bluuebunny/crossref_metadata_2025 huggingface dataset:
First Installations of the 9-5/8-in. Enhanced Single-Trip Multi-Zone Sand Control Technology in Offshore Brunei
Authors: Fourie Bernard , Marpaung Billman , Jansen Rene , Wong Andrew , Mok David , Karlsey Narmesh Singh
Published: October 2012

Brunei Shell Petroleum (BSP) operates the mature South West Ampa (SWA) and Bugan Fields in Brunei Darussalam. The fields, located 10 to 21 kilometers offshore Brunei in water depths ranging from 10 to 40m, are major sources of oil and gas production. Controlling sand production is a key completion challenge as the reservoirs are composed of multilayer unconsolidated sands, requiring sand control for safe production. Cased-hole, stack-pack systems were considered as the default solution for shallow reservoir zones and wells. Due to the reduced production rates in some reservoirs in the fields and increasing rig costs there is a demand to improve the cased-hole gravel pack efficiency.

The wells require zonal isolation and sand-control treatment. Cased-hole stack packs have been a reliable completion method, due to their capabilities for better zonal isolation and multi-zone functionality. Due to the reduced production rates in the mature fields, however, wells were no longer considered economically feasible. Therefore, BSP decided to try a new 9-5/8-in. enhanced single trip multi zone gravel pack system. This system appeared capable of providing significantly greater cost efficiency than conventional cased-hole stack-pack systems, which would make the marginal wells profitable.

This paper describes the 3 wells completed by BSP in 2010 and 2011 using the enhanced single trip multi zone gravel pack system. For the 3 wells, a total of 10 zones required a sand control treatment. The paper also will describe why the enhanced single trip multi zone gravel pack system was chosen and will discuss the wellbore configuration, the implementation, and other field possibilities for the system. Finally, the paper will discuss the "best practices" learned from the first enhanced single trip multi zone gravel pack system installations; the challenges encountered during the job execution, and also, will compare the enhanced single trip multi zone gravel pack system with the conventional cased-hole stack-pack system to highlight the advantages of the new system.
Intelligent Well Type and Optimum Completion Designs for Complex, Multi-Stacked, Compartmentalized, Oil-Rim Reservoirs
Authors: Masoudi Rahim , Jiew Danny Chong , Karkooti Hooman , Othman Mohamad B. , Chan Keng Seng , Finley Douglas
Published: October 2012

In the quest of improving the hydrocarbon recovery and reducing the development cost in the challenging multi-stacked compartmentalized fields as well as oil rim reservoirs in Malaysia, well type and completion design was found to play a major role. Intelligent well design and completions, namely multi-lateral, selective and controlled injection and depletion, dynamic active flow control valves and down-hole pressure/temperature/composition monitoring have been identified as an essential component in the enhancement of the development strategy. Smart/intelligent completions have the ability to prevent/delay water or gas breakthrough, increase the productivity index and also to properly control drawdown to mitigate wellbore instability, sand failure and conformance issue. Active flow control valves also allow for fewer wells to be drilled by enabling efficient commingled injection and production wells. Moreover, with down-hole monitoring and surveillances, unplanned and challenging work-overs can be avoided, further reducing operating costs. The study also focuses on well architecture that entails well type selection, well reservoir penetration, well inclination and orientation, well completion simplification, well placement and well-count optimization.

In this paper, examples of mature complex multi-stacked and compartmentalized reservoirs with very thin to thick oil columns have been studied for improving the development and exploitation strategies through application of intelligent well type and optimum completion design and engineering. The suggested technology tool box including the applied workflow, guideline, procedures and standards with the field examples and desired results are to be presented and discussed. The study will cover from the assessment to the implementation and execution as well as the modeling methodology of the smart well technology on the selected fields in Malaysia.
Well Des gn and Well Spacing Optimisation in Unconventional Plays
Authors: Baker M. , Mazumder S. , Sharma H. , Philpot J. A. , Scott M. , Wittemeier R.
Published: October 2012

The risk profile for an unconventional resource play differs from a conventional opportunity in that the producibility, per well Estimated Ultimate Recovery (EUR) and Unit Technical Cost (UTC) are more important for identifying potential success than proving the presence of in-place volumes.

Unconventional plays are often characterised by a large number of wells, lower density of subsurface data, large geographical extent and corresponding large range of uncertainty in subsurface parameters. The rapid economic screening of well design and spacing parameters for multiple subsurface realisations is integral in the planning stages of large unconventional plays. An additional complexity is the use of horizontal or complex geometry well designs which may limit or complicate the application of full field reservoir simulation methods.

Recoverable volumes are strongly dependent on the proposed well design and spacing. These should be systematically evaluated and optimised by identifying the well density beyond which the incremental recovery and commerciality benefit begins to erode due to the extra well costs and/or interference between wells.

A method for efficient analysis and comparison of complex well design and well spacing options has been designed to assist in unconventional play planning and evaluation. The method involves the automatic generation and analysis of a large number (thousands) of dynamic reservoir simulation models. The models are analysed systematically for major value drivers to: identify the most efficient well design and optimal spacing factors; select the most economic well designs; assess the impact of subsurface uncertainties; and assist in rig selection and surface planning.
Case Histories of Life Cycle Well Integrity Management Using iWIT Software
Authors: Smith L. M. , Lunt G.
Published: October 2012

The Intetech Well Integrity Toolkit (iWIT) is a web-based program which provides a comprehensive approach to well integrity management covering all potential integrity threats to the whole well. Using its own or existing client databases, this software carries out quantitative data analysis in real-time and provides feedback to the operator about the condition of individual wells and also overviews of the whole field integrity status to support timely, informed, decision-making.

Case histories are described of seven different operations introducing the software. The diverse reasons for introducing the software and the direct and indirect benefits ensuing are described. Each is a unique story, highlighting how flexible and comprehensive this successful software product has been. A common element is the management of data spread across multiple 3rd party datasystems which have been successfully integrated in each case, sometimes utilizing data entered in tablet PCs in the field directly linked to iWIT. More challenging is the vast range of data analysis and presentation which has been customized for each client to achieve their goal. This includes risk evaluation against complex criteria, determination of tubing condition based upon varying production conditions, calculating MAASP values per well per annulus, managing and generating well handover documentation from the software, tracking scaling issues, determining mean time to failure of equipment to establish risk-based inspection frequencies and many more detailed analyses,

The iWIT software has allowed these operators to prove their adherence to Well Integrity Management policies and provides numerous report formats including email alerts for engineers and managers. By ensuring well problems are proactively identified and responded to within guideline timeframes the software ensures that well integrity related shut-downs are reduced, thus providing improved productivity from the well stock and at the same time raising safety within the operations.

Key Benefits of the iWIT Software Identified from Case Histories
Enhanced Petrophysics Analysis to Identify By-passed Zone in Gas Field - A Badak Field Success Story
Authors: Wibowo Ari , Suhendar Ade Diar
Published: October 2012

The Badak Field, operated by VICO Indonesia, is one of the world's giant gas fields. Located in East Kalimantan, the field lies in the northern part of the Badak – Handil giant anticline. Discovered in January 1972, production started in October 1976 and reached a peak of 1,1 BCFD in December 1990. Up until now, cumulative production has exceeded 6 TCF.

Today, Badak is a very mature gas field which produces 80 MMscfd. The drilling of new wells and the well intervention activities continue to be the main way to maintain production in the field. Most of the reservoirs units, especially the larger ones, have been intensively drained over the life of the field. Only a few of them are producing, but at relatively low rates, due to their significant depletion. Finding zones with remaining production potential has become a much more difficult task, especially if some of these zones have incomplete suites of logs.

In VICO, the improvement in the subsurface analytical methods has proven successful in helping identify additional reservoir opportunities. Recently, a method has been developed to identify "bypassed gas zones" in shallow reservoirs. This method uses the sonic log as the main tool for analysis. It also incorporates all of the subsurface data that has been acquired through time. The method has proven very successful in the Badak field in areas where no Density-Neutron log has been acquired.

Theoretically, the sonic log can be used as a complimentary tool to identify gas in the reservoirs. The problem arises when trying to differentiate between the event of gas and the effect of poor or under-compacted shallow reservoirs, as in many cases these events will present a similar feature across the sonic log. The development and implementation of these methods have helped significantly to maintain production in the Badak field.
Taking the First Steps: Stimulating the Nappamerri Trough Resource Play
Authors: Pitkin M. C. , Wadham T. H. , McGowen J. M. , Thom W. W.
Published: October 2012

The Nappamerri Trough in the Cooper Basin has long been recognised as a potential unconventional resource play with both deep-basin (Hillis et al. 2001) or basin-centred gas, and, more recently, as a potential shale gas target. However, initial attempts to fracture stimulate sandstones on conventional structural highs in and around the trough proved difficult. High treating pressures reached the limits of the well designs, and unsuccessful stimulation treatments resulted. A review of geomechanical information suggested that fracture complexity might have resulted from fractures initiating vertically and then twisting off to horizontal further into the reservoir (Nelson et al. 2007).

From 2010 to 2012, Beach Energy undertook a two-well exploration drilling program aimed at assessing the shale gas potential of the Nappamerri Trough and proving the presence of gas outside of structural closure. The wells were initially planned to gather base geological information from the core, but it was recognised that key fracture stimulation uncertainties could be addressed by these wells that would have significant benefit for future well design.

With the knowledge gained from previous stimulation treatments, the wells were designed to incorporate

Acid-soluble cement to improve the connection to the reservoir A fracture completion string—wellhead and pumping equipment suitable for higher treating pressures A surface tiltmeter monitoring array to ascertain whether treatments were twisting into the horizontal plane

The two wells, Holdfast-1 and Encounter-1, were successfully stimulated with 13 different treatments. This paper summarises the interpretation of the treating pressure data and the tiltmeter responses. Through diligent pre-project planning, the observed treating pressures were manageable, although higher than pressure gradients in other published shales and tight-gas areas. Large near-wellbore (NWB) pressure losses in most intervals were successfully reduced to allow treatments to be placed using moderately low viscosity fluids.

The interpretation of the tiltmeter array data indicated predominately vertical fracture development, which is a positive outcome for maximising stimulated reservoir volume (SRV) in future horizontal wells. However, the fracture orientation determined from the tiltmeters was not consistent with the anticipated maximum stress orientation from borehole logs and regional studies, and further investigation is required to resolve this difference.
The Role of Detailed Petrophysical Reservoir Characterization in Hydraulic Fracture Modeling of Shale Gas Reservoirs
Authors: Shebl M. A. , Yalavarthi R. , Nyaaba C.
Published: October 2012

Successful production in shale gas plays largely depend on identifying hydraulically fracable zones. Considerable lithological and petrophysical heterogeneity is expressed by changes in clay, silt, carbonate, and organic content. These changes correspond to variation of the dynamic rock mechanical properties. The contrast of rock mechanical properties amongst the layers influences the fracture dimensions. Detailed petrophysical analysis of shale gas reservoirs facilitates the mapping of the vertical and lateral distribution of various petrophysical and rock properties.

Id ntifying the most suitable zones for well placement, fracture initiation, and optimal distribution of proppant, maximizes the well performance. Geomechanical modeling in conjunction with the distribution of reservoir a d rock properties, determined through detailed petrophysical analysis, can be used to determine the optimum lateral placement and fracture design in shale gas plays. Geomechanical modeling aids in estimating fracture dimensions, fracture conductivities, and also identify zones that can potentially inhibit vertical fracture growth.

This paper describes a petrophysical analysis workflow for analyzing shale gas well logs and how the results from the analysis may be used to identify potential lateral well placement targets. Sensitivity studies showing the influence of rock properties and changes in stimulation design on fracture growth are also presented.
Experimental Design Methodology for Reserves Quantification Based on Soft Computing Modelling
Authors: Gupta R , Van Elk J. F. , Tjia D. , Smith G. C.
Published: October 2012

Over the past decade the statistical experimental design and analysis (EDA) methodology has been used widely in multiple deterministic modelling for a range of applications such as the development of surrogate models for estimation of ultimate recovery, history matching, screening of potential development options etc. Typically the first step in the EDA application is to quantify all uncertainties, secondly to generate the appropriate design with a minimal number of scenarios, thirdly create and simulate 3D geological models and finally calculate a surrogate model.

The goal of the EDA methodology is to minimize the number of 3D model scenarios simulation, necessary to accurately estimate hydrocarbon reserves for a given uncertainty profile. The fundamental question here is "How is an optimal design selected with in the EDA methodology?". The answer is simple; first we lock in the method that will be used to develop surrogate model and then search for the best scenarios to simulate that minimize errors in the final surrogate model. For instance if we plan to use response surface regression modelling, then designs like Placket-Burman, factorial designs or D-optimal designs are a good choice. Alternatively if we propose to use multi-dimensional kriging for surrogate modelling then space filling designs are a better choice.

In general we cannot mix-and-match designs with surrogate modelling methods. With increasing computing power there is a trend in the industry to try new soft computing methods such as neural network and decision tree based modelling to develop surrogate models. In this paper we will demonstrate that soft computing methods can be used for surrogate modeling. However the classical designs are in this case not the best choice. In these instances, the space filling designs like LHD perform better. The use of an incorrect design can lead to serious over estimation of the P90, which must be avoided.
Stimulation of Tight Gas Reservoir using coupled Hydraulic and CO2 Cold-frac Technology
Authors: Mueller Martin , Amro Mohammed , Haefner Frieder Karl , Hossain Md Mofazzal
Published: October 2012

Conventional hydraulic fracture stimulation technique has been widely used to enhance the production from tight gas reservoirs. Success of this technique, however, substantially depends on fracturing fluids and it responses to fracturing fluid-in the treated formations. This technology predominantly has been used to stimulate the tight sandstone reservoir. There are very limited applications for low permeable tight carbonate reservoirs due to complexities associated with the physical and mechanical properties of carbonate rocks and its interaction with fracturing fluid. This study has been focused on the development of a new fracture stimulation technique especially for tight carbonate reservoir, where the fracture will be created by hydraulic pressure and cold CO2.

This paper presents a numerical model that has been developed to simulate the stimulated fracture created by proposed technology with an emphasis on the evaluation of the relative permeability of supercritical CO2, brine/liquid CO2, created achieved fracture porosity and permeability; and the prediction of the production performance of stimulated fractures. Numerical simulation employing the development model has been conducted to: understand the science; investigate the thermo-hydro-fluid-mechanical behaviour; and identify the key parameters influencing the production performance for tight carbonate reservoirs using representative field data. The potential field application of the proposed technique for other formations such as tight sand and shale plays including adsorption effects on the shale and displacement efficiency of CO2 and advantages of this technique are also elaborated in this paper.
Effect of Fluid Leakoff on Fracture Geometry Evolution during Fracpack Treatments
Authors: Karale Chaitanya , Pinto Mario , Choudhary Yogesh
Published: October 2012

In recent years, the use of fracpack treatments has gained attention and is becoming increasingly popular because of their dualbenefits of stimulation and sand control. A fracpack is a hydraulic fracturing treatment using a very high proppant concentration that attempts to "pack-off" the mouth of the fracture. Fracpacking is widely used in high-permeability, poorly consolidated to unconsolidated sandstone formations. Accurate estimation of fracture width is important for both fracpacking and hydraulic fracturing to help ensure a successful treatment.

With the development of low-leakoff fluid systems, it has become possible to force the fluid through the proppant pack and out through the tip of the fracture without losing all the fluid through the fracture faces in a high-permeability, soft formation. In such scenarios, the effec of fluid leakoff on the fracture width profile for the case of arbitrary pressure distribution developed as a result of flow of non-Newtonian fluid through the proppant pack has been discussed in the literature. In this paper, the work has been further extended to include the effect of fluid leakoff through fracture faces for radial fractures.

The fracture face leakoff phenomenon is modeled using a generalized Carter equation, with different leakoff rates being incorporated in the form of fracture face leakoff coefficient values. The effect of fracture face leakoff on the final width profile, net pressure, fracture volume, and pack radius was investigated. It was observed that the width profile is significantly affected when fluid leakoff through the entire fracture face is considered. Controlling fluid leakoff through the fracture faces can result in much wider fractures because of large net pressure developed inside the fracture from fluid squeezing through the proppant pack.
An Evaluation of Risk of Hydrate Formation at the Top of a Pipeline
Authors: Nazeri Mahmoud , Tohidi Bahman , Chapoy Antonin
Published: October 2012

Water condensation and/or hydrate formation at the top of pipelines are serious design/operation consideration in pipelines with stratified flow. Water condensation could result in top of the line corrosion, in particular in sour gas systems. Hydrate formation is believed to be another serious risk if the inhibitor in the aqueous cannot protect hydrate formation at the top of the pipeline.

In this communication we report the results of some preliminary tests conducted in a new experimental set-up constructed for investigating gas hydrate risks in various operational scenarios, e.g., top of pipelines, dead legs/jumpers, start-ups, shut-downs, etc. The reported series of tests conducted in the new experimental set-up address hydrate formation risks at the top of pipelines or dead legs due to temperature gradient, amd risk of hydrate formation in the gas phase in the presence KHI during pipeline cool down and start-up. The results give a better evaluation of the risks involved in various systems and provide guidelines for avoiding the associated problems.
Innovative Circulating Technology Delivers Reduction in Lost Time and Materials While Drilling Depleted Formations
Authors: Herrington D. , Barton S. , Hepp T. , Clausen J.
Published: October 2012

Mitigating down time, while curing losses, is a critical part of designing and executing a good well plan. Even when anticipated, the loss of drilling fluids to depleted formations is a costly event resulting in excessive down time for the entire rig as well additional costs in replacing costly drilling fluids.

The search for new hydrocarbon reserves increasingly sends us back to proven fields where drilling through depleted zones as become an increasing liability to daily operations. The costly time required to pump multiple activation and deactivation balls down the string makes operating conventional tools tedious and time consuming. A more efficient tool for the placement of lost circulation materials (LCM) that does not require the exorbitant lost time and complicated cycling methods of the current technology has not been available for over a decade.

Today, a new tool, utilizing innovative shifting technology, provides unlimited open / close cycles. With this technology, drillers can shift an unlimited number of times and in as little as 5% of the time required by conventional tools. These capabilities result in direct reduction of lost time operating the tool as well as a quantifiable reduction in fluids lost while operating the tool. Simplified operation also makes the tool uniquely easy to operate reducing the potential for user errors that frequently plague existing technology.

This paper details how the use of this innovative circulating technology has assisted a major service company in reducing downtime and excessive costs during lost circulation events. The design has proven simpler to operate and has effectively reduced the non-productive time and lost fluid versus operation of conventional circulating subs. Supporting case studies are included to detail the increase in efficiency and reduction in costs.
Step Change Jar Technology Redefines Industry Standards in North Sea Region
Authors: Herrington D. , Barton S. , Bouaziz S. , Clausen J.
Published: October 2012

While jar technology has been used in the oil industry for the better part of the last century, the basic function and capability has not taken many leaps forward. Increasingly complex well geometry and deeper target depths continue to push drillers into tighter, higher risk well conditions that raise the probability of stuck pipe events. As demand for hydrocarbons has forced our drilling capabilities to evolve, the increased risk associated with these wells has forced the evolution of jarring technology to drastically evolve.

By assessing the critical needs of the industry, a jar has been designed to operate in the harshest environments, with superior reliability, and the highest firing loads available to increase the levels of success in freeing a drill string during a stuck pipe event. Every pound of impact force delivered is critical to improve the chances of retrieving the drill string safely to surface and this new technology has raised the standard force by as much as 20%.

While the operation of this innovative technology remains consistent with industry standards, the performance in regards to torsional strength, damage resistance, and impact capabilities far exceed that of previously existing jar technology. An optional performance component offers operators a safeguard against pulling the jar beyond its mechanical and hydraulic limits which can render it useless down hole. In addition to safeguarding the tool from damage, this module also allows the tool to be pulled to its maximum rating, every time, insuring the hardest possible impact every pull.

This paper will detail how the use of this innovative tool has provided flawless performance in the North Sea and offers a true step change in jar technology to the drilling industry. Case studies and field data provided will support and demonstrate increased performance unmatched in the industry today.
Innovative Solution Successfully Recompletes Problematic Well in Malaysia
Authors: Elliott Chris , Mahzan Mohammad , Feroze Mohd Imran , Mahadi Khairul Azmi , Mahdzan Abdil Adzeem , Aziz Khairil Faiz , Forbes Murray , Dzul-Fikar Nasri
Published: October 2012

An offshore operator in Malaysia had run a completion string in a highly deviated 7-in. gas well. When continuous pressure build-up in the production casing annulus was observed during well clean-up, leakage in the completion system was suspected. After several attempts to mitigate the pressure build-up failed, the operator initiated further investigation, which confirmed the suspicion. Small tubing leaks that were allowing produced gas inside the tubing to seep through to the annulus were found. These leaks could have allowed the pressure to increase, and possibly, could have caused the casing to collapse. In order to produce through the annulus, the pressure would have to be vented. With the high demand of gas in Malaysia and since the rig was still at the location, the project team decided to initiate immediate recompletion of the project instead of waiting for a later intervention.

This well is one of three wells completed to develop the FN field within KCL area, located approximately 200 km offshore from Bintulu. The field was expected to deliver up to 100mmscf/day per well to help relieve an anticipated gas shortage.

This paper discusses the history of the wells, the diagnostic methods used to analyze the well problems, the pros and cons of each solution considered, details regarding the recompletion chosen, and the challenges encountered during the recompletion activities. The discussion also highlights the successful solution used for closing and reopening the fluid loss isolation barrier valve (FLIBV) with a wireline tractor rather than with other options considered after conducting a successful system integration test (SIT) prior to the project execution. The unique solution chosen was a first for Malaysia, and probably, for the world.

The success of the recompletion results provided improvements for future applications and will be a benchmark solution for future operations.
A Comprehensive Evaluation of the Performances of Alkaline/Surfactant/Polymer in Conventional and Unconventional Reservoirs
Authors: Dang Cuong T. , Nguyen Ngoc T. , Chen Zhangxin (John) , Nguyen Huy X , Bae Wisup , Phung Thuoc H.
Published: October 2012

Chemical flooding, especially alkaline/polymer/surfactant (ASP) flooding is of significant increasing interest in mature reservoirs because of high oil prices and larger energy demands. However, it is a very complicated process, and the success of ASP has been mostly demonstrated in laboratory scale. Additionally, ASP is very sensitive to reservoir heterogeneity; therefore, it is urgent and necessary to have a comprehensive investigation of ASP flooding in different reservoir types for a wider and more successful implementation.

This paper aims to solve the prior problems for achieving a new insight vision of ASP flooding. Firstly, a series of laboratory experiments were conducted to optimize the ASP solution. A new mixture of single and double tail anionic surfactant was proposed as a promising approach for high temperature and hardness reservoirs. These mixtures are also more compatible with polymer and increase the optimum salinity. All of the important factors such as alkaline/polymer/surfactant concentration, pH, temperature, salinity, ionic strength were taken in account. And, the experimental result was analyzed by experimental design techniques which allow for evaluating the interaction among those factors which were usually eliminated in literature.

Based on these above achievements in laboratory, full fields scale simulations have been done to assess the performance of ASP in various real field conditions from conventional to unconventional reservoirs which are including traditional sandstone reservoir, tight sandstone oil reservoir, naturally fractured basement reservoir. As an observation result, ASP flooding brings a higher oil recovery (about 10 to 28%), and lower water cut than traditional waterflooding in all of four case studies. However, the incremental amount is not similar since geology characteristics have strong effects on ASP process. The simulation result proved that the fractured reservoirs with low matrix permeability are not suitable candidates for ASP. On the contrary, ASP has great potential for enhancing heavy oil recovery, especially in small and thin reservoirs. A sensitivity analysis was performed for determining the optimal ASP solution and injective scheme for each reservoir condition.
The First Real Time Logging with Coiled Tubing Tractor in an Extended Reach Horizontal Well with Proof of True Stimulation
Authors: Arukhe James , Dhufairi Mubarak , Ghamdi Saleh , Duthie Laurie , Omairen Khalid
Published: October 2012

The world's first successful application of a wired motor head assembly to allow real time logging with a tractor in an extended reach open hole horizontal well has been recorded in Saudi Arabia. The well, located on one of two finger islands, was completed to a total depth of 29,897 ft. (9.11 km) MD; making it the deepest well with open-hole section in the field development, and outside of the reach of traditional tapered coiled tubing (CT) used for well intervention.

Using 2 inch tapered coil tubing and well tractor, the well was successfully acid-stimulated in 14 stages with a total of 3,850 barrels of (diesel) emulsified HCl acid recipe. This paper shows that although tractor interventions have a proven record and are the preferred deployment method for extended well stimulation, there still existed the uncertainty of conducting real time production logging while simultaneously tractoring. This additional challenge in the industry could be overcome by utilizing real time Electrical to Optical (EtO) production logging measurements simultaneously with the running of a tractor. A comparison of the pre- and post-stimulation injectivity indices on a separate run prior to the real time production log acquisition showed an eight fold injectivity index improvement from 53 bpd/psi to 400 bpd/psi. The resulting marked injectivity improvement from acid stimulation also showed the benefit of informed decisions from real time fiber-optic distributed temperature system (DTS) in fluid placement.

Practical applications of these outcomes include the acquisition of real time data of comparable quality with conventional e-line tools resulting in distinct technical and economic advantages in the development of the remaining parts of the field.

Others include the reduction in total well delivery costs from an ability to accurately evaluate well performanceand diagnose problems in real time. The ability to employ real time information to effectively stimulate extended reach wells provide assurance that stimulation can serve as a technical and an economic solution for addressing the relatively high skin damage problem post drilling and completion. Real time logging with the tractor is logistically efficient and allows real time acquisition of injection profiles with the possibility for improving data quality with return passes.
Qualification, Verification and Validation of Novel Subsea Tooling
Authors: Wilkinson David , Wagstaff Mark
Published: October 2012

This paper describes the design, development and testing of a set of diver operated subsea tooling used to resolve a unique issue that occurred during the construction of two subsea wells installed by Esso Australia in 95 metres of water, off the coast of south-eastern Australia.

By following a structured and rigorous process of qualification, verification and validation it was possible to successfully develop the required tooling on a fast track basis in order to meet the schedule constraints of the on-going diving support vessel campaign.

A Western Australia based company with design and manufacturing capability and demonstrating expertise in the development of comparable customised subsea equipment was selected to supply the required tooling. A considerable number of technical solutions were evaluated during the concept development phase prior to selecting a single optimised concept and finalising the design of the tooling.

Comprehensive onshore testing of the tooling and involvement of the diving personnel were essential steps in maximising the probability that the offshore operations could be executed in a safe and efficient manner. As a result of these efforts the tooling operated flawlessly in the field and a multi-million dollar re-drill campaign was avoided.

This paper focuses on the steps undertaken in each part of the qualification, verification and validation process, in order to use this work as an example of the activities that are typically involved in each of these steps, and thus provide a roadmap for the application of this process in other time critical, high consequence situations.
Spatial risk-based assessments for climate adaptation using the SimCLIM modelling system: a case study of domestic rainwater harvesting as the sole source of water
Authors: Warrick R. , Ashford G. , Kouwenhoven P. , Li Y. , Urich P. , Ye W.
Published: October 2012

This paper describes a software modelling system, SimCLIM, for simulating the effects of climate variability and change, and demonstrates its application to domestic rainwater harvesting (RWH). The paper first describes SimCLIM and then focuses on a case study of the reliability of domestic RWH systems as the sole source of water in South East Queensland, a region of high spatial and temporal variability in rainfall. Using the SimCLIM scenario generator along with gridded daily time-series data and a domestic water tank model, ‘risk landscapes’ are created based on the risk of failure of the domestic systems to provide water under both current climate and scenarios of future change. Steep risk gradients were found, with major implications for RWH system configuration. Simulations are then performed in order to examine the trade-offs between two broad strategies – increasing runoff area and increasing tank size – required to maintain a reliable system. The paper concludes that, instead of set specifications, location-specific customisation of RWH systems is preferable in order to ensure reliability under current rainfall variability and sustainability over the long term under climate change. The availability of gridded daily rainfall datasets along with modelling tools like SimCLIM makes this customisation practicable.
The potential for thermal energy recovery from wastewater treatment works in southern England
Authors: Hawley Christopher , Fenner Richard
Published: October 2012

This paper asks how much heat could be recovered from wastewater treatment plants under UK climatic conditions, and can this heat be used effectively to reduce their carbon footprint? Four wastewater treatment sites in southern England have been investigated and the available heat quantified. Issues relating to the environmental, economic and practical constraints on how this energy can be realistically recovered and utilised are discussed. The results show there is a definite possibility for thermal energy recovery and demonstrates that the financial feasibility of three options for using the heat (either for district heating, sludge drying or thermophilic heating in sludge digestion processes) is highly dependent upon the current shadow price of carbon. Without the inclusion of the cost of carbon, the financial feasibility is significantly limited. An environmental constraint for the allowable discharge temperature of effluent after heat extraction was found to be the major limitation to the amount of energy available for recovery. The paper establishes the true potential of thermal energy recovery from wastewater in English conditions and the economic feasibility of reducing the carbon footprint of wastewater treatment operations using this approach.
Investigation of the morphology and surface properties of crosslinked poly(urethane-ester-siloxane)s
Authors: Dzunuzovic Jasna , Pergal Marija , Vodnik Vesna , Spírková Milena , Poręba Rafał , Jovanovic Slobodan
Published: October 2012

Two series of crosslinked poly(urethane-ester-siloxane)s were synthesized
from ?,?-dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide)
(EO-PDMS-EO), 4,4?-methylenediphenyl diisocyanate and Boltorn? hyperbranched
polyesters of the second and third pseudo generation, by a two-step
polymerization in solution. The effect of the EO-PDMS-EO content and
functionality of the applied crosslinking agent on the morphology and surface
properties of the prepared poly(urethane-ester-siloxane)s was investigated by
FTIR spectroscopy, small-angle X-ray scattering (SAXS), atomic force
microscopy (AFM), scanning electron microscopy (SEM) and water absorption
measurement. Different techniques (FTIR peak deconvolution, SAXS and AFM)
revealed that decrease of the crosslinking agent functionality and EO-PDMS-EO
content promotes microphase separation in the synthesized
poly(urethane-ester-siloxane)s. SEM analysis and water absorption experiments
showed that due to the hydrophobic character of EO-PDMS-EO and its ability to
migrate to the surface of poly(urethane-ester-siloxane)s, samples synthesized
with higher EO-PDMS-EO content and crosslinking agent of lower functionality
have more hydrophobic surface and better waterproof performances. The
obtained results indicate that the synthesis of
poly(urethane-ester-siloxane)s based on EO-PDMS-EO and Boltorn? hyperbranched
polyesters leads to the creation of networks with interesting morphological
and surface properties, which can be easily tailored by changing the content
of EO-PDMS-EO segment or functionality of hyperbranched polyester.
Rate and Determinants of Association Between Advanced Retinopathy and Chronic Kidney Disease in Patients With Type 2 Diabetes
Authors: Penno Giuseppe , Solini Anna , Zoppini Giacomo , Orsi Emanuela , Zerbini Gianpaolo , Trevisan Roberto , Gruden Gabriella , Cavalot Franco , Laviola Luigi , Morano Susanna , Nicolucci Antonio , Pugliese Giuseppe ,   for the Renal Insufficiency And Cardiovascular Events (RIACE) Study Group
Published: October 2012

OBJECTIVE

To evaluate the rate and determinants of concordance between advanced diabetic retinopathy (DR) and chronic kidney disease (CKD), as assessed by both albuminuria and estimated glomerular filtration rate (eGFR), in the large cohort of the Renal Insufficiency And Cardiovascular Events (RIACE) Italian multicenter study.

RESEARCH DESIGN AND METHODS

Patients with type 2 diabetes (n = 15,773) visiting consecutively 19 hospital–based diabetes clinics in years 2007 and 2008 were examined. DR was assessed by dilated fundoscopy. CKD was defined based on albuminuria and eGFR.

RESULTS

CKD was present in 58.64% of subjects with advanced DR, whereas advanced DR was detectable only in 15.28% of individuals with any CKD and correlated with the albuminuric CKD phenotypes more than with the nonalbuminuric phenotype. Age, male sex, diabetes duration, hemoglobin A1c, hypertension, triglycerides, previous cardiovascular disease, and, inversely, HDL-cholesterol correlated independently with the presence of any CKD in individuals with advanced DR; correlates differed according to the presence of albuminuria, reduced eGFR, or both. Conversely, factors associated with the presence of advanced DR in subjects with any CKD were diabetes treatment, previous cardiovascular disease, albuminuria, and, inversely, smoking, eGFR, and age at diagnosis.

CONCLUSIONS

Concordance of CKD with advanced DR is low in subjects with type 2 diabetes, and CKD without advanced DR is more frequent than isolated advanced DR, at variance with type 1 diabetes. Factors independently associated with the presence of any CKD in individuals with advanced DR differ, at least in part, from those correlating with the presence of advanced DR in subjects with any CKD and by CKD phenotype.
Cuspal Deflection in Premolar Teeth Restored Using Current Composite Resins With and Without Resin-modified Glass Ionomer Liner
Authors: Karaman E , Ozgunaltay G
Published: October 2012

Aim: To evaluate the effects of four different types of composite resins and a resin modified glass ionomer cement (RMGIC) liner on the cuspal deflection of large MOD cavities in vitro. Materials & Methods: One hundred twenty-eight extracted human upper premolar teeth were used. After the teeth were divided into eight groups (n=16), standardized large MOD cavities were prepared. The distance between cusp tips was measured before and after the cavity preparations with a digital micrometer. Then the teeth were restored with different resin composites (Filtek Supreme XT, Filtek P60, Filtek Z250, Filtek Silorane - 3M ESPE, St Paul, MN, USA) with and without a RMGIC liner (Vitrebond, 3M ESPE, St Paul, MN, USA). Cuspal deflection was measured 5 min, 24 h, and 48 h after the completion of restorations. The data were statistically analyzed with Friedman and Kruskal Wallis tests. Results: A significant reduction in cuspal deflection was observed in Filtek Silorane restorations with and without RMGIC liner (p<0.05). In all restored teeth, the distance between cusps was reduced but they did not return to their original positions during the 48 h period. All teeth showed cuspal deflection, but placement of RMGIC liner reduced it. Conclusion: The use of silorane-based composites and the placement of RMGIC liner under the composite resin restorations resulted in significantly reduced cuspal deflection.
Effect of Chlorhexidine Application on the Long-term Shear Bond Strength to Dentin of a Resin-modified Glass Ionomer
Authors: Dursun E , Le Goff S , Ruse DN , Attal JP
Published: October 2012

Purpose

The aim of this study was to investigate the effect of chlorhexidine digluconate (CHX) application on the shear bond strength (SBS) of a resin-modified glass ionomer cement (RMGIC) to polyalkenoic acid–preconditioned dentin after 24 hours, six months, and 12 months of water storage at 37°C.

Materials and Methods

Cylindrical molds, placed on flat, polyalkenoic acid (Cavity Conditioner® [GC]) preconditioned dentin surfaces of 90 human teeth embedded in resin, were filled with Fuji II LC® (GC), a RMGIC, with (n=45) or without (n=45) the prior application of a 0.05% CHX solution. Within each group, SBS was determined after 24 hours (n=15), six months (n=15), and 12 months (n=15) of storage in water at 37°C. The results were analyzed with two-way analysis of variance followed by Tukey multiple means comparisons (p<0.05). The type of bond failure (adhesive/cohesive/mixed) was noted and the results were analyzed with chi-square test (p<0.05).

Results

After 24 hours, the SBS of RMGIC was not significantly different with (9.0 ± 2.8 MPa) or without (8.3±0.6 MPa) the application of CHX. After six months, however, SBS increased significantly in the group without CHX (12.7±3.4 MPa) but remained unchanged in the CHX group (9.4±4.0 MPa). Similar results without CHX (12.6±3.8 MPa) and with CHX (9.5±3.2 MPa) were obtained after 12 months. No significant differences in the type of debonding were found between the various groups tested.

Conclusion

The application of 0.05% CHX after dentin preconditioning did not seem to have affected the 24-hour SBS of RMGIC. However, the six- and 12-month SBS was significantly lower for CHX-treated samples, possibly as a result of CHX interference with both the bonding mechanism and the maturation reaction of RMGIC.
Temperature Increase at the Light Guide Tip of 15 Contemporary LED Units and Thermal Variation at the Pulpal Floor of Cavities: An Infrared Thermographic Analysis
Authors: Gomes M , DeVito-Moraes A , Francci C , Moraes R , Pereira T , Froes-Salgado N , Yamazaki L , Silva L , Zezell D
Published: October 2012

In this study, a comprehensive investigation on the temperature increase at the light guide tip of several commercial light-emitting diode (LED) light-curing units (LCUs) and the associated thermal variation (ΔT) at the pulpal floor of dental cavities was carried out. In total, 15 LEDs from all generations were investigated, testing a quartz-tungsten-halogen (QTH) unit as a reference. The irradiance level was measured with a power meter, and spectral distribution was analyzed using a spectrometer. Temperature increase at the tip was measured with a type-K thermocouple connected to a thermometer, while ΔT at the pulpal floor was measured by an infrared photodetector in class V cavities, with a 1-mm-thick dentin pulpal floor. The relationship among measured irradiance, ΔT at the tip, and ΔT at the pulpal floor was investigated using regression analyses. Large discrepancies between the expected and measured irradiances were detected for some LCUs. Most of the LCUs showed an emission spectrum narrower than the QTH unit, with emission peaks usually between 450 and 470 nm. The temperature increase at the tip followed a logarithmic growth for LCUs with irradiance ≥1000 mW/cm2, with ΔT at the tip following the measured irradiance linearly (R2=0.67). Linear temperature increase at the pulpal floor over the 40-second exposure time was observed for several LCUs, with linear association between ΔT at the pulpal floor and measured irradiance (R2=0.39) or ΔT at the tip (R2=0.28). In conclusion, contemporary LED units show varied irradiance levels that affect the temperature increase at the light guide tip and, as a consequence, the thermal variation at the pulpal floor of dental cavities.