bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Hole Cleaning on the Liner Cement Job in Papa Terra Field
Authors: Vadinal Rodolfo Balthazar , Perrout Stephan Ribeiro , Chuvas Rodrigo De Campos , Lima Gomes dos Passos Adriano Gouveia , Silva Leonardo Pacheco Da 
Published: October 2019

AbstractThis work presents the lessons learned from the studies carried out to understand the non-fulfillment of the hydraulic isolation required during the liner 10 ¾" cement job. Analyzing the drilling parameters performed and the events of cementing, it is possible that the stationary solids bed and the consequent poor conditioning of the well were probably responsibles for the failure to obtain the hydraulic isolation required for the cementing operation. The investigation report recommends some good practices for avoiding and/or removing the cuttings-bed. The results of some simulations carried out during the investigation studies showed that drillpipe rotation speed contributes significantly to reduce the cuttings-bed height. Additionally to the extended reach, the well studied is a design well, has a complex trajectory, and the computer simulations revealed that ROP control is mandatory to obtain a proper hole cleaning and well conditioning. It was identified that the reduction of the hole diameter has a huge impact on well conditioning, drilling fluid displacement and cement slurry displacement. At last, the paper presents some recommendations for backreaming, mainly for evaluation of ideal operational parameters; adjust the drilling rates according to the hydraulic simulation, to ensure the hole cleaning and optimize the total time of the drilling intervention.
A Feasibility Study of Producing Natural Gas from Subsea Hydrates with Horizontal Snake Wells
Authors: Wan Lifu , Shaibu Rashid , Hou Xuejun , Guo Boyun 
Published: October 2019

AbstractThis study focuses on technical feasibility of producing natural gas from offshore gas hydrate deposits using a new technique called horizontal snake wells (HSW). This paper addresses engineering and well productivity issues for the new technique. Coiled tubing string is proposed to drill HSW in gas hydrate reservoirs for increasing well productivity and reducing wellbore collapse problems. A new analytical model was derived to predict of maximum achievable wellbore length (MAWL) based on the theory of buckling failure. Furui's equation for gas reservoirs was used for predicting the initial well productivity at the MAWL. Gas lift method is proposed to remove water for achieving a constant bottom hole pressure that is slightly below the hydrate dissociation pressure. Gas production forecast was made on the basis of material balance. Net present value (NPV) method is employed to perform economics analysis. A gas hydrate reservoir in the South China Sea was taken as an example to investigate the feasibility of producing natural gas from gas hydrate deposits using the HSW technique. The new analytical model gave the MAWL under extreme well friction conditions prior to buckling failure of coiled tubing. Furui's equation predicted commercial well productivity at the MAWL, depending on the loop separation of the HSW. If the bottom pressure is maintained with gas lift technique at a constant level slightly lower than the hydrate dissociation pressure to prevent wellbore collapse, material balance forecasted high NPV of HSW. It is concluded that the HSW is a feasible technique for economically producing natural gas from offshore gas hydrate deposits. This paper presents a novel method called HSW for producing natural gas from offshore gas hydrate deposits. It also demonstrates how to evaluate the productivity and thus economics of the HSW.
Influence of Asphaltene Inhibitors on Wax and Asphaltene Deposition - Are Problems Associated?
Authors: Aguiar Janaina I. S. , Punase Abhishek , Mazzeo Claudia 
Published: October 2019

Abstract
Organic deposition formed at high temperatures in oil and gas production systems is commonly linked to instability of asphaltenes. Recent studies revealed that deposits collected in offshore production wells produced in Gulf of Mexico exhibited compositional variation pointing to a more complex fouling process than solely related to the asphaltene fractions. To better understand the mechanism of deposition and external factors that could contribute to this precipitation, crude oils and their respective deposits collected from the field were characterized for comparison in terms of properties and composition. Moreover, crude oils were treated with Asphaltene Inhibitors (AI) and Paraffin Inhibitor (PI) and tested applying three techniques: Asphaltene Dynamic Deposition Loop (ADDL), cold finger and rheology. The deposits collected from the ADDL and from cold finger were analyzed and compared to the field deposits. A lab-to-field correlation was observed when analyzing the deposits collected from the ADDL and cold finger tests. In both deposits, asphaltenes and wax fractions were observed to co-precipitate and form "Waxphaltenes". The efficiency of the AI on dispersing the asphaltenes was observed to have a major impact on the precipitation as possibly increasing the deposition of microcrystalline waxes. The influence of the AI at certain dosage rate in the precipitation of waxes is highlighted. In this research, the mechanism of asphaltene dispersion and instability of waxes in the presence of AI at low concentrations is proposed.
Conceptual Design of a Large Water Treatment System for Offshore Smart Water Injection
Authors: Machado Bernardo Farah , Vale Osvaldo Roberto , Pivatto Bruno Coccaro , Motta Leticia Santos , Cavaliere Carlos Carreiro , Souza Marcus Vinicius 
Published: October 2019

Abstract
Water injection is a traditional method of secondary recovery used in the petroleum industry. Typically, even with the injection of water supplementing the initial energy of the reservoirs (primary recovery), less than 50% of the original volume of oil is produced. By altering the chemical composition of the injected water, tests performed in laboratory and in pilot units have shown significant oil recovery (5 to 40%), when compared with a field with traditional water injection. The oil industry has shown great interest in smart water (SMW). Basically, the SMW comprises a seawater stream with altered ionic composition and low total dissolved solids (TDS). Membrane separation is the most suitable method for producing SMW offshore, though, it has some limitations for water ion tuning. Reverse Osmosis (RO) membrane technology plays an important role in SMW generation process due to its hability to promote a high rejection for all ionics species.
This paper describes the results of a topside conceptual design of a 39,500 m3/d Water Treatment System to produce SMW (WTSMW), that generates water with a TDS of 1,884 mg/l, from seawater with 40,000 mg/l of salt. The treatment scheme comprises RO membrane permeate plus seawater, with a device to recover energy from the RO reject stream. The product water is also used for oil desalting and may be used for membrane cleaning. Electrical consumption, weight and footprint were compared with a sulphate removal unit (SRU) of 35,400 m3/d, of an existing 150 Kbpd floating production storage and offloading unit (FPSO) used as reference design (RDF). It was also evaluated the suitability of the RDF to incorporate the WTSMW, concerning electrical consumption, weight and footprint. The WTSMW is heavier (571 t), requires one more module level, which resulted in a module 9 m higher, and consumes more energy (3.3 MW), despite the use of the energy recovery device (ERD). To receive the WTSMW, the generation nominal capacity (4 × 23 MW) of the RDF should be changed to 4 × 28 MW. The increase in height and weight do not represent any restriction for design or construction of a new production unit to include the WTSMW.
Influence of Whipping on the Structural Response of the Flare Tower Foundations of a Typical Spread Moored FPSO
Authors: Benhamou Alexis , Shimazaki Junji , Bontemps Fabrice 
Published: October 2019

Abstract
Typical ship-like floating bodies, for certain operating conditions, may experience large slamming loads in the bow or aft parts of the vessel. In addition to the local structural damages induced by slamming, a significant global hull vibration might also be excited. This vibratory response, referred to as whipping phenomenon, is usually not considered in the offshore industry, in particular in the design of ship shaped FPSOs. However, in case of resonance with slender structures such as the flare tower, these effects can have a strong influence on the fatigue performance at the interface between the FPSO’s hull and those structures. The objective of the work presented in this paper is to assess the influence of these effects on the total fatigue damage.
Numerical modelling of whipping is extremely complex from several aspects and only approximate models exist today. For this study, a state of the art whipping model is used, which couples the hydrodynamic loads (linear diffraction and radiation, nonlinear incident and slamming) with dynamic structural response of the floating body. The hydrodynamic part of the model includes a weakly nonlinear diffraction-radiation tool which is supplemented by a modified Logvinovich model for slamming. These hydrodynamic models are fully coupled with the structural vessel dynamics which are represented by a simplified finite element model. Direct assessment of hot spot stresses are performed on refined fatigue models.
Typical FPSO’s design includes the flare tower installed in the fore part, where the accelerations induced by the hull girder global vibrations are the highest. If the natural frequency of the flare tower is close to the natural frequency of the hull girder, significant flare vibrations might occur. In addition, spread moored FPSOs receive wave loads from 360 degrees and since typical FPSOs’ hull shape is similar to oil tankers’ hull shape, its stern flare is relatively larger flare than its bow flare. If waves come from the stern and FPSO’s draft is shallow, hull vibration induced by stern slamming might be large. The present work evaluates the influence of these vibrations on the flare tower structural response. The deterministic results are used within a dedicated methodology allowing for the evaluation of fatigue life of the structural details.
This work proposes an innovative methodology for including the influence of highly nonlinear loads, such as slamming induced whipping, in the structural fatigue assessment of offshore structures.
Subsea X-Mas Tree Standardization Benefits in Brazil Scenario
Authors: Beppler Veloso Raphael , Rabello Pereira Alexandre , Ramos Roberto Augustus Marcello 
Published: October 2019

1. Abstract
Subsea X-Mas Trees have been standardized in Brazil since the 1990’s and this paper will present how this standardization was evolved throughout the years and the main benefits achieved to both, the operator and the suppliers.
To achieve the standardization benefits the X-Mas Trees standardization program has followed three main approaches: -The first is related to standardization of X-Mas Tree application, becoming it possible to use any X-mas Tree from any supplier in the production or injection wells, in the most possible cases.-The Second is related to standardization of X-Mas Tree interfaces between sub-equipment and between the equipment and its tools.-The third is related to standardization of manufacturing, qualification program and inspection.
At the beginning, only the interfaces between the THS (Tubing Head Spool), TH (Tubing Hanger) and the X-Mas Tree itself were standardized. Throughout the years, more interfaces were standardized, such as Tree Cap, Flowline Connectors and Control Systems.
The standardization may lead to very big scale gains and cost reduction when is possible to look the whole projects as a portfolio, as it makes possible to combine several projects into a Bidding process (bid), enabling better competitiveness in the supplier market. For example, bids with up to 300 X-Mas Trees split in lots with up to around 130 X-Mas Tree per supplier were carried out in Post-Salt and Pre-salt projects and a huge benefit was achieved with this strategy.
In addition, the standardization brings better stock management as the projects’ schedule changes over time, minimizing the time the X-Mas Trees stay in stock. At last, it enables faster project implementation, once the equipment is already contracted, designed and, sometimes, even manufactured.
Standardization of the X-Mas interfaces brings the possibility of exchanging sub-equipment of different suppliers, as vertical connector modules, for example, between any well. This is extremely useful when there are operational issues during the installation, as it becomes possible to use equipment from another supplier until the issue is outlined. Besides that, there is another standardization benefit, regarding to wells maintenance, where the equipment removed from a well can technically be reused in another well.
Additionally, when multiplexed X-Mas Trees became the standard in Brazil for Pre-Salt wells (in the past, all multiplexed controls were located on Manifolds), it was imperative to standardize the control system interfaces, enabling it to be from a different supplier than the X-Mas Tree itself, as well.
Standardization of X-Mas Trees enabled the operator to better answer to its projects demand in a portfolio view, reducing costs, increasing flexibility and allowing the competitiveness between suppliers in all project phases.
A Practical Model for Production Forecast of Fractured Vertical Well in Coalbed Methane Reservoirs: Dynamic-Drainage-Area Concept
Authors: Sun Zheng , Wu Keliu , Shi Juntai , Fu Jin , Shao Changchun , Zhou Yu , Liu Chengyuan , Jia Yanran , Fang Jinhui , Lv Ming 
Published: October 2019

AbstractA great deal of attention has been attracted to the exploitation as well as the development of unconventional gas reservoirs, which expect to act as an essential role in counterpoising the daily increasing energy demand around the world. In this research, with the intent of contributing to the successful development of coalbed methane (CBM) reservoirs, which is an indispensable member of the family of unconventional gas reservoirs, a novel production prediction model is proposed for fractured vertical CBM wells. The main difference of the research compared with previous excellent documents is taking the effect of pressure propagation behavior on production performance of CBM wells into account. In general, CBM reservoirs possess the low-permeability (&lt;1 mD) physical property, which results in the slow pressure propagation speed during the whole production life. More importantly, because of the unique gas desorption effect inside coal matrix system, more and more adsorption gas will enter into coal cleat system with the production proceed, which will accumulate the formation energy and further mitigate the pressure propagation speed. As a result, it is a relatively time-lengthy period for the pressure propagation process with regard to CBM reservoirs, which currently has not been detailed and comprehensively analyzed. Additionally, it should be noted that the formation pressure is a key sensitive parameter affecting production performance of CBM wells, resulting from the fact that gas production rate takes place only when formation pressure is lower than critical desorption pressure. In this view, the pressure propagation behavior shows a close relationship with production performance of CBM wells, which however fails to receive due attention up to date. In these regards, research content in this paper attempts to shed light on the effect of pressure propagation behavior on production performance of CBM wells from both theoretical and application scopes. With the capacity of capturing the pressure propagation behavior, a novel production prediction model is proposed for fractured vertical CBM wells, the reliability and accuracy of which has been well verified by numerical simulator. Also, the pressure propagation details during production process can be characterized by the proposed model, which is supposed to be highlighted as the main novel point when comparing with previous models. The proposed model is able to generate sensible production performance with less input parameters and calculation time than that of a full-calibrated numerical simulator. Furthermore, details of formation pressure variation regularity are clearly presented by the proposed model, which provides a completely new pathway to evaluate and optimize production performance of fractured vertical CBM wells.
Uncovering the Mechanisms of Low-Salinity Water Injection EOR Processes: A Molecular Simulation Viewpoint
Authors: Martins Ernane de Freitas , da Silva Gabriela Dias , Salvador Michele Aparecida , Baptista Alvaro David Torrez , de Almeida James Moraes , Miranda Caetano Rodrigues 
Published: October 2019

Abstract
In this work, we present a multiscale approach based on first-principles calculations and classical molecular dynamics methods, to investigate the enhanced oil recovery via low-salinity water injection (EOR-LSWI). Salting-in effect, wettability, pH alteration, electrical double layer and the main geochemical reactions involved in the multicomponent ionic exchanges mechanism were analyzed in order to understand their contribution, also to provide an overall phenomenological perspective of the involved phenomena with a proposed feedback control system. The first-principles calculations were based on density functional theory, carry out in the Quantum-ESPRESSO package, to determine the adsorption energies of hydrocarbons (propionic and pentanoic acids and phenol) on calcite (CaCO3) {10.4} surface. In addition, we have obtained the free energy variations for the minerals dissolution processes. The solvent effect was taken into account for the geochemical reactions through a continuum dielectric. The interface between calcite and API brine was investigated through steered classical molecular dynamics, as implemented in the LAMMPs code to evaluate the brine ions adsorption/desorption on calcite surface and characterize the electrostatic environment in the vicinity of the calcite-brine-oil interfaces. Our results showed that the adsorption energies for the deprotonated molecules were lower than the ones for the neutral cases, highlighting the pH effect in the desorption processes. The pH also played a role in the calcite dissolution, since the free energy variation (ΔG) of the dissolution process mediated by H3O+ was lower than the ΔG for the neutral pH process. We found the lowest dissolution ΔG for the MgSO4 mineral (bulk), indicating that Mg2+ and SO42- ions would be abundant in the solution. In contrast, the other minerals exhibit a positive ΔG. Ions adsorption/desorption on calcite are isoergic and suggest an equilibrium between Ca2+ and CO32- ions. In contrast, the Na+ and Cl- ions adsorption were not found to be a spontaneous process. Moreover, the potential of mean force profile for Ca2+ and CO32- ions showed a layered structuring, which indicates that the ion hydration energy is related to the adsorption/desorption process. Such results may contribute to cause-effect understanding of correlations among the mechanisms in EOR-LSWI and help to propose an optimal brine composition to maximize the oil recovery.
ScaleProTect – Scale Deposition Modeling in Pre-Salt Reservoir
Authors: Bouamra Reda , Carneiro Giovanna , Machado Patrick , Feliciano da Silva Manoel , Franquiz Gabriela , Guan Hua , Lindvig Thomas 
Published: October 2019

Abstract
The complexity of carbonate reservoir in pre-salt plays dictates the use of advanced inflow devices to enable optimized reservoir recovery. Intelligent Completions are considered one of the most effective systems for flow control for a production interval. Depending on the actual design and geometry of the intelligent completion tool, inorganic scale deposition can be very difficult to prevent and/or to mitigate. The failure of such equipment tools can cause severe production impairment and affect the entire field economics.
In order to provide a high accuracy assessment of the scale deposition risk, a novel methodology involving scale deposition experiments and model generation has been developed. The proposed workflow combines 1D mechanistic methods to define scaling conditions, thermodynamic models to define the scaling tendencies at these conditions and 3D models to predict particles accumulation in complex geometries using numerical techniques describing the multiphysics interactions between solid particles and live fluids. The basis of the models will be presented in this article along with numerical results of the precipitation and deposition phenomena at downhole conditions.
This work represents the first holistic approach to characterize scale build-up in the vicinity of inflow equipment walls. Numerical results are presented in this paper.
Potential Environmental Impacts of Subsea System Installation and Decommissioning: A New Tool for Comparison of Locational and Technological Alternatives in the Oil & Gas Industry
Authors: Silva Priscila Reis da , Silva Teresinha Andrea da , Nicolosi Eduardo Ribeiro , Miranda Carlos Abraham de Knegt 
Published: October 2019

Abstract
The environmental aspect can be critical in the decision-making process at the onset of offshore E&P projects, especially in sensitive areas. Thus, we developed a methodological framework and a web tool to support the selection of technological and locational alternatives in subsea system installation and decommissioning activities. This framework relies on the assessment of environmental pressures and biological sensitivities. Our model's main assumption is that an activity can cause a number of environmental pressures, which can have different effects on each environmental component (habitats or biological groups). In the end, a potential environmental impact of a technology can be the result of its pressures on the components at a location. The work relied on experts' judgement and it was based on some previously established criteria for the classification of these environmental pressures and components' sensitivities. Scores were set and ranked in these assessments and a formula calculated the potential environmental impact of each activity/technology. A web tool called SCENARIO was developed to incorporate these results in a user-friendly interface, where one can compare scenarios made up with different technological options and different habitats or biological groups. This tool points out the potential environmental impact of each available choice. It also details how each component relates to that impact. Finally, one can acknowledge the environmental performance of its own scenario choices within the range of the best and worst possible alternatives. The tool was tested and proved to be technically sound and capable of contributing effectively to support the decision making process in the environmental aspects of offshore E&P subsea projects. It is also flexible to incorporate any pressure review, new activities and technological updates whenever necessary.