bluuebunny/crossref_metadata_2025_split huggingface dataset:
Minimizing Drilling-Fluid Invasion in Coring Operations
Authors: Waldmann A. T. A. , Leal R. A. F. , Pires I. J. , Lomba R. F. T. , Aragão A. F. L. , Martins A. L. 
Published: December 2007

Abstract
Offshore Coring are time consuming and expensive operations which, if well conducted, provide extremely important information concerning rock and fluid properties. Drilling fluid invasion may be a relevant issue to affect fluid and rock reservoir original properties. Different hypothesis for pressure dissipation in the core are formulated and their impact on invasion are quantified.
This article deals with the derivation of an analytical formulation for drilling fluid invasion in cores, based on filter cake permeability results obtained in lab testing. The formulation represents the radial flow from the external lateral walls of a cylinder and considers plug flow in the porous medium and external filter cake formation. A comparison of the prediction and the observed invasion in real cores obtained in exploratory wells is presented.
Particle Trapping Sequence During Filtercake Buildup Revealed by Coloured Tracer Particles
Authors: Turekhanov Batyrzhan , Bennaceur Houria , Currie Peter K. , Wolf Karl Heinz , De Zwart Bert Rik 
Published: December 2007

AbstractAll water injection schemes suffer injectivity decline to some degree. It is important to understand the factors that influence the formation of an external filtercake and improve injectivity. This paper introduces a new technique for examining time-dependent particle filtration processes in a sandstone core.Experimental work and analysis is presented of the filtration phenomena that occur during injection of water containing suspended particles into a sandstone core. The technique involves injecting a sequence of suspensions of different-coloured latex particles It gives valuable qualitative information about the processes taking place, such as the location and timing of the trapping of particles and gives quantitative predictions, by using Image Analysis and the RGB-colour systemTests has been performed in which coloured latex particles are injected into sandstone cores. The particles form an external filtercake on the entry face of the core, and are deposited inside the core (deep-bed filtration). By switching the colour of the injected latex particles, and analysing where the different colours have been deposited, qualitative insight is gained into the process of external and internal cake forming. Using Image Analysis based on the RGB-colour system, the particle analysis can be quantified to determine effluent concentration and particle colour. Conclusions can be made about the filtration processes taking place. The conclusions are that current theories of how and when an external filtercake forms are too simple, and that external filtercake permeability for individual particles is larger than anticipated.
Enhancing Production Using Solid Expandable Tubulars in Workover Campaigns
Authors: Jennings Iain 
Published: December 2007

Abstract
With drilling, completion and production costs rising as fast as commodity prices, some operators are looking to optimize existing production with workover projects that turn marginal wells into significant producers. Historically, workovers have been delegated to perfunctory status even though 70% of today's oil production comes from fields 30 years or older1. Some operators relegate workover projects to strictly well repair, while others take the next step and focus on how to increase production rates. New technologies and processes have provided the impetus for these operations that are reaping compelling returns for projects that not only encompass well repair but production enhancement.
In seven years, solid expandable tubulars have gone from an unconventional idea to a viable and recognized solution for wellbore construction and integrity. The appeal of these systems lies not just in the mechanism but the functionality including the ability to deepen the hole, shut off water zones and protect zones from stimulation pressures without sacrificing hole size. Maximizing inside diameter (ID) allows the operator to use the same completion previously used in the well. Operators that have planned and used expandable systems in preventive maintenance programs have realized more attractive economic and technical results than the usual one-off workover.
This paper will explain how through a planned, multi-well workover campaign, solid expandable tubulars enhance production in an affordable manner. Case histories will be used to illustrate the planning, implementation and completion stage and the tangible results of the projects. In addition, this paper will explain how these systems provide solutions for challenging downhole conditions and situations.
Advanced Numerical Simulator To Predict Productivity for Conventional and Nonconventional Well Architecture
Authors: Pacheco Eduardo , Castro Rene , Soliman M. Y. , Flores-Avila Fernando 
Published: December 2007

Abstract
The production of oil and gas will continue to be the most important components of the energy industry for the next several decades. The increasing demand for hydrocarbons is moving oil-industry operators to explore all possibilities for increasing oil and gas production. This includes exploring unconventional resources and investigating unconventional well architecture. These approaches include drilling in low-permeability oil and tight-gas formations. The use of multilateral and horizontal wells has been increasing. Fracturing horizontal wells has gained significant acceptance. Multilateral wells where the various laterals have complex paths are gaining momentum as a viable way of producing hydrocarbon reservoirs.
Analytical and semi-analytical solutions for horizontal and multilaterals wells have been presented in the literature. Because of the complexity of the problem those solutions greatly simplify the problem to the extent that they are usually of limited value and application. The complexity of the actual reservoirs and well trajectory under mature conditions require more advanced solutions to realistically simulate well trajectories and well completions like acid fracturing and hydraulic fractures. Realistic simulation of complex reservoirs and wells will enable better economic analysis and decisions, provided that simulation is outstanding.
In this paper we first discuss our simulation approach that balances the goal of reaching realistic simulation while maintaining the practicality of an engineering approach. We also present several case histories of production analysis for multilaterals and horizontal wells using a robust, stable numerical simulator, multiple–block well completion and local refinements.
Modeling of External Filter-Cake Buildup in Radial Geometry
Authors: Farshbaf Zinati F. , Farajzadeh R. , Currie P. K. , Zitha P. L. J. 
Published: December 2007

Abstract
The problem of formation damage, i.e., permeability reduction due to injection of particulates, is a matter of interest in several engineering fields. In the previous attempts to model the external cake formation, cake thickness has been considered to be only dependent on time; even though, in practical applications the dependency of the cake profile on space can be important. In this paper a novel model has been developed to describe the steady state external filter cake thickness profile along the well-bore.A set of equations are derived from the force balance for a deposited particle on the cake surface and the volume conservation of the fluid in the well-bore. These equations are combined with the Darcy's law in radial geometry and the equation of flow in the well-bore, and solved numerically to obtain the cake thickness and fluid velocity profiles along the well-bore.
Optimum Horizontal Well Placement in Very Low Resistivity Reservoir With a Directional and Deep Logging-While-Drilling Technology
Authors: Silva A. , Cavero J. , Rodriguez W. , Augusto M. , Vargas J. , Chacon R. , Bardales A. 
Published: December 2007

Abstract
In the Sub-Andean basin areas of Peru, Colombia and Ecuador, important reservoir targets present very low resistivity range and also very low resistivity contrast between pay and non-pay. These unique conditions constitute a challenge in relation to the ability to map the reservoir boundaries and to allow the successful navigation of horizontal wells in thin target zones.
Conventional logging data are not able to effectively determine the approach or prevent the intersection of a reservoir limit under such reservoir conditions. Therefore, they are not perceived as the best option to optimize geosteering decision making.
A new logging while drilling technology, developed by Schlumberger, based on directional electromagnetic resistivity measurements was applied in a horizontal well, recently drilled by Pluspetrol Norte in Peru.
The service delivered directional resistivity measurement with deep depth of investigation, which allowed estimating the orientation, distance and resistivity of nearby bed boundaries. The technology was successfully used to navigate the well, optimizing the horizontal length inside the best productive zone and stay at a safe distance from the OWC. The productive behaviour of the well was better than expected.
PWRI-Induced Injectivity Decline: New Insights On In-Depth Particle Deposition Mechanisms
Authors: Rousseau D. , Hadi L. , Nabzar L. 
Published: December 2007

Abstract
Injectivity decline during PWRI originates not only from filter-cake build-up, but also from in-depth deposition of oil droplets or solid particles. Physical modelling of particle deposition mechanisms in porous media is thus of key interest for optimizing PWRI operations. The present work brings new insights on oil droplets and solid particle deposition mechanisms in porous media.
The experimental conditions were selected such as the ratio between pores and particle sizes is sufficiently large to ensure in-depth propagation. The parameters are: the nature of the particles injected and a Peclet number calculated on the size of the collector grains (Peg), that encompasses in a nondimensional form the impact of both flow rate and particle size.
The results are analysed in the frame of the "colloidal approach". For oil droplets and solid particles, the deposition efficiency (n) shows a transition from a behaviour in which nvaries as a power-law of Peg, with exponent values -2/3 (Diffusion Limited Deposition, DLD) to -1 (Reaction Limited Deposition, RLD), characteristic of convection-diffusion regime, to a behaviour characterized by an increase of η versus Peg, characteristic of hydrodynamic deposition regime. In the case of oil droplets (not or slightly charged), the transition occurs at a critical Peg value, Pegcgeom, corresponding to a diffusion layer thickness around the collector grain equal to the droplets diameter. In the case of electro-sterically stabilized solid particles, the transition takes place at Peg&lt;Pegcgeom for small particles and at Peg&lt;Pegcgeom for larger particles.
Recycling and Final Disposal of Waste Generated While Mixing Drilling and Completion Fluids
Authors: Pedraza Johanna , Serrano Mario 
Published: December 2007

Abstract
As the emphasis on safety and efficiency increases in the oil industry, there has been a corresponding improvement in the quality of packaging for chemical products. Examples of higher standards include plastic shrink-wrap covers, better-designed pallets, and fewer sacks loaded per pallet. These improvements in packaging, however, have led to an increase in the volume of waste generated and its disposal costs.
In order to contribute to the preservation of the environment, improve employee safety and at the same time reduce operational costs, the HES Colombian environmental team designed the Integral Waste Management System (IWMS). The IWMS provides methods for efficient waste collection, recycling and disposal. The primary focus of the system is the provision of comprehensive environmental training for field personnel to help ensure that each person is fully educated concerning the process and its objectives. Formal standards for field applications are in place. One example of rig site implementation of the IWMS includes using size and dimension appropriate color-coded containers of the appropriate sizes to transport waste materials to the stock point.
Simultaneously with the intensive training undertaken by the personnel, the IWMS incorporates an equally important process for selecting the best local companies for recycling and disposal. Those companies selected received the guidance and support necessary to obtain and maintain ISO 9000 certification, assuring the quality of the service and the internal standards expected by our customers. All the selected companies are also certified by the Environmental Minister of Colombia.
Since the beginning the IWMS implementation in Colombia, waste incineration has been reduced nearly 90%, which helps decrease environmental pollution that may contribute to global warming. The IWMS efforts have assisted with the promotion of cardboard recycling companies and similar waste management enterprises. Most importantly, the cost of drilling waste disposal in participating Colombian operations has been reduced almost 60%.
Underbalanced Drilling and Completion of Sand-Prone Tight Gas Reservoirs in Southern North Sea
Authors: Veeken C. A. M. , van Velzen J. F. G. , van den Beukel J. , Lee H. M. , Hakvoort R. G. , Hollman F. J. , Evans C. , Okkerman J. A. 
Published: December 2007

Abstract
This paper describes the application of underbalanced horizontal wells to develop some different tight gas reservoirs in the Netherlands section of the Southern North Sea. Underbalanced well design presented specific issues related to the nature of these reservoirs. The construction and production experience to date is evaluated and compared against similar wells drilled offshore UK. Also the benefits of the underbalanced horizontal well concept are reviewed.
Hydrocarbon Reserves and Production Increment in Laminated Sand/Shale Reservoir From 3D Resistivity Measurements, Image Logs, and Magnetic Resonance Technology
Authors: Vielma Miguel , Atlas Baker , Vandini Ricardo 
Published: December 2007

Abstract
Oil identification and quantification in low resistivity laminated sand-shale sequences is a major challenge for petrophysics and reservoir engineers; essentially because the thickness of the sand laminas is usually bellow the vertical resolution of the resistivity logging tool. The presence of this lithology generates electrical anisotropy where horizontal resistivity is highly affected by the conductivity of the laminar shale volume, while vertical resistivity is higher and more sensitive to the laminar sand electrical properties. Once identified the productive low resistivity problem the prediction of movable water, creates enormous uncertainty when it comes to decide if this laminated sand should be open to production in the well. All this issues have caused the underestimation of Oil-In-Situ volumes and the lost of thousands of oil production per day in the upper Misoa Formation Reservoirs in western Venezuela. The incorporation of resistive image logs in the geological analysis of upper Misoa Reservoirs, have shown the existence of thinly laminated sand-shale sequences with laminations of an inch thick and less.
Traditionally the sands with resistivity values of 20 ohm-m and above are considered as potential oil bearing reservoirs. This assumption has been made with conventional induction resistivity tools with transmitter and receiver orientation parallel to the borehole axis, therefore providing horizontal resistivity. Recently a multi-component transmitter-receiver induction tool has been used to derive both horizontal and vertical resistivity in a section of upper Misoa Formation with resistivity values in the very limit of the pay cuttof. The 3D array induction tool showed the vertical resistivity of this reservoir, to be as high as 80 ohm-m, adding up to 30 % more of oil saturation in the laminated sands. In the decision process of shooting this sands, the mobility of the water remained unknown; until, magnetic resonance measurements where included in the study. 2D analysis of T2 and diffusivity indicated that 90% of the water contained in the reservoir was irreducible, so it would not be produced.
After completing the low resistive sands, production logging tests and well production showed 1300 BBD with 4% of water. This case opened a great opportunity in western Venezuela fields where this type of lithology can be found in most of the wells drilled trough Eocene reservoirs.
Physical Model Development To Study Sand Production
Authors: González Jothsimar , Alvarellos José , González Hector , Lara Victor 
Published: December 2007

Abstract
Most of heavy and extra heavy crude oil reservoirs in Venezuela are non-consolidated sand deposits. Venezuelan oil industry has a great interest to produce these reserves. Cold Heavy Oil Production with Sand (CHOPS) is an alternative for the primary production of some of these deposits; in particular those where other technologies are not applicable (i.e. sands with thicknesses are less than 10 m). In general, at field level, the application of the CHOPS has been successful around the world. In particular, it has experienced great development in Canada, China and United States. The physical and numerical studies show that change in the production rates, implies cavities formation and/or erosion zones near to the well that increase reservoir permeability. In Venezuela, experience in this technology does not exist. Furthermore, the bibliographical review demonstrates that many doubts still exist on the production mechanisms. It is the reason why this work considers the design, construction and evaluation of a sand production physical model. The main objective is to study the physical processes and to evaluate the influence of different variables like pressure, flow rate, among others, in the sand production mechanisms. The obtained data, will allow the development of models to predict reservoir behavior and its properties evolution in time. This physical model is set up with a cylindrical disc, 50 cm diameter and 20 cm thickness. Cylindrical geometry guarantees radial flow. The model is instrumented with sensors to measure pressures (injection, production and pores fluid) and fluid samples are taken to quantify total sand produced. The assembly system provides facilities to apply vertical stress. Ultrasonic wave velocity measurement is used to locate erosion zones. All data is collected by a Labview card and it is processed digitally in the computer in real time. This work shows results for a preliminary test with water and mineral oil used as fluids and calibrated glass bets as the porous media. The results prove that this system can be used to study sand production mechanism but it cannot be scale up to reservoir conditions. However the results will be used to validate numerical models.
A Unique Workflow for Reserves Evaluation in Lower Vicksburg Sands
Authors: Fan Li , Martin Ronald B. , Sehbi Baljit , Owen Keith W. , Atwood W. K. , Palacio Juan Carlos 
Published: December 2007

Abstract
This paper presents a unique workflow for gas reserves evaluation in fields with commingled production from several low permeability reservoirs. The workflow was originally developed for gas reserves evaluation of the Lower Vicksburg (LV) sands and the paper illustrates the key steps in the methodology. Developing Lower Vicksburg sands has been a great challenge to all operators in the region, not only because of the high drilling and completion cost, but also due to the high risk and uncertainty involved in the process. To make wise investments in such a difficult environment, it is crucial to understand the real value of the remaining reserves.
The outcome of a reserves evaluation depends on the amount and quality of the data, the knowledge and experience of the evaluators, and the methodology and workflow used during the evaluation process. Although we deal with dry gas reservoirs, the challenge lies in the difficulty of solving relatively simple equations that result from a combination of complicated reservoir and production characteristics. As a result, a wide range of answers may be obtained from the same data set and frequent revision of the reserves number becomes unavoidable. However, it has been our experience that the accuracy can be greatly improved through sound engineering practice and workflow. This paper illustrates a robust process to quantify the reserves in the LV reservoirs. This unique workflow includes sound data management and consistent analysis processes that allow for iterations among different methodologies aimed at minimizing the uncertainty and improving accuracy in the results. The paper also highlights some common pitfalls and mistakes normally made today in the reserves evaluation process for low permeability reservoirs, which should prove highly beneficial to the petroleum industry. In fact, the workflow would be useful toward obtaining correct reserves estimations for virtually any low permeability gas field where production from several horizons are commingled without the need of a full field reservoir simulation.
In this paper, we will use a field reserves study as an example to illustrate our unique workflow. The objective was to estimate remaining reserves in the LV reservoirs. The scope of the study includes six Lower Vicksburg sands (namely A sand, B sand, C sand, D sand, E sand, and F sand) found in less than 100 wells. It needs to be pointed out here that any analysis results presented in this paper do not represent the results from the real study. These are strictly for demonstrating the workflow process.
Neural Network and 3D Seismic Techniques Improve the Prediction of Facies Distribution Within a Submarine Channel Complex: Neuquen Basin, Argentina
Authors: Raggio F. , Ortin A. , Martinez C. , Uzzo P. 
Published: December 2007

Abstract
Los Molles Formation in the Neuquén basin (Fig 1), west-central Argentina, contains a series of deep-water submarine channel complexes deposited in an elongate basin, during the Pliensbachian-Toarcian ages. These events developed during the final stages of the rifting phase. In the studied area, these submarine meandering canyons cut the shelf and gentle slope in a SSE-NNW direction, and represent the transfer zone of the system, where erosional features are more frequent and lithological distribution is more complex. The canyons are approximately 3 Km wide and several hundred meters thick and host a number of migrating channel-fill units inside, lying on erosional surfaces that cut into adjacent interchannel facies.
Applying neural network techniques in the three wells that penetrate this deep-marine strata, allowed the identification of five main lithofacies: muddy-matrix conglomerates, sandy-matrix conglomerates, coarse-grained sandstones, fine-grained sandstones and mudstones. Furthermore, the use of 3D seismic attributes was crucial to obtain the distribution of these facies within the canyons. For this purpose, techniques based on neural network and representative supervised "seed points" next to each lithology around the well, were applied.
This work resulted in a seismic volume with the distribution of four seismic facies along the system in a very heterogeneous way. The fine grained facies clearly located in an overbank position; the sandstones and conglomerates show a distribution constrained inside the canyons, and is also easy to see how the net-to-gross relationship increases towards the distal positions of the system.
The techniques applied, greatly improve the success of prediction of potential reservoirs locations.