bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shale, Clay and Thin Bed Reservoirs: Appropriate Characterization with the Single Model
Authors: Tyurin E. , Davenport M. 
Published: October 2023

Abstract
Thomas-Stieber (TS) model analysis (Thomas et.al, 1975) has been used to define thin bed properties using standard logs in multiple reservoirs. A key model assumption is a mixture of sand and shale formation components, and the latter has been particularly discussed on numerous occasions (Kennedy 2018, Juhasz 1986, Skelt 2014, Moss 2008).
Net from Thomas-Stieber analysis models are routinely compared with core or other methods and has validated the use of Vshale in those instances. However, in the net sand fraction the presence of dispersed clay can have a dramatic impact on porosity and permeability, implying that Vclay is a preferred parameter to accurately estimate reservoir quality. Furthermore, Vclay is a quantitative core measurement allowing for a robust core-log calibration, supported by other parameters.
This paper will investigate the key assumption of the TS model by directly incorporating clay volume data in the thin bed reservoir formation model. The presented modification accurately leverages the difference between Vclay and Vshale parameters integrating them in a single solution concept. Extended TS formulae (defined as the Thomas-Stieber-Tyurin or T-S-T model) can more accurately assess the impact of dispersed clay presence on thin bed reservoir quality and at the same time treat NTG as a binary parameter, e.g. shale or non-shale laminae. An updated formation hierarchy scheme is presented to accurately reflect the occurrence of shale, sand, and dispersed clay mixes in a formation. Geology-wise we demonstrate the applicability of a single model for sand-shale-silt laminations, further highlighted in the Net-NonNet vs Sand-NonSand fractions difference discussion. A multi-parameter model for permeability that includes dispersed Vclay is also presented.
Partial derivative analysis, presented in this paper, highlights the sensitivity and irreducible uncertainty associated with T-S-T model and demonstrates the importance of in-situ corroboration with independent methods to provide robust outputs. Stochastic simulation of the T-S-T model show the uncertainty range of the analysis and alignment with core and NMR to validate the model results.
The resulting analysis provides a robust framework to define volumetric ranges, reservoir quality in thin beds, key priorities for future data acquisition and support business critical decisions. We believe that presented workflow addresses continuous conversation in the petrophysical community regarding limitations and applicability of the TS model.
Effects of Microcracks Closure/Pore Collapse in Ultrasonic Analysis in Carbonates During CO2 Core-Flood Experiments
Authors: Leite R. J. , Rashidi M. R. A. , Shah S. M. , Mohsin N. H. , Bakar Z. A. , Azuddin F. J. , Goodman A. H. 
Published: October 2023

This study evaluates how sample modification promotes ultrasonic velocities increase in laboratory analysis due to porosity collapse/microcracks closure during the buildup pressures related to supercritical CO2 injectivity from offshore carbonate fields in Malaysia.
The evaluation considered the significant increase in confinement stress and pore fluid pressure acting on the ultrasonic velocity results. The variation of the effective stresses was also considered. One sample had different stresses conditions evaluated throughout the experiment and the ultrasonic velocities results were compared with sonic log derived compressional velocities. Eight other samples were evaluated for ultrasonic velocities only at the original reservoir conditions.
A comprehension of the pore and microcracks behavior under stress during the ultrasonic experiment is conjectured as the sample condition was not directly accessed during the experiment development. A discussion of possible mechanisms for the verified velocities variations is supported by literature data comparison, targeting the causes for such behavior during the experiments.
A Novel Procedure for Addressing Compositional Uncertainty in Volatile Oils, Critical Fluids, and Gas Condensates
Authors: Watson C. D. , Mogensen K. , Krejbjerg K. 
Published: October 2023

Abstract
Accurate fluid compositions are prerequisite to the development of reservoir fluid Equation of State (EoS) models; however, previous work shows that measured plus fractions can have relative deviations exceeding 25%. This paper addresses the issue of uncertainty in reservoir fluid compositions with focus on the plus fraction amount in fluids with a GOR greater than 600 Sm3/Sm3. A new modeling workflow handling uncertainty in the plus fraction amount to improve the accuracy of predicted EoS simulations is presented.
The paper presents a comprehensive review of previous studies on composition measurement and their limitations. Based on this review, a new modeling workflow is proposed that can identify and correct potential problems with the measured fluid composition when a composition issue is identified. The workflow involves an automated procedure that determines the optimum carbon number to lump back to during fluid characterization such that the extrapolated fluid composition gives the best match to the measured fluid composition. As opposed to methodologies that rely on artificial intelligence, the proposed fluid characterization procedure is fully transparent and interpretable.
The workflow is found to be suitable for volatile oils, critical fluids, and gas condensates and is tested on several samples with plus fraction uncertainties identified in their composition measurements. Previous literature has shown that characterization methods can typically predict saturation pressures with relative deviations below 10%. However, we find that uncertainties in plus fraction amounts can potentially cause simulated saturation pressures to deviate by 30% or more from experimental measurements. When applying the new methodology to a variety of measured experimental reservoir fluid composition data, we demonstrate that the experimental match of saturation pressures can be brought back within the expected deviation of 10%. In this way, the characterization model becomes predictive, requiring only minor tuning of EoS parameters.
The workflow identifies the potential problem of inaccurate plus fraction measurements and provides an automated method for handling this uncertainty in compositional analysis. By doing so, the proposed workflow can provide more accurate and reliable predictions of the phase behavior of light reservoir fluids before any tuning, which can be of great benefit to the petroleum industry.
This paper presents novel information on how to handle the uncertainty in the plus fraction amount for reservoir fluid compositions, which is a critical issue that has not been fully addressed in previous literature. The proposed workflow offers a practical solution to this problem, providing a new approach to correcting reservoir fluid compositions. The paper can be of significant benefit to the petroleum industry by improving the reliability of fluid characterizations for lighter reservoir fluids.
The Case Study of the Effect of Fault Transmissibility on the Oil Reservoir Production in the Onshore Field, United Arab Emirates
Authors: Al Hashemi Hussain H. , Fisher Q. J. 
Published: October 2023

Abstract
A study was conducted to improve the history match of oil production from an onshore field, hereinafter referred to as the OS field, by applying realistic fault transmissibility multipliers (TMs) with or without an integrated discrete fracture network (DFN) based model. Analysis of pressure before and after the start of production, production rate, injectivity tests and geomechanical studies were used to improve the knowledge of fault behaviour. These studies indicate that faults are discontinuous and potentially cut by open fractures; the data indicates that faults act as conduits and not as barriers to fluid flow. The fault TMs used to gain a history match were higher than predicted by the fault permeability and thickness data obtained from samples collected from UAE outcrops. Three scenarios were examined in which the fault transmissibility was given various values: (i) a fixed value, (ii) approximated based on fault rock properties from UAE outcrops combined with the DFN model or (iii) a fixed value combined with DFN. The results from these models were compared with historical production data. Applying a fault TM of 5 with a dual-porosity and permeability model produced the best match to production data. Oil production was predicted to be 13% higher using this model than for the base case in which faults did not impact flow. This is because faults enhanced fluid flow within this field. The fault analysis was consistent with geomechanical studies, which led to increasing the TM of the fault above one and integrating it with the DFN model until history matching was achieved. The history matching of the model is non-unique, and one could almost certainly get the same results by altering other parameters within the model. However, this study focused on integrating all available field data, such as fault properties, porosity and permeability of the matrix, and fractures that provide a history match without changing the petrophysical properties of the reservoir.
Artificial Intelligence for the Automatic Generation of Material Take offs from Piping and Instrumentation Diagrams
Authors: Ya-alimadad Mina , Hulard Thomas , Shteriyanov Vasil , Wu Jing , Banotra Richa 
Published: October 2023

Abstract
This paper is concerned with the application of Artificial Intelligence (AI) for the automatic generation of material take-offs (MTOs) based on piping and instrumentation diagrams (P&IDs).
McDermott (MDR) AI team worked closely with domain experts to establish a business case for the automation of MTO generation from P&IDs. Furthermore, upon conducting market research, a decision was made to pursue an in-house development to protect company IP, enhance the tool over time, and increase MDR's AI capabilities. A tool was created that uses advanced Deep Learning for text and symbol recognition to identify symbols and text. Thus, the results are associated and stored in an MTO.
Despite the existence of 3D software packages such as SmartPlant P&ID and AVEVA, often a digital format of P&IDs does not exist (e.g., legacy drawings) or is not accessible (e.g., clients only share PDFs at time of bid to protect sensitive information). In such cases, Piping Engineers spend hours going through drawings manually, identifying symbols, and generating MTOs in Excel spreadsheets. This process is error-prone which can lead to poor estimations and in turn cost overruns and delayed schedules.
An AI-based web application was developed that can free up skilled engineers from manually generating MTOs and save hours. The developed AI solution primarily enables the identification and extraction of symbols and their associated characteristics from P&IDs and populates MTOs. A user interface that allows engineers to check results and provide feedback as they process P&IDs, enables the users’ feedback to be captured by the tool to further enhance the tool's accuracy. The MTO generation can optimize the estimating process by saving hours and reducing mistakes. The more mature the tool becomes, the more this potential is realized on live projects and becomes a true game changer.
A closely linked and future application of this tool, often referred to as digitalization of P&IDs, can be used to extract all information from P&IDs. This information can be formed into a highly valuable database of past project data that can be fed to Machine Learning models and make insightful predictions.
First Pilot Design of Low-Tension-Gas (LTG) Flooding in Carbonate Field in North Oman
Authors: Al-Abri Mohammed , Mahruqi Dawood Al , Al- Aamri Nawal , Kahrobaei Siavash , Batenburg Diederik van , Abram Groenenboom Jeroen Peter , Carter Sam , Nasralla Ramez , Amri Sulaiman Al , Das Anindya , Abuawad Ahmed , Ramidhi Yaqoob , Malki Zahir Al 
Published: October 2023

Abstract
Field X is a medium-large low-permeability carbonate field situated in the Northern part of Oman that is in a mature waterflood stage. Low-Tension-Gas (LTG) flooding was identified as a promising EOR technology to improve oil recovery since it screened technically and commercially for a low permeability (&lt;10 mD), high formation water salinity (&gt;200,000 ppm and hardness 19,000 ppm) and relatively shallow depth (1200 m) condition.
Experimental studies in Field X cores have shown that LTG flooding can improve oil recovery by combining two effects: reducing the interfacial tension (IFT) between oil and water; and controlling mobility through the formation of in-situ foam with an injected gas. This paper presents the design of the first field trail for integrating the foam technology and water-alternating-gas (WAG) injection into the mature water flood in Field X.
To de-risk the various elements of LTG technology and evaluate its feasibility and potential, a phased strategy was developed. The first phase of the strategy focuses on testing the foaming surfactant and confirming if foam can be generated inside the reservoir. it involves piloting the foam generation through WAG injection to establish baseline followed by surfactant alternating gas (SAG). A hybrid approach based on numerical modeling and experimental data was used to design the optimum slugs of WAG an SAG. A comprehensive surveillance program was designed to evaluate the response of foam generation inside the reservoir. The program includes monitoring pressure responses, estimating saturation profiles and evaluating gas conformance improvement due to foam generation.
The injection scheme consists of 5 cycles of immiscible WAG to establish a baseline followed by 10 cycles of Surfactant Alternating Gas (SAG) to generate foam. Based on model evaluations we expect that the trend in bottom hole pressure during SAG over WAG should be observable (&gt; 10%) due to foam generation in the reservoir. The logging program is designed to confirm the divergence of flow from higher permeability to lower permeability zones. The results also might show a reduction in remaining oil saturation due to gas conformance improvements because of foam generation.
The results of the pilot tests will be used to evaluate the feasibility of LTG flooding for low-permeability, high salinity carbonate reservoirs in Oman. The data obtained will be critical to identify the potential benefits and challenges of shifting from a water-based flooding to a staircase of introducing gas, WAG, SAG (foam) and LTG flooding and guide further design and implementation of full-scale LTG flooding projects in similar reservoirs.
Agile Field Development Workflow Enabled Fast-Tracking of Clastic Oil Reservoir Maturation: An Agile Early Adopter Success Story, Sultanate of Oman
Authors: Sulaimi Ghadna , Oladiran Olanrewaju , Shuaibi Fakhriya , Hosni Mahmood , Kalbani Abdul Malik , Mandhari Suliman , Alawi Kathiya 
Published: October 2023

Abstract
The newly introduced agile field development process entailed leveraging the use of analogues, to fast-track the Integrated Reservoir Modelling process, provide justification for key project decisions and maximizing the use of existing wells and facility capacity. This paper will describe the workflow which was used to fast track the maturation of oil resources in one of the complex clastic fields in Oman, to move the project from opportunity identification to Final Investment Decision in less than 12 months.
Early opportunity scaling through phasing, Front End Loading (FEL) and Integrated Technical Review (ITR) assist was used to structure the assurance requirement for the opportunity maturation and to obtain stakeholder alignment and endorsement for the key select-phase decisions, to enable focus on the remaining key project decisions. Standardization and Replication of existing facility and wells solutions was also applied, such as using existing urban plan as basis for well locations, working with the Asset to identify and secure available hook-up slots for the proposed wells. Agile Project Management Way of Working was also deployed for the first time within a phased maturation process, that involve utilization of in-house task management tool (Injaz), where the tasks were divided into sprints and tracked frequently during regular cadence meetings by the Scrum master. These sprints made the project more flexible and adaptable to changes throughout the maturation cycle.
The new Agile Field Development process enabled the team to quickly narrow the decisions solution space and focus on the key select phase decisions (such as build new facility vs. use existing ullage; develop new area now vs. appraise first and develop later), leading to an acceleration of the development schedule by ~2 years. The application of this Agile methodology led to a cost savings of ~ $52mln when compared to normal project maturation workflow.
This project is an Early Adopter of Agile Field Development process in the front-end of project Management and is therefore a great model for other projects across the organization to learn from and replicate. The company Agile Project Management Office (PMO) has capitalized on the learnings from this Agile project retrospective and other early successes projects to widely implement Agile Field Development across the portfolio of opportunities.
Acquiring Surface Seismic Without Surface Receivers: A 3D DAS-VSP Case Study Offshore Abu Dhabi
Authors: Mason J. , Cambois G. , Al Mesaabi S. A. , Cowell J. , Boukhanfra F. , Mahgoub M. , Al Neyadi A. M. 
Published: October 2023

Abstract
While shooting a dense ocean-bottom nodes (OBN) survey offshore Abu Dhabi, 3D Distributed Acoustic Sensing (DAS) Vertical Seismic Profiles (VSP) were recorded utilizing semi-permanent optical fibers present in wells across the field. The objective was not only to provide the benefits generally afforded by 3D VSPs, but to use the surface-related multiples and obtain a 3D image of the subsurface comparable to (if not better than) the OBN survey.
The OBN survey recorded a high density shot carpet (25m × 25m) into 4C nodes on a 25x150m grid using a wide azimuth, long offset geometry. It was shot over a producing field with four artificial islands used as drilling pads. Optical fibers clamped to the upper completion tubing are present in the majority of wells drilled from these islands.
The team decided to use DAS interrogators to "eavesdrop" on the OBN seismic sources while the seismic sources operated in the vicinity of two of the artificial islands. VSPs provide local measures of attenuation, velocity, anisotropy, and multiple content that can aid surface seismic processing. Furthermore, a 3D VSP can provide an image of the subsurface that has higher resolution than surface seismic, but which does not extend too far from the well. A recent imaging technology for offshore 3D VSP uses seismic multiples to reconstruct the subsurface as if it were acquired by surface seismic. This imaging technology is very promising but suffers from weak signal-to-noise ratio, especially in ultra-shallow water. To mitigate this issue, the team used a total of 16 wells to reconstruct the subsurface in a 300km2 combined area around the two islands. The wells were chosen for the length of their usable fiber and their diverse trajectories.
Finding the Causal Signatures of Fracture Propagation: A Knowledge-Driven Causal Inference Workflow
Authors: Liu Rui , Misra Siddharth , Jin Yuteng 
Published: October 2023

Abstract
This study introduces a knowledge-driven causal-inference model to uncover causal signatures of fracture propagation. These signatures are extracted from wave-transmission measurements, independent of variations in sensor placement, fracture orientation, and material properties. Fracture propagation and coalescence paths are simulated using the HOSS simulator, and the resulting pathways are used in the K-wave toolbox for wave-transmission simulation. Extensive feature extraction is performed on the simulated waveforms, and a causal inference workflow is applied to identify causal signatures of fracture propagation. Notably, waveform attributes such as reoccurrence count, sum of reoccurring values, and variation coefficient play a significant role in capturing the causal signatures influenced by fracture propagation. This research highlights the distinction between causation and correlation, emphasizing the benefits of knowledge-driven causal approaches in addressing the limitations of current machine learning methods. The proposed model has practical implications for enhancing fracture monitoring, prediction, and early warning systems.
Structural and Fracture Intensity Modelling, an Integrated Approach for Fracture Basement Characterization: A Case Study of Mumbai High Field, Western Offshore India
Authors: Suresh More Varsha , Malviya S. C. , Mukherjee Sanjoy , Singh Deelip 
Published: October 2023

Abstract
Fractured Basement reservoir is unconventional in the context of reservoir nature and the process involved in its reservoir characterization. Hydrocarbon is established in Basement reservoir in sporadic manner in Mumbai High area of Western Offshore India. Basement in Mumbai High is found to be prospective near fault zones, at junctions of significant tectonic cross trends and fault bounded high. The present study carried reservoir characterization through Geo-Cellular Modelling (GCM) using seismic attribute, log data, well data and geological structural modelling.
The present study has been carried out on LUMINA processed seismic data with an objective to model the Basement reservoir and possible play consolidation in Mumbai High area. The workflow adopted for this study includes structural modelling, Fracture attribute analysis, Discontinuity modelling and generation of Discrete Fracture Network (DFN) modelling. The properties derived from the well and seismic attribute studies is transformed to a geological model through GCM populated with Fracture Intensity as property for reservoir characterisation, which is further used to derive DFN.
The accuracy of fracture characterization based on integrated model has been verified by drilling results of recent wells in the area, which are used in this case study. The case study demonstrates that the model built on integrated approach explain the distribution pattern of fractures in 3D space and helped in planning well path for successfully intersecting the fractures and establishing hydrocarbons. The paper comprise of illustration of three wells (WELL 11, 20 and 23) as case study which demonstrate fracture reservoir and also the analysis of Critically Stress Fracture (CSF). The Mohr diagrams illustrates the critically stressed fracture at virgin condition and also suggests that stimulation job can help in increasing open fractures. In few wells stimulation job was carried out which yielded positive results.
By adopting this workflow we can characterise fault and structural setting of the study area along with fracture intensity for unconventional Basement reservoir. Further, this workflow can act as a tool for predictive fracture modelling.