bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Interpretation of Reservoir Architecture and Fluid Contacts through the Integration of Downhole Fluid Analysis with Geochemical and Mud Gas Analyses
Authors: Dong Chengli , Elshahawi Hani , Mullins Oliver C. , Venkataramanan Lalitha , Hows Melton , McKinney Daniel , Flannery Matthew , Hashem Mohammed 
Published: December 2007

Abstract
Understanding reservoir architecture is critically important to effective reservoir management. Misinterpreting reservoir compartmentalization, for instance, can result in non-optimal well placement, completion strategy, and facilities design as well as large errors in reserves, drainage volume and production rate predictions. Downhole fluid analysis along with complementary techniques including geochemical, mud-gas and pressure analyses provide valuable insights into reservoir architecture. Each analytic method relies on different fluid traits and has its own limitations. With systematic integration of different methods, the synergy delivers a more accurate characterization of the reservoir.
In this paper, we link traditional and novel fluid analysis methods to build a more complete interpretation of the reservoir fluids and provide greater insight into reservoir architecture. This leads to improved understanding of structural history, hydrocarbon migration and entrapment, reservoir connectivity, and fluid contact levels. This, in turn, enables better well placement and more effective development planning. We highlight three case studies in which we have successfully combined various fluid-based techniques for improved reservoir characterization.
Completion Design for a Highly Compacting Deepwater Field
Authors: Procyk Alexander D. , Jamieson David P. , Miller Joe A. , Burton Robert C. , Hodge Richard M. , Morita Nobuo 
Published: December 2007

Abstract
The Magnolia field, located in the deepwater region of the Gulf of Mexico, produces oil and gas from a TLP in 4673’ of water. The reservoirs comprise several stacked sandstone intervals within the early to mid Pleistocene with some minor production from the Miocene and Pliocene sands. A total of 8 wells have been completed, with the majority of the production from the B25 sandstone. The formation particle size is fine-grained sand to coarse silt and has relatively low K*H compared to other deepwater reservoirs. The reservoirs are significantly overpressured, highly compartmentalized, highly compacting and have experienced significant pressure declines in excess of 8000 psi in some cases during production.
The wells were completed with cased hole frac packs and each completion included a permanent downhole gauge, enabling interpretation of the K*H and skin throughout the producing history of the wells to date. The perforating guns, frac fluids and screens were extensively tested prior to completion. The perforation shot size and density was carefully chosen and tested to achieve the required production. Well test results matched inflow analysis predictions. The initial skin values generally met expectations and improved during production due to a combination of well clean-up and reduced reservoir permeability from compaction. Proppant integrity has been maintained under extreme depletion (&gt;8000 psi) conditions. Productivity was measured using perforation tunnel permeability (Kpt) analysis. The Kpt values were analyzed over the course of production and compared to similar type completions. The Kpt benchmark analysis shows that the completions are among the best in class. Well productivity has met or above expectations, and the longevity has exceeded expectations in most cases.
Peace River Carmon Creek Project—Optimization of Cyclic Steam Stimulation Through Experimental Design
Authors: Koci Paul Frantisek , Mohiddin Junaid Ghulam 
Published: December 2007

Abstract
Peace River Carmon Creek is a 100% Shell owned ultra-heavy oil lease located in north-western Alberta, Canada, approximately 700 km northwest of Edmonton (Fig. 1). It holds nearly eight billion barrels of 7°API oil in place, spread over 370 km2. The Carmon Creek Project targets possibly about half of that oil for development by cyclic steam stimulation (CSS). There are growth plans for a significant increase in oil production over the next five years.
The purpose of this study was to optimize CSS well configuration and steaming strategy for each distinct reservoir area by deploying previously improved and history matched simulation models1.
A full field static model was built, comprising over 400 wells. More detailed static sector models were also built for each distinct geological area and translated into elements of symmetry thermal simulation models.
The choice of design parameters and handling of uncertainties were addressed in a phased manner. First, the smallest possible element of symmetry simulation model and the most efficient discrete fracture realization were determined. The next phase involved optimization of the well configuration and steaming strategy for each field area (based on approximate Net Present Value, NPV). The final phase entailed uncertainty analysis for the optimized design concepts and determining P15, P50, and P85 forecasts for each area. Experimental Design and Monte Carlo simulations were applied to further reduce the runs required for each phase.
Although different optimum CSS designs were determined for each geological area, the modeling results can be generalized as follows:
Horizontal well near the base of the reservoir is the optimum well type for CSS at Peace River. Well spacing less than 75 meters appears more attractive in the higher reservoir quality areas compared to the current assumption of 150 meters.
In summary, a series of predictive CSS simulation models, primarily for horizontal wells, have been developed. Heavily aided by experimental design, a unique phased modeling workflow was applied to optimize well design and steaming strategy. Some of the suggested design components are already being tested at Peace River.
Beyond Decline Curves: Life-Cycle Reserves Appraisal Using an Integrated Work-Flow Process for Tight Gas Sands
Authors: Rushing J. A. , Newsham K. E. , Perego A. D. , Comisky J. T. , Blasingame T. A. 
Published: December 2007

AbstractDecline curve analysis is often either the only or the primary tool used for reserve evaluations in tight gas sands. However, the flow and storage properties characteristic of low-permeability sands often preclude accurate assessments using only or primarily decline curve analysis, especially early in the productive life. The most accurate reserve estimates incorporate multiple data sources and the appropriate evaluation techniques. Therefore, this paper presents a reserves appraisal work-flow process that complements traditional decline curve analyses with comprehensive and systematic data acquisition and evaluation programs that integrate both static and dynamic data.Our approach—which has been developed specifically to incorporate the production characteristics of tight gas sands— is an adaptive process that allows continuous but reasonable reserve adjustments over the entire field development and production life cycle. Implementing this process will prevent unrealistic (either too low or high) reserve bookings. Although it is applicable during any field development phase, our work-flow process is most beneficial during early stages before true boundary-dominated flow conditions have been reached and when reserve evaluation errors are most likely.
Innovative Method for Predicting Downhole Pressures During Frac-Pack Pumping Operations Facilitates More Successful Completions
Authors: Jannise Richard C. , Edwards William J. 
Published: December 2007

Abstract
Pressure limitations often prohibit engineers from placing frac-pack sand-control treatments where they are needed the most because of the collapse ratings of the bottomhole assembly equipment. Often, these pressure limitations lead to early abandonment of the well, or they create problems later in the life of the well, because they do not allow for effective sand-control, which inevitably will have a negative impact on well economics. A new method, dynamic pMAX, used to determine the amount of pressure exerted on the bottomhole tools during the sand-control treatment, enables frac-pack treatments that the industry once would have considered impossible to achieve.
An Experimental Study of Hole Cleaning Under Simulated Downhole Conditions
Authors: Yu Mengjiao , Takach Nicholas E. , Nakamura David R. , Shariff Maher M. 
Published: December 2007

Abstract
With increasing measured depths and horizontal displacements in extended-reach, high-angle wells, hole cleaning remains one of the major factors affecting cost, time and quality of directional, horizontal, extended reach, and multilateral oil/gas wells. This study involves experimental research and theoretical analysis to enhance cuttings transport capacity in oil and gas well drilling operations. The effects of drilling fluid rheology, mud density, temperature, borehole inclination, pipe rotation, eccentricity, rate of penetration (ROP) and flow rates were investigated experimentally. Volumetric cuttings concentration in the test section and frictional pressure losses were measured during the tests using two nuclear densitometers and a differential pressure transducer.
A total of 116 experiments were conducted on a full-scale, High-Pressure High-Temperature Flow Loop (57.4-feet long, 5.76" x 3.5" annular section) at The University of Tulsa under controlled experimental conditions (up to 200°F and 2000 psi). Experimental results show that drillpipe rotation, temperature and rheological parameters of the drilling fluids have significant effects on cuttings transport efficiency. A dimensional analysis was conducted in this study to develop correlations that can be used for field applications. A user-friendly simulator was developed based on the results of the dimensional analysis and correlations. This simulator can be used by drilling engineers for design and sensitivity study. Results from this study can be used to determine critical conditions for efficient hole cleaning, as well as to optimize the mud program during the planning and operational phases of drilling.
An Integrated Study of Low Permeability Reservoir in the Bekasap Field, Central Sumatra Basin, Indonesia
Authors: Pramudyo Yuni B. , Hendar S. M. , Nur Hasyim M. , Reinhold Mark R. , Jacobs Garry W. 
Published: December 2007

Abstract
An integrated geological study has been performed for a large, mature field at the Bekasap and Menggala formation. The primary goal of the study was to developed an integrated reservoir description for targeted infill drilling and improve recovery in a low-permeability reservoir. Integration of geological and petrophysical studies and reservoir performance analysis provided a rapid and effective method for developing a comprehensive reservoir description.
A 3D geocelluar model of reservoir architecture and properties distribution was made and used as a guide to further development. This model delineates distinct trends of estuarine, sand ridge, and margin facies throughout the field that reflect paleogeography. Additionally, reservoir properties and saturations were geostatistically populated within the model.
Horizontal wells were chosen as the preferred alternative to provide maximum exposure of reservoir layers and improve production and ultimate recovery compared to conventional vertical wells or frac jobs. Thirty one (31) horizontal wells were drilled in the Bekasap field, and this program was very successful and predicted ultimate recovery has improved from 14% to 28%.
The study of this low permeability reservoir in the Bekasap field is an excellent opportunity to: (1) demonstrate the economic importance of this zones, (2) understand the methodologies required for identifying and evaluating these pay types, and (3) help the company to find additional reserves in the Central Sumatra Basin.
Constant Reservoir Evaluation Through Real-Time Data as a Service
Authors: Mezzatesta A. G. , Shaw D. C. , Webb S. J. 
Published: December 2007

Abstract
Many sensors and devices in the field are now available to the reservoir manager for on-line surveillance and monitoring of his assets. Recently, systems typically termed "Intelligent/Smart Fields", "e-Fields" or "Fields of the Future" have begun to communicate this field data and information directly to his desk. However, the industry still finds itself faced with the challenge of transforming all this raw streaming data into useful information.
A multitude of potential applications for real-time field data has become apparent. At short periods, it is already widely used to identify anomalies and provide alarms in the classical Field Automation sense. At medium-long term, however, data ought to be used to identify well and reservoir pressure and flow signatures that help in Formation Evaluation, and for reservoir management and planning through the use of flow simulation and automated history matching.
However, rarely is data exploited effectively even at the short timeframes, and hardly ever at the medium and long term. This is largely because the analysis involved - which includes highly technical disciplines - simply cannot be automated by computer. This paper examines how our next big challenge in the Field of the Future will be the ability to streamline these engineering activities and to be able to deliver the associated analysis as a turnkey service to the Field Operator. In particular, it may be that the delivery of this key reservoir knowledge, given the current staff structure of the industry, will only be practical using a third-party service provider approach.
Development of a Coupled Geomechanics Model for a Parallel Compositional Reservoir Simulator
Authors: Pan Feng , Sepehmoori Kamy , Chin L. Y. 
Published: December 2007

Abstract
This paper presents a coupled geomechanics and compositional model and applies it to the oil and gas recovery process. An equation of state compositional simulator called the General Purpose Adaptive Simulator (GPAS), developed at the University of Texas at Austin, which uses a finite difference method for the solution of its governing partial differential equations (PDEs), is iteratively coupled with a geomechanics model that is developed using a finite element method in this research. An elastic constitutive model is applied to represent deformation behaviors of rocks in the geomechanics model. Porosity is selected as the coupling parameter between two coupled models. The unknowns located on nodes and block-centers in the two models are evaluated using an area weighting technique
The proposed model has been implemented on the Linux PC clusters for solving 2D compositional reservoir problems considering geomechanics effects. These results indicate that the geomechanics-coupled compositional reservoir simulator developed in this study can be used to complete simulations for stress-dependent or stress-sensitive reservoirs.
A New Azimuthal Deep-Reading Resistivity Tool for Geosteering and Advanced Formation Evaluation
Authors: Bittar M. , Klein J. , Beste R. , Hu G. , Wu M. , Pitcher J. , Golla C. , Althoff G. , Sitka M. , Minosyam V. , Paulk M. 
Published: December 2007

Abstract
Drilling services and oil companies have long been interested in acquiring the capability of landing a well accurately in a hydrocarbon reservoir and remaining in it for optimal drainage. Although traditional logging-while-drilling (LWD) propagation resistivity tools can help to achieve this goal, their overall effectiveness is not satisfactory because they lack azimuthal sensitivity. Ideally, geosteering and advanced formation evaluations, such as anisotropy calculations, require azimuthally sensitive measurements.
This paper discusses a newly developed propagation resistivity tool that is designed to be azimuthally sensitive for use in geosteering and formation evaluation while drilling. It uses the tilted antenna concept to produce directionally sensitive measurements that are lacking in traditional LWD propagation tools. This paper also discusses the theory and the development of this tool, as well as the experimentation and numerical modeling data used to characterize its azimuthal capability. Advanced application algorithms used to calculate the horizontal and the vertical resistivity (anisotropy calculation), as well as dipping angle will be explained in detail. Finally, the paper presents and discusses field examples to demonstrate that this newly developed tool is a two-in-one service: geosteering and advanced formation evaluation.
The azimuthal deep-reading resistivity is shown to bear the promise for use in optimization of well trajectory and well placement, as well as in advanced formation evaluation while drilling. This newly developed tool is superior to traditional propagation tools in locating bed boundaries and in keeping the well in the desired pay zone. In addition to providing traditional multi-depth of investigation resistivity measurements, this new tool provides multi-depth of investigation azimuthal resistivity measurements.
Estimation of Initial Fluid Contacts by Assimilation of Production Data with EnKF
Authors: Thulin Kristian , Li Gaoming , Aanonsen Sigurd Ivar , Reynolds Albert C. 
Published: December 2007

Abstract
Much recent work on automatic history matching and data assimilation has focused on the adjustment of simulator gridblock permeabilities and porosities. Here, we show that when production data are assimilated into reservoir models with the ensemble Kalman filter, it is relatively easy to account for uncertainty in the depths of the initial fluid contacts and provide estimates of these depths in addition to the traditional estimates of rock properties fields. The contact depths strongly affect the initial oil in place and cumulative oil production. We demonstrate that if one uses fixed, but incorrect fluid contacts when assimilating data with EnKF, reasonable matches of production data are obtained, but future performance predictions are inaccurate and severely biased. Considering these same inaccurate contact depths as the means of probability density functions for the two depths and including both the contact depths and rock property fields in the EnKF state vector, we obtain improved performance predictions compared with the case where incorrect depths are assumed to be correct. With uncertain initial fluid contacts, the estimates of the location (depths) of the contacts obtained by matching production data are more accurate than the prior estimates, but unfortunately, do not always provide an improved estimate of the thickness of the oil column. However, this is reflected in a larger estimated uncertainty in the predictions.
In the reservoir engineering community, there exists some uncertainty about whether performance prediction runs with a reservoir simulator should be made by predicting forward from the end of data assimilation or by rerunning the reservoir simulator from time zero using the final ensemble of reservoir parameters obtained at the final data assimilation step. We show that if the model error is negligible and the relation between data and the combined state vector is linear, then both procedures give the same predictions. We demonstrate, that for the nonlinear examples considered here the two procedures give reasonably consistent results, although rerunning from time zero tends to give slightly larger estimates of uncertainty in the predictions.
A Model for Water Injection into Frac-Packed Wells
Authors: Suri Ajay , Sharma Mukul M. 
Published: December 2007

AbstractDescription of the materialA model is presented for predicting the performance of water injection wells with frac-packed completions. The model estimates the plugging of the frac-pack because of solids in the injected water and its effect on the frac-pack completion. It takes into account the thermal stresses caused by cold water injection and pore pressure changes.ApplicationFrac-packs are increasingly being used for sand control in injection wells in poorly consolidated reservoirs. These completions allow for large injection rates and longer injector life. Many of the large off-shore developments in the Gulf of Mexico and around the world rely on these completions for water flooding and pressure maintenance. The performance of these injectors is crucial to the economics of the project since well intervention later in the life of the field is expensive and undesirable.Results, Observations, and ConclusionsInjector performance is shown to depend on the solids content in the injected water, proppant size in the frac-pack, initial width and length of the frac-pack, injection rate, injection water temperature and the minimum horizontal stress. In cases with wide and conductive frac-packs, the plugging of the frac-pack will be gradual and the injectivity would remain high. In cases where significant plugging may occur, a rapid rise in the bottom-hole pressure will result in sharp decline of initial injectivity. However the frac-packs will widen up after the bottom hole pressure reaches a critical pressure because of a high permeability channel through the frac-pack which will alleviate the injectivity decline.Significant New ContributionsA model for water injection into frac-packed wells is presented for the first time. It accounts for plugging of the frac-pack and the formation around, thermal stresses caused by cold water injection and frac-pack widening and/or lengthening.
Case History: G-Function Analysis Proves Beneficial in Barnett Shale Application
Authors: Syfan Frank E. , Newman Stacy C. , Meyer Bruce R. , Behrendt Dan M. 
Published: December 2007

Abstract
The G-Function plot originally developed by Castillo was based on the work of Nolte's pressure decline analysis. This plot provides a graphical methodology for establishing fracture closure pressure from which the fluid efficiency, fracture geometry and leakoff coefficient could be determined. The Nolte method of pressure decline minifrac analysis using the G-Function plot has become a standard for fracture calibration in the industry from the high permeability (low efficiency) to low permeability (high efficiency) tight gas formations worldwide. Minifrac analysis has become a critical part of the fracture model calibration procedure for the successful design, evaluation, and implementation of hydraulic fracture treatments.
Although Nolte's original work has many simplifying assumptions regarding fracture closure (e.g., constant leakoff coefficient, no spurt, no fracture growth after shut-in, constant compliance, etc.), it still provides the foundation for the basic first order parameters affecting pressure decline behavior. The G-Function analysis is now routinely used as a starting point for calibrating the input data required in 3D fracture simulators.
To date, little or no information has been published supporting G-Function testing and analysis in the Barnett or other fractured shale formations. Fractured shale completions are still expanding in the Barnett and are becoming more prevalent throughout many additional geographic locations. Ultimately, completion success and the commercial viability of an asset in a tight naturally fractured shale formation, such as the Barnett, depends on an optimized hydraulic fracture stimulation using design parameters obtained through G-Function testing and analysis.
Using this fracture diagnostic technology leads to increased reserve recovery and cost effective proppant fracture treatments.