Regional In-Situ Stress Prediction in Frontier Exploration and Development Areas: Insights from the First-Ever 3D Geomechanical Model of the Arabian Plate

In this paper, we present results from the first-ever 3D geomechanical model that supports pre-drill prediction of regional in-situ stresses throughout the Arabian Plate. The results can be used in various applications in the petroleum industry such as fault slip-tendency analysis, hydraulic fracture stimulation design, wellbore stability analysis and underground carbon storage. The Arabian tectonic plate originated by rifting of NE Africa to form the Red Sea and the Gulfs of Aden and Aqaba. The continental rifting was followed by the formation of collisional zones with eastern Turkey, Eurasia and the Indo-Australian Plate, which resulted in the formation of the Eastern Anatolian fault system, the fold-thrust belts of Zagros and Makran, and the Owen fracture zone. This present-day plate tectonic framework, and the ongoing movement of the Arabian continental lithosphere, exert a first-order control on the of in-situ stresses within its sedimentary basins. Using data from published studies, we developed a 3D finite element of the Arabian lithospheric plate that takes into account interaction between the complex 3D plate geometry and present-day plate boundary velocities, on elastic stress accumulation in the Arabian crust. The model geometry captures the first-order topographic features of the Arabian plate such as the Arabian shield, the Zagros Mountains and sedimentary thickness variations throughout the tectonic plate. The model results provide useful insights into the variations in in-situ stresses in sediments and crystalline basement throughout Arabia. The interaction between forces from different plate boundaries results in a complex transitional stress state (thrust/strike-slip or normal/strike-slip) in the interior regions of the plate such that the regional tectonic stress regime at any point may not be reconciled directly with the anticipated Andersonian stress regimes at the closest plate boundary. In the sedimentary basin east of the Arabian shield, the azimuths of the maximum principal compressive stresses change from ENE in southeast to ~N-S in northern portions of the plate. The shape of the plate boundary, particularly along the collisional boundaries, plays a prominent in controlling both the magnitude and orientations of the principal stresses. In addition, the geometry of the Arabian shield in western KSA and variations in the sedimentary basin thickness, cause significant local stress perturbations over 10 – 100 km length scales in different regions of the plate. The model results can provide quantitative constraints on relative magnitudes of principal stresses and horizontal stress anisotropy, both of which are critical inputs for various subsurface applications such as mechanical earth model (MEM) and subsequently wellbore stability analysis (WSA). The calibrated model results can potentially reduce uncertainties in input stress parameters for MEM and WSA and offer improvements over traditional in-situ stress estimation techniques.

Regional Tectonics to Basin Fill Architecture from Aptian Shuaiba Fm to Miocene Fars Gp of Abu Dhabi

Objectives/Scope Aptian (Shuaiba-Bab) and Cenomanian (Mishrif-Shilaif) intra-shelf basins were extensively studied with their genesis focused on environmental/climatic disturbances (Vahrenkamp et al., 2015a). Additionally, local tectonic events can also affect the physiography of these basins, especially the Cenomanian intra-shelf basin subjected to NE compressional regime. As this ongoing regime increased at Late-Cretaceous and Miocene, it led to more tectonic-driven basin physiography. This paper investigates the areal extent, interaction, and commonalities between the extensional Aptian intra-shelf basin, compressional Late-Cretaceous intra-shelf basin, Late-Cretaceous-Paleogene foreland basin, and Late Oligocene-Miocene salt basin. Methods, Procedures, Process To understand the genesis, driving forces, and distribution of these basins, we used a combination of several large-scale stratigraphic well correlations and seismic, together with age dating, cores, and extensive well information (ADNOC proprietary internal reports). The methodology used this data for detailed mapping of 11 relevant time stratigraphic intervals, placing the mapped architecture in the context of the global eustatic sea level and major geodynamic events of the Arabian Plate. Results, Observations, Conclusions Aptian basin took place as a consequence of environmental/climatic disturbances (Vahrenkamp et al., 2015a). However, environmental factors alone cannot explain isolated carbonate build-ups on salt-related structures at the intra-shelf basin, offshore Abu Dhabi. Subsequently, the emplacement of thrust sheets of Tethyan rocks from NE, and following ophiolite obduction (Searle et al., 1990; Searle, 2007; Searle and Ali, 2009; Searle et al., 2014), established a compressional regime in the Albian?-Cenomanian. This induced tectonic features such as: loading-erosion on eastern Abu Dhabi, isolated carbonate build-ups, and reactivation of a N-S deep-rooted fault (possibly a continuation of Precambrian Amad basement ridge from KSA). This N-S feature was probably the main factor contributing the basin axis change from E-W Aptian trend to N-S position at Cenomanian. Further compression continued into the Coniacian-Santonian, leading to a nascent foreland basin. This compression established a foredeep in eastern Abu Dhabi, separated by a bulge from the northern extension of the eastern Rub’ Al-Khali basin (Ghurab syncline) (Patton and O'Connor, 1988). Numerous paleostructures were developed onshore Abu Dhabi, together with several small patch-reefs on offshore salt growing structures. Campanian exhibits maximum structuration associated to eastern transpression related to Masirah ophiolite obduction during India drift (Johnson et al., 2005, Filbrandt et al., 2006; Gaina et al., 2015). This caused more differentiation of the foredeep, onshore synclines, and northern paleostructures, which continued to cease through Maastrichtian. From Paleocene to Late-Eocene, paleostructure growth intensity continued decreasing and foreland basin hydrological restriction began with the Neotethys closure. Through Oligocene until Burdigalian this situation continued, where the Neotethys closed with the Zagros Orogeny (Sharland et al., 2001), causing a new environmental/climatic disturbances period. These disturbances prevented the continued progradation of the carbonate factory into the foredeep, leading to conspicuous platform-basin differentiation. Additionally, the Zagros orogeny tilted the plate northeastward, dismantling the paleostructures generated at Late-Cenomanian. Finally, during an arid climate in the Burdigalian to Middle-Miocene, the confined Neogene sea filled the foredeep accommodation space with massive evaporites. Novel/Additive Information Little has been published about the outline and architecture of these basins in Abu Dhabi and the detailed circumstances that led to their genesis using subsurface information.

SE Abu Dhabi Aptian 5 Shuaiba System: Understanding a Heterogeneous Reservoir Trend

The study area covers 1,300 km2 in southeastern Abu Dhabi and focuses on the Aptian (Apt.) 5 Upper Shuaiba progradational clinoform system. The Shuaiba Formation has been well-studied at the regional level, but with comparatively less focus on the Apt. 5 system. Studying depositional trends and shoal facies distributions within the Apt. 5 is critical for predicting reservoir presence and quality. Given the complexity of the Apt. 5 system, understanding the key controls over depositional environments, such as paleowind direction, is an important first step. This study combined regional context and geological understanding with previous studies to confirm existing clinoform interpretation, while also delineating four additional clinoform sequences using a reprocessed depth migrated 3-D seismic volume. Isochron maps were also used to group clinoforms into three packages distinguished by common morphologies possibly linked to their respective dominant reservoir facies. Preliminary observations suggest early clinoforms had more rudist build-ups, whereas the later clinoforms were dominated by narrow-shoal beaches. Coalescing clinoform shoal patterns, observed in the spectral decomposition and amplitude extraction maps, likely result from a combination of Bab Basin morphology, longshore current, and dominant paleowind direction during the Early to Middle Cretaceous. Existing interpretations of dominant paleowind direction vary significantly, ranging between E-W and S-N. Interpretations from this study are most consistent with prevailing paleowind out of the east-southeast. The Arabian plate was likely near the equator around 10°S latitude during the Aptian, which supports the southeast wind hypothesis when considering modern Coriolis patterns. Consistent wind influence on shallow water shoal environments would have winnowed mud and increased the proportion of grain-dominated sediment preserved relative to lower energy areas. The grain-dominated facies appear to be reflected in amplitude responses around the coalescing clinoforms, and in the amplitude variations along strike coincident with clinoform edges. Reservoir presence and quality uncertainty can be reduced if these observations can be confirmed. An improved understanding of the Apt. 5 clinoform system in southeast Abu Dhabi, and possible influences on reservoir distribution and quality, will help develop a better understanding of risk for prospect maturation.

Stratigraphic Trap Potential in the Middle East – Examples from the Mesozoic

The Mesozoic stratigraphy of the Middle East is endowed with multiple world-class, economically significant petroleum systems. Since the first discovery of a major oilfield in an anticline structure in 1908 (Masjed-e-Suleyman, Iran), exploration and production in the Middle East has been largely focussed on relatively low-risk, large structural traps. However, across the Arabian Plate, unexplored structural traps at similar scales are becoming scarce. Therefore, in this mature petroleum province, attention must now focus on identifying the presence of subtle stratigraphic traps, especially within the hydrocarbon-rich Mesozoic stratigraphy. In order to locate and evaluate subtle stratigraphic traps, we have applied sequence stratigraphic principles across the Mesozoic strata of the Arabian Plate. This approach provides a regional, robust age-based framework which reduces lithostratigraphic uncertainty across international boundaries and offers predictive capabilities in the identification and extent of stratigraphic plays. Herein, we focus on three intervals of Mesozoic stratigraphy, namely Triassic, Middle-Late Jurassic and middle Cretaceous strata, in which regional sequence stratigraphic based correlations have identified stratigraphic trap potential. Each of these stratigraphic intervals are associated with the following stratigraphic traps:Triassic: Sub-crop traps associated with a base Jurassic regional unconformity and intra-Triassic unconformities. Onlap geometries associated with differential topography on the Arabian Plate.Middle-Late Jurassic: Pure stratigraphic trap geometries associated with basin margin progradation and pinch-out plays either side of the Rimthan Arch related to late Oxfordian/early Kimmeridgian sea-level fall.Middle Cretaceous: Sub-crop potential beneath the regional mid-Turonian unconformity, basin margin progradation and stratigraphic pinch-out geometries associated with onlap onto basin margins. This regional sequence stratigraphic approach highlights the remaining exploration and production opportunities within these hydrocarbon-rich stratigraphic intervals.

Erforschung der kritisch bedrohten Süßwasserfauna des Vorderen Orients

Im oberen Miozän kollidierte die afroarabische Platte mit Eurasien. So entstand die Gomphotherium- Landbrücke, welche Paläarktis, Orientalis und Afrotropis miteinander verband und einen Faunenaustausch zwischen diesen Regionen über ständig wechselnde Gewässernetze ermöglichte, der jedoch mit zunehmender Aridität immer mehr eingeschränkt wurde. In den 1970er Jahren initiierte Ragnar Kinzelbach mit einer Serie von Forschungsreisen die systematische Erforschung der Hydrofauna der Levante, die er und seine Schüler*innen später auf den gesamten Vorderen Orient ausweiteten. Die umfangreichen, in Museen deponierten Sammlungen, die aufgrund fortschreitender Umweltzerstörung und bewaffneter Konflikte in der Region heute nur eingeschränkt zusammengetragen werden können, bilden eine wichtige Grundlage für fortlaufende Forschungsarbeiten und Naturschutzinitiativen. Anhand einiger Beispiele werden die rezente Biodiversität der Binnengewässer der Region und die Geschichte ihrer Besiedlung mit Süßwasserorganismen umrissen. Research into the Critically Endangered Freshwater Fauna of the Middle East Abstract: During the Upper Miocene, the Afro-Arabian Plate collided with Eurasia, giving rise to the Gomphotherium land bridge, which connects the Palaearctic, Oriental and Afrotropical realms, allowing for an exchange of faunal elements among these realms via an ever-changing network of freshwater connections. This migration, however, was soon restricted by increasing aridity. In the 1970s, Ragnar Kinzelbach initiated research activities on the freshwater fauna of the Levant, which he and his students later on extended to the entire Middle East. Extensive collections were deposited in museums, serving scientific research and conservation initiatives. Given increasing degradation of freshwater ecosystems and armed conflicts in the region, most of these collecting activities would no longer be possible today. The extant biodiversity of the region’s inland waters and its historical biogeography are briefly outlined.

Main Ethiopian Rift landslides formed in contrasting geological settings and climatic conditions

The Main Ethiopian Rift (MER), where active continental rifting creates specific conditions for landslide formation, provides a prospective area to study the influence of tectonics, lithology, geomorphology, and climate on landslide formation. New structural and morphotectonic data from central Main Ethiopian Rift (CMER) and southern Main Ethiopian Rift (SMER) support a model of progressive change in the regional extension from NW–SE to the recent E(ENE)–W(WSW) direction, driven by the African and Somali plates moving apart with the presumed contribution of the NNE(NE)–SSW(SW) extension controlled by the Arabian Plate. The formation and polyphase reactivation of faults in the changing regional stress field significantly increase the rocks' tectonic anisotropy, slope, and the risk of slope instabilities forming. According to geostatistical analysis, areas prone to landslides in the central and southern MER occur on steep slopes, almost exclusively formed on active normal fault escarpments. Landslide areas are also influenced by higher annual precipitation, precipitation seasonality, vegetation density, and seasonality. Deforestation is also an important predisposition because rockfalls and landslide areas typically occur on areas with bushland, grassland, and cultivated land cover. A detailed study on active rift escarpment in the Arba Minch area revealed similar affinities as in a regional study of MER. Landslides here are closely associated with steep, mostly faulted, slopes and a higher density of vegetation. Active faulting forming steep slopes is the main predisposition for landslide formation here, and the main triggers are seismicity and seasonal precipitation. The Mejo area situated on the uplifting Ethiopian Plateau 60 km east of the Great Rift Valley shows that landslide occurrence is strongly influenced by steep erosional slopes and a deeply weathered Proterozoic metamorphic basement. Regional uplift, accompanied by rapid headward erosion forming steep slopes together with unfavourable lithological conditions, is the main predisposition for landslide formation; the main triggers here are intense precipitation and higher precipitation seasonality.

Constraining the timing of Arabia-Eurasia collision in the Zagros orogen by sandstone provenance (Neyriz, Iran)

The Zagros orogen, formed by the collision of the Arabian and Eurasian continental margins, represents one of the largest and richest oil and gas provinces in the world. The Zagros fold-thrust belt records collision and convergence along the Neotethys suture zone. By coupling field observations, sandstone modal analysis, U-Pb zircon dating, and Hf isotopic data from the Upper Cretaceous to Pliocene sedimentary succession of the Neyriz region, this paper documents several major provenance changes that allow us to propose a refined scenario for the Zagros orogeny. An ophiolitic complex dated by detrital-zircon U-Pb geochronology as ca. 95 Ma provided detritus to Upper Cretaceous-Paleocene strata deposited along the northeastern margin of the Arabian lower plate (ophiolite provenance). Yet, on the southwestern margin of the Eurasian upper plate, upper Paleocene-lower Eocene strata indicate provenance from Mesozoic magmatic rocks yielding zircons dated as ca. 240 Ma and 170 Ma as well as the recycling of clastic rocks. Since the early Miocene, the sedimentary basin located on the Arabian plate received both ophiolitic detritus and magmatic-arc, recycled clastic, and axial-belt metamorphic detritus from Eurasia. U-Pb ages of detrital zircons reflect polyphase magmatism at 170 Ma, 95 Ma, and 40 Ma on the Eurasian active margin. Our results indicate that progressive accretion, uplift, and exhumation of the Zagros orogen was well under way by the beginning of the Miocene in the Neyriz region. Literature data from adjacent regions suggest that the Arabia/Eurasia collision may have occurred diachronously and later in the Kermanshah and Lurestan areas to the north.

The Obstacles and Opportunities of the Mineral Resources in the Kurdistan Region, Iraq

The Kurdistan Region in Iraq is located in the extreme northeastern part of the Arabian Plate which is in a collision since the Late Cretaceous with the Iranian Plate. Therefore, large ophiolite bodies have been thrust along the northeastern margins of Kurdistan Region; accordingly, different metallic mineral can be associated with igneous and metamorphic rocks at Penjween, Qalat Diza and Rawandouz vicinities, besides, radioactive minerals like uranium and thorium. Moreover, large and long thrust fault has developed along the northern and northeastern parts of the Kurdistan Region. Along the plane of this huge thrust fault, hydrothermal liquids have deposited different metallic minerals as showings, especially between Zakho and Amadiyah towns. We have presented and discussed the discipline of mineral investment in Kurdistan Region, the announced minerals’ blocks for investment by the Ministry of Natural Resources in the Kurdistan Regional Government, the encouraging factors and obstacles of investments. To fulfill the scope of this work, we have used the best available and updated data as acquired from different sources. The main obstacles which contributed to the backwardness and non-development of the mining industry in the Kurdistan Region can be summarized in the nonexistence of a valid and promising mineral investment law which can attract the big international mining companies to invest in the region, adding to the nonexistence of comprehensive, detailed and mineral exploration studies which can give confident figures of the mineral and ore reserves in the region. The non-availability of a specialized mining education institution which prepares mining expertise and mining engineers who can lead the progress in this regard could count as another hurdle.