bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detailed Facies Definition and 3D Static Model: Reservoir Management of the Eocene Producing Units in Block X of the Talara Basin in Northwest Peru
Authors: Laverde Fabio , Pozo Gerardo , Miranda Flavio , Carrillo Gonzalo , Torres Kevin , Sanchez William , Alvarez José Luis , Contreras Fabio 
Published: December 2010

Abstract
Block X, located in the Talara Basin in northwest Peru, is one of the oldest producing basins in America. The reservoirs that have been studied are the Eocene Mogollon, Ostrea, Echinocyamus, and Helico units. The present structural model has benefited from previous jobs performed by Petrobras, where an old extensive fault system oriented northeast to southwest was affected by a later fault system trending northwest to southeast. Low-angle faults have cut the upper section of the Helico unit, consequently moving older sequences to the northwest. This structural setting controls the distribution of facies bodies, their interaction, size, and geometry, and the quantity of sand facies.
Based on an integrated facies analysis from numerous outcrops, 21 cored wells and more than 750 well-log motifs, a reliable stratigraphic framework was constructed that resulted in the identification of specific facies associations, stratigraphic or depositional surfaces, defining genetic units. Gross depositional fluvio-deltaic environments of the Mogollon succession were interpreted toward the southeast, shoreface at the Ostrea facies throughout the area, the deltaic and fluvial for the Echinocyamus in localized areas, and the tidal flat-beach-coastal plain toward the northeast, with the important development of fan deltas into submarine canyon-fills. This development was recorded within the Helico at the southwest of the study area. Because of the many years of production data available, the geologic model and facies distribution could be adjusted with dynamic data, such as pressure data, production tests and water cut. A possible way of achieving such conditions included adjusting the connectivity between sand bodies, their orientation and the vertical communication.
The products of the integrated study included: 1) mapped areas and zones of potential reservoir connectivity, and 2) geological model building used in 3D geostatic modeling. Mapping of the sequences resulted in the proposal of new infill wells and potential workovers. The results of the 3D static model work were: a) realistic fine-scale geological models that were consistent with the observed data, b) calculations of uncertainties in the oil-in-place volume.
Managing Downhole Vibrations for Hole-Enlargement-While-Drilling in Deepwater Environment: A Proven Approach Utilizing Drillstring Dynamics Model
Authors: Compton Molly , Verano Fernando , Nelson Gail , Wu Sean Xianping , Bits Smith 
Published: December 2010

Abstract
Deepwater drilling often requires simultaneous hole-enlargement-while-drilling to improve project economics and efficiently deliver wellbore requirements. The challenge is to properly adjust reamer aggressiveness to match PDC bit dynamics to reduce damaging vibrations while maximizing overall drilling efficiency.
Recent R&D efforts, focused on redesigning the BHA and optimizing drilling parameters, have successfully reduced bit/under- reamer vibrations. In addition, many operators and service providers have established rig-site procedures to recognize and mitigate vibrations. However, the results are still mixed and the lack of understanding the root causes of different vibrations is considered to be the major hurdle to improving drilling efficiency and performance.
To solve this challenge an advanced dynamics model was developed which incorporates the following critical information: Mechanical rock properties (UCS)
Bit/reamer design including cutter, body, gauge profile Physical characteristics of BHA components Formation characteristics (heterogeneous, anisotropy, interbedded) Well trajectory and borehole geometry Drilling parameters (WOB/RPM)
This model can be applied to any drillstring configuration to provide BHA detailed information about RSS, PDM, PDC/roller cone, stabilizers, reamers, MWD/LWD and other downhole tools. This FEA model accurately predicts the drilling system's dynamics behavior from bit to surface and simulates the transient response of the entire system in time domain. Using this model, the combined effects of bit, reamer, BHA and drilling parameters have on vibration can be quantified and optimized before commencing field operations. This innovative technology provides an effective tool to optimize drilling performance without using the costly trial-and-error approach.
An operator working in the Gulf of Mexico (GoM) required hole-enlargement-while-drilling to open a 12-1/4" pilot hole to 14- 3/4" from 13,000ft MD to approximately 20,000ft MD. The advanced drillstring dynamics model was utilized to optimize the BHA, bit and drilling parameters to minimize potential stick-slip and lateral vibrations. The optimization study, along with the operator's improved drilling practices, resulted in a 24% increase in penetration rate (ROP) compared to an offset well. Excluding the directional portions of the wellbore, the increase in ROP was calculated at 43%. The penetration rate increase reduced rig-time usage by 13.4hrs for a savings of $558,000USD.
Multidisciplinary Workflows Applied in Reservoir Characterization: A Heavy Oil Field Case Study During Early Stages of the Asset Life-Cycle
Authors: Astudillo D. , Porlles J. 
Published: December 2010

Abstract
New oil fields have been recently discovered in remote areas of the Peruvian Amazonian rainforest. Heavy oil was tested in Cretaceous age reservoirs of Marañon basin: Casablanca, Vivian and Chonta. Conceptual development options for these fields are being analyzed; that is why, a proper characterization of rock-fluid properties of reservoirs is particularly important in this early stage of the asset life-cycle to optimize the field development strategy.
Several methodologies of reservoir characterization have been widely discussed in the literature; however not always interdisciplinary workflows are applied in data acquisition and processing for reservoir characterization. Study cases and lessons learned from studies carried out in a recently discovered heavy oil reservoir are discussed, as well as, the workflow applied to get representative SCAL data and integrated well test interpretation is described.
On the one hand, the process to achieve representative SCAL data includes sample selection criteria, SCAL program, and data validation to come up with a high quality data set to refine reservoir models. Sample selection technique used for this study is based on Global Hydraulic Elements (Corbett et al. 2004)5, which is combined with sedimentological studies, electrofacies logs and statistics from geo-cellular 3D model. This is aimed to select representative core plug samples for a cost effective lab program execution. On the other hand, routine core analysis data was integrated into well test interpretation to understand flow units and select near wellbore flow models that are consistent with petrophysical data. Finally, after processing and validating information, a selected set of data was incorporated into reservoir models.
The workflows discussed in this paper look forward to developing synergies in multy-disciplinary teams working on reservoir characterization, which could allow to improve the making decision process during early stage of the field.
Numerical Transient Testing Deconvolution as a Reservoir Modeling Tool for Gas Fields in Early Development Phase
Authors: Quispe J. , Huerta V. A. , Quispe D. 
Published: December 2010

Abstract
Recently, new gas condensate fields have been discovered in remote areas of the Amazonian rainforest, Peru. Some of these fields tested gas and condensate from Nia, Noi and Ene reservoirs; Accuracy in well testing interpretation will play a crucial role in identifying geological features and solving uncertainties while characterizing these fields.
Conventional interpretation methods are not completely rigorous while trying to match pressure transient behavior by semi-log pseudo-pressure and derivative plots; usually, condensate banking phenomena and complex geological features are not precisely described with inferred models, especially in relatively new fields with little information.
An integrated approach composed by the combination of numerical simulation plus deconvolution technique offers comparative advantages compared to conventional transient testing analysis when discriminating between potential interpretation models and a sound reservoir characterization; contribution of geology and geophysics is very critical to identify structural features such as faults, flow barriers and fluid-contact positions, as well as, to predict pressure support intensity and predominant drive mechanism.
This paper provides general guidelines to integrate reservoir modeling disciplines to numerical deconvolution analysis so as to precise well testing interpretation of fields in early development phases; some applications, such as a sound methodology to calculate a representative drainage radius for the whole drawdown time, and its contribution to mitigate uncertainty in resources estimation, as well as, a more detailed characterization of late-time effects (facies-changes and fluid-contacts) in Peruvian gas condensate fields were emphasized.
Indexing and Normalizing Natural Gas Endowment
Authors: Aguilera R. F. , Aguilera R. 
Published: December 2010

Abstract
A novel method is presented for indexing and normalizing natural gas endowment. The approach is demonstrated with data from Latin America and Caribbean (LAC) countries. Endowment, as defined by the USGS, refers to the sum of known volumes of hydrocarbons (cumulative production plus remaining reserves) and undiscovered volumes.
The method uses a variable shape distribution model (VSD) to fit the conventional natural gas endowment published by the USGS (2000) for 29 petroleum provinces in LAC countries. The fits are good with coefficients of determination (R2) greater than 98% in all cases. The data are indexed and normalized to generate tables and crossplots of number of petroleum provinces versus normalized endowments for LAC countries.
The LAC curves are compared with normalized endowments from other petroleum provinces in regions around the world, including North America, Europe, Asia Pacific, the Middle East, NorthAfrica, and the former Soviet Union. The results give the method predictive power for estimating conventional natural gas endowment in LAC petroleum provinces that at present have very small to negligible exploration activity.
Of particular importance, from a practical point of view, is the fact that all the real data and VSD curves for the petroleum provinces of the various regions considered in this study display generally a concave pattern throughout, except for the curve of Latin America and the Caribbean, which displays a distinct convex pattern at the largest values of gas endowment. The complete LAC curve displays the shape of an inverted "S". The comparison suggests that there is potentially a gigantic volume of gas in the region that has not been considered in previous studies.
Producing the Intelligent Riser: Advances in Fiber-Optic Monitoring and Visualization Applications Within Flexible Risers
Authors: Andersen B. , Staveley C. , Worsley J. , Watley D. , Naldrett G. , Bennett P. J. 
Published: December 2010

AbstractUnbonded flexible risers are a critical part of offshore field architecture bringing oil and gas from seabed to platforms on the surface. A failure in operation will result in stop of production and hence a significant loss of revenue. Risers are subject to a number of loading issues including internal and external pressure, vessel motions and current and wave actions. As a result, risers, endure significant strain levels which can impact on their integrity and functionality.The recent implementation of fiber optic monitoring embedded in flexible risers, is an important step towards turning risers into inspectable structures. The embedded monitoring systems ensure the asset can operate safely at its optimum level for the maximum period of time. The combined use of optical point sensors and fully distributed sensors allow various events to be monitored. This includes breach of outer sheath, condensate build up, polymer temperature, pipe temperature during shut in, fatigue and wire break.The traditional industry method for combating these issues has been extensive onshore testing on small sections of the riser allowing the operator to build up a bank of fatigue and reliability data which is used to statistically forecast the strains and stresses the riser will encounter. This data takes into account expected changes throughout the lifecycle of the riser, such as material degradation and environmental issues including storms and hurricanes. The main inspection method in operation to back this up has been expensive inspection campaigns by diver or ROV focusing on external damage.New advances in optical technology and riser manufacturing techniques mean that a suite of real-time monitoring can provide a far more accurate picture of a riser's condition during operation. This improves decision making by allowing structural and temperature issues to be detected at the earliest possible stage and rectified in the most efficient manner, ensuring risers satisfy safety and regulatory requirements and help maximize oilfield productivity. The enabled condition dependent maintenance of risers will reduce the need for expensive ROV operations for inspection.Real time riser monitoring is set to play an increasingly important role as the operators start to insist on the adoption of this technology in the risers delivered to them. As oil production reaches into deeper and deeper water depths, the real time understanding of the integrity of the risers will become paramount.This paper details the advances that have been made in optical monitoring and visualization techniques and their application within the intelligent riser.
Maximum Horizontal Stress and Wellbore Stability While Drilling: Modeling and Case Study
Authors: Li S. , Purdy C. 
Published: December 2010

Abstract
Maximum horizontal stress is a critical parameter used in drilling optimization and wellbore stability modeling. Current maximum horizontal stress prediction from wellbore breakout was based on the maximum tangential stress on the wellbore wall to be equal to the rock uniaxial compressive strength. We assume that the vertical, minimum and maximum horizontal stresses define a specific relationship when the stresses in the formation are in equilibrium. Based on a generalized Hooke's law with coupling the equilibrium of stresses and pore pressure, the maximum horizontal stress can be solved using this relationship. This new technique can reduce the uncertainty of in-situ stress prediction by narrowing the area of the conventional polygon of the in-situ stresses. We also propose a new method of the maximum horizontal stress determination from analyses of drilling-induced near-wellbore stresses and breakouts. The near-wellbore stresses are obtained from poroelastic equations. By using Mohr-Coulomb failure criterion, the maximum horizontal stress magnitude can be derived from these equations and from analysis of wellbore breakout obtained from borehole caliper logs. The new technique is compared to the existing methods in an example from measured borehole failures in a case study. These comparisons demonstrate that new technique provides a much better result than the current available methods, because the wellbore failure is related with all of the near-wellbore stresses.
A case study has been conducted in a GOM oil field to predict pre-drill wellbore stability, where borehole instability was the main cause of borehole trouble time in offset wells. Using the proposed in-situ stress method, an improved borehole stability model was built to predict the pre-drill mud weight window. Applying this prediction, wellbore failures and drilling risks were greatly reduced.
Talara Basin, Peru: Structural and Stratigraphic Characterization Based on 3D-Seismic Data
Authors: Diniz S. H. , De Sá F. R. , Rodriguez C. , Santos C. G. , Cruz J. M. , Beas W. E. 
Published: December 2010

Abstract
Along the past decades the prolific Talara Basin, located at the northwest part of the Peruvian coast, has been intensively studied based mainly on the huge amount of onshore wells on the area. Beside this, contributions come up from 3D seismic. These contributions are stratigraphic and/or structural analysis, which provide suggestions about reservoir communication, fault movement and optimize well positioning.
The reservoir characterization methodology applied on this work used 3D PSDM seismic data. The first step aimed to better understand deep reservoir levels (Lower Eocene and Paleozoic), that are less sampled by wells than upper levels (e.g., Middle Eocene). The second step focused on Middle Eocene reservoirs, sampled by tens of wells with a good geological correlation. From well data and geological interpretation, it is well known that Lower Eocene reservoirs are high energy fluvial systems – this depositional pattern appeared with a distinct seismofacies in the entire seismic cube. Seismic data and well logs showed that Lower Eocene presents more fractures and faults than Middle Eocene. However, the relation between directions and fracture classification as open, semi-open or closed fractures was not conclusive.
The seismic facies found at Middle Eocene show sin-depositional differential tectonics movements that could have caused compartmentalization. At this level, seismic facies are very clear, with strong and parallel reflectors, indicating the presence of amalgamated lobes (probably derived from erosion of an eastern ridge located). Identified seismic anomalies were mainly related to structural highs, associated to hydrocarbon saturated reservoirs.
An understanding of stress field behavior along geological time is very important to achieve a better trapping model and hydrocarbon migration routes. In this work, the high number of structures observed provided the tools to set up an event chronology. According to the stress history, N70W normal faults acted as migration routes probably during Miocene. Considering the last compressive reactivations (occurred between Upper Eocene and Oligocene) these previously migration routes could be changed to sealing faults.
Gas Production From Hydrates Dissociation in Marine Sediments
Authors: Llamedo M. A. , Provero D. , Viloria A. , Yánez G. F. E. 
Published: December 2010

Abstract
The quantity of gas accumulated as gas hydrates has been estimated as more than the half of the total fossil energy, and it is considered as the most prominent energy resource to cover the needs of natural gas in the future. Due to the limited data available, important efforts in the harvesting of real data have been carried out and additional simulation studies for this not conventional reservoir like gas hydrates accumulations are considered. The two main mechanisms to define the exploitation strategy are depressurization and thermal stimulation; and reservoir numerical simulation which are considered important tools to get characterization and evaluation of the optimization production process. A three-dimensional commercial numerical simulator is used to model gas production from gas hydrates dissociation, considering the thermodynamic equilibrium and the kinetic intrinsic, both simultaneously. Depending on the defined deposit configuration, gas hydrates accumulations can be associated a biphasic zone with gas free layer below the gas hydrates zone (deposits Class 1), and for this configuration gas production by depressurization is the most favorable one. The initial production from the free gas layer drives the process of dissociation of methane hydrates zone. In the case where the configuration includes the presence of an aquifer or mainly water in a biphasic zone below to the gas hydrates zone (deposits Class 2); the more often evaluated mechanism is hot water or steam injection as thermal stimulation behave like an acceptable alternative for gas production, the rise in temperature promotes the dissociation of the upper hydrates reaching temperatures to that of equilibrium condition. Gas production is associated with water production.
New Design of High-Performance Cement Systems for Zonal Isolation: Influence on Porosity, Rheological Parameters and Chemical and Mechanical Resistance
Authors: Miranda C. R. , Toledo Filho R. D. , Fairbairn E. M. , Thaumaturgo C. , Vargas A. A. , Oliveira G. M. , Teixeira K. C. 
Published: December 2010

Abstract
High-Performance Cement Systems consist of cement slurry designs based on engineered particle size distributions that aim to achieve improved mechanical properties and higher chemical resistance compared to traditional cement slurry compositions.
The methodology used to obtain High Performance Cement Systems for Oilwells is based on the Compressive Packing Model, where higher content of solids is achieved by using materials having specific particle size distributions. With these higher solids content slurries, a lower proportion of water is required, and thus improved mechanical properties and better chemical resistance can be obtained.
The High-Performance Cement Systems, also called High-Packing Cement Systems, in the present work were designed using the Compressive Packing Model, which was developed to design high performance concretes. Various systems for oilwells were designed in this work using Class G Portland Cement, Silica Fume and Hollow Microspheres.
The high-performance cement system properties, such as rheological parameters, compressive strength, porosity and acid resistance are shown and compared to traditional cement systems properties.
Economic Evaluation of Steam and Nitrogen Injection on SAGD Process
Authors: Rios V. S. , Laboissière P. , Trevisan O. V. 
Published: December 2010

Abstract
Thermal recovery methods made possible the production of heavy oil fields considered non-commercial with conventional methods of recovery. In this context, steam injection has proved to be a major cost-effective alternative for increasing the heavy oil recovery. Steam Assisted Gravity Drainage (SAGD) is one of the field proven improvements. It uses two horizontal wells with the steam injector above the producer, which stays at the base of the reservoir. Sweeping the reservoir with the growth of a steam chamber.
The variations on conventional SAGD involving non-condensable gases show a new trend. Numerical results suggest that after a certain period of time operating only with steam is effective to inject only inert gas. In this process the steam chamber keeps growing even after the steamflood is stopped. The purpose of the gas injection is to maintain the reservoir pressure elevated to keep the oil production. The cumulative steam oil ratio has a downward trend, yielding a reduction in the project costs. In this paper, a numerical study of the SAGD method in field scale is conducted. The reservoir model is simulated with properties obtained from a Brazilian onshore field. The methodology used involves an investigation of the main parameters that influence the application of the method and, according to a sensitivity analysis. The aim is to determine the best time to start gas injection looking to maximize NPV.
A commercial software is used to simulate the injection of nitrogen after steamflooding the reservoir in order to obtain the results that are used to perform the sensitivity analysis. It was verified that the steam injection rate and the bottom hole pressure are decisive parameters to be considered. The simulations show that the nitrogen injection after a determined period of time of continuous steam injection reflects in a reduction in the order of 40% of the steam oil ratio. However, the cumulative oil production is almost the same when compared with the conventional SAGD.