bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Innovative Approach of Using Engineering Modelling to Improve Drilling Dynamics in Western Rajasthan, India
Authors: Prakash Shailesh , Zayyan Mohammad , Gjertsen Ole , Acuna Manuel Centeno , Kulshrestha Piyush Kumar , Tewari Pratyush , Sharma Anshul , Alexander Gregg , Nik MohdNajmi Nik Fahusnaza , Wares Annie , Nikalje Shiba 
Published: March 2021

Abstract
Raageshwari Deep Gas (RDG) field is a major gas field in the Barmer Basin of Rajasthan, India which comprises of a tight gas-condensate reservoir within the underlying thick Volcanic Complex. The Volcanic Complex comprises two major units – upper Prithvi Member (Basalt) and lower Agni Member (Felsics interbedded with older basalt). The production zone is drilled in 6" and has historically seen high level of shock & vibrations (S&V) and stick-slip (S&S) leading to multiple downhole tool failures and poor rate of penetration (ROP).
Individual changes in Bit and bottom hole drilling assembly (BHA) design were not able to give satisfactory results and hence an integrated approach in terms of in-depth formation analysis, downhole vibration monitoring, correct predictive modelling, bit and BHA design was required.
A proprietary formation analysis software was used to map the entire RDG field to understand the variation in terms of formation compactness, abrasiveness and impact (Figure 1,2,3 & 4). The resulting comprehensive field map thus enabled us to accurately identify wells that would be drilling through more of problematic Felsics and where higher S&V and S&S should be expected.
To better understand the vibrations at the point of creation, i.e., bit, a downhole vibration recording tool was used to record vibration & stick-slip data at a frequency of 1024Hz. This tool picked up indication of a unique type of vibration occurring downhole known as High Frequency Torsional Oscillation (HFTO), that was quite detrimental to the health of bit and downhole tools. A proprietary predictive modelling software was used to optimize the bit-BHA combination to give least amount of S&V and S&S.
Data from the downhole vibration recording tool, formation mapping software and offset bit designs was used to design a new bit with ridged diamond element cutters and conical diamond element cutters to drill through the highly compressive and hard basalt. The predictive modelling software identified a motorized Rotary steerable assembly (RSS) to give the best drilling dynamics with the newly designed bit. The software predicted much lower S&V and S&S with higher downhole RPM which was possible with the help of motorized RSS. Implementing the above recommendations from the various teams involved in the project, drilling dynamics was vastly improved and ROP improvement of about 45% was seen in the field. This combination was also able to drill the longest section of Felsics (826m) with unconfined compressive strengths as high as 50,000 psi in a single run with excellent dull condition of 0-1-CT-TD
This paper will discuss in detail the engineering analyses done for improving drilling dynamics in field along with how HFTO was identified in field and what steps were taken to mitigate it.
Utilizing Artificial Neural Network for Real-Time Prediction of Differential Sticking Symptoms
Authors: Meor Hashim Meor M. , Yusoff M. Hazwan , Arriffin M. Faris , Mohamad Azlan , Gomes Dalila , Jose Majo , Tengku Bidin Tengku Ezharuddin 
Published: March 2021

Abstract
Stuck pipe is one of the leading causes of non-productive time (NPT) while drilling. Machine learning (ML) techniques can be used to predict and avoid stuck pipe issues. In this paper, a model based on ML to predict and prevent stuck pipe related to differential sticking (DS) is presented. The stuck pipe indicator is established by detecting and predicting abnormalities in the drag signatures during tripping and drilling activities. The solution focuses on detecting differential sticking risk via assessing hookload signatures, based on previous experience from historical wells. Therefore, selecting the proper training set has proven to be a crucial stage of model development, especially considering the challenges in data quality. The model is trained with historical wells with and without differential sticking issues. The solution is based on the Artificial Neural Network (ANN) approach. The model is designed to provide users, i.e., driller or monitoring specialist, a warning whenever a risk is identified. Since multi-step forecasting is used, the warning is given with enough time for the driller or monitoring specialist to evaluate which preventative action or intervention is necessary. The warnings are provided typically between 30 minutes and 4 hours ahead. The model validation includes the performance metrics and a confusion matrix. Practical cases with real-time wells are also provided. The ML model was proven robust and practical with our data sets, for both historical and live wells. The huge amount of data produced while drilling holds valuable information and when smartly fed into an Artificial Intelligence (AI) model, it can prevent NPT such as stuck pipe events as demonstrated in this paper.
Run To End: The Way We Manage Our Late Field Life
Authors: Samsu Fatimah , Ramachandran Visumathi , Abdullah Intan Shafinas 
Published: March 2021

Abstract
Run-to-end (hereafter referred to "RTE") is a fit-for-purpose approach to manage late field life assets for realization of full potential through safe, reliable and cost effective operation by maximizing value at the end of economic life while complying to minimum technical standards through ALARP demonstration. RTE provides an overview of the multiple processes which shall be adopted and customized to the business needs of the intended facilities with the aim to minimize value leakage and ensuring safety until facility's cease of production prior to relinquishment or decommissioning. This RTE philosophy is to be applied to facilities that are within 5 years of its end of economic life so that value leakage can be minimized within the tolerable risk. The RTE provides an overview of development of case for change, guided process for the Operation & Maintenance philosophy changes and demonstration of risks mitigation & governance assurance. The safety risk of the facility shall be assessed and monitored through continuous ALARP demonstration. If the facility is deemed to be either no longer safe through ALARP or can no longer maintain a positive cash flow position, it is recommended that the facility to cease production operations and proceed with relinquishment or decommissioning activities. It has been implemented in one of late field life and resulting to 30% reduction of OPEX.
Application of Key Technique in Splitter Wellhead Cementing Enabled Successful and Safe Operations
Authors: Lau Chee Hen , Kishore Kumar Avinash , Thuzar Myat 
Published: March 2021

Abstract
This paper describes the application of key technique for splitter wellhead cementing of top-hole section in conductor-sharing wells in dozens of development wells in offshore Malaysia. Its objective is to elaborate on the challenges faced during the well planning phase, methodology of cementing technique, cementing slurry design as well as solutions outcome and lessons learnt. Limitations of current software in the industry to simulate the conductor-sharing well cementation and approaches to maneuver through these limitations are also discussed.
During the well planning phase, cementing technique to address the risks associated with splitter wellhead cementing such as accidental cementation of dummy string, poor cement coverage in shared conductor, and losses uncertainties were analyzed. The cementing execution results of first batch of wells are examined, i.e. pressure profile, cement returns as well as opportunities for improvement were documented and translated into recommendations leading to eventual success for future well design. The cement slurry design for each casing in the splitter wellhead are also established based on its associated job objectives which is based on the unique approach in splitter wellhead cementing.
The establishment of key cementing technique for such an unconventional well construction technology is important in order to ensure continuous success both in cement placement as well as cement slurry design. The best practices are currently being replicated by other major operators in Malaysia for all splitter wellhead cement design. The learnings from the technique are incorporated into the technical standard of Malaysia operator as well to serve as a specific mandated requirement for future operations.
An integrated study of wellhead design, drilling practices and cementing technologies enabled a novel methodology to assure long term zonal isolation for the wells and innovation in the cementing approach enable cost savings for the operator as the wells can be drilled in a safe, efficient and cheaper way.
Full-Waveform Inversion and Least-Squares Migration to Improve Images in Northern Carnarvon Basin
Authors: Yao Jianfeng , Li Xiang , Zhao Kai , Zhang Hui 
Published: March 2021

Abstract
Northern Carnarvon Basin is located in North West Shelf of Western Australia. The basin has over 10km sediments and owns both oil-prone and gas-prone sediments and is the current largest oil and gas producing basin in Australia. A geological section through this basin is shown in Figure 1, the complex geological settings from shallow to deep leads to significant processing challenges. In the vintage processing, the seismic image at reservoir level is deteriorated due to the presence of following geological complexities: 1) rugose water bottom, 2) shallow frequent canyons or channel systems, 3) shallow spatial-variant Tertiary carbonates, and 4) shallow gas chimneys and other geo-bodies. These complex overburdens plus limited small-angle coverage of primary reflections from narrow azimuth (NAZ) streamer surveys make it very difficult for ray-based reflection tomography to resolve the shallow velocity. As a result, the target image suffers from large well mis-ties, low signal-to-noise ratio (S/N) and severe event undulations. In addition, shallow fast-velocity layers cause severe illumination issues for deep targets which are compounded by limited offsets of NAZ surveys. Furthermore, localised absorption effects from gas pockets lead to dimming amplitudes for events beneath them.
To deal with these issues, we propose to use time-lag full wave-form inversion (TLFWI) to resolve the velocity of complex overburdens and least-squares Q prestack depth migration (LS Q-PSDM) to compensate for illumination issues and absorption effects for the latest reprocessing. In the following sections, application procedure and results of these two technologies will be discussed. Seismic inversion was also conducted to assist the processing and analysis of the final result.
Innovative and Unconventional Approach to Cementing A Ballooning Well Leading to Good Zonal Isolation
Authors: Devadass Lingges , Kumar Avinash Kishore , Lau Chee Hen , Thuzar Myat , Sion Ban Tiyor , Kun Kai Rex Lo 
Published: March 2021

Abstract
Good cement bond log and sufficient zonal isolation are important aspects of production wells. Proper cement design and displacement are essential to ensure the cement objectives are met. Well A is one of four development wells, located in East Malaysia. The well was a gas producer, therefore good zonal isolation at the gas intervals are of paramount importance. Coupled with high inclination and formation with narrow pore pressure and fracture pressure margin, ballooning condition was encountered while drilling the reservoir section. These challenging conditions push the boundary of conventional cementing design further to implementation of unique and novel cementing approach to ensure no losses, minimal mud contamination with cement slurry and ultimately produce good zonal isolation.
This unexpected conditions of the well lead to re-designing the cement slurry and revamping the placement procedure for the 7" liner across production zone. Operator’s limited experience with cementing in ballooning conditions hampered any reference which could be useful for the job design. Required formation permeability, porosity data, mud flowback volume and duration of mud flowback at static condition were carefully assessed and taken into consideration in the cementing job design and pumping program. Based on the data gathered, an unconventional cement placement technique with specialized spacer and slurry design were proposed Well A, instead of complex back-pressure application technique in order to meet all required cementing objectives.
The cementing job was executed as per plan and no losses were observed during the entire cement job. Cement evaluation through cement bond logs indicated that enough isolations across the hydrocarbons zones of interest were obtained. Moreover, cement bond logs also showed good zonal isolation were also attained above and below perforation intervals showing very little contamination of mud backflow into the cement slurry. The cementing technique used proved to be relatively simpler and cheaper as it requires no additional equipment to rig up to execute compared to complex back-pressure technique which done incorrectly may lead to losses or remedial cementing.
The successful cementing operation showcased that the planned cementing technique and slurry design were effective for the cementing of abnormal well conditions. This success also highlighted the importance of job pre-planning and necessity to acquire all required data prior to actual operation. The job technique and design was replicated in subsequent wells which had similar well ballooning condition and resulted in great success.
Easy Steps in Probabilistic Dynamic Modelling in FDP
Authors: Anupam Ankesh , Tewari Raj Deo 
Published: March 2021

Abstract
Adequate implementation of probabilistic dynamic modelling workflow allows to explore full range of solutions and helps in better decision making. Probabilistic modelling workflows comprise of a series of steps. This paper closely scrutinizes three key steps of a probabilistic workflow – sensitivity analysis, experimental design and model selection for decision making. There are different methods and processes practiced in the industry for these key steps. A comparative study of commonly available and practiced techniques is performed, and their pros and cons are demonstrated using open available Brugge field model.
In the first part the commonly used tornado/one variable at a time (OVAT) is compared against other global sensitivity techniques suchas ANOVA (Analysis of Variance) and multi-regression analysis. The difference among the techniques is explained and its application is demonstrated through field example. It is shown that the global sensitivity analysis is more robust and provides better results but at a higher computational cost.
Next experimental design techniques are reviewed with focus on the optimum experimental design. Key concepts of experimental design such as aliasing, resolution and confounding pattern are explained. It is shown that an appropriate experimental design can be used to avoid confounding of key parameters. The confounding patterns have been demonstrated for factorial design experiments. The concept is shown with the example of Brugge model.
Model selection after history matching process is a challenging task. In the last part of the paper two different multi-dimensional visualization techniques PCA (Principal Component Analysis) and t-SNE (t-Stochastic Neighbour Embedding) are explained and utilized to visualize the ensemble of history matched models. These techniques in combination with k-mean clustering has been used to select representative models for prediction. The overall uncertainty captured by the representative models is compared to the full ensemble of history matched models. It is shown that clustering along with visualization provide a robust framework for model selection.
The paper is intended to provide a good understanding of some of the key steps of the probabilistic modelling workflow. The technical concept behind each technique is briefly described but the main focus is on the practical aspects and implemtation of these techniques.
Low Cost Well Innovative for Slim Hole Application in East Malaysia Marginal Fields
Authors: M Yusof M Hatta , Sulaiman M Zarkashi , A Bakar M Faiz , Alwi M Fairuz , Muslim Fadli Adlan , Fabian Oka , Bela Sunanda Magna , A Ghani Syazwan 
Published: March 2021

Abstract
This paper describes a step change by well completion group in adopting Single Trip Liner Open Hole Completion (STRIP-LOC) technology, basis of selection, design, and operation approach. This has contributed to the reduction in initial well cost estimates thus benefited overall project cost. The technology adoption signifies the importance for continuous design improvement, operational optimization, and capital expenditure reduction, while not compromising with technical and HSE standards.
Accelerating Brownfield Redevelopment – An Integrated Subsurface Approach
Authors: Tan Yvonne , Ser Kong Aik , Rahman Rasheed , Foo Say Jeow , Lim Kok Wei 
Published: March 2021

Abstract
This paper showcases the tailored initiatives undertaken in a different economic climate in view of low oil price in maturing and capturing potential development opportunities for a large-sized, brownfield asset. The subject field is mature, having over 250 wells with over 20 years of production history and approaching its end of economic life.
The study emphasized pursuit of a fast and cost-effective approach in identification of several potential behind-casing recompletion opportunities in addition to multiple infill drilling opportunities. From well log observation to seismic interpretation, and from material balance to simulation modeling, the approaches utilized were tailored based on the level of reservoir complexities. Lower cost, lower risk, behind pipe opportunities had previously not been a focus or thoroughly assessed since the company had focused on infill drilling opportunities. A robust execution plan, minimizing rig moves, was also prepared to synergize the ongoing and planned infill drilling campaigns in the field.
An infill drilling well proposal was approved as part of the 2014 Field Development Plan (FDP) update with regulators. This plan was subsequently deferred due to drop in oil price resulting lower economics. However, with the field approaching the end of its economic producing life, a revisit of potential opportunities was conducted by a multi-disciplinary team. Results of the more recent opportunities identification and successful drilling campaigns have revived the proposal for the infill well given the synergies with rig utilization. The team went through a simplified governance process on the FDP, revisiting the simulation model and proposed to drill a horizontal infill production well instead of dual-string deviated well (originally envisioned for long string as an infill producer in the target reservoir and short string completed as a water injector in a different reservoir). Due to further well performance analysis, injection support on the other reservoir was no longer deemed necessary. The team analysis for arriving at this optimization as well as the behind-casing recompletion opportunities will be shared in this paper. This is a case study on how assimilated and innovative approaches undertaken in a different economic climate can be crucial to accelerate a brownfield re-development to extend the economic life of a mature producing field.
A multi-disciplinary team applied creative thinking and cooperative efforts to a mature field to revive economic viability. Revisiting previously identified opportunities in the context of a low oil price environment and a simplified regulatory governance process, cross functional and cooperative technical and financial team work were important in facilitating timely decisions needed to move forward. A similar approach will be undertaken for future work in other fields.
Tantawan Sludge Management: Holistic Approach Introducing New Practices
Authors: Pongpitukkul Woraphat , Chaianansutcharit Thotsaphon , Learduchasai Suppakit , Suankaew Thunyarak , Sirisampan Satiraporn 
Published: March 2021

Abstract
Following Tantawan field suspension of production, considerable volume of contaminated crude (high level of mercury and arsenic content) remains on board in Tantawan FPSO. These volumes are deemed as waste hydrocarbon sludge that hold no commercial value and must be urgently removed from the vessel as per safety requirements to maintain the vessel class and certification, according to Tantawan FPSO integrity condition.
After review of many alternatives, offshore subsurface disposal initiative is the safest and most cost-effective means for disposal. Since subsurface disposal of such waste, highly mercury and arsenic contaminated crude, has never been performed in the Gulf of Thailand, several aspects need to be considered from technical and environmental perspective and public sector concerns. A cross functional team of Reservoir Engineer, Geologist, Facilities Engineer, Health and Safety, Policy, Government and Public Affair and commercial advisor, has co-devised a holistic waste management plan to inject waste into Tantawan reservoirs after obtaining required approvals by the government.
Many challenges including limitation of the FPSO pumping system, sludge properties and seasonal increment weather, were encountered during the execution phase and many remedial actions were taken to mitigate their impact. Cross functional team initiatives on heater installation, adjusting injection procedure, and additional disposal well approval helped address project challenges. Entire volume of sludge was safely injected to subsurface reservoirs with cost effective operation. The success of this offshore injection process has reduced the cost to less than 10% compared to onshore disposal option to asset joint venture. The results set a new standard for Thailand petroleum waste management policy. Following this success, decommissioning of all remaining of Tantawan field are progressing as scheduled.
This paper will outline the holistic approach of hydrocarbon sludge management process including the subsurface injection identifcation, stakeholder engagement, environmental impact assessment and execution challenges. Lessons learned from this paper would help other offshore operators to effectively manage hydrocarbon sludge, which demonstrate how the oil and gas industry plays a vital role in protecting the environment.