bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surveillance Modeling and Operational Controls Ensure Integrity of Alaska's Grind and Inject Operations II
Authors: Zaki Karim S. , Zhai Zongyu , Abou-Sayed Ahmed S. , Marinello Stephen , Bill Michael L. , Engel Harold R. 
Published: February 2011

Abstract
Alaska's Grind and Inject (GNI) operations represent the longest and largest semi-continuous solids waste slurry injection project worldwide. More significant in the current climate of corporate responsibility is that modeling updates and assurance processes allow procedural updates to maintain efficiency and environmental integrity. The modeling program provides data for injection performance analysis and history matching that leads to better understanding of subsurface dynamics. Operational success is evidenced by unblemished capacity to accept large waste volumes with significant ultimate well disposal potential.
This paper addresses injection assurance and waste containment throughout project life. The periodic history match of created subsurface features is a major component of this process. Fracture simulation was carried out to match the subsurface response to slurry batch injection through 8 years of injection. The geomechanical modeling necessary to provide the framework on which the simulation works is described. Stress evolution and thermal effects during batch injection is also illustrated for the GNI environments. The disposal domain development has been inferred from the simulation.
The provision of designs, solutions and predictions based on the simulation sensitivity studies is described and the impact of field activities is highlighted. Designs, solutions and predictions are given based on the numerical results and sensitivity study verified by past field observations. The verification and updating of the model developed for the GNI operation is provided by the history matching of wellhead pressures through eight years of injection.
Effect of Permeability Impairment by Suspended Particles on Invasion of Drilling Fluids
Authors: Tran Tung V. , Civan Faruk , Robb Ian 
Published: February 2011

Abstract
This study experimentally and numerically investigates formation damage induced by suspended particles in the drilling fluid and its effect on limiting their near-wellbore invasion. The study applies the NMR and X-Ray digital radiography tprovide valuable insights into damage mechanisms along the formation and depth of invasion. Formation damage caused by drilling fluids is one of the key factors for economic success in oil and gas field developments. The measured permeability reduction obtained from laboratory test by injecting particulate drilling fluid in a representative core sample is used to determine empirical parameters used to model the particle migration and deposition in porous media by means of a robust simulation of the relevant processes. The study provides a concept to develop the ability to evaluate drilling fluids in term of their formation damage potential.
Effects of CO2 Density and Solubility on Storage Behavior in Saline Aquifers
Authors: Takasawa T. , Kawamura T. , Arihara N. 
Published: February 2011

Abstract
CO2 sequestration in deep saline aquifers is an essential and quick-remedial measure to reduce CO2 emissions to atmosphere. At conditions of 800 to 4000 meters deep aquifers, CO2 is supercritical and a liquid-like fluid of which density and solubility into water are strong functions of pressure and temperature. In geological sequestration of CO2, behavior of the injected CO2 undergoes multi-phase flow, dissolution into the aqueous phase, and reaction with rock. In aquifers of the closed boundary or open boundary with weak regional groundwater flow, densities of CO2 in its own phase and CO2-dissolved water dominantly influence the extent of horizontal and vertical CO2 migration. In this study, we investigated effects of CO2 and aqueous-phase densities on the migration extent for a long time scale after injection.
In order to simulate advection, dissolution, and precipitation processes, we first developed a streamline-based model assuming incompressible and immiscible two-phase flow of CO2 and water. Procedures of the common streamline method were followed. Along streamlines, 1-dimensional flow equations were solved for CO2 in its own phase and CO2 concentration in aqueous phase, where reaction of dissolved CO2 is accounted for in the latter equation. CO2 flow due to gravity was calculated on the underlying grid, and so were permeability changes.
After validating the model, we performed simulations of CO2 sequestration in 3-dimensional homogeneous and heterogeneous aquifers. CO2 migration at a long timescale depends on the aquifer pressure and temperature that directly influences density, viscosity, and solubility of CO2 phase. The gravity segregation is controlled equally by aquifer pressure and temperature, and by vertical permeability, while the advective migration is less affected by the pressure and temperature, but more by heterogeneity. As precipitation, that is the ultimate form of sequestration, is directly related to migration extents of CO2 and aqueous phases, CO2 injection schemes need to be appropriately designed in accordance with the aquifer pressure, temperature, and heterogeneity.
Solving Future Challenges: Understanding Factors That Influence Innovation
Authors: Singh Amardeep 
Published: February 2011

Abstract
Innovation is the key ingredient to the success of any technology-based company independent of its size, market position or global presence. There are numerous worldwide examples that document that a company's success is directly linked to its ability to innovate and solve complex drilling and completion challenges in increasingly difficult environments. Generally, most technology providers strive to be innovative, but many struggle to accomplish the goal. Questions arise; why cannot all companies be innovative; why are certain companies more innovative than others; why are some companies innovative over a certain period of time and then lose their ability to sustain it?
An initiative was recently launched to answer these questions. The process involved soliciting input from grass root employees about their perception of company innovations over the past 20 years. The main objective was to identify the underlying themes influencing and driving the innovation process. Finally, we wanted to determine what type of environment or culture is most likely to encourage and motivate employees to create innovative new technologies/ideas.
This paper will outline key factors that correlate to a company's ability to create innovations from within. The conclusions are derived from extensive internal studies, but they are applicable to all technology-driven companies across a broad spectrum of industries. We will include a list of action items designed to change a company's culture to encourage innovation. These recommendations will also help companies sustain and predict innovation cycles.
When the next upturn in drilling activity begins, the industry must be prepared to respond with new and updated technologies/services to meet the next generation of drilling and completion challenges. By first understanding, then fostering a culture of innovation, the service industry will be properly positioned to efficiently accomplish future operator driven goals and objectives.
Operator/Service Company Research Collaboration Leads to Reduced Downhole Vibration Levels and Improved Drilling Performance
Authors: Chesher Steven W. , Williamson Mark E. , Dougherty Bill B. , Spencer Reed W. , Schmitz Kurtis , Tyagi Sarvesh K. 
Published: February 2011

Abstract
The Cana Woodford shale play is emerging as an active natural gas field in Oklahoma, USA with over 100 wells already drilled and many more in the pipeline. However, the key to success, especially with the current depressed pricing of natural gas, is continued injection of technology leading to reduced drilling costs. The most common well profile drilled in Canadian County and Blaine County, Oklahoma consists of a vertical section followed by a curve section and a long horizontal section through the Cana Woodford shale. Downhole vibrations were identified as major drilling performance limiters in the 8 ¾ in. and 12 ¼ in. vertical hole sections in these applications. The operator and the service company started a collaborative project to measure, understand, and reduce vibrations of the bit and BHA in order to improve drilling performance. The project adopted a holistic approach that included the use of analytical drilling models, drilling lab facilities, an experimental test rig and field testing to study how bits, BHA's and operating parameters impact downhole vibrations. All testing in the drilling lab, at the experimental test rig, and in the field incorporated in-bit vibration sensors.
In this paper, the authors will illustrate how a collaborative effort between an operator and a service company can leverage the collective knowledge and experience of both organizations for scientific investigation into the most important drilling dysfunction -downhole vibration. Based on testing in the lab, the experimental rig and the field, changes in the BHA and drive mechanism were implemented. These changes led to significant reductions in vibration levels, improved performance and better bit dull conditions. It is anticipated that as the collaboration moves forward, reductions in downhole vibration will translate into continued improvement in ROP, longer tool life, and significant cost savings for the operator.
Streamlined Production Workflows and Integrated Data Management: A Leap Forward in Managing CSG Assets
Authors: Biniwale Shripad , Trivedi Rajesh , Zangl Georg , White Chris , Delaney Scott , Blair James 
Published: February 2011

Abstract
A case study of the Spring Gully coal seam gas (CSG) field illustrates how an integrated production data management and analysis system has consolidated scattered data sources into a unified repository to provide easy access for reporting and analysis. Automated surveillance workflows with notification and alarm capabilities have simplified production performance tracking and enabled proactive decision making. Current analysis techniques and expert knowledge have been captured in predefined templates and workflows to identify trend violations, flagging the issues and optimizing production.
The new system has provided a foundation layer for managing the production and deliverability of thousands of wells now and in the future, helping to translate data into information. Enabling timely decision making through the use of accurate, validated data and automated workflows has helped engineers focus on problem solving and analysis. The streamlined process will continue to help the operator's CSG teams improve the efficiency and productivity of all their assets.
Why Monitoring With a Single Downhole Microseismic Array May Not Be Enough: A Case For Multiwell Monitoring of Cyclic Steam in Diatomite
Authors: Murer Anthony S. , McNeish Greg R. , Urbancic Ted , Prince Marc , Baig Adam M. , Bleakly Doug 
Published: February 2011

Abstract
Nine wells were drilled to test cyclic steam stimulation as a recovery mechanism in the diatomite reservoir in the Belridge field. Microseismic monitoring was proposed to evaluate steam chest and fracture growth. A series of models were constructed to determine both microseismic event detectability and locatability. The modeling indicated that poor signal-to-noise ratios would constrain the ability to locate events using a single array. As a result, three monitoring wells were installed. The purpose of this paper is to evaluate the microseismic event location results obtained from the 3-well solution and compare them with the solutions obtained when turning off one or two of the arrays. This first phase of investigation was performed on the sand-propped hydraulic fracture stimulation prior to the cyclic steam operations. This study may be applied to other areas including imaging hydraulic fracture stimulations in shale plays, reservoir steam monitoring, or in any area where location precision in microseismic monitoring is necessary.
It has been demonstrated in the field that the monitoring range of a microseismic system can be increased and the potential for locating microseismic events improved by installing multiple arrays having overlapping radii of observation. Innovative system design, deployment techniques and operational procedures, plus advanced multi-well processing strategies have all contributed to creating a growing data set with over 4,000 events recorded during the first 13 months of operation. Results of turning off arrays showed increased location error with two well solutions and a significant increase in error with one-well solutions notwithstanding the reduction in event location count due to lack of multi-phase signals on a single array. Azimuth errors in single microseismic observation well solutions result in disperse interpreted fracture geometry and in misinterpretation.
Overall, our observations show that, for both multi- and single-phase events, the observed detection limits and size distribution of the seisms has far exceeded those originally predicted by the earlier modeling.
Multidimensional Reservoir Description and Data Integration Using Time- Space Wavelet Analysis
Authors: Awotunde Abeeb A. , Horne Roland N. 
Published: February 2011

Abstract
Developing computationally efficient nonlinear regression algorithms is central to reservoir parameter estimation. The problem of inverse analysis is further complicated when the constraining data exist at different scales of resolution. In this case, integrating the data to reduce the scale effect becomes necessary. A commonly adopted approach is to use different scaling factors to bring the different datasets to the same resolution. However, there is no unique way to select scaling factors and this introduces some bias into the inverse modeling giving more importance to some datasets.
In this paper, we propose the integration of multiwell production data using the wavelet transform. The method involves the use of the two-dimensional wavelet transformation of the data space to reduce the linear adjoint system for a multiphase flow sensitivity computation. The approach proved very effective at reducing the cost of computing sensitivity coefficients. Multiple datasets from different wells, representing different production responses (pressure, water cut, etc.), were treated as a single matrix of data rather than separate vectors that assume no correlation amongst datasets. This enabled us to transform the multiwell production data into a two-dimensional wavelet domain and subsequently select the most important wavelets for history match. By minimizing the square of the Frobenius norm of the residual matrix we were able to match the calculated response to the observed response. We derived the relationship that allows us to replace a conventional minimization of the square of the l2 norms of multiobjective functions with the minimization of the square of the Frobenius norm of the integrated data. The usefulness of the approach is demonstrated using several examples.
Hydraulic Fracture Monitoring to Reservoir Simulation: Maximizing Value
Authors: Cipolla C. L. , Williams M. J. , Weng X. , Mack M. , Maxwell S. 
Published: February 2011

Abstract
Hydraulic fracture monitoring with microseismic mapping is now routinely used to measure hydraulic fracture geometry, location, and complexity, providing an abundance of information that can be essential to optimizing stimulation treatments and well completions. Although microseismic mapping has added significant value in many different environments, we have yet to fully utilize microseismic data. Significant details can be extracted from microseismic measurements that, when integrated with other information, can improve the characterization of both the reservoir and the hydraulic fracture. In addition, microseismic data has yet to be quantitatively and routinely utilized in reservoir simulation, which is the key to optimization.
Geological and geophysical data and wellbore logs can be combined with newly-developed complex fracture propagation models and reservoir simulation models. These models are calibrated using microseismic measurements and production data— closing the loop from microseismic mapping to simulation. The combination of microseismic measurements and complex fracture modeling with sophisticated geological descriptions of pre-existing natural fractures can be used to evaluate existing and predict future well performance in complex shale-gas reservoirs. The application of calibrated complex hydraulic fracture and reservoir simulation models provides more reliable forecasts of well performance resulting from various hydraulic fracture designs and completion scenarios, allowing the selection of the most economic strategy.
The optimization process includes a detailed workflow to efficiently integrate the large amount of information and modeling results into a coherent work product. This includes the integration of advanced processing and geomechanical interpretations of microseismic data with newly developed complex hydraulic fracture models that significantly improve the application of microseismic measurements. An example illustrates how HFM can be taken from event locations to production forecasts, showing how the capability to integrate geophysics, geomechanics, hydraulic fracture mechanics, and reservoir simulation can result in significant economic benefits.
Leveraging Knowledge Retention and Sharing Across the Value Chain
Authors: Senivongse Chulatep , McClelland Corey 
Published: February 2011

Abstract
Knowledge walks in and out of your offices in the form of your employees experiences, built up career comprehension and organizational adroitness as your employees come to work and then leave to go home everyday. Then at some point they leave and don't come back, they retire, take a job with another company, rotate to a new position or end their consulting agreement and are reassigned to another company. Capturing that tacit knowledge before it walks out the door the last time can bring enormous benefits to your company. Through the corporate quest for knowledge during their career or tenure with the company the company has invested in these staff to acquire the right knowledge. What happens to all their knowledge? The oil and gas industry has a major portion of its work force retiring over the next five years. The process being executed at PTTEP is attacking the capture and reuse of knowledge from those staff who are retiring, rotating or being reassigned head on. They are leveraging the departing person's knowledge to the benefit of the company and those who need to know. That shared knowledge is being reused by those still working on solutions to critical hydrocarbon problems. Knowledge retention and sharing is a process utilizing knowledge management techniques focused on the reuse of the departing staff tacit knowledge across an organization or company. The process as utilized can save oil and gas companies from reinventing by using the knowledge that already exists. The focus of this paper will be how knowledge is being captured and retained from a transitioning workforce at PTTEP and how leveraging this knowledge is creating value for the individuals who are reusing the retained knowledge to the benefit of the company.
Optimal Water Flood Management Under Geological Uncertainty Using Accelerated Production Strategy
Authors: Taware Satyajit , Sharma Mohan , Alhuthali Ahmed H. , Datta-Gupta Akhil 
Published: February 2011

Abstract
Waterflood optimization via rate control is receiving increased attention because of rapid developments in the smart well completions and i-field technology. The use of inflow control valves (ICV) allows us to optimize the production/injection rates of various segments along the wellbore, thereby maximizing sweep efficiency and delaying water breakthrough. We propose a practical and efficient approach for computing optimal injection and production rates given multiple geologic models with application to smart wells. Specifically, we examine the trade-off between maximizing oil recovery vs. maximizing NPV using a penalized misfit function for optimization. The waterflood sweep efficiency is maximized by equalizing the arrival times of the waterfront at the producing wells and the production acceleration is accomplished using a ‘norm’ constraint on the arrival times to accelerate injection/production rates. The ‘optimal’ strategy is decided based on a compromise between the two. Our previous work primarily focused on sweep efficiency optimization and did not account for production acceleration. There are four important elements in our current approach that makes it particularly well-suited for large-scale field applications. First, we use streamlines to efficiently and analytically compute the sensitivity of the arrival times with respect to well rates. For finite-difference models, the streamlines are easily derived from the velocity field. Second, we account for geological uncertainty via a stochastic optimization framework that relies on a combination of the expect value and variance of a performance measure from multiple realizations for risk assessments. Third, analytical forms for gradients and Hessian of the objective functions are derived which make our optimization computationally efficient for large field cases. Finally, optimization is performed under operational and facility constraints using a sequential quadratic programming approach. Multiple examples are presented to support the robustness and efficiency of the proposed optimization scheme. These include 2D synthetic examples for validation and a 3D benchmark field application.
Quality-Assured Evaluation of Freshwater-Bearing Hydrocarbon Reservoirs
Authors: Worthington Paul F. 
Published: February 2011

Abstract
The petrophysical evaluation of freshwater-bearing reservoirs cannot be approached using the standard Archie equations because these reservoirs show departures from the assumptions that underpin the application of those basic equations. The problem is placed on a sounder technical footing by defining the preconditions for the application of non-Archie saturation models and showing where and how these are satisfied. This exercise assumes that porosity has been pre-evaluated. It reveals that there is no fixed salinity level below which reservoirs show freshwater character in an electrical sense: the level is reservoir-specific. Where the non-Archie models do break down, a conditioned pseudo-Archie approach is proposed. This approach demonstrably enhances the estimation of hydrocarbon saturation, typically by up to 20 saturation units, as evidenced through groundtruthing core measurements and comparisons with other log deliverables. These comparisons can, of course, impart additional quality assurance. The approach is illustrated using field examples. On this basis, a protocol is outlined for the optimum acquisition of petrophysical data in freshwater hydrocarbon reservoirs. Central to this protocol are charts for identifying the most appropriate values of the porosity and saturation exponents. The adoption of this protocol leads to a significant reduction of uncertainty in the volumetric evaluation of these challenging hydrocarbon accumulations.