bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy of Measuring Bladder Volumes With Ultrasound and Bladder Scanning
Authors: Schallom Marilyn , Prentice Donna , Sona Carrie , Vyers Kara , Arroyo Cassandra , Wessman Brian , Ablordeppey Enyo
Published: November 2020

Background

Removal of urinary catheters depends on accurate noninvasive measurements of bladder volume. Patients with acute kidney injury often have low bladder volumes/ascites, possibly causing measurement inaccuracy.

Objective

To evaluate the accuracy of bladder volumes measured with bladder scanning and 2-dimensional ultrasound (US) compared with urinary catheterization among different types of clinicians.

Methods

Prospective correlational descriptive study of 73 adult critical care patients with low urine output receiving hemodialysis or unable to void. Bladder volumes were independently measured by (1) a physician and an advanced practice registered nurse using US, (2) an advanced practice registered nurse and a bedside nurse using bladder scanning, and (3) urinary catheterization (cath). Bland-Altman and χ2 analyses were conducted.

Results

Mean (SD) cath volume was 171.7 (269.7) mL (range, 0-1100 mL). Abdominal fluid was observed in 28% of patients. Bias was −1.3 mL for US vs cath and 3.3 mL for bladder scanning vs cath. For patients with abdominal fluid and cath volume less than 150 mL, decisions to not catheterize patients were accurate more often when based on US measurements (97%-100%) than when based on bladder scanning measurements (86%-89%; P = .02). In patients with cath volume of 300 mL or more, decisions to catheterize patients were accurate more often when based on bladder scanning measurements (94%-100%) than when based on horizontal US measurements (50%-56%; P = .001).

Conclusions

Bladder volume can be measured accurately with bladder scanning or US, but abdominal fluid remains a confounding factor limiting accuracy of bladder scanning.
Risk Factors for Hospital-Acquired Pressure Injury in Surgical Critical Care Patients
Authors: Alderden Jenny , Cowan Linda J. , Dimas Jonathan B. , Chen Danli , Zhang Yue , Cummins Mollie , Yap Tracey L.
Published: November 2020

Background

Hospital-acquired pressure injuries disproportionately affect critical care patients. Although risk factors such as moisture, illness severity, and inadequate perfusion have been recognized, nursing skin assessment data remain unexamined in relation to the risk for hospital-acquired pressure injuries.

Objective

To identify factors associated with hospital-acquired pressure injuries among surgical critical care patients. The specific aim was to analyze data obtained from routine nursing skin assessments alongside other potential risk factors identified in the literature.

Methods

This retrospective cohort study included 5101 surgical critical care patients at a level I trauma center and academic medical center. Multivariate logistic regression using the least absolute shrinkage and selection operator method identified important predictors with parsimonious representation. Use of specialty pressure redistribution beds was included in the model as a known predictive factor because specialty beds are a common preventive intervention.

Results

Independent risk factors identified by logistic regression were skin irritation (rash or diffuse, nonlocalized redness) (odds ratio, 1.788; 95% CI, 1.404-2.274; P < .001), minimum Braden Scale score (odds ratio, 0.858; 95% CI, 0.818-0.899; P < .001), and duration of intensive care unit stay before the hospital-acquired pressure injury developed (odds ratio, 1.003; 95% CI, 1.003-1.004; P < .001).

Conclusions

The strongest predictor was irritated skin, a potentially modifiable risk factor. Irritated skin should be treated and closely monitored, and the cause should be eliminated to allow the skin to heal.
Admission Rate of Patients With Major Psychiatric Disorders to the Intensive Care Unit
Authors: King Daniel A. , Hussein Essam , Shochet Gali Epstein , Bar-Lavie Yaron P.
Published: November 2020

Background

Major psychiatric disorders such as major depression and schizophrenia interfere with patients’ life activities and ability to function. These disorders correlate with a higher prevalence of medical and psychiatric comorbidities.

Objective

To compare the admission rate of patients with major psychiatric disorders between the intensive care unit and other departments in a tertiary care center.

Methods

In a retrospective study of records of 238 721 patients, data were collected from admission files and the intensive care unit computer system. The study group was 245 patients with psychiatric disorders admitted to the intensive care unit. Control groups were 9226 psychiatric patients in other hospital departments and 3032 nonpsychiatric patients in the intensive care unit.

Results

A major psychiatric disorder was diagnosed twice as often in the 3277 patients admitted to the intensive care unit as in patients admitted to other departments (7.5% vs 3.8%, P < .001). The study group had fewer male patients than did the nonpsychiatric intensive care unit group (52% vs 66%, P < .001); the age distribution was similar. Patients with a psychiatric disorder required longer stays than other intensive care unit patients. However, their mortality rate was significantly lower (8.57% vs 17.1%, P = .001). A direct correlation between the admission and a psychiatric condition was found in one-third of admissions in the study group.

Conclusions

Psychiatric patients’ admission rate to the intensive care unit was significantly higher than their admission rate to other departments. Their intensive care unit stays were also longer, which may increase resource use.
Realistic Engineering Critical Assessment ECA Assurance for Sour Service Pipelines
Authors: Chaubey Rajeev , Singh Nawin
Published: November 2020

Through a case study this paper presents influence of design engineering on Engineering Critical Assessment (ECA) outcome and how this influence can be predicted in early stage of project life cycle. A comparison is made between controlling ECA input sensitive parameters during detail design verses optimization of standalone ECA calculations in parallel. Standardized correlation guidelines between operational strain and service sourness is developed for a typical carbon steel pipeline installed in shallow water handing sour fluid (low pH).

The outcome of ECA study is mainly dependent on two important parameters i.e. results from detail/material engineering and design aspect of girth weld. In this paper, the detail and material engineering aspect have been investigated through numerous ECA calculations with various sensitivity run for key input parameters of the ECA study. Further, backward calculations are performed within detail design deliverables to control operational strain and stress range. An equilibrium is achieved for optimized design which is best suitable for realistic ECA outcome and from overall project view point. Consequently, a standardized correlation between operational strain and service sourness is developed.

There was some significant progress made in last few years through research on tensile strain capacity (TSC) for pipelines in sour services. Gordon et al (ISOPE 2017) has highlighted ECA input sensitivity parameters (ISP) while comparing various strain-based models for predicting TSC of Material. Though weld acceptance criteria finalization comes under gamut of material and welding engineering; it is observed that managing these ISP at early stage of project life cycle has significant advantage over performing standalone ECA for the given design.

Having this parametric study done at early stage will also benefit the project in terms of the cost while meeting the challenging pipeline installation schedule. At present, this study and formulation developed is only applicable to high temperature CS pipeline installed in shallow water following S-lay method.
Collapsible Landing Sub Deployed with Mechanical Inflow Test Packer Allows Liner Lap Testing and Shoe Track Drill Out in One Trip, Decreasing Costs and Increasing Reliability
Authors: Alotaibi Ali Sanhat , Riskiawan Arris , Alotaibi Majed , Ronson Michael
Published: November 2020

Liner lap testing operations in the gas fields have evolved to include shoe track drill out operations in the same trip. Typically, a drilling BHA is run and spaced below an inflow test packer to drill out the shoe track to 20ft above the shoe. A landing sub or no-go lands in the liner top at the predetermined bit depth to activate a test packer mechanically. This order of operation exposes the packer elements to debris circulated from drill out operations resulting in damage to the packer elements or incorrect engagement of the packer elements and casing ID.

Deploying a hydraulically activated collapsible land sub in conjunction with the mechanical inflow test packer allows a change in the order of this operation. The collapsible landing sub is run in hole below the test packer and lands in the liner top to facilitate the packer activation. The liner lap test can be conducted with little or no drill-out debris in the well. Once the liner lap test is considered successful, the landing sub is hydraulically collapsed allowing entry into and below the liner top. Drilling operations can then resume without concern to packer element damage. Applications of this system include liner lap testing and any subsequent drilling operation in the same trip.

This paper introduces and discusses the step change in operational liner lap testing procedures while incorporate this new approach to market technology of the collapsible landing sub. It describes the lesson learned and the limitations of the previous method of conducting this operation. It analyzes and compares actual job data and success rates between the previous methods and methods incorporating the new technology. This paper shows that using the collapsible landing sub in conjunction with the mechanical in flow test packer cost reduction and increases reliability and profitability in these operations.
Comparison of CO2 Flow Patterns Between Offshore North Sea and Onshore United States
Authors: Ghanbari Saeed , Mackay Eric J , Pickup Gillian E
Published: November 2020

In any flooding process, the flow pattern determines the quality of the macroscopic sweep and expected recovery efficiency. The flow pattern also controls the choice of the flooding strategy. This study compares CO2 flow patterns between two major classes of reservoirs; first, the United States CO2 flooded reservoirs, considered as benchmark for CO2 application elsewhere, and second, the North Sea class of reservoirs considered as future target for CO2 flooding offshore.

An inventory of reservoir data was first prepared by inspecting the literature. North Sea reservoirs are characterised with higher temperatures, higher pressures, thicker pays and higher permeabilities. Well spacing is also larger in the North Sea and these reservoirs are depleted faster.

Using appropriate correlations, the in-situ CO2 and oil properties were inferred for each individual reservoir knowing its ambient reservoir conditions. Scaling analysis was used to characterise the CO2 displacing oil process in each reservoir by calculating a few key dimensionless numbers. Numerical simulation of CO2 displacing oil in stochastic permeability fields revealed the CO2 flow pattern in each individual reservoir.

Although CO2 and oil densities are comparable in North Sea and United States classes of reservoirs, scaling analysis shows that "gravity numbers" for a CO2 displacing oil process are an order of magnitude larger offshore North Sea. This indicates a more gravity dominated CO2 flooding in the North Sea compared to United States reservoirs principally due to thicker pays and significantly higher permeabilities in this province but not due to larger CO2 and oil density contrast.

The "mobility number" for a CO2-oil displacement process is also considerably lower (or better) in the North Sea due to lower North Sea oil viscosities. This indicates, in the absence of gravity, the viscous CO2 flooding is expected to be more stable in the North Sea. "Effective aspect ratios", illustrating the degree of cross flow are also lower in the North Sea mainly due to considerably thicker pay reservoirs in these systems.

Visual comparison of displacement profiles in different stochastic permeability fields shows that, unlike the majority of United States CO2 flooded reservoirs where the displacement may be characterised with an unstable viscous dominated process, in the North Sea CO2 flow patterns vary mostly between gravity dominated and stable viscous displacements.

Better understanding of the CO2 flow pattern can help in the selection of the appropriate CO2 flooding process e.g. selection between horizontal and gravity stable CO2 flooding or the decision to implement WAG instead of continuous CO2 injection for future provinces targeted for CO2-EOR like the North Sea. North Sea reservoirs thus may benefit from a different CO2 flood design than that observed historically in the United States since their CO2 flow patterns is fundamentally different.
Rule Based Design Application to Offshore Jacket Structures
Authors: N. Nagaraju , Pillai Syam , Kumar Chaithanya
Published: November 2020

Rule based system design has been developed in two stages - first for weight estimates and second for jacket design automation using a standardized jacket concept. A simple fixed offshore jacket design involves many governing parameters such as environmental criteria, deck size and weight, site specific parameters, construction and installation variables. A domain-based approach has been used to minimize the governing parameters in the design, so that rule-based system can be developed. The paper presents the rule-based system developed for fixed well head platform jacket with 4 legs, leg through pile, lift installed jacket in a water depth up to 60m.

McDermott has constructed and installed more than 300 jackets in the above domain. A database has been developed from these jackets installed in middle east, which included the key design variables required for the jacket design. Empirical formulae along with the information from this database, were used to develop rules to generate the gravity loads, environmental loads and installation loads required for the jacket design. A range of soil capacity curves were used to simulate the soil capacity variation in the selected jacket domain. Rules for developing the pile diameter, pile penetration and possible hammer required to drive the piles were developed. These rules formed the basis for the knowledge base required for the rule-based system. This rule-based system has been used in the first stage for weight estimation with accuracy of +/−20%, so that this can form a good input for the cost estimate with a quick turnaround.

In the second stage, a screening analysis was performed using the rules developed to select the design parameters and site-specific data to be used for jacket design without compromising the optimization of the jacket. Similarly, the appurtenances viz. conductors, risers, boat landing, etc. on the jacket were grouped into a range to minimize the parameters to be considered for the jacket design. Using this approach, few thousand possible design parameters were reduced to less than hundred governing parameters for possible range of water depth, specific to site. Standard jacket configuration developed for the selected domain has been analyzed and compared with the jacket weights derived from the rules. Rules were finetuned based on this standard jacket analysis to aid automation of the jacket for a specific location with predefined design parameters. Construction, installation and build methods were confirmed along with the jacket configuration development.

Rule based system which is a part of the Artificial Intelligence development tool, has been historically used in disease diagnosis, automobile production industry, select tactical moves to play a game, graphic interface development. This paper presents a McDermott's initiative to arrive at jacket configuration by using rule based system which can help to automate the jacket design.
The Feasibility of Resistivity Responses as Fluid Monitoring Controlled System in Conventional Reservoir-Hydrocarbon Production
Authors: Hasan Kurniawan Adha , Lubis Luluan Almanna , Hermana Maman , Latiff Abdul Halim
Published: November 2020

During field recovery optimization, EOR takes a role to keep active and always develop the techniques for increasing oil production from time to time. Foam flooding has been introduced as a new technique to overcome the limitation of gas injection by reducing gas mobility. Specifically, the foam injection was a success to optimize the recovery. Unfortunately, the utilization of foam creates several challenges, especially in the foam monitoring system. Resistivity analysis is the best parameters used for generating the foam system monitoring. This study was focusing on identifying the major controlling factor which donates to resistivity responses. Characteristic of the resistivity responses towards the fluid's injection as the function of the variances in fluids type with the divergence of reservoir properties (i.e., porosity and permeability) is the primary objectives in this study. Variances in type fluids and reservoir properties were applied in this study for enhancing the application of this project in global used. Competent clastic reservoirs samples were used in this study (Idoha and Berea), which resistivity responses was determined using the equipment rig for all samples in 4 saturation (Air, Brine, and Foam in concentration 0.5 wt%, 1.0 wt%). Resistivity measurement was conducted as a function of foam injection time to determine the correlation of foam propagation in porous media based on the resistivity difference in two reservoir condition. Generally, the resistivity of dry condition (air saturation) is higher as compared to the wet condition. Storage capacity, fluids integrity (density, viscosity, interfacial tension, and the concentration) and mix fluids windows are the most factors which influence the resistivity responses. Fluids integrity have been controlled by chemical and physical properties of the fluids, i.e., density, viscosity, interfacial tension, and the concentration. All features donate the producing of fluids resistivity responses. All parameters were sensitive to temperature changes. Foam monitoring, wherein the positive side the resistivity responses are important tools in fluids determination due to detailed answers for each condition.
Effective Wellbore Stimulation Methods Utilizing Advanced Thermal Technologies
Authors: Othman Haitham , Batarseh Sameeh , San Roman Alerigi Damian , Alhubai Ali
Published: November 2020

The objective of this study is to optimize heat generation for effective wellbore stimulation and clean up utilizing advanced thermal techniques. In this study, resistivity heat (electric), Microwave, Radio frequencies, and steam have been evaluated utilizing large patented apparatus. Different heating technologies can be configured in the apparatus using vertical, horizontal, or a combination of vertical and horizontal wells. Baselines are measured and methods of enhancing heat propagation are discussed.

Thermal stimulation techniques are the efficient for wellbore stimulation and clean up, however, these technologies have major limitations in penetrating the formation and lower efficiency in deep formations. To solve these drawbacks, alternative methods using microwave have been identified and investigated. Another alternative is to combine microwave with steam and electric heaters, among others.

A state-of-the-art Universal Apparatus has been designed and built to investigate multiple thermal stimulation techniques; namely microwave with microwave enabler materials (they can heat up to 800°F), steam injection, and electric (resistivity) heaters. The apparatus was designed to simulate a real oil formation, it can be filled with 1-m3 of sand or rock blocks. Each of the heating mechanism can be inserted into the sand/rock bed either vertically or horizontally at multiple positions. It is also equipped with 60 temperature measurement points and 5 acoustic sensors for real-time monitoring. Heating methods were tested individually to evaluate their heat propagation and efficiencies and to set their baselines. Then they were tested in-combination to optimize the controlling parameters for effective heat generation and propagation, and to develop new methods for formation stimulation.

The results demonstrated that the heating dynamics can be optimized by controlling the configuration of the heating tools, their operating parameters, and the microwave enablers distribution, type, and volume. This work also showed that the microwave enablers can be used to improve the heat transfer into oil formations. This paper will present the different evaluated scenarios and the optimized combinations for effective heat generation and propagation.
Evaluation of Hydrogen Sulfide Scavengers for Use with Static Mixers
Authors: Lehmann Marc , Pojtanabuntoeng Thunyaluk , Long Yu , Yookhong Marisa , Iannuzzi Mariano
Published: November 2020

The efficiency of hydrogen sulfide scavengers directly injected into gas streams is often compromised by short contact times due to space limitations on offshore assets. The use of static mixers is often employed to increase the efficiency of gas-liquid mixing. The performance of two commercially available hydrogen scavenger products were assessed in the laboratory utilising a specially fabricated test chamber designed to mimic a static mixer. A continuous feed of both gas and a liquid scavenger solution were mixed through a glass bead static mixer. The liquid scavenger was atomized into the gas prior to traveling through the bed. The impact of dose rate, water content, carbon dioxide and contact time were assessed on the scavenging efficiency and kinetics of two triazine chemicals used to sequester H2S from a gas stream containing 180 ppmv H2S in nitrogen, to achieve a target H2S concentrations of <10 ppmv. Efficiencies derived from the test apparatus revealed that the formulation based on the ethanolamine triazine chemistry performed significantly better than the methylamine triazine product at the two contact times of 3 and 25 seconds. The equilibration time required to reach the target concentration were significantly longer at the shorter contact time, and unachievable without the static mixer. The dosages of scavenger required to reduce the H2S concentrations from 180 ppmv to 10 ppmv were much higher than theoretical dosages. The addition of water to the scavenger mixtures was found to increase the efficiency of the ethanolamine scavenger but decrease the performance of the methylamine based triazine. The importance of atomisation of the scavenger onto the fixed bed was reinforced by the dramatic reductions in performance associated with a lack of atomisation. The presence of CO2 had no significant impact on the scavenging efficiency but had a kinetic impact and reduced the time to achieve the target concentration.
Low Noise Transducer for Logging While Drilling Borehole Imaging in Oil Based and Water-Based Muds
Authors: Jin Jing , Li Peng , Coates Richard , Hany Mohamed
Published: November 2020

High-quality borehole imaging is of great value during the evaluation of borehole conditions, such as wellbore stability, fracture identification, and dip mapping. Obtaining borehole images from logging-while-drilling (LWD) tools provides real-time information and allows access to highly deviated wells, which could be difficult to access using wireline tools.

Borehole images can be acquired in water-based mud (WBM) systems with both resistivity and ultrasonic measurements. However, oil-based mud (OBM) systems limit the use of resistivity and pose great challenges to the ultrasonic method because of the high acoustic attenuation of the muds. This high attenuation can be overcome in wireline tools using larger ultrasonic transducers with representative dimensions of 2 in. diameter and 2 in. length. However, corresponding transducers intended for LWD tools, particularly for 4¾-in. collar sizes, should be smaller and sufficiently rugged to withstand the drilling environment.

This paper describes a transducer developed by the authors to meet these output, size, and ruggedness constraints. The transducers have high acoustic output and low inherent noise to produce sufficient output to provide reliable imaging, even in heavy muds. Four of these transducers and associated electronics are integrated into an LWD tool. A real-time ringing removal algorithm was implemented to record low-noise echo waveforms in pulse-echo mode. These waveforms are then processed automatically to generate both time-of-flight and reflection amplitude measurements. The former can be used to gauge the borehole shape, while the latter characterizes the acoustic impedance and rugosity of the borehole wall, which, in turn, reveal fractures and formation bedding.

During the development phase we conducted laboratory measurements to illustrate the high signal-to-noise ratio (SNR) of the transducer, which is vital when operating in the transmitting mode. We obtained satisfactory results that demonstrate high sensitivity and well-collimated directionality in receiving mode. During laboratory tests, the transducer was able to detect a 0.1-in. fracture in a cement block immersed in water. In addition, results from a prototype tool incorporating the transducers run in 9.5-lbm/gal OBM in a test well, which are comparable to wireline quality ultrasonic results, are discussed.
How Solar Hybrid Wind Turbine Brings Continuous Power Supply and Cost Optimization to Offshore Platforms in Malaysia
Authors: Lee Joel Yong , Liew Daniel Khee
Published: November 2020

Solar power is one of the consideration for many oil & gas platform operators who are going for renewable energy to provide power. However for solar power, continuous power has been an issue especially during the Northeast monsoon (October – March) where the sun is frequently blocked by rain clouds. By using a hybrid of Photovoltaic (PV) modules and wind turbines to harvest both solar and wind power, power generation will be more stable and reliable. The results of this can be concluded by the results taken from a Malaysia offshore platform which had installed a wind turbine to their solar system in March 2018. The results show more consistent power generation with the hybridization of solar and wind power.
A Model Testing to Improve Punch-Through Failure Assessment
Authors: Hu Nanding , Yang Jin , Bao Suduna , Yang Guodong , Liu Xun , Wang Yichen , Yu Chen , Zhou Jianyi
Published: November 2020

The jack-up platform will face the risk of punch-through failure when pilling in areas where a stronger-thinner layered soil overlays a softer soil layer. The punch-through failure that occurred in the South China Sea indicates that there are still shortcomings in the existing punch-through failure assessment methods. Therefore, this paper improves the shortcomings of the existing punch-through failure assessment method based on the simulation experiment.

Firstly, the shortcomings of the existing punch-through failure assessment method were analyzed based on the case of punch-through incidents occurred in the South China Sea. Then, the main factors of punch-through were analyzed by means of simulation experiment, and the shortcomings of the existing method were improved. Meanwhile, a punch-through failure assessment method considering the spudcan tip height and loading process was established. Finally, taking a case of the South China Sea as an example, the improved model guided the penetration of jack-up platform and avoided punch-through failure successfully.

By analyzing the case of the punch-through failure occurred in the South China Sea, the soil layer in which punch-through failure occurs has the characteristics that the thickness of stronger-thinner layered soil is close to the height of pile tip. In order to explore the main factors leading to punch-through failure, a set of experimental system simulating the spudcan punch-through was designed, and a series of punch-through simulation experiments were conducted. Simulation experiment results show that the reduction ratio of bearing capacity will decreases with the ratio of stronger-thinner layered soil thickness and pile tip height (d/h) increases. When the d/h is greater than 2, the reduction ratio of bearing capacity is less than 5%; When the pile tip height is equal to the thickness of stronger-thinner layered soil, the reduction ratio of bearing capacity is more than 95%.

The innovation of this paper is that punch-through failure assessment method considering ratio of pile tip height and soil layer thickness was established.
Experimental Investigation of Ultrasound-Assisted Weak-Acid Hydrolysis of Crystalline Starch Nanoparticles for Chemical Enhanced Oil Recovery
Authors: Junin Radzuan , Agi Augustine
Published: November 2020

Ascorbic acid was used to synthesize crystalline starch nanoparticles (CSNP) for the first time. The CSNP was isolated and the influence of the process variables on the physical properties, recovery yield and crystallinity were studied. Rheology of crystalline starch nanofluid (CSNF) was compared with cassava starch (CS) solution and xanthan. Interfacial tension (IFT) of CSNF was studied at various concentration and temperatures. Influence of concentration, temperature, salinity and their interaction with ultrasound were investigated. Sessile drop contact angle method was used to determine the wettability proficiency of CSNF on an initially oil-wet sandstone core. To justify the finding highlighted above, CSNF and CS solution were applied for EOR purposes at reservoir condition. The approaches were efficient in generating sphere-shaped and elongated nanoparticles (50 nm mean diameter) and higher yield of 39%. Increase in concentration, surface area and temperature of CS and CSNF increased viscosity in comparison to decline in viscosity as the temperature increases for xanthan. Increased concentration, salinity and temperature rise of CSNF decreased IFT and altered the wettability of the sandstone core. CSNF increased the oil recovery by 23% and was effective at high temperature high pressure reservoir conditions. The energy consumption and cost estimation has demonstrated that the methods and polymeric nanofluid are cost-effective than traditional methods and products.
Hydrodynamical Study of Combined Effects of an Orifice Plate and a Bluff Body for Flow Measurements
Authors: Noui-Mehidi Mohamed Nabil , Ahmedi Abdelhadi
Published: November 2020

The effect of the diameter of an orifice plate when a bluff body is placed upstream of it is numerically studied. A circular cylinder used as a bluff body usually generates a wake of vortices known as Von Karman vortices. It was found in this study that it depends on the opening of an orifice plate behind the bluff body there is a transition from the classical Von Karman system of vortices to a pulsation type of flow. The numerical calculation performed by a Lattice Boltzmann approach reveal the nature of the vortices each time that the diameter of the orifice is changed as well as the frequencies related to the shedding of the vortices behind the obstacles.
Inhibiting Wax Deposition using Palm Oil Additives
Authors: Ragunathan Thevaruban , Husin Hazlina , Wood Colin D.
Published: November 2020

Among the various flow assurance problems that the petroleum industry faces, the deposition of paraffin waxes on to the wall of the pipeline is the most challenging. The challenge arises when the crude oil temperature decreases below the wax appearance temperature (WAT) which leads to the wax crystal in the crude oil to crystallize. An efficient method in remedying paraffin wax deposition is the utilization of chemical inhibitors. However, currently used chemical inhibitors are costly and environmentally harmful if a spillage occurs. Therefore, the use of biodegradable or environmently friendly inhibitors as potential chemical inhibitors are being studied by various researchers. This study investigated oleic acid, poly (ethylene-co-vinyl acetate) (EVA) and triethanolamine (TEA) as inhibitors that perform based on the van der Waals intermolecular interaction between the main wax component molecule eicosane C20H42 using the molecular dynamics simulation (MD) procedure via Material Studio 8.0 software package. In order to analyse the desired structural property which is the Radial Distribution Function (RDF), COMPASS force field was used. The RDF and g(r) function portrayed the functional atoms which aid in inhibiting the agglomeration and crystallization of the wax crystal formation. The presence of a carbonyl oxygen in oleic acid plays a vital role to inhibit the wax formation through the van der Waals interaction between active hydrogen atoms in eicosane molecule. Therefore, the chances of wax inhibition in eicosane is higher by introducing oleic acid as an inhibitor as compared to EVA and TEA. The results were then validated experimentally utilizing a cold finger technique under static condition.
Viscosity Model of Waxy Crude Oil Based on the Physico-Chemical Properties
Authors: Bhaskoro Petrus Tri , Japper@Jaafar Azuraien , Sariman Mior Zaiga , Norpiah Rohaizad , Shafian Siti Rohaida
Published: November 2020

Temperature-dependent viscosity is one of critical properties in designing facilities for waxy crude oil production. Several viscosity models have been developed and available in literature. Nevertheless, those models are still insufficient to cover all waxy crude oil produced from various regions. Therefore, this work aims to develop a general viscosity model for Malaysian waxy crude oils. Extensive rheological study was conducted and showed that viscosity behavior below WAT can be best described using Herschel-Buckley model. Multiple correlation and regression analysis were also performed to identify critical physico-chemical properties dictating the viscosity behavior. Based on the finding, a general viscosity model was developed by modifying Herschel-Buckley model and incorporate the critical physico-chemical properties. The general model was compared with widely used viscosity model and other models available in literatures to assess its performance on describing the viscosity behavior. The comparison showed that the general model has lowest average absolute percentage error and hence, it is more superior than the other models. Nevertheless, the model still has limitation in describing viscosity at the transition regime which is between WAT and 5°C below WAT.
Carbon Nanotubes Reinforced Stainless Steel Composites for Offshore Applications
Authors: Lau Hon Chung , Radhamani Adiyodi Veettil , Ramakrishna Seeram
Published: November 2020

Experiments have demonstrated the successful fabrication of composites of multi-wall carbon nanotubes (CNT) with both 304 and 316 stainless steel (SS) using ball milling and spark plasma sintering (SPS). The retention of CNT structures after the SPS process was confirmed by x-ray diffraction, Raman spectroscopy and field emission scanning electron microscopy. At a concentration between 0.5-2.0 wt.%, CNT increased the Vickers hardness and compressive yield strength of 304 SS and 316 SS significantly. These results show that composites of CNT and SS are harder and stronger materials than pristine steels. Potential oilfield and offshore applications can be many depending on whether the CNT-SS composites are fabricated as pellets, coatings or wires.
Impact of Caprock Type on Geochemical Reactivity and Mineral Trapping Efficiency of CO2
Authors: Al-Khdheeawi Emad A. , Mahdi Doaa Saleh , Ali Muhammad , Fauziah Cut Aja , Barifcani Ahmed
Published: November 2020

CO2 capture and storage (CCS) is an important method to mitigate greenhouse gas (GHG) emissions by injecting CO2 into deep geological formations such as depleted hydrocarbon, unminable coal beds, and deep saline aquifers. However, due to the density variations between the supercritical CO2 and formation water, CO2 migrates upwards to the atmosphere. The risk of this CO2 migration can be prevented by different trapping mechanisms (e.g. structural trapping, capillary trapping, dissolution trapping, and mineral trapping). The trapping efficiency of these trapping mechanisms is highly influenced by various factors including CO2 injection scenarios, injection well configuration, reservoir wettability, reservoir heterogeneity, reservoir temperature, and formation water salinity. One of these factors, which has received little attention, is the caprock type. Although caprock wettability has been investigated previously as a factor affecting residual and structural trapping capacities, the effect of caprock type on mineral trapping efficiency has not been addressed yet. Thus, in this paper, we studied the impact of caprock type on geochemical reactivity and mineral trapping capacity by simulating a permeable sand reservoir overlying by three different semi-permeable caprock layers with different mineralogy (i.e. sandstone, siltstone, and shale). The Chemical Composition of these different caprock samples was measured using quantitative X-ray diffraction (XRD) instrument. XRD results indicated that siltstone and sandstone samples consisted mainly of quartz (~50wt %), while shale sample consisted mainly of illite (33)% and quartz (31%), in addition to few other smaller fractions of Illite, Chlorite, Albite, K-feldspar, Hematite, Ankerite, and Calcite. Our simulation results show that caprock type has a significant effect on geochemical reactivity and the associated mineral trapping mechanism. The results clearly indicate that the geochemical reactivity of siltstone caprock is relatively high, compared to shale and sandstone caprock cases. Furthermore, the results show that siltstone caprock scenario has the highest mineral trapping capacity, followed by shale and sandstone caprock scenarios, respectively. Moreover, the results indicate that sandstone caprock has the most increase in reservoir porosity and permeability.

Thus, we conclude that the caprock mineral composition plays important roles in the geochemical reactivity and the associated mineral trapping of CO2.
Adaption of Front End Loading in Crisis Management
Authors: Muhammad Yasin Muhammad Yazuwan , Wisono Widiyanto , Murukesavan Prabagar
Published: November 2020

In an offshore setting, oil and gas assets are exposed to various environmental and operational conditions which directly influence their structural integrity hence possibly leading to catastrophic failures if not monitored. This happened at one of the Mobile Offshore Production Unit (MOPU) located Offshore Malaysia, where multiple cracks were found at two (2) of its jacked legs during a routine underwater inspection which forced the operators to cease operations and abandon the MOPU due to HSSE risks.
Systematic Approach in Testing Field Data Analysis Techniques with an Example of Multiwell Retrospective Testing
Authors: Yamalov Ilnur , Ovcharov Vladimir , Akimov Andrey , Gadelshin Emil , Aslanyan Artur , Krichevsky Vladimir , Gulyaev Danila , Farakhova Rushana
Published: November 2020

The massive industry digitalization creates huge data banks which require dedicated data processing techniques.

A good example of such a massive data bank is the long-term pressure records of Permanent Downhole Gauges (PDG) which became very popular in the last 20 years and currently cover thousands of wells in Company RN.

Many data processing techniques have been applied to interpret the PDG data, both single-well (IPR, RTA[1]) and multi-well (CRM [2] - [5] and various statistical correlation models).

The ability of any methodology to predict the pressure response to rate variations and/or rate response to pressure variations can be easily tested via numerical modelling of synthetic fields or via comparison with the actual field production history.

This paper presents a Multi-well Retrospective Testing (MRT, see Appendix A and [6] - [9]) methodology of PDG data analysis which is based on the Multi-well Deconvolution (MDCV, see Appendix B and [10] - [20]) and the results of its blind testing against synthetic and real fields.

The key idea of the MDCV is to find a reference transient pressure response (called UTR) to the unit-rate production in the same well (specifically called DTR) or offset wells (specifically called CTR) and then use convolution to predict pressure response to arbitrary rate history with an account of cross-well interference.

The MRT analysis is using the reconstructed UTRs (DTRs and CTRs) to predict the pressure/rates and reconstruct the past formation pressure history, productivity index history, cross-well interference history and reservoir properties like potential and dynamic drainage volumes and transmissibility.

The results of the MRT blind testing have concluded that MRT could be recommended as an efficient tool to estimate the current and predict the future formation pressure without production deferment caused by temporary shut-down for pressure build up. It showed the ability to accurately reconstruct the past formation pressure history and productivity index. It also reconstructs the well-by-well cross-well interference and reservoir properties around and between the wells.

The blind-test also revealed limitations of the method and the way to diagnose the trust of the MRT predictions.

Engineers are now considering using MRT in Company RN as a part of the selection/justification package for the new wells drilling, conversions, workovers, production optimization and selection of surveillance candidates.
Agglomeration of Fines and Sand in the Separator
Authors: M. Fauzi Noor ‘Aliaa , Ganat Tarek Arbi , Elraies Khaled Abdalla , Ridha Syahrir , Zainal Suzalina , Saphanuchart Wasan
Published: November 2020

Fines and sand capturing inside the separator is one of the methods to prevent solids carry over. Currently, there are ongoing studies to identify the suitable method to agglomerate the produced solids. Generally, heavier solids would be denser and easily settled at the bottom of the vessel, hence no solids carry over issues. Produced solids can be consisting of natural solids and/or artificial solids. Several types of polymers have been evaluated based on its agglomeration performance, rheology and compatibility as an approach to establish suitable particle size to minimize sand free rate.

The procedures involved include bottle test experiments coupled with particle size distribution (PSD) analysis via Laser Particle Size Analyzer (LPSA). The materials used in the experiments are glass beads with sizes of 50µm and 100µm, synthetic water (0.1M NaCl), a cationic polymer and an anionic polymer. Both polymers have high molecular weight which is known to provide good agglomeration capacity. For each experiment, a 5g of glass bead was placed together with 90mL of synthetic water in a 100mL measuring cylinder. The system was then tested using three polymer system; i) a single cationic polymer system, ii) a single anionic polymer system and iii) a combination of both cationic and anionic polymer system. Light agitation was applied on each, PSD was evaluated and results compared to those of the untreated samples.

The improvement of particle size distribution was observed for all three systems. The results will be discussed further in the paper. The novelty of this research is the application of the sand agglomeration mechanism towards surface sand capturing via separator.
Structural Health Monitoring of Unbonded Flexible Pipe Using Optical Fiber Sensor
Authors: Kuang Wenyu , Ong Paul, Pang , Quek Ser Tong , Kuang Kevin, Sze
Published: November 2020

Pipelines are critical for transportation of oil and gas. A Steel Strip Reinforced Thermoplastic Pipe (SSRTP) is applied in the offshore environment because of its superior mechanical performance. Due to the complex subsea conditions, SSRTP is subject to severe loading and may be damaged during its design life. The failure modes of SSRTP, related to four principle loading cases, are investigated in the FE models. The preliminary results will reveal the mechanical behavior of the critical layer of SSRTP prior to damage. An optical fiber sensor is then introduced within the SSRTP as a novel system to monitor the strain of the critical layer.
A Laboratory Study to Optimize Ion Composition for the Hybrid Low Salinity Water/Polymer Flooding
Authors: Karimov Damir , Hashmet Muhammad Rehan , Pourafshary Peyman
Published: November 2020

Nowadays, different studies are conducted to design new methods to improve oil recovery efficiency. The study focuses on experimental work to evaluate synergy between low salinity water and polymer flooding in carbonate formations. The main objective of this paper is to develop a hybrid method to enhance oil recovery by a possible combination of low salinity water and polymer flooding.

The Caspian Sea water was used as a base brine, and the water composition of the Caspian Sea was altered by diluting and adjusting the concentration of active ions such as Ca2+, Mg2+, SO42-, to observe the impact of modified seawater on wettability through contact angle measurements. The compatibility of the modified seawater and partially hydrolyzed polyacrylamide (HPAM) based polymer solutions is investigated by performing different rheological experiments. Different governing parameters such as water salinity, the concentration of active ions, and HPAM solutions concentration are experimentally studied to achieve the optimized rheological behavior.

The different diluted water compositions of Caspian Sea water were prepared to identify the best solution in terms of wettability alteration. Later, the diluted solutions were modified by adding active ions such as Ca2+, Mg2+, and SO42-. The wettability alteration to the more water-wet condition was observed when the concentrations of Ca2+ and SO42- have been increased 4 times, respectively. However, no significant change in wettability was observed by only increasing the concentration of Mg2+ due to low-temperature condition. The effect of modified seawater on polymer performance compatibility was studied by conducting a series of rheological experiments for various salinity levels in smart water composition, temperature range from 25-80 °C, and polymer concentration at 1000 and 3000 ppm. All the polymer solutions showed typical non-Newtonian rheological characteristics with shear thinning behavior. Further, the results based on contact angle measurement and rheological experiments were combined to identify proper optimal conditions for the potential synergy of modified seawater and polymer. Our results showed a clear dependence of the polymer viscosity on the divalent ions concentration and temperature. The target viscosity of 4 cp at a shear rate of 10 s-1, which approximately corresponds to the shear rate in porous media, was obtained with 500 ppm polymer concentration in 20 times diluted Caspian Sea Water having 4 times of Ca2+ and SO42-.

Through the series of experiments, we determined the optimum concentration of active ions in water that results in wettability alteration without compromising the effectiveness of polymer in the hybrid low salinity water-polymer flooding technique. The combination of low salinity water and polymer flooding is found to improve the performance of both methods.