bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Production Data Inversion to Evaluate Performance of Naturally Fractured Reservoirs
Authors: Marhaendrajana T. , Blasingame T.A. , Rushing J.A. 
Published: December 2007

Abstract
Many oil and gas production come from naturally fractured reservoirs. The reservoir properties and production performance of this reservoir show a unique behavior, which are different from the homogeneous reservoir. Hence, evaluation and forecasting production of these reservoirs require special models and approaches.
This paper attempts to utilize production data inversion method to obtain parameters such as permeability, skin factor, initial fluid-in-place and production potential in a naturally fractured reservoir. The model can then be used to forecast production from this type of reservoir.
The method uses type curve approach that incorporate concepts of both transient and boundary dominated flow models. Application of this method to oil field data is presented as well as comparison with results obtained from other methods (such as well test analysis and volumetric calculation).
The results of this research provide engineers a tool to evaluate and monitor production/reservoir performance of naturally fractured reservoirs regularly by analyzing production data (which are always recorded) without additional testing.

Introduction
Modeling of single phase flow in fractured reservoir involve the description of the shapes, orientation and sizes orf fractures network, and the mechanism for the transfer of fluid from the matrix to the fracture network. The process of transfer of fluid between matrix blocks and fissures (or fractures) is the points at which various model differ. Some investigators have considered a pseudosteady-state relation for the interporosity flow term. This approach was first suggested by Barenblatt et al1 and was taken up by Warren and Root2 in their pioneering study of the pressure response of naturally fractured reservoirs. Others3,4,5 considered the effect of transient interporosity flow. The transient model is physically much more appealing since it allows for all regimes of internal block flow, i.e. transient, late transient and pseudosteady-state. This was first proposed by Kazemi,3 where the matrix blocks were composed of slabs.
Combinable Through-Tubing Cased Hole Formation Resistivity Tool
Authors: Herold B. H. , Benimeli D. , Levesque C. , Dubourg I. , Cadenhead J. 
Published: December 2007

Abstract
The Cased Hole Formation Resistivity Tool (CHFR*) that measures formation resistivity through casing has detected and evaluated bypassed hydrocarbon, tracked reservoir fluid movements, performed contingency logging, and has complemented the operating envelope of nuclear saturation monitoring tools. It has to be run stand-alone and due to its 3 3/8–in. outside diameter, the completion had to be pulled before logging.
This paper will present some of the field test results of the third-generation cased hole formation resistivity tool. It has a 2 1/8-in. outside diameter and is specifically designed for conveyance through tubing. The tool is also fully combinable with production logging tools and nuclear saturation-monitoring tools. It can be run conventionally on wireline, or deployed on coiled tubing or by tractor in difficult borehole conditions.
Field tests have verified the performance of the slimhole tool. Some of the field test data collected from different locations around the world are presented in this paper. They include log examples acquired in different well completions using various toolstring configurations. The small-diameter version adds new benefits to the industry: increased versatility, improved performance, conveyance under dynamic well conditions, and cost reduction.
A Novel Approach for Globalizing Corporate Sanctioned Standards
Authors: Ross D , Godfrey R 
Published: December 2007

Abstract
The development, implementation and administration of corporate sanctioned standards throughout a multinational service company pose many challenges. Difficulties arise when corporate standards intended for global use do not account for the many influencing factors (such as differences in local governing regulations, geographical locations, climatic conditions and contractual obligations) which will affect the validity and ultimate acceptance of a corporate sanctioned standard. To complicate matters further, in many cases the multinational personnel responsible for complying with the standards may or may not have the language skills required to read or comprehend a given standard unless it is translated into their indigenous language(s). Provided all these challenges can be overcome, the timely and effective distribution of documents to all corners of the globe presents another major challenge in addition to large costs incurred. Due to the dynamic nature of the industry and the desire to continuously improve, standards require periodic revisions, so a means to track and effectively distribute updates around the world is needed. This process requires personnel resources and discipline, and if not done properly, it can lead to a state of confusion among the intended users.
The following paper describes a novel approach for globalizing corporate sanctioned standards in a multinational service company, including standards for: field operations, quality, health and safety, environmental, maintenance, engineering, laboratory, and training. This novel approach, which employs a customized database application, is presented. Most unique to the application is its user interface which allows users to view the standards specifically applicable to their particular business unit, geographic region, and country, and in their native language. The approval process required to ensure all standards are reviewed and authorized at the appropriate level of the organization is addressed. In addition the methodology used for translating documents written in English into four additional languages will be covered. Furthermore, functional aspects of the database which allow multi-language viewing, user feedback, "best practices" photo gallery and additional features will be presented.
Unique Multistage Process Allows Pinpoint Treatment of Hard-to-Reach Pay
Authors: Rodgerson James L. , Lopez Henry (Enrique) , Snider Phil 
Published: December 2007

AbstractPerforating multiple pay intervals to achieve optimum treatment coverage has long been a topic of considerable debate. Perforation selection can play a crucial role in well performance. The consequences of inadequate perforation coverage can compromise fracture optimization, limit production, result in missed pay and limit reservoir access. Multi-zone fracture treatments have been performed in the past using a variety of methods ranging from limited entry to mechanical isolation with bridge plug and packer. These and other techniques have been routinely applied to stimulate discrete intervals within a formation in an attempt to maximize the production of discrete pay zones or stringers. One method consists of perforating and isolating each zone then performing the stimulation treatment. Wireline is used to isolate the previous zone and perforate the next stage. The treatment of multiple intervals in this manner can be a costly and time-consuming process.A new multi-stage treatment process optimizes perforation and treatment design. This technique, known as "External casing perforating," allows the operator to perforate and isolate individual zones in as little as 30 minutes between treatment stages. As many as 17 discrete intervals have been treated within a 24-hour period. Moreover, this approach minimizes total treatment volume by using the flush from the previous stage as the pad on the next stage, thus placing less fluid on the formation. The time to first sales has been reduced from days to a matter of hours by eliminating bridgeplug isolation and costly post-job clean up. Production from multiple horizons may be brought on-line quickly in one rig-less operation without damaging and time-consuming shut-ins.This paper will describe the perforating and stimulation technique and will quantify cost savings to the operator associated with the reduced volumes and timesaving. Additional benefits such as reductions in friction pressure and polymer damage and means for fracture optimization also will be discussed.
Determining In-Situ Stress Profiles From Logs
Authors: Mohaghegh S. D. , Popa A. , Gaskari R. , Wolhart S. , Siegfreid R. , Ameri S. 
Published: December 2007

ABSTRACT
This paper presents a new and novel technique for determining the in-situ stress profile of hydrocarbon reservoirs from geophysical well logs using a combination of fuzzy logic and neural networks. It is well established, that in-situ stress cannot be generated from well logs alone. This is because two sets of formations may have very similar geologic signatures but possess different in-situ stress profiles because of varying degrees of tectonic activities in each region. By using two new parameters as surrogates for tectonic activities, fuzzy logic to interpret the logs and rank parameter influence, and neural networks as a mapping tool, it has become possible to accurately generate in-situ stress profiles from logs. This paper demonstrates the improved performance of this new approach over conventional approaches used in the industry.
Approximate Analytical Solutions for the Pressure Response at a Water Injection Well
Authors: Peres A. M. M. , Boughrara A. A. , Chen S. , Machado A. A. V. , Reynolds A. C. 
Published: December 2007

Abstract
The first and fifth authors have previously used the Thompson-Reynolds steady-state theory to derive solutions for the pressure response at a water injection well. In the vertical well case, their solutions assumed a complete-penetration well; in the horizontal well case, they assumed that the well is equidistant from the top and bottom of the formation. Here, we construct approximate analytical pressure solutions for the restricted-entry vertical well case and for a horizontal well for the case where the well's axis is not equidistant from the top and bottom boundaries. The solutions are based on adding to the single-phase solution, a multiphase term which represents the existence of the two-phase zone and the movement of the water front. We present models for the movement of water based on a combination of Buckley-Leverett equations that allow us to accurately compute the multiphase flow component of the analytical solution. By comparison with a finite-difference simulator using grid refinement and a hybrid grid, it is shown that our multiphase flow solutions are accurate.
The analytical solutions provide insight into the behavior of injectivity tests at horizontal an vertical wells. For example, for a restricted-entry case, it is shown that the pressure derivative may be negative throughout an injection test even when the duration of the test exceeds ten or more days. We also show that for a well near a fault, the ratio of slopes reflected by derivative data will not in general be equal to two but is given by a formula that involves the mobility ratio. In the restricted-entry vertical well case, we provide the equations for three flow regimes.
Fuzzy Analysis for Progressing Cavity Pump
Authors: Correa Jose F. , Carvalho Paulo C. G. , Filardi Vitor L. , Schnitman Leizer , Lepkison Herman A. 
Published: December 2007

Abstract
The Progressing Cavity Pump artificial lift method for oil well production is well known in the oil industry, despite that a poor literature about PCP analysis is available. PCP automation based on ladder programming deploys information such as instantaneous rod torque, production line pressure, and rods rotation to name a few. The use of this information to analyze the well performance, identify imperfections and problems depends on a deep knowledge about the system well-PCP, but the procedures to do so are yet to be developed. To optimize the production and increase the mean time between failures in this type of well is necessary not only to improve the algorithm coded on the ladder programming loaded in the PCP automation PLC but also to develop a knowledge base where the skills and knowledge of the local PCP specialists could be easily coded. To analyze data deployed by the PLC and to improve the firmware customization, an intelligent system is being developed. This intelligent system is based on artificial intelligence concepts such fuzzy functions, coded in a way to easy acquire the PCP specialist knowledge on how to understand what is going on in the well and what to do to bring it back to a proper behavior. The present paper presents an intelligent system for automation of PCP wells capable of acquire and spread the knowledge of the referring specialist in diagnosis and solutions of problems during the well operation. Fuzzy agents are proposed in order to do an intelligent analysis of a set of PCP variables such as friction, motor, pump position, production and volumetric efficiency, … The paper also describes the tools and interfaces designed to acquire the PCP specialist knowledge, the system implementation, and an acquired knowledge base example.
Fluid Front History Matching Using 4D Seismic and Streamline Simulation
Authors: Kretz V. , Vallès B. , Sonneland L. 
Published: December 2007

Abstract
History matching of flow models is typically performed by using production data to calibrate the models. This implies that deficiencies in the models cannot be revealed until the consequences are observed in the well network. The outcome can be highly undesirable, like early water-breakthrough in a production well. A new method is proposed that enables calibration of the flow-model early in the production cycle before the deficiencies can be observed in the wells, so that pro-active action can be taken.
The basic idea behind this new method is to modify a given set of flow properties (e.g. porosity, permeability, cell volume…) along the streamlines so that the computed fluid fronts coincide with the observed fluid fronts derived from 4D seismic. The latter can be extracted from time-lapse seismic cubes with amplitude-based seismic attributes or 4D classification results.
The matching of fluid fronts with this method needs very few iterative steps, contrary to traditional history-matching techniques. This feature allows to reduce significantly the number of flow simulations run during the process. The use of streamline simulators is of key importance in this step. First, the inverse problem is reduced to several easy-to-solve one-dimensional problems. Secondly, the result of the matching is an average calibration of the flow properties along the streamlines from the injector wells to the fluid fronts. Hence, more frequent time-lapse seismic measurements give improved resolution to the calibration of the flow properties.
The method proposed speeds up significantly the calibration of reservoir models to observed fluid fronts and facilitates a more active use of 4D seismic in reservoir management.
The method is then demonstrated on different case studies.
Using Horizontal Wells to Sequester CO2 and Enhance Coalbed Methane Recovery: A Simulation Study of Operating Procedures
Authors: Sams W. Neal , Bromhal Grant S. , Jikich Sinisha A. , Ertekin Turgay , Smith Duane H. 
Published: December 2007

Abstract
Because of increased concern about anthropogenic carbon dioxide emissions, a pilot project is being implemented in northwest West Virginia to study the technical feasibility of carbon dioxide sequestration in unmineable coal seams. The project consists of four 3000 ft horizontal wellbores forming the exterior of a square with four horizontal wellbores at its center. Methane production occurs from all wellbores until the reservoir is sufficiently depleted, then the central wellbores are converted to carbon dioxide injectors while production continues from the exterior wellbores. In our simulations for this project, injection and production continue until the mole fraction of carbon dioxide in the produced gas reaches 0.1.
The design factors studied were the lengths and orientations of the central wells, while the operational factors studied were the pressures in the injection wells. We examined the cases where the injectors are oriented perpendicular to the exterior wellbores and where they are oriented toward the corners. The performance of a pilot project is also compared with that of a pattern in a fully-developed field.
For a pilot project, operating parameters that give the longest project life also yield the greatest methane production. On the other hand, for a developed field the main factor controlling methane production is sweep. Although the longest injectors have poor sweep efficiency, short injectors represent little improvement over the performance of intermediate length injectors, but they significantly lower production rates. Injection pressure has only a weak effect on total methane production in a developed field. Higher injection pressures result in slightly more methane left in place in unswept areas of the reservoir, but also result in a higher production rate. The sequestration performance for either case is controlled by a combination of sweep efficiency and average pressure in the swept area. The interaction of sweep and reservoir pressure on performance results in a maximum in performance for intermediate length injectors. For low anisotropy the diagonal injectors yield better sequestration performance, but for high anisotropy the perpendicular injectors with unequal lengths perform better. In all cases a long diffusion time constant places an upper limit on injection rates that also yield good performance.
Improved Reservoir Management Through Optimal Control and Continuous Model Updating
Authors: Brouwer D. R. , Nœvdal G. , Jansen J. D. , Vefring E. H. , Kruijsdijk C. P. J. W. van 
Published: December 2007

AbstractThere is a potential for large improvements in reservoir management by using optimization and model updating techniques in a closed-loop fashion. Here we demonstrate how the combination of the ensemble Kalman filter technique for continuous model updating with an automated adjoint-based water flood optimization algorithm leads to significant improvements in net present value (NPV) of the water flooding process.Using the ensemble Kalman filter, both static parameters (permeabilities) and dynamic variables (pressures and saturations) are updated in the reservoir model as new production measurements become available. Other properties are assumed known in advance. At the start of the production process, in the absence of information on the permeability distribution, an optimal control strategy based on a homogeneous reservoir is used. Subsequently production data are at regular intervals assimilated with the ensemble Kalman filter, resulting in an updated estimate of the reservoir pressures, saturations and permeability field. Based on these updated parameters an optimal water flooding strategy is determined for the remainder of the production process. This process of model updating and optimization is continued over the life of the reservoir.The methodology is applied to two synthetic examples, enabling comparison with traditional production strategies. Significant improvement in NPV, acceleration of oil production, cumulative oil recovery, and reduction of water production were realized. Results were close to those obtained with water flood optimization based on an a-priori known reservoir description. For one example the improvement in cumulative oil recovery is about 44 %, which is quite close to the improvement obtained for an a-priori known reservoir description.
The Heat Transfer Characteristics of Vacuum Insulated Tubing
Authors: Azzola J. H. , Pattillo P. D. , Richey J. F. , Segreto S. J. 
Published: December 2007

Abstract
Thermal effects in vacuum insulated tubing (VIT) have been studied in previously reported experiments2. VIT is usually characterized by a single thermal conductivity ( k -value) based on a one-dimensional radial heat transfer analogy. Despite its simplicity, however, this physical model masks the underlying complexity of the two-dimensional axisymmetric heat transfer field.
Recent theoretical insights have demonstrated that VIT behaves as a fin around the weld and coupling regions, where up to 90% of the overall heat loss can occur. As a result, VIT does not have a single k -value; instead it has a potentially wide range of k -values, depending on boundary conditions. Recent numerical and experimental investigations of vertically aligned VIT demonstrate the highly sensitive nature of thermal performance with respect to these boundary conditions1. With this insight, previous test data2 is reinterpreted in a more revealing light. It can be demonstrated that the 10-fold spread of k -values from these tests is attributable to explainable boundary phenomena.
Another issue which requires clarification is the k -value definition. A standard definition is presented here which 1) is physically related to the effective thermal conductivity of the vacuum and 2) is relatively stable for different VIT configurations.
Transient behavior, including startup, cool down during shut in, ground soak, and convection cell development will be explained, as well as the implications for long-term thermal stability.
The discussion concludes with calculations of k -value for VIT under significantly varied boundary conditions: different annular fluids, different soils, with and without interior or exterior coupling insulators, and using high-temperature steam injection.
Risk, Uncertainty and Optimization for Offshore Gas Asset Planning in Litoral Tabasco
Authors: Solis Romeo , Rojas Santiago , Ramírez Guillermo Bernal , Saputelli Luigi , Narayanan Keshav 
Published: December 2007

AbstractLitoral Tabasco Integral Asset Management is planning to develop a series of recently discovered offshore gas fields by extensively planning, designing and deploying a world-class reservoir drainage architecture that efficiently produces gas reserves and optimally uses existing offshore surface facilities. The objective of this development is to recover 373 bcf of dry gas from five recently discovered fields (Hap, Akpul, Uchak, Isiw and Chukua) in the most cost-efficient manner and contribute to Mexico's goals of increasing its gas supply.We develop a case study planning process by using a strategy for balancing reservoir uncertainties (rock properties), optimum field development scenario (rate schedule and start time) and associated risks in the capital expenditures (price inflation and discount factor).The methodology has proven to optimize capital investment, by selecting an optimum scenario, namely one that best balances risk and uncertainty, and maximize asset profitability. Faster decision making process is enabled by a series of key digital oilfield components, such as an integrated framework for multi-disciplinary and multi-scenario modeling and optimization, and the potential for continuous real-time adaptation of the development plan to prevailing reservoir and market conditions.