bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Relationship Between Axial Stiffness and Inner Core's Compressibility for Dynamic Cable
Authors: Chen Kai , Chen Kailang , Feng Ru'nan , Shi Luhao , Yu Guojun , Huang Yun , Lang Chunli 
Published: November 2020

Abstract
The theoretical calculated axial stiffness values of helical stranded structures which contain a soft inner core always result in a deviation from the test result, such as axial stiffness of dynamic cables. The deviation is normally caused by the compressibility of inner core. To compute the axial stiffness of a dynamic cable, it is necessary to get a way to evaluate core radial contraction, then to confirm the relationship between core compressibility properties and axial stiffness reduction. Fortunately, KNAPP's formula has already given a method to calculate the axial stiffness of helical strand structures which contain a compressible core and a soft inner core. However, some key input parameters still need to be carefully defined, which will significantly affect the calculation result.
This paper gives methods to define the input parameters. FEA and experiment are used to compare these four methods in order to obtain axial stiffness values estimates. The first method that taking the softest of inner core material as the dominant factor is regarded as the optimal one.
Field Cases Showing Little to No Impact of Reservoir Depletion on the Mud Weight Window
Authors: Salehabadi Manoochehr , Cid Alfaro Marcela , Tarang Ravie-Tajit , Zaini Mazlan , Leegte Henk 
Published: November 2020

Abstract
The fracture pressure in the reservoir is a function of reservoir pressure. Reservoir depletion will reduce the magnitude of reservoir pressure and consequently the reservoir fracture pressure. The fracture pressure changes because of reservoir depletion can lead to challenges like closure of mud weight window. Hence, the ability of predicting the fracture pressure changes due to reservoir depletion is a key for field development including infill drilling campaign.
A reasonable amount of field data has been published across the oil and gas industry to understand fracture pressure reduction as a function of reservoir depletion. The data show approximately a linear relationship between the reduction of fracture pressure with reducing reservoir pressure. Several studies and laboratory measurements have also been made to assess the impact of the reservoir depletion on the fracture pressure. Almost all the studies and laboratory measurements show reduction of fracture pressure as a function of reservoir depletion.
In this study, we present several field examples showing that severe reservoir depletion has little to no impact on the fracture pressure and consequently on the mud weight window. The examples show that heavily depleted reservoirs were drilled with high over balanced mud weight without seeing any sign of loss events. These observations are not fully aligned with what has been observed in the published field data.
Application of Thermo-Gel Treatment Assisting Multiple Thermal Fluid Huff and Puff for Enhancing Offshore Heavy Oil Recovery
Authors: Wu Jintao , Zhang Lei , Huang Jianting , Li Hao , Li Hongyuan 
Published: November 2020

Abstract
Multiple thermal fluid huff and puff, which uses nitrogen, carbon dioxide and hot water as thermal medium, has achieved a high increase of oil production rate in BN reservoir, a heavy oilfield locating at Bohai Bay. Six wells have completed two cycles of thermal huff and puff. Comparing to initial conventional production using natural energy, the periodic well production in first cycle increased to 1.6 times and the annual production rate of the whole reservoir increased from 0.4% to 0.7%. However, due to high formation oil viscosity (413∼741mPa•s) and strong heterogeneity, the injected fluid breakthrough happened three times in the second cycle. On one hand, the well production rate didn't gain an obvious increase because of the heat loss, on the other hand, the surrounding wells which were broken into had to be shut down. Consequently, the annual reservoir production rate was only 0.5%, which was much lower than project design. There is an urgent need to find a suitable solution to the injected thermal fluid breakthrough.
The most effective way to restrain the fluid breakthrough is injecting the thermal fluid into all the thermal recovery wells simultaneously, which is not realizable due to the offshore platform space limit. Combinatorial method with thermo-gel treatment have been optimized for more cycles of thermal huff-puff. Thermo-gel polymer and cross-linking agent spontaneously gel when they reach a critical temperature, which is configured between original reservoir temperature and reservoir temperature during thermal huff period. Thermo-gel was injected ahead and entered the high permeability channels mainly. With the plugging effects, the fluid breakthrough was prevented. Meanwhile, the thermal fluid permeated into low permeability zone where remaining oil concentrated, resulting to higher efficiency of injected heat.
Thermo-gel treatment was carried out for the rest three wells in the second cycle. Around each of the three thermal injection wells, there were 2∼3 wells that could have fluid breakthrough and only one surrounding well happened. Compared with the first three wells in the second cycle, the periodic oil increment of the last three wells increased to 2.6 times and the average effective period extended 105 days. Field practice showed a positive synergistic effect between thermal huff-puff and thermo-gel treatment. In the help of thermo-gel treatment, incremental oil production for single well has reached 1.58×104m3 in the past few years.
Our experiences show that such thermo-gel treatment assisting technology for thermal recovery is effective for enhancing oil recovery of heavy oil fields and meets the demand of high speed development for offshore oil fields.
Mechanism Investigation and Optimization of Conformance Control by Polymer Microsphere in Heterogeneous Offshore Oil Fields
Authors: Chen Xin , Li Yiqiang , Liu Zheyu , Zhang Jian , Li Xianjie , Zhang Han 
Published: November 2020

Abstract
As a good deep profile control and displacement agent, polymer microspheres have broad application prospects in oil fields. Three kinds of microspheres (MG-1 to MG-3) with different particle sizes are synthesized and evaluated. The microspheres observed by SEM are regular spheres with initial particle sizes of 3μm, 6μm, and 10μm, respectively, and the swelling ratios are between 2 and 4. The matching relationship between microspheres and pore throat is established and the optimum matching factor is determined based on the long core migration experiment. The optimal matching factors of the microspheres obtained by the plugging strength are respectively 1-1.2 to MG-1 and 0.5-0.8 to MG-2. In the range of the best matching factors, the effect of injection parameters on microsphere plugging effect and profile improvement capacity is obtained by a long core migration experiment. The results show that the concentration of microspheres mainly affects the timing of their injected into the cores. The increase in concentration and injection speed will decrease the injection performance of microspheres. The concentration and injection velocity of microspheres do not affect the deep migration of microspheres in the core. Microspheres have better profile improvement and EOR effect, and the permeability ratio has less influence on them. Finally, the mechanism of microspheres with different particle sizes on profile control and displacement is studied by the microfluidic model. The results revealed that the plugging mechanism of microspheres are single microsphere direct plugging and bridging plugging with different particle size.
Drill String Connection Backoff: Phenomenon, Fact or Fiction?
Authors: Plessis Guillaume , Morgan Dan , Hussain Raza , Goodwin Robert 
Published: November 2020

Abstract
Drilling practices continue evolving with a global quest for efficiency and an increased focus on the lower total cost of ownership. This leads to equipment/electronic upgrades on rigs and the use of new methodologies or tools in oil and gas well drilling. These have a potential to induce substantially higher loads throughout the string, which can remain invisible to the driller but have consequences on the drill stem product connections. As an original equipment manufacturer (OEM), we have noticed an increase in the number of queries related to connection backoff in the well. We would like to take this educational opportunity to share with the industry, especially younger generations, the most common root causes of loosening and/or backing off a connection down hole and ways to address them.
Over decades we have gained experience when dealing with our customers/users who have experienced connection loosening or backing off. We saw that every connection technology, from the API rotary shouldered connection to the premium ultra-high torque connections, could be exposed. Through investigations, rig visits, analysis, and adjustments made to the drilling practice, we have helped numerous players address this effect on land and offshore. As a result, we have identified several causes that can lead to these incidents.
Sometimes, basic physical principals can be overlooked. Often, dynamic phenomenon downhole is not captured, thoroughly understood, or ignored until they impose themselves. Finally, the running practice and connection torque management on surface can often be improved. With a minimum of preliminary planning at the time of well design, by embracing best industry practices on the rig floor and by monitoring what is happening, one can greatly reduce the chances of experiencing downhole back-offs and/or be in a position of making better decisions when they occur. This paper discusses, in detail, the likely root causes and offers ways to address these. While it will not completely eliminate the risks, our experiences and related investigations indicate that it will reduce the effect.
Effect of Crude Oil on CO2–Foam Stability
Authors: AlYousef Zuhair , Gizzatov Ayrat , AlMatouq Hana , Jian Guoqing 
Published: November 2020

Abstract
The use of foams is a promising technique to overcome gas mobility challenges in petroleum reservoirs. Foam reduces the gas mobility by increasing the gas apparent viscosity and reducing its relative permeability. A major challenge facing foam application in reservoirs is its long-term stability. Foam effectiveness and stability depends on a number of factors and will typically diminish over time due to degradation as well as the foam-rock-oil interactions. In this study, the effect of crude oil on CO2-foam stability and mobility will be addressed.
Two-phase flow emulsification test (oil-surfactant solutions) and dynamic foam tests (in the absence and presence of crude oil) were conducted to perform a comparative assessment for different surfactant solutions. A microfluidics device was used to evaluate the foam strength in the presence and absence of crude oil. The assessment was conducted using five surfactant formulations, and using different oil fractions. The role of foam quality (volume of gas/total volume) on foam stability was also addressed in this study. The mobility reduction factor (MRF) for CO2-foam was measured in the absence and presence of crude oil using high salinity water and at elevated temperatures.
The results indicated that foam stability has an inverse relationship with the amount of crude oil. Crude oil has a detrimental effect on foams, and foam stability decreased as the amount of crude oil was increased. There is good agreement between the results obtained from the two-phase emulsification test with those obtained from the dynamic foam tests in presence of crude oil. Depending on the surfactant type, the existence of crude oil in porous media, even at very low concentrations 5%, can significaly impact the foam stability and strength. The oil can act as an antifoaming agent; it enters into the thin aqueous films and destabilizes the film. This, ultimately, resulting in lower foam viscosity and less stable foams. Thus, the CO2 MRF dropped significantly with higher oil fractions.
Challenges and Practice of Key Technologies for Ultra-Deepwater Drilling with Very Narrow Pressure Window in South China Sea
Authors: Xu Dongsheng , Yang Jin , Liu Hexing , Qu Ximo , Yang Furong , Chen Lei , Yu Chen , Zhu Guojing , Hao Mingxuan , Wang Ning , Cai Rao , Xia Xi 
Published: November 2020

Abstract
Qiongdongnan Basin has deep water and narrow pressure window in South China Sea. In the process of drilling, it is often accompanied by complicated conditions, such as gas invasion, well leakage and breath effect during drilling. Therefore, we have carried out long-term research and practice. According to SPP, dc index, drilling fluid displacement and density and so on, we established a real-time gas invasion early warning neural network model. We formed multi factor measures to prevent lost circulation during drilling. We have drilled more than 20 deep-water narrow pressure wells, and the success rate of drilling reached 100%.
Key words: Ultra-deepwater drilling; Narrow pressure window; Gas invasion; Well leakage; Breathing effect
Effect of Gravity Drainage Models on Production Efficiency of Naturally Fractured Reservoirs
Authors: Aljuboori Faisal Awad , Lee Jang Hyun , Elraies Khaled Abdalla , Stephen Karl Dunbar 
Published: November 2020

AbstractThe gravity drainage process is one of the essential recovery mechanisms in the naturally fractured reservoirs. The contribution of the process to the ultimate oil recovery is quite uncertain, and it highly depends on the mathematical models that used in representing the process besides matrix characteristics such as shape factor and matrix block dimensions in addition to the matrix permeability. The fluid exchange rate between the matrix and fractures is the main controlling factor on the oil recovery, as most of the oil reserve stored in the matrix. Therefore, appropriate gravity model selection supported by accurate matrix characterizations can enhance the simulation accuracy and to avoid an overestimation to the oil recovery.In this work, an outcrop-based model was used to provide a realistic representation of the fracture network in a dual-porosity model. The constructed fracture model was employed to assess the impact of the gravity drainage mechanism. The investigation comprises several sensitivity scenarios and cases to evaluate the influence of both mathematical models and matrix properties using an intermediate resolution model with a single producer located the grid centre and a natural depletion scenario.The simulation results indicated remarkable differences in the producer's performance and productivity. The variation in performance is purely mathematical and related only to the gravity drainage options. Furthermore, the sensitivity results highlighted the significant impact of the matrix characteristics on the fluid exchange between the matrix and fractures, hence oil recovery. Therefore, misunderstand the impact of the mathematical models, and the influence of the matrix properties could result in a compound error in predicting the reservoir performance and its recovery, hence making an inappropriate development decision.
Critical Elements in Delivering Expedited Upstream Field Development Project: Gated Phase Approach, Team Work, Synergy, Open Communication, Quick Data Analysis and Fast Decision Making
Authors: Moid Farrukh , Nutaifi Abdulrahman Mohammad 
Published: November 2020

Abstract
The upstream Field Development Plan (FDP) and project delivery requires gated approach, close team collaboration, and synergy among all disciplines for success. This paper discusses a thorough phase-gate process with five phases and four gates to develop gas fields. The five phases comprise of Scoping of Project, Building Business Case, Appraisal and Testing, Full Field Development, and Monitoring. Critical elements before embarking on a field development with limited available data, and initial data gathering requirements in successful field development are discussed in details. Added benefits from project management, open communication, synergy and quick data analysis and decision-making during planning and executing are also described.
Effect of Biobased Lipid Surfactant on the Rheology and Morphology Properties in Alkaline–Surfactant–Polymer and Crude Oil System
Authors: Borhan Noorazlenawati , Salleh Intan Khalida , Numin Mohd Sofi 
Published: November 2020

Abstract
Injection of chemicals in enhanced oil recovery (cEOR) such as alkaline (A), surfactant (S), and polymer (P) can increase the oil recovery by changing the properties of the injected fluid to make better interaction with oil in the reservoir. In this work, micellar fluid interactions were studied via microemulsion rheological behavior using naphthenic crude oil and stimulated brine contains ASP. The influence of water cut (WC), temperature, salt concentration, shear, and viscoelastic properties were studied using a chemical cocktail consist of ASP and Naphthenic Acid (NAs) crude oil with a formulated biobased chemical that contained synthesized compound. The rheological properties, when added biobased formulation labeled as surfactant S53 and S57 in the ASP-crude oil system, resulted in a different viscosity — viscous-like behavior of emulsion and microemulsion in varying quantity of synthetic brine and temperature. At a specific volume of brine, both emulsion and microemulsion from S53 and S57 undergo a shear-thinning phenomenon where it behaves like a non-newtonian micellar fluid, as when viscosity decreases with the increase of shear rate. This thixotropy characteristic is suitable to be applied at the injection well in which high shear rate condition requires lower viscosity to assist in injectivity. The fluid when it flows into the reservoir, the viscosity increases sweep residual oil in pore and oil film in pore throats. Overall in this paper will describe the rheology and its microscopic behavior of emulsion and microemulsion generated on the addition of S53 and S57 surfactants in determining the condition of cEOR micellar fluids application.
Schizophyllan as Potential Environmental Friendly EOR Polymer for A Selected Malaysian Field
Authors: Ahmad Wazir Norhidayah , Abdul Manap Arif Azhan 
Published: November 2020

Abstract
This paper presents a comprehensive laboratory evaluation of Schizophyllan as an EOR polymer candidate for a selected peninsular Malaysia field. The polymer was chosen due to its well-known structure and properties. Schizophyllan, which originally produced from Schizophyllum commune was evaluated for its performance under controlled laboratory condition and the results are discussed accordingly. Rheology analysis at 96°C, showed that, at low concentration of 250ppm, Schizophyllan can achieve 11 cP which is about 90% more than live crude oil viscosity. Thermal Stability of this polymer was also excellent for the entire 3 months of exposure at reservoir temperature, whereby only 2.8% of viscosity degradation recorded with a very clear solution observed representing the heat and hardness resistance of the polymer. Injectivity test using actual native core indicated that, there was no plugging tendency or injectivity problem observed from the coreflooding test based on its low RRF value of 1.5. The resistance factor value of 9.93 indicates that this polymer is effective in viscosifying the water and injectable into the core. Dynamic adsorption study also showed that only 0.09mg/L of polymer was found adsorbed to the actual native core, despite the presence of clay in the core. Hence, from all the analysis, it was found that Schizophyllan meets the technical requirement to be applied as an EOR polymer
Application of Structural Health Monitoring for Structural Digital Twin
Authors: Liu Xiang , Liu Haitao , Serratella Christopher 
Published: November 2020

Abstract
The load-carrying capability of marine steel structures often suffers degradation and at times structural failure during their service life due to the corrosive sea environment and the extreme wave loads which they experience. Structural integrity is a high priority during asset design and operation to preserve human safety, environment protection, and to maintain operations.
Structural Health Monitoring (SHM), a process of deriving the health status and predicting structural damage via sensor-based measurements, data trending and analysis, has been commonly implemented in marine and offshore assets for decades. There are mature commercial SHM products on the market and available international and industrial regulations, guidance and classification rules (such as IMO MSC/Circ. 646, ABS Guide for Hull Condition Monitoring Systems, etc.). With the emergence of the Structural Digital Twin (SDT) concept in the marine industry in the recent years, the application of structural sensors on marine structures and the integration between sensor-based SHM techniques and structural digital twin approaches have attracted more attention. As a digital representation of the physical asset, the structural digital twin typically involves multiple-scale, multiple-physics, and data driven models and simulations. Leveraging the high fidelity full-scale SHM data, the structural digital twin is capable to provide more accurate assessments, predictions, and insights on structural integrity conditions and support the decision-making process regarding asset operation, structural inspection, repairs, and condition-based asset integrity management.
This paper reviews the mature and commonly employed SHM sensor techniques (such as electric resistance strain gauge, fiber Bragg grating (FBG) strain gauge, accelerometer, pressure transducer, etc.) and discusses their implementation on marine assets and integration with structural digital twin. The paper elaborates to provide some general guidance on the selection of the structural sensors and their installation, as well as the proper sensor specification, in the context of a structural digital twin implementation. The paper also discusses the required engineering mindsets and skillsets for developing and deploying sensor plans, and for implementing a sensor-based structural digital twin framework. The paper concludes that a successful SHM plan and structural digital twin implementation rely on sensor planning, data acquisition, data processing, analytic models and a proper integration of the data and data analytics. The overall planning and implementation should be governed by the suitability for the business purpose and implementation expectation.