bluuebunny/crossref_metadata_2025_split huggingface dataset:
Downhole Pressure Prediction for Deep Water Gas Reservoirs Using Physics-Based and Machine Learning Models
Authors: He Jincong , Avent Matthew , Muller Mathieu , Bordessa Lauren 
Published: April 2022

Abstract
Pressure measurement from permanent downhole gauges (PDHGs) during extended shut-ins is a key piece of information that is often used for model calibration and reserve estimate in deep-water gas reservoirs. A key challenge in practical operation has been the failure of permanent downhole gauges (PDHGs) within the first few years of operation. To overcome this challenge, innovative modeling solutions have been developed to enable accurate bottom-hole well pressures to be calculated.
Both the physics-based model and machine learning model are developed to predict PDHG pressure and temperature measurement from the wellhead and other measurements during well shut-in events. These models are calibrated and blind-tested with data collected while the PDHG is still functioning. The key to the physics-based model is our model of the gas temperature profile within the wellbore and cool-down rate on shut-in, which has been inspired and validated by independent OLGA transient well simulations. In addition to physics-based models, machine learning (ML) models have also been developed, which directly perform regression on available data.
The physics-based model is shown to be able to predict PDHG pressure and temperature accurately by capturing two key physics. Firstly, on well shut-in, a significant gas density gradient develops, as the wellhead (usually on the ocean floor) cools rapidly, while the bottom-hole temperature remains high. This changing temperature profile along the wellbore path has been accurately captured by a data-driven temperature model in the physics-based model. In addition, the decline of temperature along the wellbore has been observed to depend on the well's production history. With higher/longer production of hot gas through the wellbore and additional heating of wellbore surrounds, a slower cool-down rate is observed. A data-driven decline-curve model is devised within the physics-based model and has been shown to successfully capture this dependency.
Compared to the physics-based model, the machine learning model is much simpler to devised. It also has the flexibility to incorporate new input features other than those that we can physically interpret. Multiple ML models are tested, and the random forest has shown the best performance. The accuracy of the ML model is comparable to that of the physics-based one.
In this work, novel physics-based models and ML models are presented and compared for estimating PDHG measurement from wellhead measurements. The build-up pressures from PDHG during well shut-ins are the principal input for reservoir surveillance, analysis, and optimization (SA&O) activities, including material balance estimates of gas-in-place and reservoir simulation history matching.
Safe Delivery of H2 and CO2 in Offshore Pipeline Systems: Novel Methodology and Tools for Technological Risk Assessment
Authors: Mercuri Andrea , Gianfelici Floriano , Blasioli Giuseppe , Luci Vincenzo , Branduardi Luca , Arcangeletti Giorgio , Aloigi Elvira 
Published: April 2022

Abstract
The transition to a decarbonised energy system requires gathering, transport and distribution over short and long distances of CO2 and H2. For such systems, concerning offshore applications, the track record is very limited or null.
The scope of this paper is to provide an overview of critical safety aspects and knowledge gaps associated with CO2 and H2 offshore pipelines. This will pave the way for a novel methodology to assess technological risk and will open the path for designing the roadmap to develop new tools for the evaluation of the hazards and their consequences.
The starting ground of the novel methodology is the review of the state of art of safety aspects for CO2 and H2 offshore pipeline systems. The paper presents the status of international regulations, applicable tools and methodologies for safety analysis in the new transport scenarios and the available data on fluid release and its consequences (asphyxiation, flammable gas clouds etc). In addition, a specific approach to underwater dispersion modelling is proposed as well as the effort to collect experimental data for validation purpose.
The review of the state of the art revealed that, particularly for the offshore system, safety issues are compounded by limited or no experience, lack of accident statistics on which to base risk assessment, limited availability of experimental data on underwater release and dispersion of the product into the atmosphere, toxicity and impact on health, safety and the environment. Last but not least, international regulations need to improve and reach a sufficient level of definition and coverage of topics has not yet been achieved for engineering to have a solid regulatory footprint.
In order to ensure that subsea pipeline systems meet the safety and environmental requirements of companies, regulations and international standards, this paper proposes a novel methodology to develop a risk assessment process, from the initial phase during design to the operational life of offshore pipeline systems, exploiting and adapting Saipem knowledge of hydrocarbon risk analysis and consequence modelling tools available to date.
Mechanism Analysis and Prediction of Lost Circulation in Igneous Formation: A Case Study from B Oilfield, Bohai Bay Basin, China
Authors: Li Shaoxuan , Huang Xiaobo , Xiong Yu , Su Kai , Zhu Yongchao 
Published: April 2022

Abstract
Volcanic reservoirs are gradually becoming an important target for exploration and development in Bohai Bay, China. At the same time, the igneous formation is more prone to lost circulation than the conventional sedimentary formation. On the one hand, there is a lack of understanding of the mechanism of drilling fluid leakage in igneous formation; on the other hand, there is a lack of measured data on the leakage pressure of igneous formation. As a result, the risk prompt for well leakage in igneous formation before drilling is insufficient, and there is a lack of targeted plugging measures in case of well leakage during drilling, resulting in the original formation being polluted by mud and even abandoned by the project, which restricts the effectiveness of exploration and development of the oilfield.
In response to the above problems, firstly, innovatively carry out research on the loss mechanism of igneous rock to help drilling engineering professionals formulate specific plugging measures for special lithological formations. Then summarize the igneous rock leakage laws of different lithofacies, and quantitatively evaluate the pressure bearing capacity of different lithofacies. Finally, the fine identification and characterization of pre-drilling igneous facies are carried out based on the difference of seismic reflection characteristics. Comprehensively apply the above research results to quantitatively predict the risk of lost circulation before drilling in B oilfield in Bohai Bay Basin to avoid lost circulation accidents.
Compressible Carbon: Particle Behavior in Drilling Fluids and Field-Scale Deployment
Authors: Petersen Thomas , Wu Qian , Liu Nanjun , O’Donnell Brian J. , Korn Gene , Hewitt Parker , Zhou Changjun 
Published: April 2022

Abstract
Annular pressure buildup (APB) can occur due to an increase in fluid temperature during the production of hot reservoir fluids, geomechanical loading from the surrounding rock formation, and hydraulic connectivity to pressurized reservoirs. In this study, a novel, compressible, carbonaceous fluids additive was deployed and tested for APB mitigation in a well-scale field trial. The additive is shown to appreciably reduce pressure changes in trapped, downhole volumes by increasing the fluid mixture's compressibility and reducing its thermal expansivity. The proposed additive, referred to as compressible carbon, is a granular spongy carbon with an internal porosity that remains closed to fluid ingress. Lab-scale results demonstrate the durability of compressible carbon in high temperature and high pressure environments when immersed in typical drilling fluids. At a loading of 20% by volume, the use of carbon reduced pressure buildup by 30%-50% relative to reference measurements performed in fluids without carbon. Moreover, the particles showed no long-term relaxation while being held at 10,000 psi and 220°F for up to three months, and exhibited only a marginal loss in reversible compressibility over 100s of pressure cycles between 500psi and 13,500psi. Following the material's characterization in the lab, field trial results were collected during the deployment and testing of carbon in two unconventional land wells above the cemented section of the production-by-intermediate annulus. Wireline logging on both wells confirmed minimal fluid losses to the formation and an adequate cement barrier that reached above the outer-lying casing shoes. Field-scale performance of compressible carbon was confirmed by pressuring up on the annuli at surface and comparing the injection volumes to those collected on an offset well without carbon. Although alternate methods of reducing pressure buildup in wells exist, compressible carbon is a versatile new material that provides repeated APB relief across the pressure ranges that are relevant to deepwater wells. To minimize the risk of first application in deepwater wells, successful deployment and expected performance were demonstrated in two unconventional land wells, paving the way for subsequent applications offshore.
Mechanistic Study of Non Acid Chemistries in the Inhibition of Calcium Naphthenates
Authors: Vargas Jonathan 
Published: April 2022

Abstract
The formation of oilfield calcium naphthenate deposits poses detrimental challenges for flow assurance with occurring blockage of surface equipment, scaling at the wellbore, buildup of calcium naphthenate deposits in water separators, entrapped oil in sludge's, and requiring lengthy periods of shutdown for costly removal in offshore and onshore fields. Oil field treatment of calcium naphthenate deposition is traditionally treated with the use of acid, most commonly acetic acid along with formic acid, glycolic acid, HCl, and dodecyl benzene sulfonic acid. Interfacially active chemistries provide an alternative approach to acid chemistries to mitigate the formation of calcium naphthenates with lower treatment rates, non-corrosive properties, and pH independence. This contribution presents the evaluation of three non-acid chemistries as calcium naphthenate inhibitors using a two-step process to select the best performing chemistry and understand the mechanism of inhibition to treat and prevent oilfield calcium naphthenates. Results revealed two mechanistic forms of inhibition, surface active and complexation inhibition with the latter contributing to greater calcium naphthenate inhibition.
A Modal Approach for Holistic Hull Structure Monitoring from Strain Gauges Measurements and Structural Analysis
Authors: Sireta François-Xavier , Storhaug Gaute 
Published: April 2022

Abstract
In this paper, a general method is presented which combines strain gauges’ data with 3D Finite Elements analysis of a hull structure, allowing the complete reconstruction of the structural response everywhere in the structure, based on the measurements from only a few sensors.
By using sensors, one is getting rid of all the usual assumptions on wave loads and structural response which are made in standard desktop analyses. Usually, the main drawback of using sensors is that only a limited number of them can be used so in most current implementations, the structural response is only monitored in a few selected areas. The new method developed here allows to rebuild the response everywhere from just a few sensors measurements.
The method is based on earlier works using a conversion matrix approach and a linear decomposition of the structural response on a base of a few modes. The measured time series at the strain gauges are then used to reconstruct the linear combination of modal responses which gives at those locations the same values on the 3D FE model as measured.
The modes are defined as the response of the structure on selected load cases and a specific methodology is developed for the selection of those modes since their selection is fully dependent on the number and location of the strain gauges in the hull.
The method is also used to automatically derive an optimized strain gauges’ setup by looking at correlations between strain gauges’ measurements in numerical simulations.
The method is validated numerically by simulating measurements in an analysis and using them to reconstruct the complete response. Then actual strain gauges’ measurements on a hull are used to validate the method on a real case. Both fatigue damages and extreme stress values are compared, and it is found that on a real case, the fatigue damage and extreme stresses can be predicted with good accuracy in most of the hull structure based on less than 8 strain gauges’ measurements.
From that new insight, an optimized inspection and maintenance plan can be developed and updated throughout the life of the structure, leading to safer and more cost-effective operations.
Another key benefit to operators is the possibility to keep track of the remaining life of the structure and being able to demonstrate it, which is crucial when it comes to selling or redeploying an asset.
The method has been used by DNV on commercial projects for various offshore structures including flare towers, MOPU platforms and sloating structures.
On Strain Ageing Testing Methods for Reeled Offshore Pipelines
Authors: Mukhamejanov Radmir Ershatovich , Pyshmintsev Igor Yurievich , Khramkov Evgeniy Vladimirovich , Akhatov Iskander Shaukatovich , Sergeichev Ivan Valerievich 
Published: April 2022

Abstract
The pipeline design standard DNVGL-ST-F101 requires performing the reeling simulation tests with subsequent strain ageing evaluation. The experimental methods for evaluation of strain ageing of low-carbon microalloyed steels upon reel-laying process were analyzed and compared for API X60 and X65 grades seamless line pipes with outer diameters 355.6mm and 219.1mm, respectively. The strain ageing tests were performed using the full-thickness segments of the pipes and pipe samples by small-scale reeling (SSR) and full-scale reeling (FSR) simulation, respectively. The finite element modeling is performed in order to analyze the distribution of stress and strain within both test specimens.
Firstly, the difference in stress-strain behavior between the preliminarily aged small-scale full-thickness segments and full-scale pipe samples was experimentally observed. Finite element analysis and experimental data showed the non-uniform stress and strain distribution in the gauge length of the segments samples with increasing global strain. Calculations of stress triaxiality showed the significant difference in the stress state of the segments and the pipe samples which lead to different growth of yield strength of the material after strain ageing. Therefore, the present work attempts to turn attention to the interchangeability problem of the strain ageing methods using FSR and SSR simulation as the qualification tests of the reel-laid pipes and study of the pipe material behavior.
Waterflooding Optimization Under Constraints on Oil and Gas Reservoir Using Modified NPV Gradient
Authors: Barroso Neto Emanuel Pereira , Cuéllar Sánchez William Humberto , Rodrigues Miranda Marco Emílio , Pimienta Braulio Gutierrez , Munerato Fernando Perin , Barroso Jonathan Bastos , Fortaleza Eugênio Libório Feitosa 
Published: April 2022

Abstract
In this article, we present a production optimization strategy for a reservoir which has both oil and gas production. To perform such production optimization, we maximize the Net Present Value (NPV) with a sequence of short-term optimization of a Modified NPV. The search for the optimal solution is made through a Stochastic Simplex Approximated Gradient. This strategy of breaking the global optimization into a sequence local optimization makes the computational cost increases linearly with the time instead of exponentially as the global optimization problem does. Other advantages of the technique are a significant increase in NPV, and a strong cash flow on the beginning of reservoir production life.
Use of Nanomaterials for Early Detection of Flow Restricting Substances
Authors: Louis Stephen George , Wang Luke Qiliang 
Published: April 2022

AbstractObjectives/ScopeDeposition of inorganic and organic flow-restricting substances are critical flow assurance issues that results in oil and gas production loss of over $10 billion annually (Frenier, W.W. 2008). These depositions can cause a serious degradation of or cessation of production flow and require additional maintenance of facilities. In the context of a subsea environment, the loss in revenue and intervention costs are even more substantial.A novel solution has been developed in the form of an inline physical sensor, containing a nanoscale particle coating, that can prognostically detect the deposition of flow restricting substances, and dynamically adjust chemical dosage in the production system. The process patent was granted in March 2021 (#10,947,818).This paper describes the preliminary flow test demonstrating the scale inducing properties of the nanomaterial referred to as FloSav. Next the paper discusses the 24-month, onshore field trial which was successfully used to reduce chemical inhibitor dosage by 20% without any production loss or downtime. Thirdly the paper examines what additional testing will be employed in order to be fully qualified for deployment.Finally this paper provides an overall plan on how to deploy this technology for an offshore application and the benefits that can be achieved including the reduction of production chemical usage while enhancing flow from the subsea well to the topside facility.
Cost Effective Fixed Offshore Platform in Shallow Water without Jacket
Authors: Chatterjee Prabir Kumar , Shah Jinesh 
Published: April 2022

Abstract
This paper proposes an alternative design of small wellhead platforms in shallow water that require permanent manning due to operational requirements. The proposed structure is a combination of two monopods of moderate diameter (54″) connected rigidly by structural members. Multiple wells can be drilled through one of the two piles by using conductor sharing wellhead technology. The inadequate structural stability of the twin-pile platform without a jacket against environmental loads will be ensured by a few tie members connected to seabed with help of specially-designed small concrete foundations. Tie members will be bolted to the pile and the foundation. Each tie member will be lifted offshore together with the concrete foundation for quick installation and correct positioning of the foundation on the seabed. The pre-fabricated deck will be welded to the top of the pile. Numerical studies include structural design of a platform at 20m water depth for omnidirectional waves of 10.5m height as per API RP 2A working stress design method. Analytical method is provided to simulate interaction of concrete foundations with soil that can be easily implemented in structural analysis. The results indicate that the proposed structure has considerable reserve strength against failure due to extreme environmental loads and impact from medium sized boats.
The Importance of CO2 Composition Specification in the CCUS Chain
Authors: Erickson Dale D , Haghighi Hooman , Phillips Chris 
Published: April 2022

Abstract:Carbon Capture and Storage (CCS) has seen growing momentum as a crucial strategy for meeting CO2 emission reduction targets. However, it comes with different technical and strategical challenges. One of the major challenges associated with CCS is the multi-actor value chain, which based on individual actor requirements, may not be necessarily aligned with each other and therefore requires coordination and agreement.An important design consideration is the quality of the CO2 stream as it moves through the CCS process. Various industries still consider CO2 as a waste stream and as such it only has limited quality control based on local regulations. This paper will discuss the various issues associated with CO2 quality in the various elements of the CCS chain, from collection, through transportation to storage.There are various technologies providing discrete solutions for different elements of the CCS chain. However, for a cost-effective CCS design, a holistic approach should be applied.At custody transfer points within a CCS chain, CO2 will need to meet specification criteria for type and quantity of allowable impurities. Impurities may be inherent in the captured CO2 or carried over from processes or reaction by-products. Some impurities may have significant impact on the behaviour of CO2 rich fluid even in small ppm quantities and adversely affect the CCS chain integrity or operation. CO2 not meeting specification criteria risks non-acceptance at custody transfer points. This paper shall address the critical considerations for CO2 quality at each of the CCS chain interface points.This paper will provide a high-level overview of how impurities can significantly affect the calculation of CO2 rich fluid properties and behaviour, chemical reactions, corrosion risk, etc. Additionally, some of the gaps in the current understanding and standards will be addressed and their possible economic impact on CCS chain design and operation.The novel part of this work is holistically looking at the whole CCUS chain and addressing how CO2 quality and specification can affect each part of the chain and their impact on the economics and viability of the solution.
Aoka Mizu FPSO Hybrid Twin Pilot - A Spectral Approach for Holistic Hull Structure Monitoring from Strain Gauges Measurements and Structural Analysis
Authors: Sireta François-Xavier , Van der Cammen Jeroen , Storhaug Gaute 
Published: April 2022

Abstract
Bluewater has partnered with DNV to pilot the hybrid twin solution on the Aoka Mizu FPSO, using data from that sensor system to monitor the fatigue damage in the hulland then update the RBI inspection plan accordingly (if needed).
In this paper, the hybrid twin method is presented which combines strain gauges’ data with 3D Finite Elements analysis of the hull structure, allowing the complete reconstruction of the structural response everywhere in the structure, based on the measurements from only a few sensors.
The method is validated using one full year of actual strain gauges’ measurements on the hull. The responses at main deck level are cross validated using some sensors as references and predicting their responses from the other sensors. The FPSO heading is also predicted from the deck strains and compared to direct heading measurements to validate the implicit calculation of the environment from the response. By combining the deck sensor readings with the 3D Finite Element model the fatigue damage at selected hot spots in the hull is calculated.
Those damage values are then used in the RBI calculation to replace the design damage values so that the RBI is updated based on measurements.
The key benefit for such approach to operators is the possibility for operators to keep track of the remaining life of the structure and being able to demonstrate it, which is crucial when it comes to optimizing inspection plans, selling, or redeploying an asset.