bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Simulation of the Impact of Flow-Induced Geomechanical Response on the Productivity of Stress-Sensitive Reservoirs
Authors: Osorio Jose G. , Chen Her-Yuan , Teufel Lawrence W. 
Published: December 2007

Abstract
Fluid production from oil/gas reservoirs perturbs the local stress state, both through variations in pore pressure and also changes in the local total stress. In stress sensitive reservoirs, these changes in the stress state cause deformation in the solid part of the rock which, in turn, affects the fluid-flow properties and, consequently, the reservoir productivity. Different reservoir conditions and production scenarios yield different degrees of reservoir productivity reduction. Therefore, a model that can be applied to study the effect of fluid flow/ deformation processes on the productivity of stress-sensitive reservoirs is essential for optimum reservoir management.
This paper presents a 3D finite difference, fully implicit model to simulate the physical phenomena occurring during the production from reservoirs with stress-sensitive mechanical and fluid-flow properties. The model considers two different physical domains: (i) an inner porous domain representing the reservoir, where fluid-flow and rock deformation occurs, and (ii) a surrounding domain representing the extended stress-disturbed region caused by the reservoir depletion. The inclusion of the surrounding domain leads to a more realistic modeling of the actual reservoir geomechanical boundary conditions. The reservoir is treated as a poro-elastic system consisting of a deforming solid skeleton and a moving compressible fluid. Nonlinear elastic deformation is assumed for both domains.
The model has been applied to illustrate the effect that rock deformation has on reservoir productivity. Results show that for stress-sensitive reservoirs, calculated flow rates obtained from conventional fluid-flow models can be significantly different from flow rates calculated from coupled fluid-flow/geomechanics models. Also, production rates calculated from fully coupled, single-domain models may differ from flow rates calculated from fully coupled, two-domain models.
Application of a New Two-Phase Upscaling Technique to Realistic Reservoir Cross Sections
Authors: Wallstrom T. C. , Hou S. , Christie M. A. , Durlofsky L. J. , Sharp D. H. 
Published: December 2007

Abstract
This paper describes further development and testing of the Renormalization and Nonuniform Coarsening (RNC) scale up algorithm, which was recently introduced in Ref. 13. RNC scale up combines nonuniform coarsening with upscaling of the absolute and relative permeabilities to provide coarsened descriptions of two-phase immiscible flow. We diagnose a known bias in the two-phase upscaling algorithm used in RNC. An unbiased alternative is introduced and incorporated into RNC scale up. The modified RNC scale up algorithm is tested on displacements through two dimensional cross sections with permeability and porosity data from conditioned reservoir simulations, and three dimensional linear and quarter-five-spot pattern displacements through computer generated permeability fields. Each reservoir description, measured or synthetic, contains highly heterogeneous and highly layered permeability fields. RNC scale up is used to coarsen these reservoir descriptions by a factor of 300 to 1000. The coarse grid oil cut curves show consistently close agreement with the fine grid curves in overall shape and in breakthrough time. The results are comparable to earlier results in Ref. 13 on displacements through synthetic two dimensional data.
The Development of Pseudo Functions for Gravity-Dominated Immiscible Gas Displacements
Authors: Darman N. H. , Sorbie K. S. , Pickup G. E. 
Published: December 2007

Abstract
In this paper, we investigate the use of pseudo functions in immiscible two phase displacements in oil-gas systems, where the effects of large mobility differences and gravitational forces are normally encountered. For this specific reason, a new pseudo-isation scheme known as the Transmissibility-Potential-Weighted (TPW) method has been developed and tested against several well-known pseudo methods such as the Kyte and Berry1, the Stone2 and the Vertical Equilibrium3 (VE) methods. Better performance relative to the other well-known pseudo methods was found especially in the gravity-dominated cases encountered in immiscible gas injection. This is shown for a wide range of cases. In addition, a detailed discussion on the limits and applicability of the VE method is also included.
Based on results from the TPW method, a new grid coarsening scheme for pseudo-isation has been developed and validated. This technique takes into account not only the static properties (i.e. permeability, porosity etc.) of the fine grid models, but also the dynamic properties of the fluid flow. The idea of this coarsening scheme is to identify regions (possibly layers) of the fine grid where there is low variability of gas saturation, and to take such regions as the corresponding coarse grid blocks. The measure of variability used is the coefficient of variation of the gas saturation. The resulting coarsening scheme may be non-uniform, but fulfils the purposes of using pseudo functions (i.e. to control numerical dispersion, to capture the effects of small scale heterogeneity, to reduce the number of grid blocks etc.) with less error and without any adjustment to the pseudo equations themselves.
Seamless or ERW for Sour Gas Service?
Authors: Mueller R.A. , Howden D.G. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Abstract
The shortage of seamless API standard 5L Grade B pipe, a preferred choice for sour gas service, is forcing consideration of ERW (electric resistance welded) pipe as a replacement. ERW welds, unless they are adequately post weld heat treated, can contain hard zones post weld heat treated, can contain hard zones that are susceptible to sulfide cracking. The use of metallurgical cross-sections and microhardness surveys as quality control tests are discussed as they apply to the ERW heat affected zone. The conclusion reached is that ERW pipe is satisfactory for sour gas service provided adequate quality control is maintained. provided adequate quality control is maintained

Introduction
Sour gas wellhead equipment and related gathering lines as found in East Texas, Mississippi, western Canada, and other locations are subject to failure by sulfide stress cracking mechanisms. The potential release of toxic hydrogen-sulfide gas to the atmosphere due to leaks is a major concern. Hydrogen sulfide can be fatal after a few breaths in concentrations as low as 0.1 percent. The safety record of the industry has been good, largely due to the prudent selection and quality control of both materials and fabrication techniques. Cities Service Co. has been conservative in this regard and currently specifies that only seamless API 5L Grade B pipe be used for gathering lines. Recently, seamless pipe has become more difficult to acquire with suitable delivery schedules; therefore, consideration was given to the use of electric resistance welded (ERW) pipe for sour service. pipe for sour service. Tuttle, in a paper describing selection of material for use in a sour gas environment, proposes a sound philosophy, "During engineering proposes a sound philosophy, "During engineering design, materials selection, quality control, and construction, the key issue should always be, is this item suitable for sour service? Economic considerations can be included only if this question can be answered 'Yes' on all items." Mr. Tuttle goes on to state, "Before new material is chosen for sour gas service, it should be fully tested in the laboratory and the hardness determined."
The preceding considerations become extremely pertinent, since ERW pipe is more economically attractive than seamless. Furthermore, the thinner walls available in ERW pipe permit a weight savings of steel and longer pipe permit a weight savings of steel and longer mill lengths, and require fewer field girth welds as compared with seamless. These two latter factors further increase the desire to use ERW pipe. The criterion is therefore one of suitability of ERW pipe for sour gas service, particularly as related to hardness level. particularly as related to hardness level.
Field-Scale Research on Intermittent Gas Lift
Authors: Hernandez Ali , Gasbarri Sandro , Machado Miguel , Marcano Luisana , Manzanilla Raul , Guevara Jose 
Published: December 2007

Abstract
Experiments on intermittent gas lift were conducted in a field scale test loop to measure: a) the effect of injection pressure, liquid column length, formation gas-liquid ratio, crude API and gas flow rate injected per cycle on the liquid fallback and b) the dynamic behavior of gas lift pilot valves.
The test loop used consisted of an 8,000-foot deep well with surface storage capacity of 3,000 Br of fluids, gas-liquid separators, surface pumps able to handle up to 12,000 Br of fluid per day, natural gas supply of 3 MMSCFD at 1,500 psig, surface and downhole pressure and temperature sensors, data acquisition system and surface control equipment.
The choice of liquid column length, gas injection pressure, size and type of pilot valves, point of injection depth and type of crude used were made based on a first set of limited tests performed at the same test site in 1996 and pressure and temperature surveys performed in more than 50 real wells in Lake Maracaibo in 1997. The survey procedure used for this work was such that the liquid fallback, along with an important number of other engineering parameters, could be obtained.
Injection pressures from 450 to 900 psi, and liquid columns from 200 to 800 ft were studied in the test loop. Two different types of crude's API were used to measure the effect of fluid viscosity on the liquid fallback for the first time. Different liquid column gradients were obtained for a particular type of crude by changing the amount of free gas present in the liquid column. In this way, the effect of the formation gas present in the liquid column on the fallback was also studied for the first time. The points of gas injection were located at 4,839 and 2,516 feet.
The dynamic behavior of both, spring loaded and nitrogen charged, gas lift pilot valves was studied using different port to bellow area ratios. As it was found in the first experimental work [1] conducted in 1996 for a limited set of conditions, the behavior of spring loaded and nitrogen charged gas lift pilot valves deviates from currently accepted theoretical behavior in opposite ways. The dynamic behavior of the gas lift pilot valves used is presented for a wide variety of operating conditions and a general analysis of the deviations found is discussed.
Predictive Models for Filter Cake Buildup and Filtrate Invasion with Non–Darcy Effects
Authors: Civan Faruk 
Published: December 2007

Abstract
Rapid filtration problems associated with the near-wellbore radial flow and near-fracture linear flow are modeled phenomenologically and the resulting equations of the models are solved numerically. The case studies presented demonstrate the effect of the non-Darcy flow on the filter cake thickness and filtrate volume for linear and radial filtration processes. The new models provide advantages over the previous models and provide better insights into the relevant filtration and filter cake formation processes.
Implementing Recirculation System ESPs in Gaines County, Texas
Authors: Knight J. W. , Bieschke T. M. 
Published: December 2007

Abstract
Design features and limitations, and operational successes and problems associated with converting selected wells in Gaines County, Texas, from rod pumps to electric submersible pump (ESP) recirculation systems which operate below the perforations are presented. Economic and operational justifications for making the conversions are addressed and limitations associated with the particular applications are discussed along with enhancements utilized in an attempt to increase run time.
The recirculation system and operational characteristics are described for two wells; one in 5½" casing and one in 7" casing, from variable speed drive (VSD) test through permanent installation. Field results indicate recirculation system ESP has increased oil production in the subject wells, with the potential to reduce downtime formerly associated with rod pumps and with shrouded motor ESP systems run below the perforations.
The field results provide additional case history to support the utility of below-the-perf operations with ESP recirculation systems to increase production in low bottomhole pressure wells, and to show the success of chemical treatments done in conjunction with submersible operations.
Applications of Diversion Techniques To Improve Gas Production in Naturally Fractured Carbonate Formations, Veracruz Field, Mexico
Authors: Perez D. R. , Huidobro E. , Navarrete R. C. , Rodriguez N. 
Published: December 2007

Abstract
One of the most challenging problems in stimulating multiple interval and open-hole wells is to effectively divert the acid among the intervals of interest. A new divergence technique is presented for acidizing open-hole and cased multiple interval wells of highly fractured carbonate formations with high permeability contrasts. The divergence technique uses a unique acid system, which forms a temporary barrier as it reacts with the carbonates of the formation.
Six field case histories from Veracruz, Mexico are presented, comprising open vertical and horizontal open-hole wells, and cased multiple-interval wells. The designs comprise simultaneous acid fracturing and matrix treatments of up to six intervals. The advantages of the new divergence technique with respect to conventional divergence techniques are demonstrated under challenging conditions, such as 2300 ft of open hole. The majority of the cases were traced with multiple radioactive isotopes to evaluate the effectiveness of the technique. The methodology, design and production were documented in each case.
Production Data Analysis and Forecasting Using a Comprehensive Analysis System
Authors: Poe B. D. , Zheng-Poe A. , Boney C. L. 
Published: December 2007

Abstract
Analysis of production data to obtain estimates of the intrinsic properties of a reservoir and of the current well condition can be performed using a number of available analysis procedures. Each of these analyses were developed using differing assumptions and often result in poor agreement between the parameter estimates obtained with each analysis when performed separately. A logical and comprehensive analysis system has been developed and used for field applications which enables the engineer to rapidly perform each of these production data analyses on the same set of production data and obtain a "best-indicated" set of parameter estimates of the reservoir and well properties. The analyses that can be performed on the production data include water control diagnostics, material balance analyses, empirical and advanced decline curve analyses using integral and derivative functions, automated history matching using analytic pressure or rate-transient solutions, and commingled reservoir production forecasting and economic evaluations. The systematic analysis of production data in this manner can be used to obtain estimates of the reservoir and well parameters for cases where other means of obtaining these values are often not available.
Artificial Neural Networks Identify Restimulation Candidates in the Red Oak Field
Authors: Shelley Robert F. 
Published: December 2007

Abstract
Existing wellbores represent a resource that must be properly managed for a maximum return on investment. Many of the initial completions on existing wellbores are, in some manner, deficient: stimulation is inadequate, wellbore communication with the reservoir has not been achieved, productive pay has not been included in the initial completion, or well mechanics are inadequate. Identifying restimulation candidates can be a time-consuming process because of limited personnel and resources, variability in reservoir quality, incomplete data in well files, and the lack of data for conventional wellassessment procedures. In this paper, we discuss how an artificial neural network (ANN) analysis of public information can help identify well restimulation candidates with the highest potential for production improvement.
The subject of this paper is an ANN analysis of Red Oak restimulations in Oklahoma's Latimer and Le Flore counties. Readily available and measurable well attributes were selected as inputs for ANN training. These inputs included geographical location, surface elevation, initial and current reservoir pressure estimates, perforation location, initial completion procedures, refracture procedures, current production, etc. Relevant conclusions and generalizations quantify the effect of these reservoir, well, and completion factors on the potential for production improvement. This paper documents the development of an ANN that predicted Red Oak postrecompletion production with an average absolute error less than 5% (an R2 of 0.99).
Fracturing Low-Permeability Formations in Gulf Coast Presents New Opportunities, Overlooked in the Past
Authors: Sagar Rajiv , Nemec Tom , Gray Larry , Opsal Steve , Mukherjee Hemanta , Dyson William , Morales Hugo 
Published: December 2007

Abstract
This paper presents a case study highlighting the process of selecting Gulf Coast of Mexico candidate wells for fracturing. The paper also describes the economical and logistical justifications used to design the most optimum fractures, the operational aspects of pumping the fracture treatment, and the pre and post fracture evaluation based on the production decline data.
In the Gulf Coast, low permeability and porosity reservoirs were routinely passed over as non-commercial. Recent advances in offshore frac-pack operations have created an abundance of equipment that make hydraulic fracture treatments feasible. The success of the fracture treatments is demonstrated in the Terrebonne (TB) 110 sand in the Caillou Island field.
Advances in Heavy Oil Lifting in the Morichal Area of Venezuela
Authors: Blann Jack R. , Garcia Roberto , Guaramata Francisco , Lozano Pilar 
Published: December 2007

Abstract
Although heavy oil has been produced in the Morichal area of Venezuela for over twenty-five years, significant advances have recently been made to improve performance of the heavy oil wells. These advances include new techniques for injecting a diesel diluent at the bottom of the well and further optimization of artificial lift systems. These new techniques have resulted in a significant increase in production over a short period of time with minimal outlay of resources.
The Role of Single Point Moors in the North Sea
Authors: Lenihan Jeremiah E. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Abstract
Cost effective Single Point Moors in the North Sea will require superior performance and outstanding reliability. Based on system requirements and environmental conditions major design considerations are developed. The articulated spar platform selected for the Beryl Field following these considerations is briefly described. The Single Point Moor as a component in a simplified marine transportation system is discussed and SPM performance for an assumed North Sea oil field is estimated by computer simulation. Possible development trends are pointed out.

Introduction
Throughout the last 15 years the Single Buoy Moor (SBM) has served the oil industry well and has added an improved capability in transporting crude oil and petroleum products. After some initial reluctance, the concept of tanker loading and unloading operations in waters through the use of a single mooring point has been accepted as commonplace. At the end of 1974 some 165 SBM installations had been installed or planned in widely scattered locations throughout the globe. From a single starting base the industry has developed a range of designs to cover more demanding applications and the more inclusive name of Single Point Moor (SPM) has evolved to embrace all designs of this kind.
Notwithstanding past successes, the extension of SPMs and tanker loading operations into the reaches of the North Sea brings forth a new frontier. There is a new challenge made up of functional importance, environmental severity, technological difficulty, and the ubiquitous element of costs. Naturally the experience of the last two decades will propel the efforts for the North Sea and similar areas, but the oil industry must grow from past SPM successes and not be captives of them. To highlight the SPM problem in the North Sea it is well to review the nature of the problem particularly in reference to past SPM particularly in reference to past SPM experience.
Sound Basis for North Sea Platforms - Programming of Essential Geotechnical Surveys
Authors: Krause E.R. , Mosch H.J.M. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Abstract
This paper describes the general considerations underlying the planning of geotechnical investigations for offshore oil and gas platforms.
The investigations are split into three phases. The first phase consists of a site selection survey; the second phase deals with detailed surveys at specific sites, and the third phase includes laboratory testing, foundation analysis, construction planning and foundation evaluation. Details are given of the scope of the investigations and the equipment which can be used.

Introduction
oil companies, developing offshore hydrocarbon fields are bound to time frames. As far as the geotechnical consultant is concerned, these schedules run from the first commercially exploitable strike through the phase of final design to the installation and subsequent operation of the offshore facilities. The consulting geotechnical surveyor must meet the target dates set by the oil companies, so that sufficient information is available first when decisions on the number, type and lay-out of structures have to be made and later during the design and construction phases.

THE PROCESS OF PLANNING AND DESIGN OF OIL/GAS FACILITIES
Reservoir engineers and civil engineers jointly consider the layout, number and type of the production facilities. This takes production facilities. This takes place in stages in the period between place in stages in the period between the first commercial exploitable strike, the sinking of additional step-out wells and the consequential reservoir evaluation. As more information becomes available, the civil engineer can consider alternatives as to the most suitable sites, within the leeway given by the reservoir engineer, and the types of structures. The final lay-out and choice of the structures will be a compromise between both civil and reservoir engineering requirements. Once this has been completed, the final design work can start.