bluuebunny/crossref_metadata_2025_split huggingface dataset:
Openhole Stability and Solids Production Simulation in Emerging Reservoir Shale Using Transversely Isotropic Thick Wall Cylinders
Authors: Hoang Son K. , Abousleiman Younane N. , Ewy Russell T. 
Published: October 2009

Abstract
Even with the emerging gas and oil shale plays, little laboratory data exists for the simulation of openhole completion and production accounting for the inherent anisotropy of shale. Contrary to the success of the thick wall cylinder test in simulating openhole production stability and/or solids production in sandstone and carbonate formations, the application and modeling of this test in shale, while subjecting the sample to in-situ openhole conditions, presents considerably greater complexity. Shale in general possesses anisotropic mechanical material properties that will alter the stress distribution around an open hole. Moreover, time-dependent pore pressure and permeability effects will modify the effective stresses and can cause delayed formation failure. In this study, the response of anisotropic hollow cylindrical shale samples under laboratory time-dependent loading, simulating near-wellbore production stresses, is investigated under the realm of coupled fluid and shale matrix interaction to address these challenging issues. Experimental results on thick wall cylinder testing of an anisotropic and low permeability shale were analyzed using the developed physical and mathematical model. The results showed that significant pore pressure could be generated and sustained in even small shale specimens (3.81 cm outer diameter and 1.27 cm inner diameter), depending on shale anisotropic properties, permeability, and loading rate, and cannot be ignored when the collapse strength from thick wall cylinder tests is interpreted for field conditions. Furthermore, commonly employed elasticity analyses for the thick wall cylinder test fail to account for the coupled fluid and shale matrix interaction under time-dependent loading condition and produce oversimplified and inaccurate results for not only the effective stress distribution but also failure analysis. The new modeling, therefore, will be essential for designing, simulating, and interpreting laboratory thick wall cylinder tests on shales as well as the subsequent modeling of sustainable gas and oil production from these formations.
Real Time Decision Support in Drilling Operations Using Bayesian Decision Networks
Authors: Rajaieyamchee Mohamad A. , Bratvold Reidar B. 
Published: October 2009

Abstract
Today's decision makers in the petroleum industry have access to remarkable new technologies, huge amounts of information to help them make high-quality decisions, and the ability to share information at unprecedented speeds and quantities. A central hypothesis in the concept of digital oil field is that these tools and resources should lead to better decisions. Yet, the tools bring with them daunting new problems: the available data, though massive, are uncertain and often incomplete, unreliable, or distributed; interoperating/distributed decision makers and decision-making devices need to be coordinated; and many sources of data need to be fused to yield a good decision.
In this paper, we shall illustrate the use of influence diagrams, also known as Bayesian Decision Networks, to frame, analyze, and support real-time drilling decisions. Influence diagrams provide compact graphical representational and computational frameworks that are based on rigorous probability theory. They consist of a framing part, which encodes the decision basis elements along with their interrelationships, and a probabilistic part, which uses conditional probability distributions to quantify the strengths of the relationships.
Following a systematic decision analytic framework, particularly the decision analysis cycle, we developed influence diagram models for drilling operational decision situations. Also, an object-oriented influence diagram is built and tested for a real world casing setting decision situation. The influence diagram models are updated with the arrival of new data to reflect the current state of knowledge about the decision situation.
The study shows that influence diagrams are well-suited and efficient decision analysis tools for real-time support of the large and complex drilling decisions in which uncertainty is predominant.
The Growing Importance of Petroleum Reserves Estimating and Auditing Standards
Authors: Harrell D. Ronald 
Published: October 2009

Abstract
The most recent version of the "Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information" (the Standards) was approved by the SPE Board contemporaneously with the release of the March 2007 SPE/WPC/AAPG/SPEE Petroleum Resources Management System (PRMS). This represents the first significant revision of the Standards since their issuance by SPE in 1977. A few minor changes were made to the Standards in 2001 but only as necessary to achieve conformance with the 1997 SPE/WPC Reserves Definitions. The 2007 Standards incorporate revisions targeted to elevate the qualifications of evaluators and auditors along with clarifying several previously undefined terms and conditions. A copy can be obtained through www.spe.org.
Conditioning on Effective Permeabilities from Well Tests in Geostatistical Reservoir Characterization: Real Test Case Evaluation
Authors: Skorstad A. , Islam M. A. , Smørgrav E. 
Published: October 2009

Abstract
The effect of including permeabilities obtained from well tests in geomodeling of permeability and porosity fields is tested on real data from the Heidrun reservoir in the Norwegian Sea. Dynamic data are integrated into the reservoir description on a geologically detailed resolution by handling well log data and well test data in the same manner. The test shows that both the predictive power of the reservoir model in terms of history match and the local inflow probed by Production Logging Tool (PLT) data are improved.
Effective permeabilities derived from PLT data will hereon be denoted well test data. The conditioning method uses an inverse block co-kriging of both log and well test data, and a Fast Fourier Transform to speed up the calculations. Well log data and well test data are observations on different length scales. In order to condition geological models on an intermediate resolution, the data must be associated with an uncertainty. This uncertainty is estimated from the data.
The test is performed on the Ile formation of the Heidrun reservoir. Well log permeabilities and porosities from 26 wells are available in the studied area, and three wells also contain well test data. The mismatch between the responses from flow simulations of the geostatistical realizations and the real dynamic data is reduced compared to the flow simulations from a benchmark suite of geostatistical realization without the well test conditioning; obtaining an improved reservoir characterization. A detailed comparison of measured PLT data with the simulated well inflow of the three wells containing well test data shows that the local subzone inflow is significantly improved by accounting also for the well test data in the geostatistical reservoir characterization. The inflow match is improved in 83% of the investigated subzones. In particular, the largest improvement is found in the least permeable zone where the deviances from the true to the calculated inflow were on average only 17% of that from the benchmark case.
The paper presents a general methodology for including effective permeabilities from well tests when modeling petrophysical fields. Using real data, we demonstrate that the proposed methodology can be successfully used in direct conditioning of geological realizations. Thereby, both improved detailed geological models and better forecasting from coarser flow simulation models can be obtained.
Catenary Well Profiles for Extended and Ultra-Extended Reach Wells
Authors: Liu Xiushan , Samuel Robello 
Published: October 2009

Abstract
Extended-reach drilling (ERD) technology has rapidly developed during the past two decades and the drilling of ultraextended-reach (u-ERD) wells to extend their reach to greater depths requires improved models. Wellbore friction is an important issue for ultra-long wells, and optimizing the well path design is an effective means of reducing torque and drag.
This paper presents the dimensionless mathematical model and provides a new method for planning a catenary well profile. The new mathematical model of a catenary well path does not involve hyperbolic functions and uses an exact mathematical solution. The method of explicit solution avoids a trial-and-error procedure and provides excellent maneuverability of planning requirements.
Conversely, bit-walk is a natural tendency of the drill bit to drift sideways while drilling. To reduce azimuth correction frequencies and wellbore tortuosity, effective well path planning and design should account for bit-walk effects. This paper presents a newly developed a 3D mathematical model of the catenary well path and the method for planning bit-walk catenary paths to fit the bit-walk rate by a given rock layer. This paper analyzes the compositive relation of inclination units and azimuth units, provides a method to divide the catenary well profile into many shorter intervals for calculation, discusses the characteristics of planning bit-walk paths, and presents the constraint equations and solutions for ERD wells.
The results show that the essential elements of planning a 2D or 3D catenary profile include determining the position of the catenary section, parameters, such as starting and ending inclinations, and length of the succeeding hold-up section. The model and methods provided use an exact mathematical solution and results. The planned catenary well path completely fits the predetermined bit-walk rates and is absolutely smooth from the wellhead to the given target.
MEOR Success in Southern Saskatchewan
Authors: Town K. , Sheehy A. J. , Govreau B. R. 
Published: October 2009

ABSTRACT
A Microbial Enhanced Oil Recovery (MEOR) Process was successfully applied in a mature waterflooded reservoir in Saskatchewan, Canada. A nutrient solution, which was designed specifically for this reservoir to stimulate certain indigenous microbes to grow, multiply and help to release oil was tested and piloted. A significant decrease in water cut and increase in oil production has been realized through the selective stimulation of bacteria using nutrient injection.
The field is a mature waterflood averaging over 95% water cut. To combat the increasing water cut issue an In-Situ Microbial Response Analysis (ISMRA) was performed on a typical high water cut producer in the area. The test well was treated with a nutrient solution and then shut-in for a number of days to allow specific indigenous microbes to grow and multiply. Upon return to production the well produced at an average of 200% more oil with a 10% decrease in water cut for a year. Pretreatment rates averaged 1.2 m3/day oil and post-ISMRA treatment daily production peaked at 4.1 m3/day oil.
As a result of the successful test, a pilot project was initiated and the nutrients were applied in three batch treatments on an injector with three offset production wells. Three weeks after the first batch treatment, a water cut decrease was seen at one of the offset producers. This well's oil production gradually increased from 1.4 to over 8 m3/day. Oil production in another producer doubled from 1.5 to over 3.0 m3/day. Subsequent treatments were tried on marginally economic wells and on a reactivated idle producer. The average decrease in water cut on these wells was over 10%. On the idle well oil production increased from 0.5 m3/day pre-treatment to an average of 3.0 m3/day post treatment.
Throughout the world there remains a huge target for EOR processes to target. This successful MEOR application will have tremendous impact on ultimate recovery in many of these reservoirs not only through an increase in production, but a decrease in operating costs through associated reduction in lifting costs with less water production.
WITSML "Comes of Age" for the Global Drilling & Completions Industry
Authors: Pickering J. G. , Kreijger J. , Grøvik L. O. , Franssens D. , Deeks N. R. , Doniger A. , Schey J. 
Published: October 2009

Abstract
The development of WITSML started in 2000 with the objective of building an XML standard for the transmission of wellsite data in a consistent form that would enable the integration of information from different suppliers. Energistics (formerly POSC) was involved from the outset and has provided independent hosting of the standard since early 2003. BP and Statoil were early sponsors and a Special Interest Group was formed. This has evolved steadily and today it includes representatives from all major energy and service companies.
Most energy companies have now either implemented WITSML technology for real-time and historical wellsite data transmission or are planning to do so in the near future. The number of WITSML compliant products is growing rapidly in response to this demand and increasingly WITSML is being specified as a contractual requirement, particularly at green field sites. The industry is approaching a position where the non-use of WITSML will be by exception.
This paper has two main areas of focus. The first is the technical delivery of the new version 1.4.0 WITSML release and the second is the business justification for the continued energy company uptake which is based on successful use cases. The paper is co-authored by members of the WITSML SIG and therefore contains detailed information from end users and suppliers with considerable working experience.
More than ever there are now compelling reasons to deploy WITSML. It is an enabler for data integration and smart tools and is the underlying technology behind many drilling collaboration centres. It is helping drilling operations globally to benefit from better access to engineering expertise at a time when the number of experts is declining and the complexity of operations is increasing.
Permeability Variations in an Upper Freeport Coal Core Due to Changes in Effective Stress and Sorption
Authors: Jikich Sinisha A. , McLendon T. Robert , Smith Duane H. 
Published: October 2009

Abstract
Permeability is a key property for injectivity of carbon dioxide in enhanced coalbed methane/carbon sequestration projects. In addition to cleat spacing and connectivity, permeability is affected by the in situ stresses, the geomechanical properties (Young's modulus, Poisson's ratio) of the coal, the amounts and compositions of the fluids (e.g., CH4, CO2) sorbed by the coal matrix, and the dependence of the matrix swelling on the amounts and compositions of the sorbed fluids.
In this paper, we have tested bituminous coal coal cores from the Upper Freeport formation, Marshall County, West Virginia in the Appalachian Basin. This coal has generated considerable interest, because of a current industry/DOE/NETL sponsored project to inject carbon dioxide into this seam for the purpose of developing and testing carbon sequestration.
The cores were tested in a composite core holder allowing hydrostatic confinement and X-ray computerized tomography (CT). Permeabilities for helium, methane, and carbon dioxide were measured using a conventional method of simultaneous pressure-drop and flow-rate measurements. Compressibility and carbon dioxide sorption of the sample were calculated from CT measurements of density variations in the core.
Permeability was reduced considerably by increases of effective stresses in the coal, and by sorption of carbon dioxide in the coal. Due to the heterogeneous nature of the coal, its sorption and elastic properties varied greatly among different locations within the core. As a corollary, samples from the same well and coal seam may show large variations in methane content, carbon dioxide storage capacity, permeability, and mechanical properties.
Unique String Tools Combine to Save Over USD 11 Million in Challenging Hole Opening Rotary-Steerable Applications
Authors: Barton Steve , Garcia Alexis , Luther Charles , Noriega Ivan , Cordova Adrian , Aguilar Rafael 
Published: October 2009

Abstract
The May field in Offshore Mexico is difficult to drill due to the presence of boulders and conglomerates within the top hole section. The interval is traditionally drilled with a conventional 18 1/2" bit and BHA. However, an enlarged hole is planned as contingency to provide an improved cement bond with the casing utilized. Due to casing drift, this requires the use of hole opening string tools to provide a final hole diameter of 21".
Prior hole opening runs have endured significant vibration and resultant mechanical damage to the tools and pilot bits. An offset well utilized commercial concentric hole opening tools that have cutter blocks that can be activated and retracted so that it can be pulled back through the casing. The hole opening section required a total of eight string reamer tools and three 18 1/2" pilot bits to reach TD.
A unique eccentric string reamer tool was selected that utilizes a mid-reamer section for improved string stabilization and hole enlargement. This was coupled with an eccentric vibration dampening tool, specifically positioned in the string to disturb damaging vibration harmonics. In order to refine parameter recommendations, Finite Element Analysis Software was utilized to model the harmonic behavior of the drill string. This assembly, combined with a point-the-bit rotary steerable tool drilled this challenging hole section in 9 days, delivering low vibrations and gauge hole. An estimated $4.4 M was saved compared to the original well plan and $11.5 million compared to the direct offset well for this interval.
Development and Application of a New Well Pattern Optimization Algorithm for Optimizing Large-Scale Field Development
Authors: Onwunalu J. E. , Durlofsky L. J. 
Published: October 2009

Abstract
The optimization of large-scale field development is challenging because the number of optimization variables can become excessive. A way to circumvent this difficulty is to constrain wells to exist within patterns and to then optimize parameters associated with the pattern type and geometry. In this paper, we introduce a general framework for accomplishing this type of optimization. The overall procedure, which we refer to as well pattern optimization (WPO), entails a new well pattern description (WPD) incorporated into an underlying optimization method. The WPD encodes potential solutions in terms of pattern types (e.g., five-spot, nine-spot) and pattern operators. The operators define geometric transformations (e.g., stretching, rotating) quantified by appropriate sets of parameters. It is the parameters that specify the well patterns and the pattern operators, along with additional variables that define the sequence of operations, that are optimized by WPO. The well pattern description developed here could be used with a variety of underlying optimization methods. Here we combine it with a particle swarm optimization (PSO) technique, as PSO methods have recently been shown to provide robust and efficient optimizations for well placement problems.
Detailed optimization results are presented for three different example cases using several variants of the WPO algorithm. In one case, multiple reservoir models are considered to account for geological uncertainty. For all examples, significant improvement in the objective function is observed as the algorithm proceeds, particularly at early iterations. A two-stage optimization procedure, in which the first-stage optimization considers multiple well pattern types while the second stage focuses on the most promising pattern, is applied and shown to be effective. Limited comparisons with results using standard well patterns of various sizes demonstrate that the net present values achieved by the WPO algorithm are considerably greater. Taken in total, the optimization results highlight the potential of the WPO procedure for use in practical field development.
Modeling Analysis of Sand-Screen Collapse Resistance Under Geotectonic Load
Authors: Fuh Giin-Fa , Morita Nobuo , Furui Kenji 
Published: October 2009

Abstract
The manufacturer's specifications of sand screen usually provide information such as base pipe collapse pressure, maximum tensile load, and bending strength. However, the problem is that a very heavy base pipe is thus required to satisfy such specifications if the pipe collapse pressure indicated by manufacturer is used for field application. The reason is that the screen collapse tests are conducted under hydrostatic loading for screens wrapped with rubber jacket by screen manufacturers. Observation of these tests shows that screen collapse occurs immediately after the base pipe starts yielding. However, this is not the case if screens are installed in the wellbore under geotectonic load. A series of laboratory tests are conducted using either straight pipes without screen or pipes with screen installed in a drilled borehole of some large rock sample. Since the base pipe failure is the dominant factor for screen failure, half of the experiments shown in this paper used straight pipe without including screen or shroud. These tests show that tubular strings may initiate yielding earlier than the specified yielding data provided by screen manufacturers. However, after the initial yielding, the base pipe deforms gradually and it never collapses even after exceeding the ordinary base pipe yielding (0.2-0.4% deformational strain) by more than 10 times.
Based on these laboratory tests, a numerical model is constructed for screen design along with gravel pack or standalone screen in openhole completions. The numerical model first simulates hydrostatic screen collapse tests conducted by manufacturers to confirm the design specifications as measured. Then, it is extended to simulate screen behavior after it is installed downhole. It assumes that a screen is placed in the borehole, and then gravel-pack covers the screen, followed by reservoir depletion and drawdown in production mode.
This paper sheds light on the sand screen collapse resistance under three typical loading types: hydrostatic, geotechtonic load without void around sand screen and geotectonic load with void for openhole standalone screen applications. Distinctly different failure scriteria are proposed for these three types of loadings. Empirical data undedr such high stress levels are rarely found in the literatures.
Digital Oilfield Projects: A Perspective Using Examples From Reservoir and Reserves Management
Authors: Lasrado Vineet 
Published: October 2009

Abstract
Digital Oilfield programs are underway in many oil and gas companies. The term ‘Digital Oilfield’ covers a wide range of areas from the usage of smart downhole sensors to the integration and transformation of data across technical and business applications for decision making in the oilfield. Ultimately the decisions made at the operational level affect the company's performance and hence Digital oilfield projects are connected with the decision making at different levels in the company.
This paper analyzes different types of digital oilfield projects from the literature and draws upon the authors experience to create a perspective based on the common requirements of such projects. Such a perspective should help reducing silos within organization often looking at their own data and work processes. Examples from the area of Real-time Reservoir management and Reserves management will be analyzed by going into the details of the common elements across these areas in terms of process and data requirements, data standards and components of the work processes. By understanding the common requirements organizations can lower cost in terms of reuse and deployment of the solutions across the company.
This paper will help engineers understanding of digital oilfield projects and assist in increasing the uptake of such projects within their organization.