bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methodology and Approach of Lightweight Cement Evaluation in Horizontal Well for Integrity Assurance and Future Reservoir Development
Authors: Jongnarungsin Sarunya , Nimchinda Paritas 
Published: November 2020

Abstract
Well integrity is a critical issue for oil and gas companies. The failure of a wellbore integrity can result in financial consequences, have environmental impacts, and could damage a company's reputation. Cement placement is one of the most critical components with respect to ensuring mechanical support of the casing, protection from corrosion and isolation of permeable zones. Light weight cement recipes can help to overcome lost circulation problems during drilling or cementing, however, there are challenges with respect to the applications of Cement Evaluation logs, which are used to determine the effectiveness of the cement job. This is due to the fact that light weight cement exhibits high amplitude and little alteration in the log waveform on conventional bond logs because of its lower fluid density and compressive strength.
This research describes the application of an Advanced Ultrasonic Imaging Tool that combines traditional pulse-echo techniques with a new ultrasonic technique, which can differentiate low-density solids from liquids and distinguish light weight cements from contaminated cement or liquids. Furthermore, this research describes the application of the tool in a highly deviated well, which required the usage of a tractor deployed wireline operation. The results indicated low decentralization readings across the logging intervals and reflected the good data quality observed in the ultrasonic measurements. The processing flag track did not identify the presence of any errors related to the echo acquisition and data processing throughout the logged interval. Overall, a strong signal reflection was observed along the logging interval, suggesting clean inner casing surface. The combination of light weight cement logging on a tractor conveyance tools has been proven to be a successful approach. The application of this technique benefits Mubadala Petroleum Thailand with significant cost savings and reduced Health, Safety and Environment (HSE) risks for the overall operation.
This paper will demonstrate the following:
Cement bond log and evaluation of light weight cement by Advanced Ultrasonic Imaging Tool in comparison to conventional cement bond log tool Job design, efficiency gains and improved well integrity assurance from the operation Special cement designs intended to reduce the weight while maintaining important physical properties, i.e. compressive strength. Efficient downhole data acquisition methods utilizing wireline tractor logging
The material presented in the paper is based on the actual operations of Mubadala Petroleum, with examples illuminating light weight cement used in a horizontal well, as well as the combined application of an isolation tool with a wireline tractor, which is the first such application in the Gulf of Thailand. It will also show the well integrity assurance achieved, operational efficiencies gains and risk reduction obtained.
Critical Success Factors for EPRS Planning and Management
Authors: Cavallini Francesco , Quick Anthony 
Published: November 2020

Abstract
In the current market distress, characterized by reduced oil price and uncertain future, the focus on subsea integrity management is becoming crucial. Operators are often seeking comprehensive Life of Field services, over-taking the former conventional, planned and reactive Inspection, Maintenance and Repair strategy.
In this historical phase, maximization of uptime and extension of producing field operational life are deemed paramount, and such focus on asset integrity is even more crucial for aging subsea assets. Likewise, when a new development is sanctioned, many resources are invested to ensure efficiency and long-term productivity in a sustainable manner. This is particularly true subsea, where technological implications have a greater impact and where risk exposure can be high due to ship traffic, fishing or the like. Inevitably, these developments require constant attention to ensure a satisfactory productivity is maintained, and this is typically achieved by planning and executing IMR campaigns. However, experience has shown that regular inspections may not be enough due to the threats posed by external interfaces (vessels, anchors, fishing gears…), unexpected environmental influence (extreme conditions, earthquake, seabed motions, etc.) or even sabotage, which may be more demanding than the usual conditions a subsea pipeline is designed for, e.g. operational loads, corrosion, vibrations, fatigue, etc. Consequences may be either reduced production or a complete shutdown, which in some cases may be associated with extreme, temporary, containment measures.
These risks require to be identified and addressed by developing an Emergency Pipeline Repair (EPR) strategy grounded on reliable/field-proven solutions and specialized capabilities, which privileges the safest diverless approach over traditional diving solutions, especially when dealing with unknown pipeline conditions. In all regions, such EPR strategy shall address the Critical Success Factors presented in this paper, i.e. Engineering, Technology, Intervention capabilities and Preparedness, which are the cornerstones where to develop a proactive approach towards emergency situations in the frame of a comprehensive Life of Field philosophy. This paper also provides an overview of repair solutions adopted in various regions around the World, with an insight into the technological challenges to be faced for repairs in the Arabian Gulf present and future developments.
Underbalanced Well Intervention to Re-Enter a Dead Well Changed the Future Dynamics of the Largest Gas Field in Pakistan – A Successful Pilot Project
Authors: Ashraf Qasim , Khalid Ali , Luqman Khurram , Hadj-Moussa Ayoub , Hamim Nasir 
Published: November 2020

Abstract
The world was feared to hit peak oil early in the 21st century but oil demand continued to grow and most oil and gas companies dedicated a large budget into developing advanced techniques to maximize production from existing maturing fields while minimizing costs in future exploration. Some of these techniques focused on managing the reservoir heterogeneities, enhancing the production lift mechanisms and reducing reservoir damage while drilling. The end goal however was always to increase the ultimate recovery of hydrocarbons from proven reserves.
Pakistan an energy deficient country and a net importer of oil and gas is in dire need of self sustainability in oil and gas. Located in southern Pakistan, Qadirpur field once produced upto 600 MMSCFD of gas, currently produces only 250 MMSCFD of gas. The primary reservoir in the field is a water drive reservoir which after extensive pressure depletion has caused water conning and fingering in a large number of wells. Recent attempts to drill new wells have suffered massive lost circulation resulting in severe reservoir invasion damage, and ultimately zero production was observed in a most recently drilled well.
As a final resort the operator opted to perform a well intervention in an old and dead well with underbalanced drilling techniques to drill a horizontal leg in the narrow pay zone of the reservoir. The underbalanced drilling campaign was expected to eliminate lost circulation and the ensuing invasion damage to the reservoir formation, characterize the reservoir while drilling and identify sweet spots, and finally increase efficiency of the drilling process and reduce the associated costs.
For the pilot well, a multiphase underbalanced drilling fluid was designed to achive extremely low bottom hole pressures, then appropriate directional drilling equipment with electromagnetic measurement while drilling tools were selected to operate with multiphase fluids, and finally a downhole isolation valve was incorporated in the last casing string to allow tripping without the need of ever killing the well.
The execution of underbalanced drilling in the pilot well resulted in an unprecedented gas production rate of 14 MMSCFD, identified a sweet spot of hardly 0.5 meters in true vertical depth (TVD) of the pay zone, and increased drilling performance upto 3 times of a conventionally drilled well. The success of the pilot well changed the dynamics of the depleting Qadirpur field as a well intervention on an old and dead well could yield the same production as on a new well while costing half as much. The paper elaborates on the techniques applied and lessons learnt on the pilot well.
Protect Wells During Frac Plug Drillouts and Well Flowback Operations for Hydraulically Fractured Wells – The State of The Art in 2020
Authors: Potapenko Dmitriy , Theuveny Bertrand , Williams Ryan , Moncada Katharine , Campos Mario , Spesivtsev Pavel , Willberg Dean 
Published: November 2020

Abstract
Highly efficient multi-stage hydraulic fractured horizontal wellbores are the dominant completion method for many basins worldwide. This completion workflow is followed with the well start up operations, usually consisting of the frac-plug drill out (FPDO) and the well flowback, designed for preparing the well to the production period. Poor management of FDPO and flowback operations on wells with freshly constructed hydraulic fractures, may jeopardize the investments made in completing the well, and may seriously reduce the well’s profitability. Previously reported results show that flowback and initial production practices have a major impact on proppant production, maintenance and disposal costs, and the subsequent well performance. In this paper we present the summary of the results obtained from the analysis of over 200 FPDO and flowback operations in the United States and Argentina. These results show that operating a well within the safe stability limits of the hydraulic fracture network minimizes risk of fracture damage and maximizes well performance.
Earlier it was shown that typical plug drillout operations consists of a series of underbalance, overbalance and balance periods. Multiple rapid transitions between these conditions and performing plug drillout operations outside of the fracture stability limit, was shown to destabilize the proppant pack and mobilize proppant from the fractures. In this paper we evaluate the impact of the various plug drillout strategies on the proppant distribution in the fracture, and draw conclusions about the strategies that help to preserve fracture conductivity. We also demonstrate that using high-frequency monitoring of the surface rates is key for managing plug drillout operations to minimize mobilization of the proppant from hydraulic fractures.
Use of the recently introduced Secure Operating Envelope (SOE) concept was found to be very beneficial for managing well flowback and the production operations. In this paper we demonstrate how the use of the SOE methodology was used for identification of the root cause of the proppant flowback and deriving the appropriate choke management strategy for solving this problem.
At the end we conclude that majority of the highlighted problems can be solved through optimizing the well start up operations as a part of the entire well construction process with making changes to the well construction workflow. Implementing certain changes to fracture treatment design should enable maximization of the well production performance and optimize the well economics.
Geologically Consistent History Matching Honouring Rock Types Driven by Adjoint Method
Authors: Jenei Bettina , Ganzer Leonhard , Almuallim Hussein , Manasipov Roman 
Published: November 2020

Abstract
Most history matching (HM) tools consider only the minimum and maximum geological constraints during their calculations. As a result, after several iterations, the link between petrophysics and SCAL data is often lost. The iteratively created model suffers from certain geological inconsistency, as for example porosity/permeability relations are not honouring their petrophysical constraints. In this paper the relation between model parameters is coupled to rock types which are iteratively updated as a part of the history match process.
An adjoint history match method is used to predict permeability updates for all individual grid blocks. Whenever the permeability (or other property) value of a grid block falls outside the typical range or violates the geological consistency limits, the rock type of the related grid block is moved to a better fitting class. This approach coupled with the adjoint method will provide an improved history match workflow. The workflow is presented for synthetic simulation models and the results are compared against benchmarks.
The modification of rock types driven by areal permeability improves the HM workflow. The rock types have different permeability ranges, relative permeability curves with different connate water and residual oil saturations. Based on the areal permeability, the rock type is changed with corresponding parameters at grid block level. The extended workflow of HM allows parameters to be modified co-dependently according to the rock type definition, after the permeability adjustment suggested by adjoint based algorithm. The results show obvious improvements in HM quality in terms of geological consistency with less iterations. This workflow is an efficient extension for HM of oil and gas fields. Potential challenges can arise in this approach. The rock type distribution may change compared to the initial setting. Since the initial volume calculation is based on rock type dependent properties, it can cause small changes in initial hydrocarbon volumes (STOIIP). Conflicting indicators (different model parameters suggest different rock types) must be handled, which requires prioritizing in order to avoid inconsistency. Properly including the porosity-permeability correlations, priorities and model specific details, the rock type can bind all the geological properties together, which allows consistent parameter changes for an improved HM process.
This paper investigates a new workflow that improves the geological consistency of the process of assisted HM with a strong consideration of different geological constraints with respect to the different rock type definitions. The new workflow is provided as an external tool that can be applied as an extension for existing assisted HM workflows.
Evaluation of In-Situ Gelation Behavior by Slim Tube Technique for Deep Conformance Control
Authors: Wang Jinxun , AlSofi Abdulkareem M. , Alzahid Yara A. , Boqmi Abdullah M. 
Published: November 2020

AbstractGel-based conformance control is a potential method to ensure optimal contact with remaining oil in heterogeneous reservoirs. Conventional gel screening focuses on evaluating bulk gel properties, such as the gelation time and the gel strength. Evaluation of gel in-situ properties is limited to residual resistance after gelation (static property). A clear understanding of the gel dynamic properties in-situ is necessary for accurate performance evaluation and numerical upscaling of gel-based deep conformance control applications. In this study, we present a representative technique to evaluate polymer gel dynamic properties. Continuous gelant flow experiments are performed in an 80-ft long slim tube at reservoir conditions. The porosity of the slim tube is 37.0%, and brine permeability is 8.5 Darcies. Multi-point pressures along the tube are monitored to evaluate the variation in the gelant's ability to flow. The time-dependent permeability reduction and in-situ gelation time are determined based on the pressure responses. With which, we conducted a systematic study of in-situ gelation of an organically cross-linked polymer gel system at 95°C. A low molecular weight copolymer of acrylamide and acrylamide tert-butyl sulfonate was used in this study, which was crosslinked by polyethylenimine (PEI). Bottle tests conducted on gels with different polymer and crosslinker concentrations showed that the gelation time of the studied gel system can reach up to 10 days at 95°C. This indicates the potential of the studied organically cross-linked gel for deep conformance improvement applications. In the slim tube test, the polymer solution is injected before and after the gelant slug, which helps to diminish viscous fingering and maintain the gel-slug integrity. The in-situ gelation time, determined as the time when a clear shift (significant increase) in pressure drop buildup rate is observed, was consistent with that determined by the bottle tests. The slim tube technique presented in this study can simulate the propagation of gelants through porous media across long distances at actual reservoir conditions, providing essential data for the upscaling and design of gel-based deep diversion treatments.
Cost Effective Decommissioning Liability Solutions for Offshore Structures
Authors: Boondao Isara 
Published: November 2020

Abstract
The objective of this paper is to provide an outline of current decommissioning guidelines andtypical practices, and to explore cost effective ways in which companies can navigate through this multifaceted process. This is demonstrated via a revealing case study which illuminates an optimum, cost effective decommissioning methodology for offshore facilities and structures, which is closely aligned with emerging decommissioning guidelines and regulations and with industry best practices.
Decommissioning is governed by local regulations and is triggered by a number of specific factors, such as when the remaining reserves are less than 40%, or when the concession has a remaining period of less than 5 years, or in some cases when production has ceased. Normally, at some points in the process, security deposits are placed by the operator, which can be significant. Since this cost is seen as a liability and is based on an estimated decommissioning costs, a cost effective, yet regulatory compliant solution is required. This paper discusses various best practice technical strategies for decommissioning, which can be applied in the South East Asia (SEA) region, and throughout the world. The strategies proposed can result in an estimated operator saving of over 30% over the entire decommissioning execution expenditure. The processes that are discussed are included in the typical steps of preliminary design, detailed design and execution.
Paleo Environment Analysis Using Geochemical Data of the Intershelf Basin in Cenomanian, Cretaceous of Abu Dhabi
Authors: Yamanaka Motoyoshi , Amo Miki , Nanjo Takashi 
Published: November 2020

Abstract
The central part of the Cenomanian intrashelf basin in Abu Dhabi is composed of mudstones with high TOC concentration. The mudstone with high TOC in the Cenomanian interval is divided into three zones as named of OAE1d, MCE, and OAE2 of OAE (Ocean Anoxic Events). In this study, the two wells (Well A and Well B) were re-evaluated to confirm carbon isotope curve (chemostratigraphy) and geochemical/biomarker analysis including TOC measurement and to consider paleo environment developing these mudstones within the intrashelf basin.
Regarding this intershelf basin, there are several papers to study of the relationship between TOC (Total Organic carbon) and OAE (Ocean Anoxic event) using geochemical analysis. We conducted core observations, GR log correlation, carbon and oxygen isotope analysis, trace elements analysis, mineral mapping, TOC analysis and biomarker analysis of two wells. Sampling was taken at 3ft for both wells. The results of carbon isotope were almost the same as the OAE zone (three OAE zone from lower to upper OAE1d, MCE and OAE2) within previous studies.
Flat ammonite/inoceramus in OAE1d mudstone were recognized in both wells. It is highlighted that the ammonite/inoceramus indicates a good example to understand the productivity and preservation of the OAE. The cross lamination of mudstone contained ammonite/inoceramus had not received any bioturbation, therefore, the OAE1d interval is considered to have been buried earlier than biodegradation. This mudstone shows the alternation of gray- and dark-colored (each thickness is 10-30cm) and high TOC contents around 11-13%. However, mineral mapping suggested that illite and pyrite were only partially confirmed in well B. Same samples were increasing C35 Homohopane. Regarding paleo topography, well B was located near hinterland area, which provided carbonate debris with clay minerals. In addition, the results of two wells are plotted with variation of C28 sterane in the ternary diagram. However, oil samples in the Afield located on east side of intershelf basin are plotted in the almost same area in the ternary diagram. The differential was dependent on seawater circulation between intrashelf basin and open marine of Eastern Tethys. By combining the newest technologies like carbon Isotope, ICP-MS, mineral mapping analysis and biomarker analysis, this allows an in-depth understanding of regional geological interpretation. In addition, core and thin section observation is an essential part to the geological understanding.
Virtualization in Operational Technology OT Environment
Authors: Mookonil Vijay , Almeqbaali Meirah 
Published: November 2020

Abstract
The objective of this paper is to present the Virtualization concept, its anticipated benefits and demonstrate how it is the future for OT (Operational Technology) environment and Oil & Gas industry in general.
In ADNOC Gas Processing plants, there are several control systems commisioned and operational. Majority of these systems such as Distributed Control system (DCS), Supervisory Control And Data Acquisition System (SCADA), Emergency Shutdown System, Fire & Gas Systems, Turbine Control System, Anti-Surge Control Systems, etc. are very critical operationally, due the safety of the plant. Lifetime of these assets is not as long as it used to be in our industry during the past few decades, due to various dependencies and concerns related to Operating Systems obsolescence and the associated dependency on the hardware.
All Control System applications run on various versions of Microsoft Operating System (OS), as Microsoft is the sole Windows operating system supplier, to supports computer's basic functions & interact with advanced applications and control peripherals.