zone ca. 5 Ma. The formation is still in the main oil zone at present-day. In well Atrush-2, the highest rate of oil generation for the Sargelu Formation was in the 8.5 Ma, the onset of oil expulsion from Sargelu Formation was in 50 Ma and the expulsion mass has been reached 0.5 Mtons at present-day.

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Geothermal gradients in Iraqi Kurdistan deduced from bottom hole temperatures

Cited by 14 publications

References 3 publications

Quantifying vertical movements in fold and thrust belts: subsidence, uplift and erosion in Kurdistan, northern Iraq

Quantifying vertical movements in fold and thrust belts: subsidence, uplift and erosion in Kurdistan, northern Iraq

Palaeogeographic reconstruction and sequence architecture of the middle‐upper Jurassic successions of Hawraman Basin (NW Iran): Implications for tectono‐depositional processes of the northeastern passive margin of the Arabian Plate

Source Rock Evaluation and 1-D Basin Modelling Approach for the Sargelu Formation, Atrush-2 Well, Kurdistan Region-Iraq

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