bluuebunny/crossref_metadata_2025_split huggingface dataset:
Minimizing the Risk of Well Collisions in Land and Offshore Drilling
Authors: Poedjono B. , Akinniranye G. , Conran G. , Antonio T. San , Phillips W. 
Published: December 2007

Abstract
Today's increasingly complex and crowded drilling environments have placed a greater emphasis on wellbore collision avoidance. The safety and financial implications of shutting in production on platforms or repairing damaged wells have established a need for the industry to evaluate the potential for collision with a producing well. This paper will describe an effective approach to evaluating, minimizing and mitigating these hazards, and will include a number of case studies illustrating the successful application of this approach in the field. This paper, the latest in a progressive series will detail the importance of gathering appropriate data—such as completion type, offset surveys, well pressures, casing depths, reservoir fluids and mud densities—and analyzing this data to accurately assess potential collision risks.
Each well and field poses different challenges; not all data is available and wells can vary from simple vertical land wells to crowded offshore and fishbone designs. The well position uncertainties are determined by using survey error models from the Industry Steering Committee on Wellbore Survey Accuracy. This method was chosen because it is an industry-recognized standard of defining the magnitude of survey uncertainty. Recommendations for minimizing risk are based on the status and conditions of the adjacent wells and the nature and severity of the risks associated with a collision. These recommendations are formulated to minimize the risk while ensuring that production is disturbed as little as possible.
A Dynamic Maximization Model for Exploration and Development Efforts in a Petroleum Field
Authors: Marques J. B. , Trevisan O. V. , Suslick S. B. 
Published: December 2007

Abstract
Many works on dynamic models for the maximization of the Net Present Value (NPV) on upstream projects have been published in recent years, originating in the academy as well as the industry. These models usually treat the effort considering either the exploration stage or the development stage of the petroleum field, but not both together. This paper will investigate of the optimum net present value in the upstream project considering both exploration and development efforts simultaneously. This model will enable to address some of the following question: (a) What is the optimum exploratory effort for a petroleum field? (b) What is the optimum time span which the exploratory efforts deserve investment before the beginning of the development stage? (c) What is the appropriate value of the reservoir recovery factor? The maximization of the NPV is represented by an objective function. The influence of the parameters in the estimation of the proposed objective function is shown by means of sensitivity analysis. Among the companies in the world exploring petroleum, several do not usually adopt a methodology combining the exploration and development efforts. Filling this gap in the methodology is the main motivation for this work, which intends to disseminate the use of the combined model in the analysis of the economic viability project of the upstream area.
An Innovative Approach to Uncertainty Assessment of Hydrocarbon Estimates in Fluvial Systems: A Case Study
Authors: Al-Khalifa Mohammad A. , Payenberg Tobi H. D. , Lang Simon 
Published: December 2007

Abstract
A novel method was developed and applied to a fluvial reservoir for the uncertainty assessment of hydrocarbon estimates related to geological input. Uncertainty assessment is a crucial step in any volumetric study, because it exists in all variables used to estimate hydrocarbons originally in place. Conventional volumetric estimation methods such as Monte Carlo simulation and curve decline methods do not consider the uncertainties in depositional facies proportion.
Monte Carlo simulation is a powerful tool in measuring uncertainty in hydrocarbon estimates. Monte Carlo models can be easily built and run extremely fast. The output results can be examined visually as well as statistically. However, the main drawback is the absence of any geological knowledge in the simulation process. The geological knowledge comes from different sources such as drilled cores, wireline well logs, facies maps, modern and ancient analogues and most important of all it grows with the geologists experience. This knowledge is currently employed in the stochastic modeling process only.
The new method presented here merges stochastic facies models with the Monte Carlo Simulation method to produce geological driven volumetrics (GDV). The stochastic facies models are built based on different facies proportions associated with their respective uncertainties. Facies volumes were extracted from the different stochastic facies models and were used as a geological input into the Monte Carol simulation algorithm to generate GDV estimates. Using the GDV method gave hydrocarbon estimates that were higher in volume and had less uncertainty compared to the Monte Carlo Simulation and the stochastic modelling method. The Stochastic modelling method is much more time consuming, for uncertainty assessment because it requires running hundreds of stochastic realisations, while the layout of the GDV is equally as efficient as a Monte Carlo Simulation.
The Effect of Fluid Saturation Profiles on Three-Phase Oil Relative Permeabilities and Oil Recovery
Authors: Mahmud Walid Mohamed 
Published: December 2007

AbstractNetwork models are often used to predict oil, gas and water relative permeabilities and residual saturations. It was recently shown that most previous network model calculations involving significant numbers of double-displacement events were invalid because of material balance errors1.The current study used a model that conserved oil, gas and water volumes. The model accounted for heterogeneity and the snap-off displacement mechanism. Gas injection followed waterflooding to displace the remaining oil saturation. The remaining saturations were a function of the level of snap-off events that occurred during waterflood imbibition. The model was used to study the effect of the fluid saturation profiles at the end of waterflooding on three-phase oil relative permeabilities and oil recovery from a subsequent gas flood.The level of snap-off events during waterflood imbibition displacement significantly affected the remaining oil and water saturations before gas flooding. This, in turn, affected three-phase oil relative permeabilities and recoveries. Residual oil saturation to gas flood increased with increased remaining oil saturation following waterflood. Introducing spatial and local correlations significantly increased oil, water and gas relative permeabilities and reduced remaining oil and water saturations.Oil relative permeability was found to be a function of both oil saturation and the oil remaining after waterflood. Gas and water relative permeabilities were only functions of their respective saturations.
Real-Time Onshore Control Center Enables Offshore Personnel Reduction in Coiled-Tubing Managed-Pressure Drilling Operation
Authors: Geddes Martin , Deady Andy , Speagell Mal , Fernandez Raj 
Published: December 2007

Abstract
One of the main constraints facing many offshore platforms is the shortage of accommodation. The balance between continuing field development and maintaining existing production and platform integrity inevitably requires a compromise in the crew allocation for well engineering activities.
This paper will discuss the challenge faced on Shell’s Gannet Alpha platform in conducting a coiled tubing managed pressure drilling (CTMPD) operation with a 20% reduction in crew numbers over the previous CTMPD operation. The key enabler of this reduction was the use of a supplier’s established onshore control centre located in Norway for remote support. A two-way real time data connection from the platform was established that allowed two key roles to be removed from the platform – drilling data acquisition and quality control, and control of a dynamic annular pressure control system.
This implementation of remote support was unique as the main drilling supplier not only used this facility to reduce his rig-site presence but also facilitated other third party suppliers to remotely operate their equipment by providing space and IT infrastructure within the facility.
As well as the principle benefit of reducing personnel on board required to run the CTMPD, additional benefits were realised through the dissemination of real-time data throughout the operator and supplier organisations. By utilising the WITSML data protocol, the operators reservoir model and well-planning programs were populated in real-time enabling subject experts to participate in the decision making process. Additionally, onshore technical support and engineering personnel were able to utilise the two way connection to access the offshore systems in real-time in order to troubleshoot problems, perform software upgrades and carry out diagnostics on surface hardware and downhole tools as required.
This paper will describe the upfront preparation both in terms of the IT infrastructure and the personnel multi-skilling. It will then describe the ways in which the data was transmitted and used during the operation, and the contingency procedures that were developed in the event of loss of communication. Finally, the future of real time operations will be discussed and how the learnings from this operation can be used in the ongoing development of this technology.
First Field Applications of Microflux Control Show Very Positive Surprises
Authors: Santos Helio , Catak Erdem , Kinder Joe , Franco Emmanuel , Lage Antonio , Sonnemann Paul 
Published: December 2007

Abstract
After a series of successful tests conducted at a research facility for a vertical well using full scale equipment, the Micro-Flux Control (MFC) equipment was taken to its first field applications to begin exploring the performance of the system under actual drilling conditions. These conditions include the presence of cuttings in the return fluid and effects of pipe movement; neither of which could be tested at the research facility.
The accuracy of the MFC had been demonstrated for both WBM and OBM at the research facility, detecting influxes and losses at very low volumes. The first two field wells drilled confirmed the accurate measurement capabilities and showed additional and unique information in terms of flow and pressure.
This paper describes the first two wells drilled with the system. The first was a shallow exploratory well for Petrobras in Brazil using WBM (1824 ft drilled and 3018 ft TD). The second well, drilled for Chevron in Texas using OBM was a development well in a challenging area with ROP approaching 300 ft/hr (2587 ft drilled and 13,000 ft TD).
The system proved to be capable of being used on a wide variety of rigs; whether conventional, without any automation or sophisticated controls and employing a kelly; or latest generations, with fully automated controls and employing a top drive.
The results to be presented include the summary of the planning, the challenges and problems targeted, preparation of the wells, rig up of the equipment, and the results. Among data disclosed is the influence of pipe movement, accuracy of the flow measurements under various conditions, and identification of drilling related problems using the various parameters collected. Several influxes were detected along the well and positively confirmed when gas reached surface. The influx detection data was analogous to the mud logging data.
Underbalanced Drilling Technology for the Exploration of Tight Sands in the Neuquen Basin: An Evaluation of Results from 11 Wells
Authors: Garcia Daniel G. , Moreyra Juan D. 
Published: December 2007

Abstract
The objective of this paper is to summarize the future application, limitations, advantages and disadvantages of UBD technology, based on eleven wells that were drilled in this type of reservoir.
The geographic location of the wells is the Center of the Neuquen Basin, located in the state of Neuquen, Argentina. The objective was to define the reliable range of the stratum flow capacity value or permeability, in order to forecast the reservour productivity with UBD Technology, assuming the absence of formation damage (skin).
The method used was based on the transient-state production equation theory. Implementation was based on the drilling hydraulics design: maintaining constant Pwd close to the reservoir of interest formation pressure; stopping drilling to allow the development of transient production; establishing drilling conditions and detecting the production contributions in new stratums to be evaluated; determining the average production; correlating detected inflows with the pressures obtained by formation testing.
The method, together with other data, allowed us to estimate the structure potential productivity, despite the poor petrophisycs characteristics (Tight gas reservoirs) and to demonstrate that the results during completion could give reliabie properties estimatations used in the forecast.
Combining a Mechanical and Chemical Solution to Mitigate Corrosion in MPD/UBD/Air Drilling Operations
Authors: Kippie David P. , Bellinger Charlie E. , Scott Paul D. 
Published: December 2007

Abstract
Corrosion mitigation is critical for successful managed pressure drilling (MPD), underbalanced drilling (UBD), and air drilling operations. During these operations, large volumes of gas are injected to lower the hydrostatic pressure in the annulus. Most often the injected gas contains some oxygen and the gas is circulated in combination with some quantity of drilling fluid or liquid. Due to the oxygen content and aqueous environment, corrosion potential during MPD/UBD/air drilling operations is high.
Without a proper corrosion mitigation program during these operations, corrosion can lead to the catastrophic failure of drillstring components with corrosion rates 15 times or higher than the industry-acceptable rate of &lt;2 lb/ft2/yr. These high corrosion rates can lead to numerous operational problems resulting in higher well costs and/or formation damage.
This paper discusses how to properly design, implement, and monitor a successful corrosion program to mitigate corrosion during MPD/UBD/air drilling operations. Furthermore, it highlights a process that utilizes membrane technology as a mechanical means of reducing oxygen concentration in the gaseous media in combination with chemical corrosion inhibitors to alter the drilling fluid environment. By using this process, the corrosion rates can be controlled to satisfactory levels during these operations.
Other areas of discussion include membrane technology, drilling fluid chemistry in terms of corrosion control, and the types of corrosion that occur during a MPD/UBD/air drilling operation. Laboratory data will be presented demonstrating the development and limits of the various corrosion control chemistries. And finally, the operational considerations of an effective corrosion control program with case histories will be presented.
Produced-Gas Measurement Using Ultrasonic Metering During Underbalanced Operations
Authors: Wiemers Timothy O. 
Published: December 2007

Abstract
The accurate measurement of produced gas during underbalanced and managed pressure drilling operations is recognized as one of the most critical requirements for determining production capability of drilled producing zones, accurate wellbore flow modeling, quantifiable reservoir characterization, and for determining methods for well control.
Most underbalanced equipment service providers currently use conventional orifice meters to measure annular gas flow during underbalance drilling operations. However, there are a number of disadvantages with the use of conventional orifice metering technology for this application. Such disadvantages include:
Inaccuracies in flow calculations if incorrect gas compositions are assumed Difficulty of measuring widely varying gas-flow rates and high turn-down ratios Difficulty of rapidly removing and/or changing orifice plates when flow rates change quickly Possible downstream equipment damage as the result of dislodged orifice plates.
An ultrasonic meter can resolve some of the above problems, since it has no physical restrictions or moving parts, and therefore, the need to physically remove and/or change a plate due to varying gas-flow rates is eliminated along with the danger of damaging downstream equipment due to dislodged plates. The local computer provides for "hands-off" measurement once the electronics are calibrated and properly programmed. The meter is capable of turn-down ratios of over 250:1 to accommodate varying gas-flow rates. The electronic capabilities also provide automatic flow correction for rapidly changing gas composition.
This paper discusses several lessons learned from designing and testing a portable ultrasonic metering system in the field that was customized specifically for underbalanced operations. Suggestions are given for comparing an ultrasonic measurement system versus conventional orifice measurement system for use in an underbalanced application.
Comparisons of Reservoir Knowledge, Drilling Benefits, and Economic Advantages for Underbalanced and Managed-Pressure Drilling
Authors: Finley Doug , Ansah Joe , Gil Isabel , Lovorn Randy , Shayegi Sara 
Published: December 2007

Abstract
Underbalanced drilling (UBD) and managed pressure drilling (MPD) are gaining in popularity as drilling methodologies to overcome some of the problems faced in conventional overbalanced drilling. These techniques are complimentary technologies rather than completely separate techniques, MPD techniques at one time having been classified under UBD. Therefore, with the current terminology and the many similarities they are often confused with one another. Underbalanced drilling is a tool both for reservoir performance improvement and reservoir characterization as well as for addressing drilling problems. MPD, on the other hand, is primarily a solution for mitigating drilling related problems. Both result in a reduction of non-productive time (NPT). Sometimes a combination of both techniques may be required for the same well.
Different operators have chosen UBD and MPD with the goal of curtailing severe fluid losses and other drilling-related problems associated with conventional overbalanced drilling. Often times, while applying this technique to solve these drilling problems, the reservoir benefits have become apparent and have convinced the operators to go to full underbalance to realize the full reservoir production benefits without any period of overbalance throughout drilling, tripping, and completion operations. They have often found that when using UBD for reservoir production improvement, it is possible to perform comprehensive characterization of the reservoir while drilling. In some cases, zones that were not seen as productive during overbalanced operations have come to light, and reservoir characterization has enabled appraisal of these formations. Reservoir information obtained during the drilling phase can significantly reduce the time and cost associated with gathering and analyzing "well test" type data post-completion with conventional methods and these methods have been field tested and results compared to conventional well testing with favorable results.
Nonintrusive Pipeline-Inspection Techniques for Accurate Measurement of Hydrates and Waxes Within Operational Pipelines
Authors: Benson Dan , Robins Lee 
Published: December 2007

Abstract
This paper will describe the use of externally mounted, non-intrusive on-line diagnostic techniques for pipeline inspection that can be used to accurately measure the amount, location, and profile of any type of deposits within any pipeline. Therefore allowing timely intervention to take place reducing costs, allowing optimization of chemical treatments thus increasing environmental compliance and ensuring greater availability of the pipeline.
Three methods will be described:
Gamma-ray transmission scanning for accurate point measurements. Tomography measurements for detailed density mapping of pipeline contents. Radioisotope tracer injections to determine deposit profiles and inventory over long distances.
The gamma-ray transmission technique uses a small sealed source and a sensitive radiation detector positioned on adjacent sides of the pipe. The measured radiation intensity is directly related to the amount of deposit in the pipeline.
The Tomography scanning technique is an advanced method of gamma ray scanning. Multiple scans around a pipelines circumference using a single point source and a phased array of sensitive radiation detectors enables a very detailed density map of pipeline contents to be produced.
The tracer injection technique requires the injection of a small sharp pulse of low activity radioactive tracer into the line, enabling the fluid velocity between externally mounted radiation detector data loggers to be measured to better than 0.1% accuracy. Comparing this to the pipeline flow rate for the duration of the tests enables the amounts of deposit between successive detectors to be calculated.
The paper will give details of research work and results of several recent pipeline inspection projects.
Highly Successful Batch Application of Surfactant in North Sea Gas Wells
Authors: Schinagl Werner , Green Steve R. , Hodds Alan C. , Caskie Mark , Docherty Martin 
Published: December 2007

Abstract
Liquid loading in gas wells is a phenomenon that increasingly limits production in mature gas wells where reservoir pressures are insufficient to lift liquids out of wellbores.
Various technologies to artificially lift liquid associated with gas production exist, however in offshore fields most of them are not applicable for well completion or legal requirements. In the past soap sticks have been tried to foam up liquids, however these may never have reached the area where liquid had accumulated due to wellbore deviation. It was therefore decided to try liquid batch injection in several North Sea gas wells. The paper speaks about candidate selection, chemical screening, laboratory testing, operational considerations and the results of the offshore field trials.
The results from the first trials were above expectations. One cycling well was able to be kept online five times longer than under normal operating circumstances, while for another well, its time online more than doubled.
These results were the trigger for the next two sets of surfactant trials in the southern North Sea region, which were again successful.
In one well a downhole gauge was utilised to monitor the dramatic change in well behaviour, which gave great insight into the way the surfactant acted. This is discussed in detail in the paper. No foam-related problems were encountered at the platform as defoamer was injected at surface.
From these successful North Sea surfactant batch trials, it can be concluded that de-liquifying gas wells with the aid of surfactants can be a very effective and cheap way to increase gas production, mainly by keeping wells online for an extended period of time. Resolving the issue of liquid loading in maturing gas fields across the North Sea will lead to higher production rates (up to 30% from cycling wells) and an increase in reserves recovery.