bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scale-Dissolver Application Under HP/HT Conditions -- Use of an HP/HT "Stirred Reactor" for In-Situ Scale-Dissolver Evaluations
Authors: Williams H. , Wat R. , Chen P. , Hagen T. , Wennberg K. , Viken V. , Graham G. M. 
Published: December 2007

Abstract
In several high temperature and high pressure (HT/HP) production environments severe downhole carbonate scale formation is often anticipated and effective carbonate scale dissolvers are required. However for most cases the selection of scale dissolvers is conducted under much less severe conditions, involving simple bottle tests conducted at temperatures up to 95°C and ambient pressure. These tests although generally accepted for screening purposes suffer a number of significant limitations. In addition to the moderate test conditions the low pressure means that carbon dioxide is readily released following the dissolution and results in changes in the test pH which may mean the efficiency of the dissolvers could be overstated.
This paper describes the use of a novel a novel HP/HT "stirred reactor" test rig to more closely examine the relative performance of selected scale dissolvers including organic acids (formic and acetic acids), inorganic acids (16% HCl) and other more conventional scale dissolvers under typical field application conditions. The equipment is specially designed for the extraction and stabilisation of samples at or ‘near’ tested conditions and therefore allows the equilibrium dissolution level to be determined under more representative HP/HT conditions. In this work preliminary tests were conducted using 16% HCl under progressively more severe test conditions (RT & 1,500 psi; 150°C & 1,500 psi and then 150°C & 4,500 psi. Further tests were then conducted to compare the performance of organic acid based scale dissolvers (formic acid and acetic acid based products) together with other selected scale dissolvers at 150°C and 4,500 psi and compared with the results obtained for 16% HCl. For these HP/HT tests, samples were collected and analysed after 2 and 20 hours equilibration time and results were compared with those obtained in more conventional "bottle tests conducted at less severe environmental conditions (90°C and ambient pressure).
In summary the results demonstrate the importance of conducting scale dissolver tests for field applications under more representative (HP/HT) conditions. Of particular significance was the impact of the cooling and pressure reductions. For one of the products tested, although very good dissolution was recorded under the HP/HT conditions, re-precipitation of a different polymorph of calcium carbonate occurred very rapidly resulting in a significant increase in the volume of carbonate precipitation within the reaction vessel and various sample lines. The paper will describe the details of the test equipment used in this work and present a mechanistic interpretation of the various results obtained.
The Challenge of Federation of Information for Automated Surveillance of ESPs: Field Examples
Authors: Theuveny B. , Kosmala A. , Cosad C. , Pulido F. , Destarac P. 
Published: December 2007

Abstract
Real Time Production is not just a buzzword today. A number of assets is experimenting implementations of real time production systems and some have made the leap of faith and rely extensively on it to optimze part of their production processes. A number of trial and errors have enabled to construct a number of rules of thumbs in the design, implementation and operation of such system. Because of the easy (or easier) case for value generation, the surveillance and optimization of artificial lift systems have been preferential targets for such implementations (in this paper we will focus on ESP operations).
One of the main operational issues related to the realisation of the value expect from this type of project is to ensure that all of the required information is correct. This is not a little feat!
This paper describes the challenge of the federation of the information required to perform automated surveillance of ESP in remote wells. The end-to-end delivery of reliable workflows requires the following elements: –Validated streaming real time information (pump measurements, intake and discharge pressures etc…)–Validated episodic information (well test flowrates, choke and back pressure information)–Static information (tubing size, formation parameters etc…)
The reliability of a real time production workflow in an automated system requires the insurance that all of these three types of information be correct.
The evaluation of the dependency of reliable information of information to the quality and reliability of the final surveillance information is demonstrated through the use of graph analysis. This methodology enables to focus the field data capture in the right areas, which are not always intuitive.
Field examples from South America demonstrate the value of such real time production workflows. Case histories also demonstrate instances of raising wrong alarms and the analysis of such event confirms the theoretical sensitivity analysis.
The paper concludes with a number of recommendations towards the field practices related to the real time enabling of the production operations some that can be extended to the futuristic full field automation.
Designing the Perfect Drilling Fluid Additive: Can it be Done?
Authors: Hall J. 
Published: December 2007

Abstract
The environmental and technical performance of drilling fluid additives is a key characteristic of such products. However, at times, the technical performance and environmental characteristics of materials used to make such additives seem to be at odds with each other. For example, materials that show good technical performance (stability) at high temperatures are frequently poor biodegraders, and those that are the most chemically active can show the highest toxicities.
In addition to the paradox of performance vs. environmental acceptability, international drilling fluids companies face diverse environmental regulations when operating in geographically distinct areas. Some of the most marked contrasts are observed when comparing regulations in the two most active offshore operating areas: the North Sea and the Gulf of Mexico. Regulatory discrepancies like these should be taken into consideration at the product design stage, when there is a potential for global technical performance to be sacrificed for environmental compliance in just one of the areas. One may be forced to ask which regional regulation should shape an additive's design? Are there oilfield chemicals that have been rendered unusable by regulations in one area while showing excellent economic and technical performance in another, without any apparent degradation of the environment?
This paper will discuss and present real-life examples of drilling chemicals that have been designed and often redesigned to fit stringent environmental criteria, according to the areas in which they are used.
The Development and Implementation of a Comprehensive System of Care in Remote Locations
Authors: Cram R. S. 
Published: December 2007

Proposal
Operations in remote areas of the world are, by definition, a long way, either in time or distance, from a location where extensive medical care is available. Often, frontline medical facilities are limited to a paramedic, many times with little support in terms of specialist input or equipment to deal with victims of serious trauma. Injuries that might normally be considered relatively low risk in urban areas within the developed world may rapidly become life threatening in the absence of adequate medical facilities and expertise.
A successful medical evacuation ends when the casualty steps through the door of his or her home and not when the aircraft takes off or the ambulance departs the location of the accident. Achieving this goal involves several different teams of people from a variety of disciplines along the route who need to operate as part of a cohesive team if the evacuation and subsequent treatment of the casualty are to have a successful outcome.
Of critical importance is the need to implement a comprehensive system of care that will ensure as far as possible that a medical evacuation is properly handled at every stage in the process. This paper describes the components of such a system and how it was implemented for a remote location in the Sahara desert.
Assessment of Produced Water Injection Performance during Waterflooding of a North Sea Field Using Data-Mining Techniques
Authors: Zaki K. S. , Abou-Sayed A. S. , Roehl E. A. 
Published: December 2007

Abstract
This paper presents a study in which injector performance is evaluated during water flooding operations in a North-Sea Field. It is well known that water quality and well conditions strongly affect injection performance. Poor water quality leads to plugging and bacterial growth which results in a loss of permeability and injectivity decline. The effect of poor water quality can be mitigated through the treatment and removal of harmful solids, dissolved oxygen (DO) and bisulfites (BI). Long-term remideation can be achieved through various stimulation techniques. However, technology limits and frequent treatment plant upsets can negate the effects of these mitigations and frequent stimulations would result in significant costs.
Optimization of injection operations depends on the selection of the proper strategy and answering questions such as "Which water contaminants have the biggest impact?" and "How much would stimulation improve injectivity?" Surprisingly, reliable answers are difficult to obtain because interactions among injection variables are obscured by highly- complex, process dynamics (time-dependencies). In this study, data mining techniques were applied in order to understand factors that affect field injection performance. The study used 11 years of injection and water quality data from 14 wells in two different blocks. Dynamic models of well behavior were synthesized using a combination of "artificial neural networks" (ANN), a machine learning technique from the field of Artificial Intelligence and "multivariate state space reconstruction" from the Chaos Theory.
Sensitivity analysis performed using the ANNs revealed the relative impacts of each variable on injector performance. Despite different histories for each well, the models were relatively uniform in quantifying the relationships between the variables. Findings included - a different response to acidizing in each block; delayed cumulative formation damage from each variable of 1-3 months; the impact of DO was more than twice that of particulate matter (PM) and BI; and clorides (CL) had only a small affect on suppressing bioactivity. The uniformity and clarity of these results reduce uncertainties and provide operators with detailed knowledge to help optimize their injection designs.
Effect of Well Placement on Production and Frac Design in a Mature Tight Gas Field
Authors: Cipolla C. , Peterman F. , Creegan T. , McCarley D. , Nevels H. 
Published: December 2007

Abstract
This paper details the application of microseismic fracture mapping in conjunction with in-depth treatment evaluation to improve infill well placement and understand fracture treatment behavior and well performance. Microseismic mapping was performed on two nearby infill wells, with a total of total of nine treatment stages mapped. The wells were Canyon sand completions located in the Sonora Field, Sutton County, Texas.
The microseismic mapping results for Well A showed long fractures, averaging 845 ft, while the Well B mapping showed short fractures, averaging only 360 ft. Fracture heights varied considerably, ranging from 60 ft to 415 ft, with variations similar in both wells. In some cases fracture height growth from a lower stage would extend into the upper stage sand(s), indicating possible opportunities to optimize the number of stages pumped and perforation placement. The fracture azimuth in Well A exhibited a definite N40°E trend, while the results for Well B indicated very complex fracture growth with fracture propagation in more than one direction. The treatment behavior for these two wells was also very different, with Well A exhibiting lower instantaneous shut-in pressures (ISIPs) at the end of the jobs compared to Well B.
Gas production from Well A was significantly better than Well B. After reviewing the placement of Well A & B in conjunction with the likely fracture azimuth and subsequent elliptical production patterns for existing (older) offset wells, it became clear that offset well production in the vicinity of Well B had influenced fracture growth due to lower pore pressure and local changes in the stress field – resulting in complex fracture growth. In contrast to Well B, Well A was located in an area that was not significantly influenced by offset well production.
Treatment of Produced Water from Polymer Flooding Process Using a New Type of Air Sparged Hydrocyclone
Authors: Liu S. , Zhao X. , Dong X. , Miao B. , Du W. 
Published: December 2007

Abstract
Produced water from polymer flooding(polymer produced water) was difficult to be treated by conventional two-stage settling process. A new type of double-cone air sparged hydrocyclone (DcASH) was designed to treat produced water from polymer flooding. The experimental results showed that DcASH had a high capacity, and it was a very promising device for treatment of produced water from polymer flooding.
Short-Term Numerical Simulation of Geological Sequestration of CO2 in the Barrow Sub-Basin, West Australia
Authors: Yang Q. , Dong Y. , Zhou F. 
Published: December 2007

Abstract
It is important to predict the economical feasibility of geological sequestration of CO2. This paper applies reservoir simulation to model the characteristics of CO2 injection in the specific injection site location.It could provide input to the economic evaluations by defining Bottom Hole Pressure and injection relationships. Selecting an appropriate grid system was particularly discussed in this study. The flexible corner point grid system and grid refinement technology were proven to be suitable for the simulation of CO2 geological sequestration. By this approach, we finally obtained the ultimate capacity of reservoir to store CO2, and further produced data about different possible injection scenarios needed for economic modeling. It was concluded that the geological structure and direction of CO2 migration were two important factors in the selection of the optimum well pattern. The results showed that using one well can satisfy the injection requirement, and also CO2 geological sequestration in the Barrow Sub-basin is feasible.
Reducing the Footprint of 3D Seismic in the Tropical Rainforest of Ecuador
Authors: Thurber M. , Westlund D. , Benalcazar F. L. 
Published: December 2007

Abstract
Multiple seismic exploration programs have been conducted in the Ecuadorian Amazon since the 1970s without reusing previously cleared areas for heliports and camps, resulting in unnecessary cumulative deforestation impacts. Walsh Environmental Scientists and Engineers (WALSH) and EnCana have developed a remote sensing technique to eliminate these redundant impacts by accurately identifying historic heliports and camps in mature tropical rainforest for reuse in a 3D seismic exploration program.
Evolution of Frac-Pack Design, Modeling and Execution in the Ceiba Field, Equatorial Guinea
Authors: Cipolla C. L. , Shucart J. K. , Lafitte J. R. 
Published: December 2007

Proposal
The paper details a study of fifteen frac-packs in twelve wells in the Ceiba Field, offshore Equatorial Guinea. Initial frac-packs were very unpredictable, experiencing numerous early wellbore screenouts and unpredictable tip screenout (TSO) behavior, placing proppant volumes of 10 to 160 klb with TSO net pressure increases ranging from 100 to 1,500 psi. The goals of this study were to: (1) develop a fracture modeling approach that would more reliably predict TSO behavior using mini-frac data, (2) develop reliable mini-frac analysis procedures and (3) determine the primary cause(s) of the early wellbore screenouts. The study resulted in improved designs, better execution procedures, more predictable TSO behavior and a reduction in early screenouts.
After reliable analysis procedures were developed, it was clear that mini-frac fluid efficiency and net pressure varied dramatically in the Ceiba frac-packs, with efficiencies ranging from less than 5% to over 30% and net pressure ranging from 170 to 900 psi. After reviewing rock mechanical data and evaluating various fracture modeling approaches, the variations in net pressure were attributed to complex fracture growth due to high wellbore deviation and long perforated intervals (as opposed to differences in modulus). The combination of consistent mini-frac analysis procedures and a fracture modeling approach that included fracture complexity resulted in a much more reliable prediction of TSO behavior.
Deconvolution of Variable-Rate Reservoir Performance Data Using B-Splines
Authors: Ilk D. , Valko P. P. , Blasingame T. A. 
Published: December 2007

Abstract
This work presents the development, validation and application of a novel deconvolution method based on B-splines for analyzing variable-rate reservoir performance data. Variable-rate deconvolution is a mathematically unstable problem which has been under investigation by many researchers over the last 35 years. We believe that this work is an important addition to existing well test/production data analysis methods where few deconvolution methods are practically applicable.
We use B-splines for representing the derivative of unknown unit-rate drawdown pressure and numerical inversion of the Laplace transform is utilized in our formulation. When significant errors and inconsistencies are present in the data functions, the direct and indirect regularization methods (i.e., mathematical "uniformity" processes) are used. We provide examples of under and over-regularization, and we discuss procedures for ensuring proper regularization.
We validate our method with synthetic examples generated with and without errors (for this work we provide cases with 10 percent error, but we have considered cases with as high as 40 percent error). Upon validation, we then demonstrate our deconvolution method using a variety of field cases — including traditional well tests, permanent downhole gauge data as well as production data. Our work suggests that the new deconvolution method has broad applicability in variable rate/pressure problems — and can be implemented in typical well test and production data analysis applications.

Objectives
The following objectives are proposed for this work: To develop and validate a new deconvolution method based on B-spline representations of the derivative of unknown constant rate drawdown pressure response (i.e., the undistorted pressure response).To create a practical and robust deconvolution tool that can tolerate relatively large (random) errors in the input rate and pressure functions. The proposed process should also be capable of tolerating small systematic errors in the input functions (via calibrated regularization).To apply this new method to traditional variable-rate/ pressure problems, such as wellbore storage distortion, long-term production data, permanent downhole (pressure) gauge data, and well tests having multiple flow sequences.
The Use of Swell Packers as a Replacement and Alternative to Cementing
Authors: Kennedy G. , Lawless A. , Shaikh K. , Alabi T. 
Published: December 2007

Abstract
Today the cement job is the most common technique used to achieve the critical hydraulic seal between casing and formation to isolate individual zones and prevent annular flow. As such, it is often considered one of the most important operations during construction of the well. However as an isolation mechanism, it can fail, and may not provide the down hole zonal isolation needed during the life of the well.
Annular packers based on the swelling of rubber in hydrocarbons are being used by different operators to replace cementing and provide the critical zonal isolation required down hole. The swell packer is able to overcome many of the shortcomings associated with conventional cement operations, and provide superior zonal isolation in both simple and complex well environments. Using swell packers also simplifies and reduces the risk of the well construction process and provides significant cost savings due to reductions in rig time and materials.
This paper focuses on the application of swell packers to provide an effective hydraulic seal between the formation and the casing as an alternative to cementing and perforating. Specific case histories from Nigeria, Malaysia and the North Sea are used to illustrate the success and application of this innovative technology.
Food for Thought—A Strategy for Improving Food Hygiene and Safety in Catering Operations
Authors: Phillips B. , Minshell C. 
Published: December 2007

Abstract
Providing safe and nutritious food and water to employees in remote areas is not without challenge, particularly in a large project where the number of employees is increasing rapidly and the caterer is expected to cope. The control of catering contracts can become more fragmented with the risk of illness from food and water hazards exponentially increased.
To manage this, a ‘food safety specialist’ was brought in to join the regional health team to identify essential issues and produce a methodology and strategy based on minimum acceptable standards in food hygiene and catering management.
A 3 stage process was designed: Introducing ‘effective’ hygiene inspections and action trackingEquipment and infrastructure improvementsFood hygiene training and awareness for all levels, accredited by a professional body in the UK.
Laboratory and Simulation Investigation of Enhanced Coalbed Methane Recovery by Gas Injection
Authors: Tang G.-Q. , Jessen K. , Kovscek A. R. 
Published: December 2007

Abstract
Methane/carbon dioxide/nitrogen flow and adsorption behavior within coal is investigated from a laboratory and simulation perspective. The samples are from a coalbed in the Powder River Basin, WY. They are characterized by methane, carbon dioxide, and nitrogen sorption isotherms as well as porosity and permeability measurements. This coal adsorbs almost three times as much carbon dioxide as methane and exhibits significant hysteresis among adsorption and desorption isotherms that are characterized as Langmuir-like. Displacement experiments were conducted with pure nitrogen, pure carbon dioxide, and various mixtures. Recovery factors are greater than 94% of the OGIP. Most interestingly, the coal exhibited ability to separate nitrogen from carbon dioxide due to the preferential strong adsorption of carbon dioxide. Injection of a mixture rich in carbon dioxide gives slower initial recovery, increases breakthrough time, and decreases the volume of gas needed to sweepout the coalbed. Injection gas rich in nitrogen leads to relatively fast recovery of methane, earlier breakthrough, and a significant fraction of nitrogen in the produced gas at short times.
A one-dimensional, two-phase (gas and solid) model was employed to rationalize and explain the experimental data and trends. Reproduction of binary behavior is characterized as excellent, whereas the dynamics of ternary systems are predicted with less accuracy. For these coals, the most sensitive simulation input were the adsorption-desorption isotherms, including scanning loops. Additionally, the coal exhibited a two porosity matrix that was incorporated numerically.