bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiscale Compositional Simulation of Naturally Fractured Resevoirs
Authors: Ramirez B. , Atan Safian , Kazemi Hossein 
Published: June 2014

Abstract
To obtain accurate descriptions of fluid flow in the reservoir, it is necessary to include detailed geological information on the scale of geocellular models. However, computation resources are often overwhelmed by the vast amount of information that geocellular models contain.
The multiscale approach presented in this paper is designed to include the detailed geological information into the flow calculations while making computations less expensive. The distinguishing characteristic of this paper lies on the procedure used to carry out the computations. The procedure splits the computation into pressure solution on a coarser grid and the saturations and compostions calculations on a very fine scale. This is based the physical and theoretical evidence that pressure effects travel at much higher velocities than saturation and composition fronts – thus, different scales on computation. Splitting up the computations through appropriate physical rules, the multiscale approach divides the computation of pressure propagation and convective processes like the saturation and composition fronts. The pressure propagation is diffusive in nature, while the saturation and composition computation being transport processes are convective in nature. These characteristics allow the computation of the solution at different scale levels. The multiscale approach of this paper is a sequential formulation based on a volume balance model using partial molar volumes. It starts with a compositional pressure equation based on the overall components balance. Once the pressure solution is obtained, the total phase and component velocities are calculated on a fine scale to track the saturation and composition fronts.
The multiscale method begins with the use of coarse grid blocks, which contain numerous finer grid blocks (the geocellular scale). Flux calculations based on the total face velocities at the boundaries of the coarse grid blocks are used to set up the fine grid calculations for both the pressure and saturations within each coarse grid block for accurate tracking of the displacement fronts. The finer scale solution is subsequently employed to improve the accuracy of the coarse grid block boundary conditions. The scheme is intended to capture the fine scale physics of gravity, capillarity, and phase behavior interactions as well as the global effect of rock heterogeneity (the dual-porosity effects), pore structure, stratigraphy, and reservoir architecture.
Accelerating the Build up of Experience with a View to the Imminent Big Crew Change
Authors: Bos C. F. M. , Berkhout A. J. , Currie P. K. , Weijermars R. 
Published: June 2014

Abstract
This paper describes a number of features of the E&P sector that impact on the staff qualities and attitudes required to optimally run E&P projects. The first is that the E&P sector, when compared to other sectors in the industry, has to face relatively high levels of uncertainty in its project outcomes. This is due mainly to data sparsity, technological depth, multidisciplinary breadth and business process complexity. Second, in order to survive in the international arena, E&P companies in essence compete on their ability to attract, develop and retain scarce human talent. Managing the above uncertainties puts exceptional demands on employee skills and internal business processes. It is argued that the gap between the required and available skills pool is widening and that, consequently, the sector is increasingly becoming a human talent constrained industry. A third feature therefore is that relatively more resources should be invested in continuing education to turn experience into deeper insight for improved performance. We postulate that with a properly trained workforce the executive mandates given to staff should be made more flexible at their local (disciplinary, business-unit, asset etc.) level, but more stringent at the global (overall corporate value chain, context) level.
When relating the above considerations to the imminent "big crew change", one should grasp this perspective as an opportunity to revisit the E&P sector's traditional approach to education. This paper describes the results of three years experience with a new executive training program for midcareer E&P professionals. It is designed to achieve, within twelve months, a quantum leap in their integration and abstraction skills, enabling them to solve efficiently complex managerial problems much earlier than traditional training programs. The course focuses on E&P decision-making under uncertainty using a comprehensive definition of added value. Students learn to integrate the pertinent information, and switch between abstraction and integration levels as a function of the decision to be made. Mastering this skill is normally achieved after many years of industry experience. The course could be labeled "the MBA for E&P professionals', however with both feet firmly on technical ground. The results are remarkable. Graduates are ready to assume responsibility as E&P asset and portfolio manager.
A Model Integrating Surface to Subsurface Models under Uncertain Conditions, for Optimizing Production in Santa Barbara and Pirital Fields, Venezuela
Authors: Rodríguez Vera Rosa Angélica , Muziotti Cesar , Caraballo Nelson 
Published: June 2014

Abstract
Located at the northern area of Monagas state, Venezuela is the Santa Barbara and Pirital Fields; known to be two of the principle hydrocarbon fields in the country. Since their discovery, several characterization studies have been done for improving the understanding of its complex geologic structure and fluid column distributions; which vary greatly within each of the eight, independently modeled, sectors of the two fields.
Opportunities for improving exploitation plans, of these fields, have been identified based on characterization studies. Accordingly, It was realized the importance of evaluating different scenarios of hydrocarbon production, considering the unique characteristics of each of the eight reservoir sectors, as well as the surface installations capacities for handling production in the short, medium and long terms; taking into account the different levels of risk and uncertainties.
This article presents the development of a subsurface-surface model for the evaluation of multiple production scenarios, taking into account the reservoir characteristics, well bore design and surface installations in an integrated manner scoping the unexpected out of plan deviations that was not considered in the initial planning process, as well as the inherent uncertainties of the models used for designing the exploitation plan.
This model allows the selection of the most adequate infrastructure for handling Oil and Gas production, based on the reservoir behavior over time and considering the margin of error as a function of the possible risk and uncertainties at the reservoir level as well as delays in drilling future wells and variations in the produced hydrocarbon densities. The results of this model will finally be used for the economic evaluation that decides on the profitability of the projects associated to these fields.
This article will focus on the procedure of integrating the different surface-subsurface model components supported by a case history from the area.
Optimizing Wireline Gun System Design and Perforating Performance for Very Late Changes in a Gulf of Mexico HPHT Deepwater Well
Authors: Sabbagh L. , Blalock D. , Melvan J. , Leung H. 
Published: June 2014

Abstract
Thunder Horse field, a new subsea development in 6,000 ft of water in the Gulf of Mexico (GOM) has stacked consolidated sandstone reservoirs that occur at 20,000 to 30,000 ft subsea with pressures of 14,000 to 18,000 psi, temperatures of 190 to 270°F, and mean rock strengths of 4,000 psi. The reservoirs do not require sand control and are completed with perforated casing. Four wells have been completed, perforated, and cleaned up since 2004 using drillship Discover Enterprise and a completion workover riser. The 2004 flowtest in Thunder Horse was the first time the industry produced hydrocarbons to surface from the GOM HPHT environment. The wells are normally completed with a 7-in. liner and perforated with ⅜-in. HSD wireline guns with deep penetrating charges. In 2006, as a result of drilling problems, a 4 ½-in. production liner was cemented in the 8 ½-in. hole. To achieve a productivity index and skin factor close to the original design, it was necessary to perforate using 2 ⅞-in. HSD guns. The tight tolerance between the fired guns and the pipe ID created an additional challenge. Extensive analysis, design, and yard testing revealed that the well could be safely perforated using 2 ⅞-in. HSD guns with the new enhanced deep penetrating charges and that this could deliver better perforation performance than the original gun system. The results from the well's cleanup program indicated an even better perforation efficiency than observed earlier. Downhole permanent gauges were essential to minimize underbalance conditions during perforating to prevent gun and line damage. Perforating was done between cleanup flow stages. Bullheading partial wellbore volume reduced surface pressure during perforating. The gauges monitored wellbore pressure at the reservoir during the bullheading operations for signs of perforation plugging.
Linking Sequence Stratigraphy, Depositional Environment and Sedimentary Facies to Model the Sandstone 3D Architecture Within Palaeozoic Clastic Reservoirs, Saudi Arabia
Authors: Mohd Zain Nazhri , Khalifa Mohammad A. , Stanley Rowan J. 
Published: June 2014

Abstract
Paleozoic clastic sediments, comprising continental to transitional marine depositional environments, form excellent hydrocarbon reservoirs in Saudi Arabia. In order to develop a realistic dynamic model that can be used in reservoir performance prediction, a robust geological model is required. Detailed modeling of sand accumulations, their lateral continuity and vertical stacking patterns is needed to capture reservoir heterogeneity at all wavelengths.
To build an understanding of the sandstone ‘lumbing’ within the reservoirs, the Depositional Related Environment Architecture Modelling (DREAM) workflow is invoked. Initially, the fabric of the medium-to-long dimension gross depositional environments is described in 3D. The distribution resides within the envelope of a sequence stratigraphic structural framework that links the main time-correlative boundaries. This model captures the progradational and retrogradational depositional behaviour and employs a stochastic distribution process to address population uncertainties. With the broad-scale environments defined, a subsequent step involves the distribution of short-to-medium scale sedimentary facies conditioned to the environment model. Lateral probability distribution maps and vertical proportion curves, combined with geological templates, are invoked within each environment to ensure that the facies distributions conform to as many observable and analogue trend constraints as possible.
In this paper, the DREAM workflow was applied for two case studies and the results are presented. The output models combine the structural framework based on seismic and sequence stratigraphic interpretation principles with linked environment and facies distributions.
Angsi K–Sand Production Performance: A Case History of Hydraulically Fractured Retrograde Gas Condensate Reservoir
Authors: Othman Mohamad , Yang Juhari , Chong Mizan Omar , Zakaria M. Sukri , Ali Bohlool Asgar , Cheng Cheong Boon 
Published: June 2014

Abstract
Angsi K-sand is the first tight gas reservoir development in Malaysia, developed in 2002 to meet an increasing domestic gas demand. K-sand is high temperature (320 °F), multi-layered over pressured retrograde gas condensate reservoirs ranging from 10-90ft net thickness and permeability of 0.1 – 3.0 mD. It was developed through multi-staged propped hydraulic fracturing to improve well deliverability and to mitigate productivity impairment due to condensate dropout near the wellbore. In general, initial gas production from these wells exceeded expectation with condensate level significantly higher than initially anticipated in the development plan. However, several wells exhibited relatively faster and steeper production decline with indications of productivity loss related to the liquid drop out in the vicinity of the wellbore. Scale problem and proppant flow back were also observed at surface during clean-up of production facilities.
There are many challenges in managing this complex reservoir and ‘unconventional’ well performance in an area with a history of conventional gas well operation only. The main challenge is to develop operating strategies in producing these wells at sufficient rate and recovery to meet the short term gas commitment and provides sufficient return on the projects economics. The strategies adopted are flexible enough to face the decision making required by this type of reservoir under anticipated production operations. Additionally, these strategies are the key in identifying opportunities, defining uncertainties and developing specific plans to gather information to allow fast response. Based on actual performance and surveillance data, various changes to the original plan are being implemented. Active reservoir surveillance planning and execution were carried out to provide a better understanding of well behavior and the effect of strategies to the well performance.
This paper summarizes the reservoir management challenges, techniques and technologies applied to monitor and evaluate the reservoir performance and operating strategies.
How to Extend the Heptanes plus Fraction for Gas Condensate Systems for Use in Compositional Simulation
Authors: Hosein Raffie , McCain William D. , Jagai Tennyson 
Published: June 2014

Abstract
An accurate description of pseudo-component compositions and properties provides the heart of Equation of State predictions for gas condensate systems. Very often these extended experimental data are unavailable and are generated using mathematical relationships. The exponential and the three-parameter gamma distribution functions are the two most widely used models. Their development was based on the assumption of a continuous molar relationship for pseudo-components. However, experimental compositional data for gas condensate systems show discontinuities in this relationship at C8 and C13.
The above models when applied to extend the C7+ fraction under predict the C8 mole percent and over predict the C12 mole percent due to discontinuities in the molar relationship at C8 and C13. The Average Absolute Deviation between the predicted and experimental C8 and C12 data were both greater than 25 percent. The two coefficient method described by Ahmed et al., when applied, took care of the discontinuity at C8. The deviation was less than 10 percent. However the C12 fraction had a deviation greater than 25 percent. These results show that existing schemes were not designed to take care of these discontinuities and should be used with extended experimental data beyond C13 for a more accurate description of the pseudo-component composition.
The "Four Coefficient" model described in this study takes care of the discontinuities in the molar relationship at both C8 and C13. The Average Absolute Deviation between the predicted and experimental compositions is less than 12 percent. This model can be quite easily included in Equation of State packages for a more accurate description of compositions for gas condensate systems. A partial analysis beyond the C7 fraction is not required with this model.
Oil and Gas Expertise for Geothermal Exploitation: The Need for Technology Transfer
Authors: Falcone Gioia , Teodoriu Catalin 
Published: June 2014

Abstract
Renewable energy is seen as the future source to meet the world's growing demand, with geothermal resources offering a constant and independent supply.
Over the past century, the oil and gas sector has developed high level technologies for the exploitation of hydrocarbon reservoirs and this expertise should be directly transferrable to geothermal exploitation.
In contrast to hydrocarbon developments, geothermal projects typically only become economic after decades of operation, which implies a long period of debt service before costs can be recovered from the sale of energy in the form of heat, electricity or a combination of both. Thus, the technology transfer between the petroleum and geothermal sectors has not been as efficient as initially hoped for.
This paper begins with a review of the principles and uses of geothermal energy in today's sustainable energy scenario, from District Heating systems to the more recent Hot Dry Rock (HDR) concept. As exploiting HDR resources becomes more economic, the geothermal energy resources of countries like the U.S. could meet domestic demand for electricity for thousands of years. The challenges presented by HDR projects around the world are discussed, with a special focus on those aspects of geothermal exploitation that overlap with the oil and gas expertise, such as drilling and completions practices, the characterization of fluid flow through porous media and in wellbores and reservoir fracturing issues. The comparison shows how hydrocarbon exploration and production complements that of geothermal exploitation and identifies technical areas where future research efforts should be addressed to enhance the technology transfer between these energy sectors.
Impact of Multilateral Wells on Oil Recovery in an Oil Rim Field Development Using Multilateral Wells with Natural Gas Lift and Inflow Control Devices in a Fractured Carbonate Reservoir
Authors: Iyamu O. , Coll C. , Bouhafs C. , Butter M. , Bejaoui R. , King P. 
Published: June 2014

Abstract
Use of sector models with fine grids that preserve the boundary conditions of the full field model has been of particular benefit to studying well coning behaviour for the different well geometries while allowing detail studies of the physics of flow and to optimize production rate by different well designs.
The objective of this project was to carry out simulation studies to investigate the pattern of gas coning and water encroachment for a bilateral well with the primary aim of producing oil from a reservoir overlain by a large gas cap in Field A. High precision local refinement studies in the simulation model were undertaken to help place the wells and optimize the completion design at the same time capturing the global field behaviour. This methodology was also used to properly simulate multilateral wells containing inflow control devices, allowing for pressure losses along the wellbore to be equalized and to minimize gas and water coning.
Prior to undertaking the simulation studies, several sensitivities were carried out to determine how other parameters such as boundary conditions and grid refinements could affect the output of near well bore models. By taking advantage of the time savings resulting from the generation of reduced fine grid models, several simulations were run to investigate the impact of different well configurations and operations due for instance to close/opening of valves or laterals.
The simulation studies resulted in the determination of the pattern of gas coning, water encroachment, optimum vertical placement of the oil lateral and the orientation of the gas lateral as they affect total recovery. The use of Inflow Control Device (ICD) was determined to be of benefit especially in controlling water and gas influx while providing a uniform production profile along the wellbore that delay gas and water coning and this is being incorporated now in the plan of development.
Real-Time Water Detection and Flow Rate Tracking in Vertical and Deviated Intelligent Wells with Pressure sensors
Authors: Aggrey George , Davies David 
Published: June 2014

Abstract
Value addition via real-time reservoir monitoring and optimisation is one of the main drivers for the increasing implementation of intelligent (I-)well completions. The benefits from these more expensive completions will be realized through increased reserves generated by increased drainage efficiency and reduction in well numbers and intervention frequency. A more rigorous exploitation of the real time production data is necessary to fully achieve this objective.
We previously showed that water influx time and source could be detected in horizontal wells in real time1. Extension of this technique will be shown to allow confident detection of water influx in vertical or deviated, multi-zone and/or multi-lateral I-well completions. The source of water influx into the well and the zonal fluid contribution will be quantified, allowing this unwanted fluid's production to be reduced. Knowledge of the influx time and source permits both production optimisation and improved reservoir sweep efficiency; processes that increase the well's productive life and reserves.
It will be demonstrated that monitoring of the pressure drop, called dP trending in this paper, across multiple pressure sensors correctly located within a multi-zone vertical or deviated I-completion can identify the time and location of the water influx into the well. We will discuss the necessary conditions to ensure clear identification of these parameters.
The concept of "Normalised Pressure Drop Signatures" will be introduced. It has proven to be particularly valuable for water influx detection and zonal flow rate monitoring purposes. The concept will be tested with data generated from a synthetic model of a 4-zone, deviated, I-well completion and with real-field data from an instrumented North Sea well.