bluuebunny/crossref_metadata_2025 huggingface dataset:
A State-of-the-Art Water Shutoff System in Carbonate Reservoir: From Lab to Field
Authors: Alabdrabalnabi M. I. , Almohsin A. M. , Baiz A. I. , Busaleh A. S. , Al Bin Saad H.
Published: October 2023

Polymer gel systems have been utilized extensively as a water shutoff material to control and reduce excessive water production and eventually improve oil recovery. A novel water shutoff material with excellent gel strength and thermal stability has been developed to minimize water production zones based on various operational parameters such as pressure, temperature, pumping rate, treatment duration, and shut-in time. This paper presents the state of art polymer gel with an adsorption system from the laboratory phase to the thriving field implementation of water shutoff technology in carbonate formation. The developed polymer gel system comprises copolymer, organic crosslinker, and adsorption constituents. The water shutoff agent's gel strength and gelation time were deeply examined using high-pressure, high-temperature (HPHT) rheometers. The rheological properties, such as storage modulus (G’) and loss modulus (G") of matured gels with different compositions, were studied to identify the gel strength of each system. Additionally, the effect of temperature, polymer, and crosslinker on the gelation reaction was captured as part of the experimental research. Based on extensive lab experiments at downhole reservoir conditions, the water shutoff treatment was optimized to control water production from vertical oil well producers.

The experimental results indicated that this water shutoff technology exhibited low initial viscosity for all systems below 20 cP at standard conditions, giving an advantage of pumping requirements during fluid mixing and injection to the targeted zones in the field execution. Once the water shutoff fluid travels downhole to the targeted zone, the temperature starts to buildup, and the gelation reaction begins. Consequently, the fluid viscosity is controlled at a specific bottomhole temperature based on liquid compositions, mainly polymer, crosslinker, and adsorption agents. This determines the gelation time between minutes to more than 10 hours. Therefore, this water shutoff gel can be placed smoothly into the target zone as a single-phase fluid with desired gelling time to plug the targeted formation. As for treatment design, the field testing utilized an E-coil string to run a production logging tool to spot the sources of water production and detect the bottomhole temperature and pressures essential to formulate the water shutoff system. The post-treatment flowback revealed promising results of this novel polymer gel system. The water shutoff fluid minimizes more than 60% of water production based on pre-treatment flowback. The newly developed water shutoff system is a promising polymer gel technology to control water production from carbonate oil formations. The experimental findings and field outcomes unveiled that this robust polymer gel efficiently plugged the water zone at high temperature and pressure conditions.
Reducing Geomechanical Model Uncertainty Through Multiple Trajectory Stability Analysis Using Vertical and Highly Deviated Wells
Authors: Rajaiah Nanthakumar , Guerra Julian , Al-Asadi Yousif Mohammed Baqer , Xi Guifen , Aljaberi Salem Mubarak , Alblooshi Jamal Rashed
Published: October 2023

The wellbore stability back analysis is an easier task for vertical wells compared to deviated wells, since the stable mud weight window is highly affected when deviation is accounted for; furthermore, the limited drilling events encountered in vertical and slightly deviated wells compared to highly deviated wells led to uncertainties in the 1D mechanical earth model (1D-MEM) construction and the wellbore stability analysis (WBS).

This paper details a multiple trajectory stability analysis strategy to construct a representative MEM for wells with a wide range of azimuths and inclinations, in an offshore field in Abu Dhabi. The strategy helped to reduce the uncertainties associated to the stress magnitudes, when other geomechanics parameters are properly constrained, like the rock mechanical properties and pore pressure. Initially, the 1D-MEM's were constructed mainly for vertical and slightly deviated wells and calibrated with drilling events. Later, a blind test conducted in a highly deviated well showed excessive shear failure, contradicting the low mud weight using during drilling and the lack of wellbore stability problems. This inconsistency, led to include additional highly deviated wells during the MEM construction phase. Since all mechanical properties and stresses were properly constrained, the horizontal stresses were the variables to adjust, especially the maximum horizontal stress.

A parametrization study was conducted for the stresses till honoring the wellbore failure for additional highly deviated wells. The minimum horizontal stress was kept almost consistent to honor the offset field data and the 3D-MEM minimum stress. The maximum horizontal stress, on the other hand, was varied significantly, producing different stress scenarios and regimes. Eventually, there was a stress scenario that yielded reasonable wellbore failure results for a wide range of azimuths and inclinations, as proven during a post-mortem analysis conducted in a recently drilled well, where the amount of drilling problems was consistent with the new model. The multi-trajectory strategy can be used with higher confidence to optimize the safe mud weight window for any trajectory and well type.
The Hydrogen System in the Subsurface: Implications for Natural Hydrogen Exploration
Authors: Zhao Hongwen , Jones Ernest A. , Singh Rajput Seemant , Ismail Hasnol Hady B. , WahTan Seng
Published: October 2023

In the context of global efforts to achieve carbon neutrality, Hydrogen (H2) has emerged as a key solution for reducing greenhouse gases emission. However, current methods of hydrogen production, such as thermochemical and electrochemical processes like electrolysis, methane reforming and pyrolysis, are generally expensive and suffer from issues including intensive carbon dioxide emission and high electricity consumption etc. (Ishaq et al. 2022; Younas et al. 2022).

In fact, hydrogen gas can naturally occur in the subsurface which has been manifested by numerous hydrogen seepages found across the world (cf. Zgonnik 2020 and the references therein). Notably, a significant discovery of natural hydrogen was made accidently during drilling a water well (Bougou-1) in Mali in 1987. Subsequent exploration in the vicinity of Bougou-1 confirmed the existence of an active hydrogen system in the area (Prinzhofer et al. 2018), highlighting the possibility of commercial hydrogen accumulation in the subsurface. Moreover, there is a growing consensus that natural hydrogen could be an important alternative for hydrogen production (Zgonnik 2020).

In recent years, extensive exploration activities and scientific research focusing on natural hydrogen occurrences, generation mechanisms, and accumulation processes have been conducted, particularly, in Africa (Moretti et al. 2022; Prinzhofer et al. 2018), Australia (Boreham et al. 2021; Frery et al. 2021; Leila eta al. 2022; Rezaee, 2021), Europe (Combaudon et al. 2022; Larin et al. 2015; Lefeuvre et al. 2022; Leila et al. 2021), Brazil (Moretti et al. 2021; Prinzhofer et al. 2019), and the USA (Guélard et al. 2017; Zgonnik et al. 2015). Geological investigations indicate that natural hydrogen is dominantly found on Precambrian cratons, ophiolite belts and mid-oceanic ridges (Rigollet and Prinzhofer, 2022). It occurs as gas leakages on the surface or is associated with other gases in the conventional and unconventional gas plays (Milkov 2022).
A Novel Methodology to Capture Anisotropy in Unconventional Reservoirs: Theory and Methodology
Authors: Ibáñez E. , Alvarellos J. , de Melo R. C. Bezerra , Laksmikantha R. H.
Published: October 2023

A novel methodology is presented based on the concepts of poro-elasticity and tectonic strains to capture material anisotropy, later to determine stress anisotropy. An accompanying article in this conference presents the results of a case study to demonstrate the applicability in real case. Stress anisotropy determination requires material anisotropy as input and acquisition of these properties is expensive & not common practice, thus the methodology is an efficient cost-effective alternative to a complete anisotropic characterization. Current methodology proposes multi-well inversion applying poro-elasticity to obtain the lateral effects of tectonics in the stresses. Each well uses isotropic poro-elastic, VTI or Orthotropic models depending on the type of information available. The approach has the following options: (1) Individual /direct strain calculations with a set of 1D Geomechanical Models (1DGM), (2) Pair of strains for each well, (3) Multi-well inversion using 1DGM´s with custom depth range selection. The proposed novel methodology integrates the interpretations from options (1), (2) and (3) to locate anomalies and determine strains at field scale. The current methodology has been applied to variety of reservoirs/plays: unconventional/Shale, conventional, and complex structural setting (salt environments, etc.). Applying options (1) and (2) any horizontal anomalies in the field scale strains could be identified. In another application using options (1) & (2) local stress rotations due to the salt dome was detected. Tectonic strains in a well showed clear signs of local stress perturbation due to the nearby strike slip fault. Option (3) is applied to locate vertical anomalies, usually by removing formations from top to bottom in a muti-well fitting. Higher strain values were obtained when a specific formation was excluded from the analysis. Later a deep inspection of the seismic data a reverse incipient fault was found in the excluded formation marking a global detachment level that was not active at present day. In addition, another benefit of the proposed method is far-field strains can be determined as a vertical profile or a pair of values at field scale, that serve as boundary conditions for stress initialization process of a 3D Geomechanical model with no iterations. The proposed methodology has demonstrated the capacity to obtain the strain far-filed effects of tectonics at field scale. Current methodology applied at early stages of field characterization only with 1DGM can locate anomalous strain/stresses that helps mitigating drilling hazards in future wells and in unconventional wells as input to hydraulic fracture design. Conventional stress initialization of a 3D geomechanical model requires several iterations to reach an acceptable stress field.
Assessing the Impact of CO2-H2S at 400 ppm for Storage: A Geochemistry Perspective
Authors: Zaidin M. F. , Razak A. A. , Abdullah W. M. S , Tewari R. D.
Published: October 2023

The presence of impurities, such as H2S, in CO2 injection carries a higher risk of sulfide mineral precipitation. This can have detrimental effects on rock properties, leading to a reduction in rock porosity and permeability. Consequently, it affects the injectivity and storage capacity of the reservoir. In addition, the reliability of fluid-rock reaction simulations is uncertain and requires calibration using laboratory data. However, there is a scarcity of published experimental data on the geochemical effects of CO2-H2S under reservoir conditions. The objective of this study is to measure the key parameters of geochemical reaction kinetics between injected CO2-H2S at 400 ppm concentration level, brine, and carbonate reservoir rocks, and their effects on fluid and rock properties. Carbonate core samples from the X Field have been selected as a case study due to their identification as potential CO2-H2S storage sites, and the availability of the core samples. In this study, H2S gas with a concentration level of 400 ppm is pre-mixed with CO2 and brine water. The CO2-H2S-brine mixture is aged with core samples under X Field reservoir conditions using two different setups: high-pressure chamber (static) and core flood (dynamic) for a duration of 30-days and 14-days respectively. These setups were designed to represent two different scenarios during injection: far from the wellbore and near wellbore scenario. At the end of the ageing period, cores and effluent were collected for analysis to measure changes in key geochemical parameters, including rock porosity, permeability, mineralogy, and images from CT scans, between the post-ageing and pre-ageing stages. The findings offer valuable insights into the behavior and stability of carbonate rocks within near wellbore and far from the wellbore environments during CO2-H2S interactions. Understanding the geochemical processes involved is crucial for evaluating the long-term stability and containment of CO2 or natural gas containing impurities such as H2S in geological storage scenarios.
Enhancing Pipeline Integrity Management with Machine Learning and Integrated Monitoring Technologies
Authors: Wang Kang , Chughtai Adnan , May Joshua C. , Poddar Sneha
Published: October 2023

As the oil and gas pipeline industry shifts toward digitalization, machine learning and artificial intelligence (AI) play an increasingly important role in asset integrity management, including operation monitoring, leak and intrusion detection, corrosion protection, and flow assurance, among others. This paper introduces an integrated approach using fiber optics, inspection reports, and fluid flow simulations and demonstrates how machine learning and AI can help operators by producing unified insights.

Fiber-optic distributed acoustic sensing (DAS) technologies are routinely used to monitor pipeline activities; critical events such as product leaks, digging near the pipeline, and pigging are captured by quantitatively analyzing unique signatures on the fiber-optic generated space-time image. This can be treated as a pattern recognition or machine learning problem. YOLO, a state-of-the-art fast object detection algorithm, was used to demonstrate accurate tracking of pipeline inspection gauges (PIGs), among other activities, using a small quantity of training data. In addition, using AI, routine inspection reports and flow simulation results were automatically calibrated, cross-validated, and then contextualized with the fiber-optic DAS generated events.

The event detection and classification algorithm used in this work achieves high location accuracy, superior to current industry-standard methods. As a result, this method significantly improves the tracking of PIGs. More importantly, these detections are automatically calibrated with inspection reports for cross-validation. Traditionally, fiber-optic systems are an independent and isolated sensor technology, which require field teams to perform manual activities approximately every 2 km along the entire pipeline for georeferencing. This is inefficient and does not provide the location accuracy needed to link the fiber-optic system to other sources of data, such as inspection reports or flow simulation results. This lack of integration has been a longstanding challenge that prevented operators from easily isolating important signals or repeated trends for each weld, valve, meter, or road crossing, for example. With our machine learning - assisted integrated management system, various sources of data can be consolidated and analyzed to provide valuable information that was previously unavailable.

This paper presents the novel use of fast machine learning models to accurately detect and track pipeline activities. In addition, data analytics aids in the calibration and cross-validation of different monitoring technologies under a single integrated pipeline integrity management platform, providing operators with unique insights.
On-Line Full Molecular Characterization of Flashed Gases with a New Generation of NGD Detectors for Micro-GC
Authors: Maniquet A. , Sobrado L. Alonso , Collell J. , Colinet E. , Loriau M.
Published: October 2023

Today, to get a full molecular characterization of gases, a gas chromatographic system hyphenated to both flame ionization (FID) and thermal conductivity (TCD) detectors is essential. However, for on-site, on-line analysis (mostly ATEX zone) FID are forbidden and TCD only allows quantification up to C7. A new universal detector (NGD for Nano Gravimetric Detector) covering a hydrocarbon range from C1 to C40+ has been developed and implemented in miniaturized and transportable system [1].

The first step is to evaluate the NGD response for different families of compounds present in the gas (synthetic and process gases) and develop different approaches to simplify the quantification. This one will be carried out in laboratories. To increase productivity and accuracy for PVT experiment, this detector will be implemented on a PVT unit. Once validated on fully controlled flashed gases, the system could be updated to work with batteries to be fully transportable for on-site or adapted for on-line analysis to be able to monitor any gas anywhere up to C11/ C12.

All compounds were well separated and detected with the chromatographic resolution required for this study. Different standards gases have been used: from nC1 to nC10 with BTEX (benzene, toluene, ethylbenzene, m-xylene, p-xylene, and o-xylene). To achieve an external quantification, two approaches were carried out. A first approach based on the linear relationship that exists between the NGD response (as the logarithm of the peak area normalized by concentration) and the number of carbon atoms. These linear relationships are different depending on the family of compounds analyzed. The second approach uses a hyperbolic method based on the Langmuir model by applying an inverted Langmuir equation. This approach allows calibration of the NGD detector using a single linear relationship for all compounds regardless the family to which they belong. A quantification on diluted standards gases was carried out (4 levels) and the relative error was less than 10%. Moreover, a hyperbolic Langmuir approach improved the accuracy of the results with errors inferior at 5%. During 2023, the aim is to calibrate the NGD detector for the quantification of all compounds present in a process gas from a PVT unit and to proceed to the on-line monitoring.

Today, only FID detector allows C5+ quantification on gaseous effluent, only present off-line. Tomorrow, thanks to the NGD detector, the gas analysis could be carried out on-line with a full molecular characterization of gases with a complete automatization of monitoring.
Shale, Clay and Thin Bed Reservoirs: Appropriate Characterization with the Single Model
Authors: Tyurin E. , Davenport M.
Published: October 2023

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

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

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

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

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 (<10 mD), high formation water salinity (>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 (> 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

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

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

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

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.
Collaborative Research on Grouted Pile-Leg Sleeve Connections Enabled Life Extension of Aged Platforms
Authors: Rao Aita Raja. S. , Sarkar Anjan , Eissa M. , Qian X. D.
Published: October 2023

Background

For an older fleet of the bottom founded steel jacket type platforms which has been operating in Abu Dhabi offshore oil & gas fields, each of the platforms is secured by pile-leg grouted connections with shear keys provided on the outside of the pile only. · As the leg diameter was about 800mm, this precluded the provision of shear keys· on the inside of the leg. This connection design pre-dated the API or ISO recommended practice, which specifies the provision of shear keys on the pile and leg to offer a more direct load transfer mechanism.

Majority of existing fixed offshore platforms in offshore Abu Dhabi have non-conventional grouted connection between pile and jacket where grout is the only medium for load transfer between the two components. Due to their confinement these connections are not inspectable. Moreover, grout parameters associated with these structures do not comply with codal provisions. Hence the applicability of codal formulations to fixed jacket structures in offshore Abu Dhabi is a major uncertainty. Many Fields in offshore Abu Dhabi have significant life extension necessitating many structures in operation beyond their original design life. Quantification of grout performance considering ageing effect plays vital role in life extension of these structures and is currently beyond industry knowledge. In addition to this, continuous requirements of significant load additions make this problem more intense. This has raised a major concern for ensuring integrity of these structures while allowing life extension of these aged structures.

To address the above, ADNOC Offshore entered into a collaborative research program with one of the leading offshore Institutions at Centre for Offshore Research & Engineering, National University of Singapore (NUS) aimed at conducting experimental investigations supported by analytical simulations to develop ADNOC Offshore specific grout strength design equations which will be helpful in assessment of strength of aged grouted connections.
Repurposing Networks for Hydrogen
Authors: Peace C. , Waple N. , Haghighi Hooman , Cotton Harry
Published: October 2023

This paper presents an overview for repurposing and the potential blockers with respect to current code compliance based on Wood case studies of international code requirements and recent repurposing study work.

Based on rudimental calculations, comparing both energy Natural Gas (NG) and H2 carriers, repurposed pipelines can be capable of achieving circa 80-90% of the energy flow rate if design pressure can be maintained, or 50-60% if the design pressure is de-rated. If other operational restrictions are considered, such as flow velocity it can potentially have additional knock-on effect on the achievable flowrate and consequently to energy ratio. 

The feasibility of pipeline repurposing for hydrogen service is critical to the energy transition. Careful consideration of code requirements, and further research and development currently ongoing is required in order to remove over-conservatisms in design to maximise the achievable energy flow rate when repurposing to hydrogen service.
Vehicle Detection and Tracking for the Gas Station Digital Twin System
Authors: Yue F. , Ma J. , Qian Z. , Xu T. , Jiang W. , Dong J.
Published: October 2023

Objectives/Scope

A digital twin is a virtual representation of a real-world system used to digitally model performance, identify inefficiencies, and design solutions to improve its physical counterpart. With the success of digital twin systems in various scenarios, the digital twin system of gas station is expected to effectively improve the management efficiency and intelligence level of gas stations. Some typical applications include data analysis, traffic prediction, and route planning in gas station, etc.

Methods, Procedures, Process

The key part of the digital twin system of gas station is how to achieve accurate and efficient vehicle detection and tracking under various environmental conditions. Aiming at this goal, this paper proposes a practical vehicle detection and tracking method for gas station scenarios. We assume the digital twin system consists of a number of digital cameras and precisious 3D models of scene and facilities in gas station. We then present the proposed vehicle detection and tracking pipeline which includes the following three steps: 1) camera internal and external parameters calibration with known scene; 2) vehicle detection and real-time multi-target tracking, and 3) cross-camera re-identification and occlusion handling.

Results, Observations, Conclusions

We have conducted extensive experiments on several datasets. Experimental results show that the proposed method has good robustness to lighting and occlusion, and can effectively solve the problem of vehicle detection and tracking for the digital twin system of gas station.

Novel/Additive Information

In a real gas station scenario, real-time tracking of multiple vehicles can be achieved with an accuracy over 90%.