bluuebunny/crossref_metadata_2025_split huggingface dataset:
How In-Place Volumes of Subsurface Reservoir Models are Impacted by Using 3d High-Resolution Outcrop Analogue Data. A Case Study Using Depositional Architectural Heterogeneity of Stromatoporoid/Coral Buildups of the Hanifa Fm, Saudi Arabia
Authors: Ramdani Ahmad , Khanna Pankaj , de Jong Sander , Gairola Gaurav , Vahrenkamp Volker 
Published: February 2022

Abstract
High porosity-high permeability stromatoporoid/coral facies are important components of the Late Jurassic carbonate reservoirs in the Middle East. This facies exhibits sub-seismic depositional heterogeneities that subsurface models often overlook due to the limited interwell resolution of subsurface data. Understanding the effect of this facies on the 3D distribution of static reservoir properties and uncertainty in volumetric calculations of hydrocarbons in-place will improve estimates of the ultimate recovery and hence reservoir development decisions. A 3D high-fidelity outcrop-based geocellular depositional model that honors the spatial and petrophysical heterogeneity of the stromatoporoid/coral facies was constructed based on the Hanifa reservoir outcrop analog in central Saudi Arabia. The model was constructed from a 1.2 km × 1 km drone photogrammetry survey, measured sections (total length 150m) and spectral gamma-ray data, &gt;200 thin sections, a 50 m-long core, a 19 km-long network of 2D and 3D Ground Penetrating Radar, and 600 m-long 2D seismic profiles. The facies model was populated with porosity and permeability equivalent to subsurface reservoir facies and utilized as the baseline petrophysical model for the comparison study. A set of pseudo wells at ~1 km spacing were simulated from the model capturing the model's 1D facies stacking and properties around the wellbore. The pseudo wells were utilized to stochastically build facies and static reservoir models scenarios to replicate the baseline model from limited well data. The volumetric calculation of each realization is compared with the baseline to investigate the range of volumetric uncertainty that would be introduced by the lateral distribution of stromatoporoid/coral facies. Early results show that depending upon the modeling methodology, the volumetric discrepancy between stochastic simulations and the deterministic outcrop baseline model is ~10-15%. Using a high-fidelity outcrop-based reservoir model, we have demonstrated the strong influence of 3D depositional heterogeneity of the stromatoporoid/coral facies on the uncertainty associated with hydrocarbon in-place volumes. We conclude that a static reservoir model can be significantly improved by using data-driven geological models that reflect the 3D heterogeneity of depositional facies.
Penta Source 3D Marine Acquisition in the Sarawak Basin, Malaysia
Authors: Law Chung Teck , Engku M. Shukri Engku Ali Aminulhakim , Sukhdev Singh Sukhveender Singh , Lim Sarah, Suet Hoey , Muhamad Abdul Aziz 
Published: February 2022

Abstract

Summary
The hunt for more data at lesser the cost is a never-ending quest in the world of seismic acquisition. The latest offered solution in that vein – multisource 3D marine acquisition Here, we present the first-ever penta source 3D Marine Acquisition to be adopted commercially in Malaysian waters, largest survey area of its kind to date ~ 6920 sqkm of data in total. This paper provides an overview of the execution and the outline of the challenges faced, and adaptations made to absolve it, in both acquiring and processing the penta source data. The results are compared with pre-existing legacy data, and with it, recommendations for better acquisition efficiency and processing results.
The Ionian-Crete Basin: Is this the Next Frontier?
Authors: M. Zaffa Farisa , Ayub Amir , Sherkati Shahram , M. Makhatar Nur Bakti , Januri Ahmad Fahrul , M. Zanal Fariza , Khor Ka Cheng , Alai Riaz , A. Rahman Sharmizi , Tengku Hassan Tengku Mohd Shazwan , Chin Soon Mun , Sy Khastudin Sy Nur Ain , Burhanuddin Farah Syafira , Ting King King , Ranajit Das , Abdul Razak Siti Saradila , A. Hamid Nurazura , Timothy Edward Johnson 
Published: February 2022

Abstract
Over the past decade, the Eastern Mediterranean has been the prime focus of E & P Companies, mainly attributed to the giant discoveries of Zohr-Egypt, Glaucus-Cyprus and Levantine-Israel involving isolated Miocene-Cretaceous carbonate build-ups and Miocene-Pliocene deepwater clastics turbidite plays. A total of 13 Bboe of proven 2P reserves have been added since 2010. These plays are the focus of exploration. Being located in the center of these giant discoveries and the only remaining unexplored region in the Eastern Mediterranean, the frontier Ionian-Crete has recently attracted the attention of the Oil and Gas industry and concessions have been allocated to number of operators (Fig.1). This study is aimed to investigate the hydrocarbon potential of this basin utilizing an integrated play-based exploration approach. Triassic to Pliocene stratigraphic successions and associated thermogenic petroleum systems and plays have been evaluated and areas of high prospectivity have been identified. A crustal model was built to establish the basin geohistory and to understand the impact of crustal reconfiguration during the Hellenides Orogeny and its implications to the petroleum systems maturity.
A Probabilistic Unified Depth Velocity Model and Associated Uncertainties Estimation Based on Bayesian Approach
Authors: Liew Wei Long , Rajput Sanjeev 
Published: February 2022

Abstract
There are high emphasis and expectations placed on obtaining the most accurate depth structure map from seismic data. These maps set the expectations, for drilling depth prognosis and hydrocarbon volumetric estimation of reservoirs. The viability of a hydrocarbon prospect and the success of drilling to tap the resources heavily relies on depth map accuracies. However, achieving precisions have been challenging due to the limitations of the seismic data.
This paper describes a novel integrated depth modeling workflow that successfully quantifies the depth uncertainties through a geostatistical simulation-based approach of integrating seismic interpretation inputs, well tops, and seismic velocity together with their associated uncertainties. The method proposed to conciliate seismic uncertainties and to address structural depth uncertainty is called stochastic time to depth conversion. It is a geostatistical driven approach that uses Bayesian Co-Kriging and relies on well depth markers using appropriate time-derived external drifts. The method accounts for uncertainties attached to the seismic time of events picked and velocity uncertainty integrated into a single stochastic workflow. Time Uncertainty is related to the seismic data quality aspects such as resolution limit and tunning thickness and velocity uncertainty is due to imperfectness of the velocity model due to anisotropy or inaccuracies in velocity picking. Both uncertainties can be defined by a 1st standard deviation sigma value or defined by a lateral varying sigma map. Realizations of depth maps are simulated, and the best-estimated depth map is produced. A confidence interval that envelopes the multiple realized horizons can provide meaningful measures of depth uncertainty for drilling depth prognosis giving a window of anticipation of where the top of the reservoir may be encountered.
The stochastic approach allows for proper quantification of gross rock volume (GRV) uncertainty which impacts hydrocarbon in-place estimations. Ranking of all GRV outcomes is now possible using the expectation curve where the P10, P50, and the P90 volumes and associated maps can be identified. These maps could then contribute to structural modeling of the low, base, and high case scenarios allowing for hydrocarbon in-place sensitivity analysis. The geostatistics-based time-to-depth method offers a consistent framework to address the bias at the core of the upstream Front-End Loading (FEL) process which ultimately maximizes the accuracy of depth models and improved E&P decision-making. The method is based on Bayesian Co-Kriging and offers the consistent integration of all sources of uncertainty throughout all layers within a unique probability model. Field data applications show that the stochastic depth modeling method is reliable due to its strong dependence on mathematically sound geostatistical principles, scalable that integrates the sequential processes.
Chemostratigraphy Enables Correlations and Reservoir Characterization with High Resolution Elemental Data
Authors: Hussain Maaruf , Amao Abduljamiu , Al-Ramadan Khalid , Babalola Lamidi , Humphrey John 
Published: February 2022

AbstractPrevious studies have shown that by applying multivariate statistical analysis to chemostratigraphy, indistinct sequence stratigraphic correlations can be enhanced. Chemofacies and correlatable chemozones can be defined within highly homogenous strata, using specially designed statistical algorithms. In this study, we first investigated the better performing of linear and non-linear dimensionality reduction techniques in analyzing geochemical datasets for chemofacies and chemozones development. The general applicability of this conceptual model for sequence stratigraphic correlations, was subsequently tested. The results show that the linear method was able to account for 63% of input data variance while the non-linear technique accounted for 100% of the variance. In addition, the linear techniques are better utilized to establish chemofacies, whereas the non-linear techniques considerably perform better in establishing correlatable chemozones, while also improving accuracy.
Extended Elastic Impedance and its Application in Prediction of Reservoir and Fluid Properties for Late Messinian Reservoir, Onshore Nile Delta Egypt
Authors: Eloribi Mahmoud , Raslan Hytham 
Published: February 2022

Abstract
The study area is situated within the eastern portion of the Nile Delta. As the Mediterranean Sea "dried up" during the Messinian extensive erosion process resulted in the formation of large canyons and valleys which cut into the underlying Qawasim and Sidi Salim Formations, but the number of such incised valleys may have been limited. The entrenched valleys became filled predominantly with sandstone as sea levels frequently rose and dropped in the late Miocene to early Pliocene. The marine influence on deposition during the late Messinian became strong toward the end of the Miocene when thick marine shale separated the sand bodies.
Late Messinian reservoir within the study area exhibits a good quality reservoir for gas and condensate accumulation. The target reservoir section consists of structural and stratigraphic elements that control the gas presence and the GWC.
Late Messinian reservoir has a lot of heterogeneity and ambiguity for the attributes and amplitude interpretation, so the DHI within the study area has pitfalls and uncertainty to determine the hydrocarbon prospects, which caused the drilling of several dry wells. For lithology and pore fluid prediction, several hypotheses and approaches had been proposed. Amplitude versus offset (AVO) modeling and analysis for the wells log and seismic angle gathers data results in non-unique output, whereas several AVO classes were found for the gas sand within the study area. The AVO analysis for gas sand of the late Messinian reservoir could be Class II and Class IIp, while the wet sand is Class I.
Following the first discovery within the study area, Extended Elastic Impedance (EEI) inversion was carried out for the Late Messinian reservoir for better identification and delineation of the reservoir boundaries and to determine the pore fluid content. During this study, several iterations have been made to determine the most appropriate chi angles to illuminate the presence of both reservoir and borehole content.
The EEI inversion results show a strong correlation between a certain chi angle and the presence of gas. Maps for the late Messinian reservoir have been produced to illuminate the gas sand presence, which matches the results of the drilled wells. The technique has been so successful, as there are unexplored EEI anomalies that have a gas signature within the fault downthrown area. These EEI anomalies had been tested with encouraging results of a gas-bearing sand reservoir, as the EEI anomaly had been predicted correctly.
This paper discusses the methodology involved, the calibration, and the selection of the appropriate chi angles for the Late Messinian Reservoir within the study area.
Geologically Consistent Multiphysics Inversion
Authors: Hallinan Stephen , Soyer Wolfgang , Mackie Randall , Scholl Carsten , Miorelli Federico 
Published: February 2022

Abstract
A subsurface volume that can be reliably interpreted in terms of geologically relevant attributes is a desirable objective for products from geophysics inversion workflows. Geophysics data contain uncertainties, however, and the solution of the inverse problem is non-unique. Some form of constraint is then required to obtain geologically reasonable outputs. Our inversions may include a priori geological information quantitatively in the regularization, e.g. to test two or more structural models for consistency with the observed geophysics data sets, updating the models accordingly. We have implemented a cross-gradient constraint for diverse geophysical data types at several geological settings for the O&G, geothermal, mining E&P community (e.g. Scholl et al 2015, 2016, Soyer et al 2018, 2021 and Mackie et al 2020). The basic application covers the familiar structural similarity objective introduced by Gallardo and Meju 2003 and 2011 - comparing the gradient fields of property volumes, e.g. velocity, resistivity, density, derived from different geophysical domains - but a distinct advantage comes when gradient control from geology (e.g. surface dip and strike data, subsurface interpreted structural models, etc.) or an ancillary geoscience property (e.g. porosity volumes as a proxy for geological structure, structural tensors extracted from PSDM, etc.) is included during single or joint domain inversions of geophysical data. In reverse, the cross gradient application may be used to de-risk competing geological or structural models, testing the consistency of the structure in each model variation – as defined by the 3D gradient field – against the observed geophysical dataset(s) (e.g. Miorelli et al 2019).
A range of applications is summarized in Figure 1. The method behind our implementation and representative practical examples are discussed in the sections below.
Parihaka Reservoir Characterization by Integrating Well and Seismic Data through Seismic Inversion and Multiattribute Analysis
Authors: El Gandy Eman Ahmed Ibrahiem 
Published: February 2022

Abstract
A geophysical study to understand and Identify Pliocene - Pleistocene channels system and improve better understand of the channel geometry, fill lithology and connectivity and Generate rock property volume, Enhance reservoir quality, Hydrocarbon distribution and sweet spot detection with min. risk in Miocene reservoir (Moki formation). The Taranaki Basin is the only New Zealand basin to produce commercial quantities of hydrocarbons and still being underexplored. The Parihaka field is on the north-western Taranaki Peninsula located along the west coast of New Zealand's North Island (Veritas, 2005) which there only dry hole drilled based on 2D lines (Arawa-1).
Moki formation is our main reservoir its depositional environment is turbiditic fan complex. Hydrocarbons are yet to be commercially produced from the Moki Formation on onshore Taranaki, (Smale et al., 1999).
There was AVO study called "Investigation of the Miocene Moki Formation Within the Parahaki 3D Survey; Taranaki Basin, Offshore New Zealand Using Some Geophysical Tools" in Moki reservoir to Investigate and assess the AVO response of the Moki sand formation.
By using the results of The AVO study, the inversion can apply in the area to enhance the result, generate rock property volume, Enhance reservoir quality, Hydrocarbon distribution and sweet spot detection with min. risk.
By running three volumes of post stack inversion (vp, vs, density) and use λ, μ and vp/vs to identify the hydrocarbon contact distribution. Then by using AVO Inversion (Another different fast technic in the relative domain) to prove the results and using Extend Elastic Impedance Method.
The result of this study is there are three prospects in Moki formation, the maps show that Arawa -1 at very low probability of hydrocarbon content which provide our result as it is a dry hole.
By using multi-Attribute analysis, we can find new channels system in Pliocene age. Depending on the complexity of the channel system, different attribute analyses had varying success with each system. By using 3D curvature, variance and RMS Amplitude we can improve understanding of the Pliocene channel elements in terms of structure, channel evolution, and lithology.
Based on the previous results for these channel systems, RMS amplitude and sweetness attributes can use to detect lithological changes that highlight both shale and sand dominant regions of the channel. These results suggest that the lithology of the small channel is refer to the delta lithology in this individuals channel area, and we can interpret the small channel is filled with a sand lithology, which allows the RMS and sweetness to detect in against the mud rich background lithology.
Automated Sensor Agnostic Zero-Offset VSP Processing
Authors: Bettinelli Pierre , Chen Yu , Mizuno Takashi , Calvez Joel Le 
Published: February 2022

Abstract
We developed an automated zero-offset VSP processing workflow utilizing visco-elastic waveform inversion technology to obtain seismic velocity and attenuation profile along the borehole at minimal human intervention. The workflow is capable of leveraging different types of sensors such as geophones, DAS, and hydrophone so that all zero-offset, check shot processing can be performed using the same technology. The ray-theory based forward modeling engine is capable for attenuation effect using ray theory, which makes visco-elastic inversion as simultaneously, and not two steps approach as it used to be. Different types of objective functions are employed, which makes inversion robust for commercial use. The workflow applied in three cases studies, and feasibility of real time zero-offset VSP processing is demonstrated. The workflow described in this paper, is designed for human-less intervention and robust computation, truly applicable for answer products at the wellsite.
Improved Cement Properties Prevent Well Control Incidents Potentials at Top of Liners
Authors: Al-Yami Abdullah , Shakhouri Aqeel , Al-Bahrani Hussain , Al-Khalaf Sara , Wagle Vikrant 
Published: February 2022

Abstract
Potential well control incidents at Top of Liners (TOL) may take place after cement placement. Typically, liners are run and cemented. After liner hanger is set, reverse circulation takes place. Positive and negative tests might be conducted to ensure integrity at TOL position. Then a clean out run is conducted, and well fluids is displaced to lower fluid density to conduct a flow check after displacement. Potential well control incidents could be indicated from the previous flow tests (positive test, negative test, or flow check test). If potential well control incidents are detected, a proper well control procedure followed by remedial cementing operation will be conducted.
The objective of this study is to detail proper cement formulations that is suitable for liner primary cementing, to resist any potentials for possible well control incidents. To mitigate potential well control incidents, cementing practices should be optimized. The cementing practices include cement composition, drilling fluids composition, spacer composition and operations such as pumping procedure and pressure testing. As cement slurry sets, hydrostatic pressure is reduced on the formation. During this transition, gases or fluids can travel up through the cement column resulting in potential kicks.
Spacers, cements, and drilling fluids should be designed and tested for compatibility for good displacements and bonding. Different types of spacer are required for each type of drilling fluid, such as salted drilling fluid or oil-based fluids. Testing should include running rheology tests, thickening time tests, and compressive strength development tests.
Cement shrinkage is another factor that can lead to potential well control incidents. Expansion additives are usually added to overcome this shrinkage. However, attention should be made to optimize the concentration and type used to avoid over expansion behavior. The study also evaluates the performance of the improved cement formulation against a conventional one. This is achieved by first measuring the relevant mechanical properties of both cement samples using tri-axial loading equipment. The measured properties are then used to populate a numerical model with the required input data. The numerical model is aimed to simulate the performance of each cement formulation within the context of a common and challenging operational scenario that could result in potential wellbore integrity and potential well control incidents.
Case Study: Single Well Design Targeting Three Water Bearing Formations
Authors: Al-Qattan Hamad , Al-Jassam Emad , Mansour Magdy , Morcey Mahmoud 
Published: February 2022

Abstract
Designing an onshore pilot well to be drilled and functioning as water disposal well targeting one of three potential formations to test and evaluate their injectivity. Based on evaluation results, an alternative new and deeper formation will be selected to dispose the unwanted associated produced water, instead of the current shallow formation that is considered as a natural aquifer by authorities.
The well is designed to reach the first target in a deviated angle after which evaluation of the barefoot injectivity testing will begin. The decision whether to continue drilling to a secondary target or complete the well depends heavily on the injectivity testing results.
The deviated angle of drilling will be dropped to reach a vertical position for the secondary target upon which the last liner will be run and perforated, then the formation testing will be conducted. In case of encounterg failure in the second injectivity testing, drilling to the deepest target will continue and final barefoot testing will be performed.
A final optimal design for the pilot disposal well is intended to meet the reservoir and geological team with minimal drilling risks. The distance between this well and the other deep offset wells was the main challenge where the planned total depth was never reached in the disposal location. Also, the design was tailored to accommodate the drilling sections with the separation and long intervals between the targets. Furthermore, the uncertainty of the deepest formation fluid in addition to the uncertainties of formations pressure and formations fracture pressure were a big dispute while preparing the drilling fluids programs particularly across the target in which a water based mud was used as drilling fluid not to damage the formations nor to jeopardize the results of the injectivity tests.
The pilot disposal well is drilled successfully penetrating two targets without the need to drill to the third formation. Hence, the new formation that will be used to dispose of the produced but unwanted water is defined after the reservoir team have evaluated the two injectivity tests. The results of the injectivity evaluation also provided the required number of wells that can handle all the expected produced water, and provided the required upgrade for the surface facilities to accommodate the injection pressure.
This unique challenging well design, combining slanted and vertical trajectories, can be utilized whenever the budget is limited to one well, while you have multiple different targets to explore.
Moreover, a specialized environmental impact study, conducted by independent contractor, confirms that there was no harm from the injected water to the groundwater.