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Location map of Iraq showing northeast Arabian Peninsula of the region Iraq with locations of basins, oil fields, and wells on which this study is based
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1D petroleum system modeling was performed on wells in each of four oil fields in South Iraq, Zubair (well Zb-47), Nahr Umr (well NR-9), West Qurna (well WQ-15 and 23), and Majnoon (well Mj-8). In each of these fields, deposition of the Zubair Formation was followed by continuous burial, reaching maximum temperatures of 100°C (equivalent to 0.70%Ro...
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... studied area composes geographically the oil fields of Zubair, Nahr Umr, Majnoon, and West Qurna. It extends between 30.00-31.10 latitude and 47.10-47.55 longitudes as shown in Fig. 2. The Zubair Formation in this area was deposited in Mesopotamian basin of geographically facies distribution of southern part in Iraq. It is part of the major Total Petroleum System of Cretaceous-Tertiary in South Iraq ( Pitman et al. 2004 andAl-Ameri et al. 2009) that extend between the evaporates Upper Jurassic Gotnia Anhydrite ...
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... and cuttings samples were collected from Zubair Formation and its suggested hard data source rocks from eight wells (Fig. 2) of five oil fields in South Iraq (Basrah region): they are six samples from Zb-40, ten samples from Zb-43, and five samples from Zb-47 of Zubair Oil Field, six saples from NR-9 of Nahr Umer Oil Field, seven samples from W.Q-15, eight samples of WQ-1 of West Qurna Oil Field, four samples from Mj-8 of Majnoon oil field, 29 samples from ...
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Citations
... Generalized stratigraphic of southern Iraq oilfields(Al-Ameri et al., 2011) ...
Precise forecasting of pore pressures is crucial for efficiently planning and drilling oil and gas wells. It reduces expenses and saves time while preventing drilling complications. Since direct measurement of pore pressure in wellbores is costly and time-intensive, the ability to estimate it using empirical or machine learning models is beneficial. The present study aims to predict pore pressureusing artificial neural network. The building and testing of artificial neural network are based on the data from five oil fields and several formations. The artificial neural network model is built using a measured dataset consisting of 77 data points of Pore pressureobtained from the modular formation dynamics tester. The input variables are vertical depth, bulk density, and acoustic compressional wave velocity, with the activation function of tangent sigmoid. The average percent error, absolute average percent error, mean square error, root mean square error, and correlation coefficient (R2) were applied for evaluation. The results revealed that the best artificial neural networkstructure was (3-8-1), with average percent error, absolute average percent error, mean square error, root mean square error, and correlation coefficient R2 of -0.52, 1.01, 3994, 63.2, and 0.995, respectively. A C++ computer program is provided with a calculation sample to simplify the implementation of the proposed artificial neural network. The dependency degree of pore pressureon each input parameter is investigated, revealing the highest impact of depth on pore pressureprediction. Furthermore, to check the validity of the artificial neural network against the different datasets, the artificial neural networkperformance was compared with 84 new data points and showed an advantage over the existing models. The very good performance of artificial neural networkfor different types of oil reservoirs and formations reveals an insignificant effect of lithology on the prediction of pore pressure.
... Iraq represents part of the Arabian platform and can be subdivided into five different tectonostratigraphic zones bordered by significant faults: the thrust and folded zones (Zagros basin), the Tigris, Euphrates, and Zubair subzones (Mesopotamian Basin), the Rutbah, Jezira, and Salman zones [29,30]. Zagros basin covers over 553.000 km2 of Turkey, northeastern Syria, Iraq, and the northern to southeastern Iranian provinces, making it the secondlargest basin in the Middle East [31][32][33]. On the east, the Zagros Mountains border this basin, while on the west, the Mesozoic stable shelf (Pitman et al., 2004). ...
The hydrocarbon generation potential of Chia Gara strata and their genetic link with produced oils from the Zagros basin are still not comprehensively investigated. Forty-seven rock samples from the Tithonian–Berriasian interval were subjected to geochemical analyses to infer organic matter enrichment, hydrocarbon potential, thermal maturity, and timing for hydrocarbon generation/expulsion and their implications regarding upcoming petroleum explorations in the Zagros basin. The results showed that the Chia Gara rock samples have fair to very-good generation potential, as confirmed by higher total organic carbon (TOC=0.68–3.95 wt%) and Rock-Eval (S1+S2=3.37–8.52 mg HC/g rock). The hydrogen index (HI=171–462) and Rock-Eval Tmax over 430 °C support the presence of Types II and mixed Types II/III kerogen. These results confirm the high generation potential of the Chia Gara Formation in the study region. 1D basin models of the KK–109 well show that over 55% of kerogens were converted into oil in the Cretaceous (77–67 Ma). Expulsion started from the Miocene until now (22–0 Ma), consistent with 0.71–0.80 of modeled Easy%Ro and 55–80 %TR. Consequently, this project confirms the potential oil expulsion from the Chia Gara Formation, which can be a resource for upcoming hydrocarbon investigation in the Zagros basin, Iraq.
... (2) Innovative modelling techniques should facilitate interdisciplinary collaboration, producing specialized software for applications including oil and gas exploration and structural analysis [208][209][210][211][212]. ...
This study examines the development trajectory and current trends of three-dimensional (3D) geological modelling. In recent years, due to the rising global energy demand and the increasing frequency of regional geological disasters, significant progress has been made in this field. The purpose of this study is to clarify the potential complexity of 3D geological modelling, identify persistent challenges, and propose potential avenues for improvement. The main objectives include simplifying the modelling process, improving model accuracy, integrating different data sources, and quantitatively evaluating model parameters. This study integrates global research in this field, focusing on the latest breakthroughs and applications in mineral exploration, engineering geology, geological disaster assessment, and military geosciences. For example, unmanned aerial vehicle (UAV) tilt photography technology, multisource data fusion, 3D geological modelling method based on machine learning, etc. By identifying areas for improvement and making recommendations, this work aims to provide valuable insights to guide the future development of geological modelling toward a more comprehensive and accurate “Transparent Earth”. This review underscores the global applications of 3D geological modelling, highlighting its crucial role across various sectors such as mineral exploration, the oil and gas industry, urban planning, geological hazard assessment, and geoscientific research. The review emphasizes the sector-specific importance of this technology in enhancing modelling accuracy and efficiency, optimizing resource management, driving technological innovation, and improving disaster response capabilities. These insights provide a comprehensive understanding of how 3D geological modelling can significantly impact and benefit multiple industries worldwide.
... The Zubair formation is a large part of the Lower Cretaceous sequence in Iraq, extending in Iraq, the Persian Gulf region, Syria and Iran, and designated as the prevalently terrigenous clastic and oil-bearing sequences of the southern oilfields of Iraq (Ali and Nasser, 1989;Al-Ameri et al., 2011). ...
This study was accomplished in oil drilling wells located in the Mishrif and Mauddud carbonate formations and in the Zubair sandstone formation to ensure safer, efficient, and economical cementing operations, a better bond between the cement, casing, and formation, and a better isolation between the zones. Moreover, it was also undertaken to obtain competitive cement at the shoe. The study developed a cement slurry programme of 1.55 lead and 1.9 SG tail slurry for both the primary and secondary stages in well WQ1-XX0, as well as a new programme for the wells that would follow (the same primary stage, and 1.45 and 1.75 SG for the secondary stage), so as to improve the casing and cementing stability and reduce costs. The results indicated that well problems were gradually reduced in wells WQ1-XX1 and WQ1-XX2 and were entirely eradicated in well WQ1-XX3. The reduction in cement cost was 62% (from 0.756 to 0.47 barrels per metre), and the cement shows good bonding at the top of productive formations (Mishrif, Mauddud, and Zubair). The problems and costs in the Zubair sandstone and Mauddud carbonate formations were higher than in the Mishrif formation, and the programme adopted would prove to overcome them all. The lightweight high-performance slurry, with a specific gravity of 1.45, achieved the objectives of liner cementing in the Mishrif wells without involving any losses.
... Glynn Jones assigned the name "Zubair" to a sandstone formation in the Zubair oil field in 1948 51 . This Lower Cretaceous formation has become one of the most prolific classic reservoirs in the region 52 , particularly in southern Iraq 53 . The Zubair's clastic sequence consists mainly of sandstones deposited in fluvial-deltaic and marine environments 49 . ...
For complex and multi-layered clastic oil reservoir formations, modeling lithofacies and petrophysical parameters is essential for reservoir characterization, history matching, and uncertainty quantification. This study introduces a real oilfield case study that conducted high-resolution geostatistical modeling of 3D lithofacies and petrophysical properties for rapid and reliable history matching of the Luhais oil reservoir in southern Iraq. For capturing the reservoir's tidal depositional setting using data collected from 47 wells, the lithofacies distribution (sand, shaly sand, and shale) of a 3D geomodel was constructed using sequential indicator simulation (SISIM). Based on the lithofacies modeling results, 50 sets of porosity and permeability distributions were generated using sequential Gaussian simulation (SGSIM) to provide insight into the spatial geological uncertainty and stochastic history matching. For each rock type, distinct variograms were created in the 0° azimuth direction, representing the shoreface line. The standard deviation between every pair of spatial realizations justified the number of variograms employed. An upscaled version of the geomodel, incorporating the lithofacies, permeability, and porosity, was used to construct a reservoir-flow model capable of providing rapid, accurate, and reliable production history matching, including well and field production rates.
... The anticline consists of four domes, which are Hammar, Shuaiba, Safwan, and Rafidyah, separated by saddles. Fig.2, shows the Stratigraphy column for Zubair field which extends from Dibdiba to Zubair Formation (Jassim and Goff, 2006;Al-Ameri et al., 2011). ...
The wellbore instability issues are firmly occurring in the Iraqi oilfield and particularly in the southern region of Iraq. It is causing a significant loss of time dealing with many types of downhole problems, as well as an increase in the operations costs because of the instability consequences. By using the well information and open-hole logging data, the One-Dimensional (1-D) geomechanical model generated with Schlumberger Techlog software (V.2015) was used to assess the mechanical stability of the wellbore. The model was calibrated and validated by using core data (Triaxial test), the formation pore pressures, and the Mini-frac test). The 1-D model was validated across the actual well conditions (i.e., the original mud weight and the actual wellbore failure) by using three criteria of failures which are Modified Lade, Mogi-Coulomb, and Mohr-Coulomb. The validation process showed that the failure criterion of Mogi-Coulomb is better than the other two criteria in presenting the actual borehole failure, and thus it can be used to develop the plans of wellbore orientation. By investigating wellbore orientation with various scenarios, ranging from a vertical trajectory to the horizontal strategy, the wellbore orientation is mainly safe (with the minimum breakout) in vertical and inclined wells up to 40º with minimum mud weight of 11.7 and 12.6 ppg. The optimum wellbore trajectory should be in the direction of minimum horizontal stress, which is North-West to South-East (130º-160º). The developed plans provide a guideline for performing stable drilling operations in the south of Iraq and the nearby areas, thus effectively contributing in reduction the overall cost.
... We collect the new test dataset from Harvard Arc-GIS WorldMap 10 . Here, the locations of the existing petroleum deposits matched with a similar dataset we find in the experiment done by Ameri et al. 53 . In the case of the new test dataset from Harvard, the testing region is the same as our earlier experiment. ...
The method of finding new petroleum deposits beneath the earth’s surface is always challenging for having low accuracy while simultaneously being highly expensive. As a remedy, this paper presents a novel way to predict the locations of petroleum deposits. Here, we focus on a region of the Middle East, Iraq to be specific, and conduct a detailed study on predicting locations of petroleum deposits there based on our proposed method. To do so, we develop a new method of predicting the location of a new petroleum deposit based on publicly available data sensed by an open satellite named Gravity Recovery and Climate Experiment (GRACE). Using GRACE data, we calculate the gravity gradient tensor of the earth over the region of Iraq and its surroundings. We use this calculated data to predict the locations of prospective petroleum deposits over the region of Iraq. In the process of our study for making the predictions, we leverage machine learning, graph-based analysis, and our newly-proposed OR-nAND method altogether. Our incremental improvement in the proposed methodologies enables us to predict 25 out of 26 existing petroleum deposits within the area under our study. Additionally, our method shows some prospective petroleum deposits that need to be explored physically in the future. It is worth mentioning that, as our study presents a generalized approach (demonstrated through investigating multiple datasets), we can apply it anywhere in the world beyond the area focused on in this study as an experimental case.
... Three-dimensional (3D) basin modeling has been widely used in the study of conventional petroleum and gas hydrates [22,23,26,[29][30][31][32][33][34]. By reproducing the paleo and modern heat flow and temperature field, the maturity of source rocks and hydrocarbon generation with time can be simulated. ...
... Deep lacustrine shale in the Wenchang Formation of the Eocene is the main source rock in the region [54]. The main characteristics of the source rocks are that they are rich in low biomarker C 30 cording to the geochemical information obtained [55][56][57], the Enping Formation source rocks have the characteristics of coals, rich in terrigenous higher plants-resin compounds (W, T double dussonne) and coal, and the content of low biomarker C 30 4-methylsterane is very small, with an average TOC of 2.19%. The average value of chloroform asphalt A is 0.1976%, and the atomic ratio of kerogen H/C is mostly between 1.2 and 0.7, indicating that the type of organic matter is mainly type II-III. ...
Gas hydrates have been considered as a new energy that could replace conventional fossil resources in the future because of their high energy density, environmental friendliness, and enormous reserves. To further analyze the potential distribution of gas hydrate stability zones (GHSZ) and the formation of a gas hydrate system in the Shenhu area of the South China Sea (SCS), a 3D petroleum simulation model (PSM) was built from 3D seismic interpretations and all available geological data. Based on the thermal calibration of the 3D model, the evolution of the GHSZ, hydrocarbon generation and migration, and the formation and accumulation of gas hydrates were simulated for the first time in the area. Thermal simulation shows that the methane source of gas hydrate originated from shallow biogenic gas and deep thermogenic gas. Most areas are dominated by shallow biogenic gas, while, only about 3% of the deep thermogenic gas derived from Enping Formation source rock and contributed to the gas hydrate formation within a few areas in the southeast. The thermogenic gas migrated vertically into the GHSZ through connecting faults, mud diapir, and/or gas chimney to form gas hydrate. The source rocks of the Wenchang Formation, a deep thermogenic gas source, began to enter the main hydrocarbon generation window at 28.4 Ma. The Enping source rock began to generate oil from 25 Ma on and gas from 16 Ma on. Since 5.3 Ma, most areas of the source rocks have generated a gas window, and only the shallower parts in the east still in the oil window, which had lasted until now. The shallow biogenic gas source rocks from the Hanjiang, Yuehai, and Wanshan formations generated gas in different periods, respectively. The Qionghai Formation began to generate hydrocarbon from 0.3 Ma and until now. Other results show that the GHSZ developed mainly during the Quaternary and Neogene (Wanshan Formation) and the GHSZ is thicker in the southern area and thinner in the northern part with a positive correlation with water depth. Starting at 11.6 Ma, the GHSZ developed in the Hanjiang Formation in the south of the Shenhu area and gradually expanded to the north to cover most of the study area at 5.3 Ma during the Yuehai Formation. From 1.8 Ma on, the GHSZ covered the entire study area. At the same time, the GHSZ in the Hanjiang Formation disappeared because of the change in temperature and pressure. At present, the GHSZ in the Yuehai Formation has disappeared, while the Quaternary and Wanshan are the two main formations for GHSZ development. The formation and distribution of gas hydrates are fundamentally controlled by the space-time coupling between the hydrocarbon generation and expulsion time and distribution of the GHSZ. The simulation results of gas hydrate accumulation and distribution were verified by drilling results and the matching rate is 84%. This is the first time that 3D simulation was successfully conducted with PSM technology in the Shenhu area and it provides important guidance for gas hydrate study in other areas of the SCS.
... It is about 30 km away from the SW of the Hilla, located among Najaf and Karbala cities. Here, geological and tectonic settings indicate that the Eocene sediments are from the SW portions to fresh depositions Fig. 9 Convergence curves of two parallel vertical dike sources shown in Fig. 10 through the CFFI method for examining wrong cluster numbers: a gravity data, and b magnetic data Fig. 10 The oil and gas distribution map of Iraq which presents most hydrocarbon reserves within the country (reproduced from Al-Ameri et al. 2010) at the east of the Euphrates. These sediments have a slight dip with two degrees toward east and northeast portions. ...
... The magnetic effect of the fluid accumulation is chemically controlled by the migration of iron oxide-content oil migration and interaction with the surrounding environments (e.g., Schumacher 1996;Zeeh et al. 1997;Schneider et al. 2004). On the basis of previous researches (e.g., Al-Farhan et al. 2019;Al-Ameri et al. 2010), four clusters were assumed to run the fuzzy-guided focused inversion methodologies (C = 4). Within zero background properties (assuming 1 = 1 ), the sedimentary sequences with a density contrast of 150 kg/m 3 and a magnetic property of 0.001 in SI unit and a weight of 2 = 1 were assumed. ...
This work illustrates the application of a fuzzy-guided focused technique for cooperative 2D modeling of magnetic and gravity data on common geological sources responsible for anomalous observation, whereby a well-known fuzzy c-means clustering tool is inserted in the center of the inversion mechanism to search different clusters of geophysical properties which are magnetic susceptibility and density contrast within several zones. An unstructured meshing is performed with triangular cells which captures the accurate borders of a rugged topography area and any complex-shaped sought sources. The efficiency of the proposed cooperative inversion algorithm is examined along 2D profiles with simulation of several synthetic sources by which the retrieved geophysical properties indicate sharp edges, correct depth and shape pattern of the sought sources. Imposing a model stabilizer, a depth weighting function and petrophysics constraints of physical models within the clustering inversion, greatly promotes the performance of the constructed models over the outputs of running individually each data set. Of note is that a conjugate gradient solver is utilized here with a preconditioner to estimate approximately sought physical properties from an objective function with two constituents that are a model and a misfit norm. Ground-based gravity and magnetic observations over a plausible oil-trapping structure are investigated at the Kifl region, situated in Iraq. Cooperative inversion output can pave the way for imaging of a fault feature which has been filled by a thick sequence of sediments, presenting a configuration of a graben-horst structure. The main notable output of this work proves the existence of an oil-trapping structure responsible for a distinct potential field geophysics anomaly.
... The PetroMod software is a finite-element basin simulator that models the evolution of sedimentary basins. 24 In this study, one-dimensional (1D) basin modeling was applied to rebuild the burial, temperature, and pressure histories of the Ha6, Xinken, Repu, and Yueman blocks in the Halahatang Depression using PetroMod 2016 (1D) software by Schlumberger Limited. The basic data required for basin modeling include stratigraphic parameters (age, thickness, and lithology), tectonic events (unconformities, erosion time, and erosion thickness), and boundary conditions (heat flow, paleowater depth, and sediment-water interface temperature). ...
The diversity of fluid phases in the oil-gas system and complexity of petroleum genesis bring difficulties to the exploration and development of oil and gas. The phase state and evolution of the complex reservoirs in the Halahatang Depression, Tabei Uplift of the Tarim Basin remains unresolved. In this paper, we simulated the phase characteristic of reservoirs in different blocks and layers including Xinken (O), Ha6 (C), Repu (K), and Yueman (O) distributed from north to south of this area using PVTsim software; rebuilt the burial, temperature, and pressure histories of different blocks and layers by using the PetroMod (1D) software; and recovered the fluid phase evolution process by combined basin modeling, PVT simulation, and fluid inclusion thermal metrics results. The phase modeling results show that the Xinken (O), Ha6 (C), and Yueman (O) reservoirs are confirmed to be oil reservoirs, and the Repu (K) reservoir is in the condensate gas phase currently. The vital time points and temperature and pressure conditions for the three oil reservoirs of Xinken (O), Ha6 (C), and Yueman (O) that transited from the gas−liquid phase to the liquid phase are 356 Ma (57.45°C, 12.93 MPa), 331 Ma (35.67°C, 4.03 MPa), and 454 Ma (63.63°C, 13.27 MPa), respectively. The Ordovician reservoir in the Xinken block underwent three stages of accumulation, which occurred at 400−379 Ma (Devonian), 282−256 Ma (Permian), and 18−16 Ma (Neogene), respectively, and after final accumulation, it remained in a single oil phase state. The Ordovician reservoir in the Yueman block underwent two stages of accumulation in the 294−290 Ma (Permian) and 25−12 Ma (Paleogene−Neogene) and remained in a single oil phase state until now. The Carboniferous reservoir in the Ha6 block was deduced to be charged in the 94−86 Ma (Cretaceous) according to the published authigenic illite K−Ar isotope dating results and then stayed in a single oil phase state unalterably. As for the Cretaceous reservoir in the Repu block, the time point of 11 Ma (98.86°C , 35.56 MPa) is vital for changing from the gas−liquid coexistence phase state to the condensate gas phase one. In contrast with the Ordovician (ZG7−5) and Cambrian reservoirs (ZS1, ZS5) in the Tazhong Uplift, the oil and condensate gas reservoirs in the Tabei Uplift enjoy a lower pressure range, lower GOR, and a heavier oil density and viscosity. This study provides a quantitative way to rebuild the geologic evolutionary process, phase characteristics, and phase evolution process in complex reservoirs.
