bluuebunny/crossref_metadata_2025_split huggingface dataset:
Key Technology and Industrial Application of HPHT Drilling and Completion in South China Sea
Authors: Shujie Liu , Zhong Li , Jin Yang , Renjun Xie , Yanjun Li , Gang Tong , Ming Luo , Yi Wu , Guoxian Xu , Qishuai Yin , Nanding Hu 
Published: April 2020

South China Sea is one of the offshore HPHT region, with the maximum 2.38 pressure coefficient, 480 degF bottom temperature and 50% CO2. The drilling and completion are challenging problems.
This paper reviews the past 20 years' researches and practices in South China Sea HPHT area. Based on theoretical study, laboratory tests and site experiments, the project team has been working on solving problems of formation pressure prediction, wellbore integrity, testing and operation technology.
The understanding and achievements are abundant. First, an accurate prediction method of multi-source abnormal pressure was built and a quantitative control drilling technique was developed, which helps relize continuous circulation in 0.01∼0.02 g/cm3 density window. Second, the "self-repair" HPHT cement slurry systems have been created and the multi-barrier wellbore integrity protection technology has been constructed to implement normal pressure in casing annulus. Third, an intrinsically safe testing system, which includes 7 major factors, was created. The safety of offshore HPHT testing can be guaranteed. Fourth, a water-based high temperature resistant drilling fluid and series acceleration tools were created, realizing the high-quality and efficient HPHT field operation.
This series of technology has helped build China's first HPHT gas field and can be a reference for similar area.
An Innovative Approach for Free Span Analysis of Subsea Pipelines to Optimize Free Span Corrections
Authors: Saleem Qasim , Al-Shiban Riyadh Saad 
Published: April 2020

The integrity of subsea pipelines is required to be verified through external surveys and inline inspection to ensure safe operation. If free spans based on external subsea inspection exceed the design calculated allowable free span length, free span corrections are performed by placing grout bags or mechanical supports along the span. However, as free span corrections are very costly, therefore, further free span assessment should be performed prior to any subsea intervention.
An alternative approach of "local free span analysis" is proposed to optimize the free span corrections. Local free span assessment can be performed for each survey span exceeding allowable span length taking into consideration the relevant input data applicable for the specific free span location rather than for a section of the subsea pipeline. It shall be noted that during design phase, allowable free span lengths are calculated by dividing the total pipeline length into segments, and for each segment the worst case input data is conservatively taken. On the contrary, local free span analysis approach considers key input factors such as effective axial force, wave and current (environmental) data, water depth and pipe-soil interaction parameters pertinent to explicit span location.
Local free span analysis has been successfully applied for free span assessment of a number of operating and new subsea pipelines. This paper will present case studies where revised allowable free span lengths have been calculated prior to previous approach of direct subsea intervention and highlight the associated benefits.
Local free span assessment approach will significantly reduce the number of required free span corrections especially for long length subsea pipelines. The optimization of free span corrections will result in significant cost savingsas well as schedule improvement.
Systems Thinking to Value Protection
Authors: McLachlan Duncan 
Published: April 2020

Abstract
This paper demonstrates how the adoption of systems engineering practices, where functional requirements are established and interdependencies are dynamically modelled, allows optimisation of the project holistically to create value at the earliest stage, and for this value to be protected throughout the lifecycle.
We will explain how functional requirements and project value drivers are identified; causal loop diagrams are utilised to ensure causal precision; the conversion of causal loop diagrams to stock flow diagrams to allow the incorporation of algorithms, which dynamically model the interdependencies. We will demonstrate how this model is utilised to optimise and protect value.
This has been implemented successfully on several projects. Two case studies will be presented: one where systems engineering was used where field production from a complex group of 350 offshore wells producing from different reservoirs was anticipated to decline in the medium term and a best technical solution to maximise Net Present Value (NPV) for the asset was required. The second application of this approach was the development of a Normally Unmanned Installation (NUI) concept that removes 250t of topsides equipment, a 90% reduction based on previous wellhead towers in the same basin, achieves a 98% reduction in power consumption, and only requires planned offshore working once per year. The systems model was established in concept and is continuing to be used through the Front End Engineering and Design (FEED) phase of the project to protect this value created and prevent "death by a thousand cuts", or the slow process of erosion of value brought about by individual, seemingly inconsequential, decisions that aggregate over time to cause project failure.
Design Considerations for the Configuration of a Production Riser for Deepsea Mining of Polymetallic Nodules
Authors: Wu Shukai 
Published: April 2020

Abstract
The technical feasibility of deepsea mining operations of polymetallic nodules in 5,000m+ water depth has been demonstrated through a number of pilot tests done in the later 1970s and early 1980s. Since then, there have been significant technological advances, especially those in the offshore deepwater oil and gas exploration and production. Market demands for rare-earth minerals and specialty metals, such as cobalt which is essential for a wide variety of high-tech and industrial applications have seen a rapid growth, and the trend is projected to accelerate. The existence of these mineral resources in large abundance in many parts of the world's deep oceans are well known, such as the Clarion-Clipperton Zone (CCZ) and southeastern regions of the Pacific Ocean. All those factors have contributed to the renewed interest in commercial-scale deepsea mining development projects.
A key component in a deepsea mining system is the production riser used to transport the production stream, usually in the form of multi-phase slurry, from the seabed level to a production vessel at the surface. For this reason, the riser is also known as VTS (Vertical Transport System). Unlike a normal production riser for oil and gas field development where the riser is "anchored" to the seabed, a production riser for deepsea polymetallic nodule mining operations is suspended and free-hanging off, and is under tow by, a production vessel floating on the surface during normal mining operations. To fulfil other functional requirements, the riser also needs to carry other pipes bundled to it as well as the umbilicals for system monitoring and seabed mining operations.
This paper presents an outline description of the mining operations and a production riser design using airlift proposed for a prospective deepsea mining project. The principal design drivers and major considerations in the production riser configuration development for commercial deepsea mining of polymetallic nodules are the primary focus of the discussion presented in this paper. Critical load cases to be considered for the preliminary engineering design assessment are summarized.
Challenges for Design, Manufacture and Installation of HP/HT Risers for Deep Water
Authors: Jones Richard Lloyd , Karunakaran Daniel , Toguyeni Gregory 
Published: April 2020

Abstract
With the increasing development of high temperature/high pressure wells, particularly in deep water, riser designs using conventional strength material are utilising increasingly heavier wall thickness pipe, up to 50mm wall thickness in 8" and 10" OD X65 linepipe. Such riser designs are challenging existing seamless linepipe manufacturing and girth welding capabilities. Consequently, Subsea 7 undertook a linepipe material and welding qualification programme in order to provide confidence in the use of heavy wall pipeline and riser designs and installed by R-lay.
Riser designs with heavy wall thickness may impose excessive top tension requirements making them difficult to install cost effectively using R-lay technology. Additionally, such risers may pose excessive payloads on the floating production vessel. Fatigue requirements at the hang off and touch down zones pose further limitations on the use of heavy wall risers. These limitations may impede cost effective development of HP/HT fields.
The application of high strength steel for HT/HP applications as riser material is an attractive alternative. High strength steel reduces the wall thickness and thereby reduces payloads on floating hostfacility and top tension requirements for R-lay installation. Application of high strength steel improves the top end interface design also, due to reduced tension. The qualification status of reelable X80, including CRA lined pipe will be presented.
Another challenge for HP/HT riser application is the top end connection to the floater. Traditional flex-joint solutions may not be feasible, requiring a Stress Joint at the top. For ultra-deep water conditions, special stress joints with titanium may be necessary. The limitation and application of such top end solutions for HP/HT application will be presented in this paper.
Applications of Metal Additive Manufacturing in the Oil and Gas Industry
Authors: Wooldridge Madison , Wangenheim Christoph , Herberg Wolfgang , Wettmarshausen Thomas 
Published: April 2020

Abstract
Additive Manufacturing (AM) is a set of technologies that has historically found fertile applications in the aerospace and healthcare industries, while adoption in the Oil and Gas (O&G) sector has progressed slower. Nonetheless, AM is reaching maturity in this industry as well, allowing for significant innovation. The scope of this paper is to describe how AM is integrated within the value chain of a major O&G service company, highlighting specific peculiarities for each of its business segments. "Fullstream" activities cover the whole O&G value chain, from the exploration of reservoirs and production (upstream) to the transportation and storage of hydrocarbons (midstream), as well as refining and industrial power processing (downstream). AM technologies within the O&G service provider have originally been deployed for rapid prototyping and have matured as strategic manufacturing pillars. Several manufacturing methods within the AM landscape can be deployed, depending on the technical requirements of the components and the environment in which they are operating. Here, powder bed processes are in focus, with an emphasis on the Selective Laser Melting (SLM) process. O&G equipment end users face several challenges when dealing with spare parts management, such as performance, total cost of ownership, procurement time, inventory levels, and obsolescence. From an OEM standpoint, serving a wide fleet with a variety of products and their different versions (with an unpredictable and unstable demand) is challenging. AM is the tool that enables a new way to serve such an installed fleet. The O&G service provider has already experimented several applications regarding obsolete spare parts reintroduction through AM, gaining strong benefits (50%+) in terms of cost and procurement time reduction. Thus, it is important to continue adopting AM to deliver faster outcomes for the customer. This, in turn, fosters the development of sound know-how and references, which can then be used to develop further solutions and value propositions for the customers.
Discovery of New Oil Reserves by Combining Production Logging with Open Hole Log Interpretation in Low Resistivity Pay
Authors: Shi Xinlei , Wang Peichun , Xu Jinxiu , Yang Hongwei , Xu Sainan 
Published: April 2020

Abstract
In this paper, we examine the evaluation of a low resistivity pay siliciclastic reservoir in Bohai Bay, China. The reservoir consists of fine to silt sized sand grains with dispersed illite and smectite minerals filling the pore throats. Due to the large surface area associated with the small grains and the clay minerals, a significant amount of irreducible water is bound to the rock surface, dramatically lowering the resistivity of the pay zone. This phenomenon makes open hole log interpretation quite challenging because pay zone resistivity can sometimes read very close to that in water zone. Wireline formation tester shows oil gradient in sands where open hole logs indicate as wet and shaly. However, these sands were excluded from the initial reserves estimation so that uncertainty is minimized.
In order to confirm hydrocarbon production potential and grow reserves in the low-resistivity sands, the operator perforated these sand intervals and acquired production logs. The borehole fluid density and water holdup from production logs clearly indicate that there's hydrocarbon production coming from the low resistivity zones. Detailed analysis revealed that these sands contribute 46 cubic meters of oil per day with no water production. This result confirms our theory that the low resistivity is caused by bound water trapped in clay minerals. These rocks are actually saturated with oil with almost no free water. Based on this finding, we made a few adjustments to our petrophysics model. We modified the amount of bound water associated with clay so that there's no free water in the zone. Also, we adjusted the parameters used in the shaly sand saturation equation to better account for the conductivity contributed by clay.
With this improved interpretation model, we made production predictions for a few offset wells based on their open hole logs. Additional perforations were added in the low resistivity sands of these wells according to log interpretations. Production history of these wells are highly consistent with our predictions and shows that the low resistivity sands produce good quality oil with almost no water. These newly discovered pay zones increased proven reserves by about 430 thousand tons.
Production logging is typically a production diagnosis tool to improve the understanding of reservoir petrophysics. The novelty of our idea is that we use production logging to provide the ground truth of reservoir fluids in the low resistivity pay and use this information to improve our petrophysics model. The improve model allows us to accurately predict the production from low-resistivity pay sands in other wells, without the need for further production logging.
Experimental Investigation of LNG Underwater Release and Combustion Behavior on Water Surface
Authors: Zhang Yixiang , Zhu Jianlu , Peng Youmei , Song Cunyong , Li Yuxing 
Published: April 2020

Abstract
This work foucs on the safety transportation and risk evaluation of LNG accidental release and vapor cloud flame. The experimental was conducted in water tank with dimension of 1×0.5×0.5 in height × long × width and placed in a wind tunnel. The LNG released from a storage tank which connected by a flexible insulation tube. A stainless steel pipeline placed through the plexiglass tank with three orifice sizes and 0.6 m water depth. The leakage pressure and volume flow rate was measured by a pressure gauge and liquid flow meter with online monitoring. The dynamic behavior of LNG jet release was recorded by a high speed camera from a full and micro view. The flammable vapor was immediately ignited on the water surface under different crosswinds. In addition, a new correlation of the radio between flame height to width with mass loss rate and wind speed has been proposed. The flame temperature was employed by an array of K-type thermalcaplous in vertical and horizontal directions. An infrared camera was used to compare the thermal distribution for quantitative.
Condition Based Monitoring of Pumps Using Machine Learning
Authors: Chakraborty Ishita , Kluk Daniel J 
Published: April 2020

Abstract
A variety of pumps are employed in all aspects of the oilfield life cycle, such as drilling, completion (including hydraulic fracturing), production, and intervention. There is no well-established method to monitor the pump fault states as they are operating based on sensor feedback. As a result, maintenance is performed either prematurely or reactively, both of which result in wasteful downtime and unnecessary expense. A machine learning based neural network model is used for identifying different fault states in a triplex pump from measured pressure sensor data. In a laboratory test, a triplex pump was seeded with eight different fault states (different combinations of damage in discharge valves, stuffing boxes, and suction valves). The time series data for suction and discharge pressures are recorded for 1500 different runs for a combination of eight different fault states and nominal condition. An efficient neural network model is trained on the observed data. This model is tested with multiple cross validation sets and is seen to have over 90% accuracy in predicting the correct fault class solely from the suction and discharge pressure data. In almost all cases, the model was able to correctly differentiate between the nominal response and response with different faults in the system. Different parameter transformation or feature engineering is performed to select optimal input features for the machine learning model. This work demonstrates that machine learning techniques can accurately predict different faults in pumps in operation from monitoring the suction and the discharge pressure. This work also demonstrates the importance using engineering domain knowledge for feature extraction and feature manipulation in creating insightful machine learning models.
Full Wellbore Geohazards; Evolution of Subsurface Hazard Assessments at the Tahiti Field, GOM, USA
Authors: McCarren Heather , Gutenkunst Michele , Ruberg Daniel 
Published: April 2020

Abstract
Chevron has applied an increasingly robust approach to wellbore geohazards assessment over the Tahiti Field life. We discuss here how hazards assessment has evolved over nearly 2 decades. The last ~5 years we have applied a standardized approach to identify conditions of concern and incorporate knowledge gained from previous drilling results. Applying this approach, we have seen communication improvements among the Integrated Drilling Team (IDT). Results of the well-specific assessments assist in providing an informed and improved well design and drilling program. Retrieval of former drilling results though our lookback documentation has similarly seen benefit by employing this approach to documentation of events. Subjectivity of the assigned project team is minimized through the employment of standardized classification criteria. In order to tie-back to the drilling department metrics, we leverage geologic non-productive time coding and actual drilling events to qualify our consequence guidance not just within the Tahiti field but within the Gulf of Mexico Business Unit (GOMBU) and across the enterprise.
LWD Acoustic Application for Cement Bond Evaluation: A Case Study in Brazil
Authors: Bicalho Lorena , Barbosa Ariane , Wu Lei , Salazar Jesus , Rodrigues Augusto 
Published: April 2020

Well integrity is very important for well operation in oil and gas industry. Advanced technologies and analyses have been developed to ensure well integrity. One of the most important analysis to be done is the evaluation of the cement bond which measures the presence and bonding of cement between casing and the formation in a particular depth or interval. This evaluation is critical for hydraulic isolation to withstand subsequent completion and production operation.
Usually, Cement bond evaluation is done from wireline logging, with a tool that transmits acoustic waves and compute the acoustic energy propagating through the casing, the cement and the formation. The amplitude and the attenuation of the returned wave can be correlated with Bond Index (BI), due to the difference in acoustic impedance between casing and cement.
Over years, different wireline technologies have been developed and matured for cement bond evaluation. Nowadays, it can be found scenarios where wireline operation is not feasible, such as in highly deviated wells or when a quick turnaround is needed.
Acoustic technology in Logging While Drilling (LWD) has been developed to measure the compressional and shear slowness of the formation. These devices are able to transmit acoustic wave at different frequencies and receive them after propagation through a medium, applicable in cased hole condition. This paper presents a case study where the LWD Acoustic technology was successfully used to evaluate the cement bond in a high deviated well in Brazil and the results show the capabilities of the technology to generate a qualitative cement bond data quality. These results were successfully validated using sonic and ultrasonic wireline technologies. This comparison, between LWD acoustic and wireline results, is shown in this paper, including details of the methodology applied to the test, parameters considered and the data processing.
Intelligent Subsea Condition Monitoring by Digitization and Mining of Big Data
Authors: Ferreira Joel Stephen 
Published: April 2020

Abstract
Inspection Maintenance and Repair activities can typically be reactive in nature, often relying on adequate inspection intervals in addition to Risk Based techniques to minimise production down times.
To compliment current IMR technologies, a suite of Digital Applications is currently being developed to provide operators with additional ‘real time’ remote condition monitoring information. The aim is to provide a focused up-to-date status of subsea equipment and insights on equipment remining life, in the form of both predictive and prescriptive analytics. Combining this information with more traditional inspection techniques will provide a powerful tool in defining support strategies including planning activities to support operations through planned ROV/intervention campaigns, use of remaining life metrics to drive spares holding, location and SIT of spares or use of deep understanding of equipment performance to drive campaign based ROV maintenance activities.
The condition monitoring services and digital suite currently in development will enable, optimisation of operational performance, early identification of system degradation, prediction of equipment failures before they occur (prognostics) and immediate notification of equipment failure.
Although the condition monitoring services and digital suite currently focuses on Subsea Production System Performance, development of an ongoing ‘vulnerability matrix’ with participating operators is providing impetus to broaden the breadth of scope to include process measurands. The goal being to provide a useful suite of focused applications and services which have the potential to significantly improve overall production efficiency tailored to the specific needs of the oil and gas production industry.