bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling Deepwater Reservoirs
Authors: Ezekwe J. N. , Filler S. L. 
Published: December 2007

Abstract
Deepwater reservoirs pose significant challenges worldwide to companies exploring and producing such reservoirs because of the high exploration, development, and production costs. Great uncertainty and risk attend the evaluation of deepwater reservoirs because of the environment, sparse well control, and lack of direct measurement of reservoir properties. Proper modeling of deepwater reservoirs provides companies with tools to evaluate these reservoirs and quantify risks associated with their development.
There are five critical areas in the process of modeling deepwater reservoirs. These are geological and geophysical modeling, reservoir characterization, reservoir flow modeling, facilities/flow assurance, and uncertainty/risk analyses.
This paper presents methodologies found useful by experience in the modeling of deepwater reservoirs. Actual field cases describe our experience in using systematic steps based on the five critical areas to model the Zia reservoir, a Manatee reservoir in the Troika Basin, and the Magnolia reservoirs using the Markov Chain Monte Carlo technique.
Design and Development of Quaternary Amine Compounds: Corrosion Inhibitors With Improved Environmental Profiles
Authors: Tiwari L. 
Published: December 2007

Abstract
Stringent environmental constraints imposed by government regulators upon the oil and gas producing industry has led to the need for new ‘greener’ chemistries, which have less environmental impact to be developed and employed. The environmental impact of a corrosion inhibitor is often defined by three tests, biodegradation, bioaccumulation and toxicity. All three criteria have limits that must be met for a chemical to be permitted for use, with different emphasis on each depending which regulator controls the waters. This has become the motivation for the research into modifying old chemistries and developing new ones.
Quaternary amines (quats) have been known for a long time as excellent corrosion inhibitors for their ability to form a film on the surface of the steel; however, their biotoxicity profile is not particularly acceptable to qualify them as "Green Corrosion Inhibitors". This work covers the structural modifications that have been imparted on quats to qualify them as green corrosion inhibitors with excellent corrosion protection.
Uncertainty Modeling of the Gas Volume of Manati Field: The Challenge of Taking Into Account a 'Stochastic' Unconformity
Authors: Filho P. C. S. , Monteiro M. C. , Gonçalves P. 
Published: December 2007

Abstract
An uncertainty analysis study of the gas volumes in the field of Manati was conducted using gOcad™/Jacta™. The main uncertainties are associated to two important lateral limits of the reservoir, both ill-defined due to the poor quality 2D seismic lines available: the geometry of a major regional unconformity, and the Mutá fault.
A number of alternative realizations of the conjugated unconformity/Mutá fault surface were generated, using four seismic interpretations. A p-Field-like algorithm was used to sample from a probability function locally taken as a trapezoidal pdf, defined by four sub parallel envelopes built from the four interpretations available.
An artifice was conceived in order to overcome a deficiency of the software for dealing with multiple alternative lateral extensions of the model. This artifice consisted in modeling the grid with an extension taken as a maximum, and then computing only the volumes of interest by informing Jacta™ a number of alternative possible realizations of the unconformity/Mutá fault surface, as if they where gas/oil contact scenarios.
Accordingly, the real gas/water contact was given to Jacta™ as if it were an oil/water contact. Thus, with the corresponding fluid parameters informed in a coherent way, the gas volumes of interest where reported by Jacta™ as oil volumes.
Other sources of uncertainty where taken into account by means of Jacta's regular workflow.
What Level of Sulfate Reduction is Required to Eliminate the Need for Scale-Inhibitor Squeezing?
Authors: Boak L. S. , Al-Mahrouqi H. , Mackay E. J. , Inches C. E. , Sorbie K. S. , Bezerra M. C. M. , Mota R. O. 
Published: December 2007

Abstract
Scale deposition is often controlled using chemical scale inhibitors. However, for high scale severity, sulphate reduction in the injected seawater may provide a more attractive economic solution to the problem.
This study uses data based on Marlim Leste (Campos Basin, offshore Brazil) reservoir brine compositions and conditions for both reservoir modelling and experiments. Using reservoir modelling, supersaturation and precipitation potentials in the system are first calculated assuming no precipitation reactions in the reservoir. Sensitivity calculations are then performed to investigate the effect of brine mixing both deep in the reservoir and at the production well. Supersaturation and precipitation levels are then recalculated assuming in situ stripping has reduced [Ba2+] and/or [SO42-] levels at the wellbore.
Static (uninhibited) BaSO4 precipitation experiments have been conducted to determine the limiting sulphate level that removes the requirement for applying squeeze treatments. A simple rate law is found and this is used to define "safe operating envelopes" where the barite precipitation is sufficiently slow that we expect no squeeze treatment is required. Some risk is associated with these envelopes due to uncertainties in the determination of the rate constant, k, for barium deposition. Based on further kinetic analysis using data on the safe envelopes, we establish what rate the barite deposition may occur thus identifying where the system would deposit barite slowly and where it would reach its full equilibrium deposition limit quickly. This work presents both a methodology and also some analytical modelling tools for establishing, on a sound technical basis, the answer to the question: What level of sulphate reduction is required to eliminate the need for scale inhibitor squeezing?
Laboratory and Field Study of the Influence of Simple Carboxylates on Oilfield Corrosion and Inhibition
Authors: Martin R. L. , Logan P. D. 
Published: December 2007

Abstract
The influence of simple carboxylates on oilfield chemistry measurements, steel corrosion, and corrosion inhibition was studied. In most cases, the error in the field measurement of dissolved CO2 was found to be small. In all but two cases examined, the error in bicarbonate ions measurement was small because of the large actual bicarbonate ion to carboxylate ratio.
The presence of acetate and propionate ions in laboratory tests always accelerated the uninhibited corrosion rate of mild steel because of an increase in cathodic kinetics when the steel was behaving actively. In passive systems, anodic increases were seen.
Both acetate and propionate were detected in field samples; in only one case butyrate was observed. Corrosion inhibitors were effective at controlling corrosion even in the presence of these ions in both laboratory and field conditions.
Modeling and Implementing a Scale-Inhibitor Squeeze in a Deep, Hot Gas Well in Mobile Bay.
Authors: Lopez T. H. , Fielder G. D. , Yuan M. , Williamson D. A. , Blair E. S. 
Published: December 2007

Abstract
A major operator was experiencing severe scale deposition in a deep, hot gas well in Mobile Bay, Gulf of Mexico. The deposits primarily consisted of calcium carbonate, with much smaller amounts of mixed calcium fluoride, lead and zinc sulfide scales. A squeeze application was the desired treatment, but test work had to be performed to ensure the chemical would not cause damage to the formation. Although scale deposition in the production wells are common, no such scale inhibitor application had been attempted in this region previously, primarily due to concerns for formation damage in this complex and extremely high temperature (≥204°C) Norphlet sandstone formation.
Core flooding tests were performed in the laboratory at 204°C to simulate the squeeze treatment using actual core material from the well. Once a suitable scale inhibitor product had been identified, core flood tests were performed by injecting gas and brine through the core and assessing the change in permeability.
Historically scale buildup had been found in the subsurface safety valve and production tubing deep downhole. Steady productivity declines were observed after each near wellbore acid stimulation. When the untreated well had to be shut-in, it often experienced a decline in production upon restart if not a complete well loss. Since the squeeze has been performed in the field, the well has maintained the production in spite of being shut-in and reactivated numerous times due to hurricanes or other tropical storms.
This paper documents the first ever successful scale squeeze treatment in this extremely hot and complex reservoir formation. It describes the results from the detailed lab work leading up to the successful implementation of the scale inhibitor treatment in the field. The paper also discusses the results seen in the field following treatment.
Comparing Efficacy of Scale Inhibitors for Inhibition of Zinc Sulfide and Lead Sulfide Scales.
Authors: Lopez T. H. , Yuan M. , Williamson D. A. , Przybylinski J. L. 
Published: December 2007

Abstract
A large independent operator in Mobile Bay, Gulf of Mexico was experiencing a buildup of common and exotic scales where the produced waters are commingled. The scale species encountered included barium sulfate, zinc sulfide, and lead sulfide. Traditionally, scale inhibitor chemistries have not been used in the past to inhibit these exotic sulfide scales in this region. This is due to some amount of belief within the industry that conventional inhibitors alone could not inhibit these scale species.
Prior to the application of the scale inhibitor in the field, the platform's overboard water line required cleanout every two months due to scale buildup. Not a single cleanout has been necessary since a polymeric scale inhibitor has been applied downhole via continuous capillary injection for over one year.
This paper presents the results of laboratory tests which were used to demonstrate how a polymeric scale inhibitor was identified and approved for inhibition of lead sulfide and iron sulfide, as well as the more common scales. The sulfide scale tests performed in an anaerobic dynamic tube-blocking test unit showed this inhibitor chemistry to be as effective as combined scale inhibitor/dispersant products. The paper then presents the field treatment results, which shows good agreement with the lab test results.
Selecting X-Ray Energy Levels for Three-Phase Saturation Measurements
Authors: Lackner A. S. , Haaskjold G. , Torsaeter O. 
Published: December 2007

Abstract
The effect of pressure and rock type on optimal dual energy levels and minimalisation of saturation uncertainties for three-phase core experiments was investigated.
X-ray scanning of a composite core comprising of two chalk plugs and one Berea sandstone core was done. Reference scans using CO2, natural seawater, n-Ci10 and a CO2/n-Ci10 mixture at four pressure stages and five different pre-defined dual energy levels were acquired. Two unique typical given saturations were input together with data from the reference scans in a routine for back-calculating three-phase intensity data. A detailed uncertainty analysis using these synthetic three-phase data and combining low and high energies was performed. The resulting combination of low and high energy level giving the lowest uncertainty was selected as a given setting for all dynamic scans. Saturated with live oil, the core was waterflooded while dynamic X-ray scans were acquired. After the waterflood, the core was depleted below the bubble point to atmospheric pressure while scans were acquired continuously.
The results show that the rock type largely effects the selection of energy levels for both two- and three-phase X-ray scans. To minimise the uncertainty, the chalks generally required a higher low energy level independent of pressure than the sandstone. Also, at high pressures and for all rocks the optimal high energy level was found in the same range. At lower pressures, a lower high energy level was favourable.
New Horizons in Wide-Bore Drilling and Completion Technology
Authors: Sinha D. 
Published: December 2007

Abstract
Cantilever drilling technology (CDT) is a new concept of drilling which will enable us to drill superwide boreholes with radii of the order of a few feet selectively in zones of our choice. We do this using the cantilever drilling tool. This enlarged hole will facilitate better artificial lift and enhance production among other things. This paper discusses CDT and RESIN CASING technology which can be used to case holes with such a unique geometry. Resin Casing is done using an expandable wire frame balloon structure which forms a mould for the specially modified resin forming a hard shell - overcoming the hurdle of casing and cementing the hole.
Calculations of Fluid Saturations from Log-Derived J-Functions in Giant Complex Middle-East Carbonate Reservoir
Authors: Obeida T. A. , Al-Mehairi Y. S. , Suryanarayana K. 
Published: December 2007

Abstract
Calculation of initial fluid saturations is a critical step in any 3D reservoir modeling studies. The initial water saturation (Swi) distribution will dictate the original oil in place (STOIP) estimation and will influence the subsequent steps in dynamic modeling (history match and predictions). Complex carbonate reservoirs always represent a quit a challenge to geologist and reservoir engineers to calculate the initial water saturation with limited or no SCAL data available. The proposed method in this study combines core data (permeability) from 32 cored wells with identifiable reservoir rock types (RRTs) and log data (porosity and Swi) to develop drainage log-derived capillary pressure (Pc) based on rock quality index (RQI) and then calculate J-function for each RRT which was used to calculate the initial water saturation in the reservoir.
The initialization results of the dynamic model indicate good Swi profile match between the calculated Swi and the log-Swi for 70 wells across the field. The calculation of STOIP indicates a good agreement (within 3% difference) between the geological 3D model (31 million cells fine scale) and the upscaled dynamic model (1 million cells). The proposed method can be used in any heterogeneous media to calculate initial fluid saturations.
Improving Drilling Performance in the Chalk Reservoir of the Valhall Field
Authors: Strachan M. , Kinn S. , Eide Ø. , Mason C. , Chen D. C. -K. 
Published: December 2007

Abstract
Historically, drilling long horizontal wells in the Valhall field offshore Norway has been challenging. Due to high drag levels, the Chalk formation is best drilled with rotary steerable systems (RSS). However due to severe stick-slip vibrations, a high number of LWD and RSS failures have occurred. The necessity to "geosteer" in the reservoir has also contributed to tortuous well paths that have further increased drilling and liner-running difficulties. In order to achieve 2,000m long reservoir sections, BP used a multi-disciplined team to leverage improvements in both drilling and linerrunning performance. The initial focus was on reducing stick-slip vibration and frictional drag. Drill string, BHA and bit design, LWD and logging tools, well profile design and mud design were all considered in the analysis. Significant improvements in both drilling and liner-running performance have been achieved.
The Penetration of Coiled Tubing with Residual Bend in Extended-Reach Wells
Authors: Zheng A. , Adnan S. 
Published: December 2007

Abstract
Residual bend exists in every coiled tubing string. When the coiled tubing is placed inside a wellbore, its initial configuration is not straight but has a certain residual bend. This paper's objective is to explain how this residual bend in coiled tubing affects its extended reach.
This paper presents a new modeling technique to account for the effect of residual bend on coiled-tubing post-helical buckling behavior and maximum penetration. The initial configuration of the coiled tubing is assumed to be the form of a helix along the wellbore. By using the energy method, a set of solutions are obtained for the helix configuration and the radial contact force under the conditions of applied axial force and initial residual bend. These solutions are used to analyze axial load transfer and extended-reach capability of coiled tubing on horizontal wells. It is shown that in a horizontal well, with a relatively small residual bend radius, the existence of residual bend significantly reduces the maximum depth the coiled tubing can reach. Results of this work can be used to enhance job design for extended-reach applications.
Dynamic Reservoir Data Assimilation with an Efficient, Dimension-Reduced Kalman Filter
Authors: Zhang D. , Lu Z. , Chen Y. 
Published: December 2007

Abstract
The Kalman filter has been widely applied for assimilating new measurements to continuously update the estimate of state variables, such as reservoir properties and responses. The standard Kalman filtering scheme requires computing and storing the covariance matrix of state variables, which is computationally expensive for large-scale problems with millions of gridblocks. In the ensemble Kalman filter (EnKF), this problem is alleviated with sampling from a limited number of realizations and computing the required subset of the covariance matrix at each update. However, the goodness of the (ensemble) covariance approximated from the limited ensemble depends on the number of realizations used. In this study, we propose an efficient, dimension-reduced Kalman filtering scheme based on Karhunen-Loeve and other orthogonal polynomial decompositions of the state vector. We consider flow in heterogeneous reservoirs with spatially variable permeability. The reservoir responses such as pressure head are measured at some locations at various time intervals. The aim is to dynamically characterize the reservoir properties and to predict the reservoir performance and its uncertainty at future times. In our scheme, the covariance of the reservoir properties is approximated by a small set of eigenvalues and eigenfunctions using the Karhunen-Loeve (KL) decomposition, and reconstruction of this covariance from the KL decomposition can be done whenever needed. In each update, the forward problem is solved using the KL-based moment method, giving a set of functions from which the mean and covariance of the state vector can be constructed, when needed. The statistics of both the reservoir properties and the reservoir responses are then updated with the available measurements at this time using the auto- and cross-covariances obtained from the forward problem. The new approach is illustrated on a heteroge neous reservoir with dynamic measurements and its superior performance in terms of accuracy and efficiency relative to the EnKF method is discussed.
Harnessing the Wisdom of Crowds—Case Study
Authors: Velasquez G. , Odem P. 
Published: December 2007

Abstract
Sustainable innovation is considered one of the most important business differentiators in the market place as market forces continue to push the envelope of productivity and performance. The most important source of sustainable innovation in any organization is its people. Because of that, it is critical that organizations focus on growing the best and most skilled work force in the industry. According to a survey conducted by the US Bureau of Labor Statistics1, informal training accounts for over 70% of all the training an individual gets in his/her job. This indicates the importance of having a system in place that can fulfill the training needs of the work force in a timely manner. Perhaps one of the most viable alternatives to help develop skills and competencies of the organization's workforce are communities of practice.
This case study discusses how Halliburton Energy Services has used communities of practice to boost and strengthen organizational and individual learning. People frequent these communities because they learn about issues that pertain to their jobs2. This paper discusses the importance of the participation in communities and its relation to professional development. The data presented here tell an important story for the Oil and Gas Industry. Within Halliburton, these communities are transforming the culture and the way we do business in addition to being a very important element of professional development for the individuals who participate.
The Application of Flux-Based Sand-Control Guidelines to the Na Kika Deepwater Fields
Authors: Keck R. G. , Colbert J. R. , Hardham W. D. 
Published: December 2007

Abstract
The Na Kika offtake guidelines were developed jointly by Shell and BP using a blending of recent sand control operational methodologies from each company. In this paper, we focus on the use of the bpflux™ guidelines, which give the maximum safe operating rates for sand control completions, and allow wells with excellent completion quality to produce at twice the rate of wells with lower completion quality.
Before the Na Kika field started up, we estimated the completion quality by reviewing 20 different elements of completion design and operations. We used these estimates to set the initial off-take limits for each zone. As the wells started producing, we performed pressure build-ups to measure the actual completion quality (skin), and adjusted the maximum operating rates accordingly.
Using this methodology early in field life, we were able to bring the field up to targeted production rates without unnecessarily compromising long-term sand control reliability. As the field matures, we will identify opportunities to extend the production plateau, which will provide an incremental production impact. Finally, later in the field life, we also expect to lower the number of workovers, which will provide an additional cost savings from using these guidelines.
A Capacitance Model to Infer Interwell Connectivity from Production and Injection Rate Fluctuations
Authors: Yousef A. A. , Gentil P. , Jensen J. L. , Lake L. W. 
Published: December 2007

Proposal
This paper presents a new procedure to quantify communication between vertical wells in a reservoir based on fluctuations in production and injection rates. The proposed procedure uses a nonlinear signal processing model to provide information about preferential transmissibility trends and the presence of flow barriers.
Previous work used a steady-state (purely resistive) model of interwell communication. Data in that work often had to be filtered to account for compressibility effects and time lags. Even though it was often successful, the filtering required subjective judgment as to the goodness of the interpretation. This work uses a more complicated model that includes capacitance (compressibility) as well as resistive (transmissibility) effects.
The procedure was tested on rates obtained from a numerical flow simulator. It was then applied to a short timescale data set from an Argentinean field and a large-scale data set from a North Sea field. The simulation results and field applications show that the connectivity between wells is described by model coefficients (weights) that are consistent with known geology, the distance between wells and their relative positions. The developed procedure provides parameters that explicitly indicate the attenuation and time lag between injector and producer pairs in a field without filtering. The new procedure provides a better insight into the well-to-well connectivities for both fields than the purely resistive model.
The new procedure has several additional advantages. It can be applied to fields in which wells are shut-in frequently or for long periods of time,allows for application to fields where the rates have a remnant of primary production, andhas the capability to incorporate bottom hole pressure data (if available) to enhance the investigation about well connectivity.