bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production Performance Analysis of Cavity-Completed Wells
Authors: Goktas B. , Ertekin T. 
Published: December 2007

Abstract
A parametric study investigating the performances of cavity-completed wells is presented. A three-dimensional, two-phase fluid flow model is used to conduct the study. Cavity-completed wells are described as a combination of fine rectangular grid blocks. The constructed fine grid lines are terminated at the coarse/fine grid block interfaces by implementing a local grid refinement technique. The model utilizes the residual equation rather than a wellbore equation to determine the flow into cavity-completed wells. The proposed approach is a significant departure from the current practice in which the performance of a cavity-completed well is predicted by assigning large wellbore radii and/or large negative skin values to a conventional well equation.
During the cavity completion process in coal seams, it is hypothesized that fracture networks are generated in certain directions around the cavity. These fracture networks are generally incorporated into a simulation study by modifying the permeability values around the wellbore. The model proposed in this study provides not only a more precise approximation to the shape of the cavity, but also an opportunity for altering the permeability values around the cavity more realistically to represent these fracture networks, utilizing the fine grid cells that are already in place around the cavity completions.
The effects of cavity dimensions and generated fracture networks on the flow performances of the cavity are investigated for various coal seam permeabilities. This study provides some quantitative and qualitative information for a well design engineer who is facing the challenge of making critical decisions for the cavity completion practice in coalbed field development studies.
Characterization of an Induced Hydraulic Fracture Completion in a Naturally Fractured Antrim Shale Reservoir
Authors: Hopkins C. W. , Rosen R. L. , Hill D. G. 
Published: December 2007

Abstract
In 1993, Shell began a cooperative evaluation with the Gas Research Institute to study factors controlling gas production from the naturally fractured Devonian shale Antrim formation in Montmorency Co., Michigan. The presence of multiple intersecting sets of natural fractures is the primary control on well deliverability and the Antrim must be fracture stimulated to be economical. However, due to the shallow depths (500-2000 ft) and naturally fractured nature of the Antrim, fracture geometry is complex, and the determination of the optimal fracture treatment or completion methodology is not straightforward.
To evaluate the effectiveness of fracture treatments in the Antrim, Shell conducted pressure transient modeling, microseismic tomography surveys for imaging created fracture dimensions (length, height, and dip), and the cutting of multiple coreholes to core the created hydraulic fractures. The integrated results suggest that fracture growth in the Antrim is very complex. A series of sub-vertical fractures were created that were parallel to the maximum principle stress and defined a zone of fracturing at least 50 feet wide. The fractures grew asymmetrically in height above the top perforation and appeared to follow a tortuous path along joint-set directions. Two coreholes drilled at 35-degree angles from vertical encountered 8 propped hydraulic fractures. Several of the cored propped fractures had varying azimuths suggesting that pre-existing natural fractures, which trend primarily NE/SW and NW/SE, were propped during the fracture treatment.
Case History: Cased Hole Horizontal Antrim Well Fractured in Multiple Intervals
Authors: Fink Kent T. 
Published: December 2007

Abstract
This paper discusses the design and execution and results of a Horizontal Antrim Shale well drilled to a depth of 3300' MD with a TVD of 852'. The well was cased with 5 ½" casing to TD, perforated and fractured in six isolated intervals. Drilling methods presented will be: drilling and running casing with a pull down top drive drilling rig. Pull down technology enabled the drilling and casing the hole with a KOP of 100'. Coil tubing completion methods presented are perforating and zone isolation methods allowing multiple stages in one day. Six separate intervals were successfully hydraulically fractured with foam fluid treatments. Design and observations of treatments will be given.
The Applicability of Waterflooding in the Appalachian Basin
Authors: Weber L. C. , Freeman D. C. 
Published: December 2007

Abstract
Oil production has been an important industry in the Appalachian basin for over a century. Most oil reservoirs in this region have been produced by primary recovery only, yielding some 5-25% of the stock tank oil originally-in-place. As a result, 75-95% of the STOOIP remains in the reservoirs. Waterflooding is one technique that could be used to recover these potential reserves. Waterflooding, the process of injecting water into an oil reservoir to displace the crude, is perhaps the most economical of any improved oil recovery process due to the general availability of water, ease of injection, and limited development costs. The waterflooding potential of the Berea, Big Injun, and Medina sandstone formations was evaluated to explore the applicability of waterflooding in the Appalachian basin. This paper documents those evaluations and gives guidelines for examing reservoirs of a similar nature. First, the geologic and engineering considerations for implementing a waterflood were assessed for each reservoir in detail. Then, predicted performance was modeled using the Dykstra-Parsons technique. The predictions of the model were verified by matching performance data from two Berea pilot waterfloods. Each of the reservoirs evaluated displayed good potential for waterflooding given sufficient oil to warrant an improved recovery process. A cursory economic analysis of a pilot waterflood in the Medina formation was also performed that showed a waterflood could be economical at $15/barrel. Since each reservoir evaluated displayed characteristics favorable for waterflooding, it was concluded that waterflooding is indeed applicable in the Appalachian Basin.
Drying of Porous Media To Create an In-situ Barrier
Authors: Aminian K. , Ameri S. 
Published: December 2007

Abstract
Containment is the primary technology for environmental protection when the contaminated subsurface sites cannot be economically remediated. In parallel to remediation efforts, confinement technologies are needed to retard or prevent the advancement of contamination plumes into the environment. This paper aims at investigating the feasibility of an innovative approach for preventing the movement of liquid contaminants toward groundwater. The concept involves using either vertical or horizontal wells to establish a pattern of air circulation to dry a soil layer. If the water saturation in the soil layer is lowered below the minimum required water saturation for liquid flow, the soil will tend to retain rather than transmit the liquids and as a result it will act as barrier to liquid contaminants. This technology can provide many advantages including non-physical confinement, commercially available oil and gas technology and equipment, active monitoring and leak detection, and high potential for integration with other remediation technologies. This type barrier is a crosscutting technology that would greatly benefit from proof of concept to gain regulatory acceptance.
A series of experiments have been designed and conducted to evaluate the feasibility of the concept. Several issues including the influence of the soil characteristics on drying profile, sweep efficiency and barrier performance have been investigated. Sand-packs, of different but uniform grain size have been utilized to investigate the drying process in porous media. The results have provided significant information regarding drying processes and the nature of fluid infiltration in porous media has been obtained. The experimental results indicated a great potential for applicability of the concept.
Application of Polymer Specific Enzymes To Clean Up Drill-In Fluids
Authors: Suhy Thomas E. , Harris Ramon P. 
Published: December 2007

Abstract
The industry recognizes that drilling muds can damage a well's producing zone, especially in highly deviated and open-hole completions. So-called "drill-in" fluids have been developed and used to reduce mud damage in vertical, horizontal, and multi-lateral completions. Although "cleaner" than conventional muds, drill-in fluids include polymers to build the required viscosity to transport cuttings and deposit a filter cake around the wellbore to reduce fluid loss. Most drill- in fluids are composed of starch, cellulose or xanthan polymers, plus bridging agents such as calcium carbonate or salt particles. Some of the polymer in drill-in fluids invades the near wellbore formation and creates skin damage. This is most noticeable in expensive horizontal and multi-lateral wells.
A break-through technology offers environmentally friendly enzymes that are tailored to remove most of these types of polymer damage. These polymer linkage-specific enzymes offer a safe, effective alternative to conventional clean-up methods that usually consist primarily of oxidizers like bleach and acid. This product has none of the "side effects" associated with non-specific reactants such as premature reaction, corrosive damage to down hole tools and tubular goods, and disposal problems.
This paper will detail the candidate selection process, applications methods, and the enzyme reaction mechanism. A number of selected application case histories in the South and Northeast U.S. production and gas storage fields will also be described.
Industry Attitudes Toward Slim-Hole Drilling
Authors: McLaughlin Philip L. 
Published: December 2007

Abstract
From a technical and economic standpoint slim-hole drilling promises to reduce drilling and completion costs. It may also result in reduced workover costs.
From the standpoint of industry acceptance, slim hole drilling does not fare so well. Producers, generally, have not accepted slim hole completion techniques for field development.
Contractors, generally, have been dissatisfied with profits. A mail survey indicates a need for additional information. Suggestions are given for improving the slim-hole picture.

Introduction
Since late 1952 there has been a considerable revival of interest in slim-hole drilling. Behind this revival are some hard economic considerations. There is no question that demand for new oil reserves will be greater in the future than in the past. The cost and difficulty of finding and exploiting these reserves will almost certainly be greater than ever before. Faced with this situation the oil industry is confronted with two alternatives.Industry can accept these higher costs without struggle and pass them on to the consumer.Industry can exert every effort to reduce the cost of finding and producing oil. This is the course industry will want to take if at all possible.
Of all the contributing items that make up the total cost of discovering oil reserves, drilling costs are by far the largest single item. (H. J. Struth, stated, In 1953, direct drilling cost comprised 61.9 per cent of total exploration expenditures.") It is quite evident that in order to cut the costs of finding oil, it would be a good idea to consider ways to reduce drilling costs.
With regard to field extension or field development, figures similar to those reported above are not immediately available. It is known, however, that drilling and completion costs are very large elements in the total costs of production, and well servicing costs are another important element. These two items will become even more important relatively, as the trend toward automatic leases continues.
Practical Tools to Assist History Matching
Authors: MacMillan D. J. , Pletcher J. L. , Bourgeois S. A. 
Published: December 2007

Abstract
We developed a set of tools to assist the history matching process where we emphasize how the engineer's knowledge and expertise can be best utilized. A method is presented for obtaining meaningful residuals that correspond with what the engineer is trying to achieve. We then show how sensitivity information can be extracted for every variable and residual using every run, even if more than one parameter is adjusted. This allows continuous sensitivity updates throughout the history matching process. These sensitivities can be used to predict the parameter adjustments needed to obtain a better match. Our method accounts for all the complicated interactions involved when simultaneously changing multiple parameters, even those that are not intuitive to the engineer. It is very robust, easy to implement and is independent of the simulator used. It can even be used after the model has been drastically changed, e.g., reworking the geology, without completely starting over. The ability to detect redundant parameters is also discussed, even those that are not apparent by simply examining the sensitivities. Our method can determine if an improvement in the match can be made, and if so how much improvement is expected. Finally, we describe how to tell when the best match has been obtained and how to avoid bypassing the optimal match only to be stuck with a less than optimal match.
Geologic Modeling, Upscaling and Simulation of Faulted Reservoirs Using Faulted Stratigraphic Grids
Authors: Chambers K. T. , DeBaun D. R. , Durlofsky L. J. , Taggart I. J. , Bernath A. , Shen A. Y. , Legarre H. A. , Goggin D. J. 
Published: December 2007

Abstract
A key difficulty associated with modeling faulted reservoirs is honoring both the structure and stratigraphy while simultaneously generating models that are acceptable in terms of practical simulation run times. In this paper, we describe our approach for designing finely gridded, faulted simulation models which we then scale up using a flow based nonuniform coarsening technique that takes into account the impact of the faults. Two field examples of faulted reservoirs are presented to demonstrate the new grid design and upscaling tools and, also, to investigate the impact of faults on flow behavior.
An important characteristic of our work process to generate faulted simulation models is that all of the tasks, from horizon and fault mapping to geostatistical reservoir characterization to scale up, are performed within an integrated earth modeling environment. Our grid design and scale up calculations accommodate complex fault networks and non-vertical faults (including reverse faults), although in the current implementation we allow only "logically-vertical" faults; i.e., faults with slip along the w or nominally vertical coordinate in a u, v, w stratigraphic grid. The rationale for specifying logically vertical faults is that they represent a compromise between accurately modeling fault geometry while maintaining computational efficiency when simulating flow in faulted reservoirs.
Although fault geometry, which we capture with our grid design and upscaling tools, is an important component of fault transmissibility, it is not the only one. Consequently, we present a technique for modifying fault transmissibility by introducing transmissibility multipliers at fault locations in the grid. We use this technique to generate sealing faults. We then compare reservoir performance predictions based on sealing, partially communicating, and no-fault formulations. Plots of individual well performance from the field examples reveal significant differences between the three formulations.
An Algebraic Approach to the Adaptive Implicit Method
Authors: Watts J. W. , Ramé M. 
Published: December 2007

Abstract
We approach the adaptive implicit method (AIM) in a new way that is based on the implicit matrix equation. The first step is to recover from the implicit equations the underlying capacitance and flow coefficients. Then, from these, we compute switching criteria that determine whether a given gridblock is to be treated implicitly or in IMPES fashion. These criteria are closely related to the CFL condition and offer insight in certain instances in which a computation is stable despite having a CFL greater than one. We also use the capacitance and flow coefficients to construct the IMPES pressure equation at all gridblocks.
We solve the resulting mixed-implicit matrix equation using an iterative method based on a two-stage preconditioner. The first preconditioning stage is to solve the IMPES matrix equation for pressure at all gridblocks. The second stage is solution of the full set of equations on the implicit gridblocks only.
Limited computational results indicate that, though the adaptive implicit procedure works, it is not efficient. It obtains only an approximation of the implicit matrix equation solution, leading to an increase in the number of Newton iterations required. The two-stage preconditioner for solving the resulting mixed-implicit matrix equation appears to work well, but further evaluation of it is needed.
Low Frequency Vibration Recovery Enhancement Process Simulation
Authors: Zhang Lie Hui , Ho Peter , Li Yun , He Shengning 
Published: December 2007

Abstract
In China, reservoirs with low permeability and heterogeneity play an important role in recoverable reserves and production rates. These types of reservoirs have complex geological features, poor reserve employment, production rate decline, and unbalanced water-intake capacity between layers, low water sweep efficiency and low recovery. These phenomena are more pronounced especially when the reservoir reaches high water cut. Different types of well stimulation such as fracturing, acidizing and recompletion etc. are used in these reservoirs recently, but these remedies just temporarily slow down production decline, while they cannot change the fact of low recovery in essence. Therefore, how to improve EOR has a remarkably practical meaning for these types of reservoirs. Artificial seismic recovery process is a very effective physical process that can improve oil recovery.
Artificial seismic recovery method is a low frequency vibration recovery enhancement process. It is to apply low frequent wave produced by the surface high power extra - low frequency controllable seismic source on the formation, so as to improve the physical characteristics of groundfluid and the percolation condition of the formation, and achieve the purpose of enhancing the ultimate oil recovery. Field tests such as Xinjiang, Jiling oilfield in China are very successful and encouraging.
In order to get a further understanding of vibration recovery, this paper uses a coupled geomechanic black oil simulator to simulate flow behavior of a reservoir with vibration recovery -Block 1764 of Xinjiang under surface vibration and have successfully matched the production history of this technology of the reservoir.
This paper provides field test, simulation results and some in-sights to the mechanisms of the process.
The Effect of Discontinuous Shales on Reservoir Performance During Immiscible Flow
Authors: Jackson M. D. , Muggeridge A. H. , Huxley T. H. 
Published: December 2007

Abstract
We investigate quantitatively the effect of inclined and intersecting discontinuous shales on horizontal waterfloods, using generic, dimensionless 2- and 3-D models. We find that dis-continuous shales have a significant effect on reservoir performance only if they are &gt;95% continuous, and are steeply dipping or intersecting, or if the displacement is unfavourable. 2-D simulations can significantly overestimate the effect of discontinuous shales, because they assume that the shales are entirely continuous in the third dimension.
Exploratory Reservoir Evaluation for Sour Gas or Crude
Authors: Montgomery J.M. , Gaskins J.F. , Coleman J.E. 
Published: December 2007

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

Abstract
The early evaluation of a reservoir's contents has become extremely important. As it has become necessary to investigate deeper production zones, completion costs have increased by geometric progression.
In the drilling phase it should be determined as early as possible whether zones that are penetrated present a hostile environment. The energy of each zone must be fully determined to insure safe drilling practices.
After the well has been drilled to total depth, the reservoir's extent and capabilities should be thoroughly evaluated. The presence of H2S and CO2 should be determined, both from a qualitative and quantitative standpoint. This, along with producing temperatures, will determine the most efficient and economical completion.
Conventional means of open hole sampling are not consistent with safety requirements necessary for evaluating the deeper, hotter, and higher pressured reservoirs. When these samples are brought to the surface under a charged condition, containing sour gas or crude, they are potentially dangerous to anyone trying to potentially dangerous to anyone trying to evaluate its contents.
A joint cooperative effort in the industry has set practical and basic guidelines for a method that will meet these requirements. This paper will discuss methods that will give considerable additional reservoir information that wig help in a safer drilling and completion program. program

Introduction
The energy situation has been constantly changing over a short period of time. The rising costs, increase in the price of crude and gas, the scarcity of pipe and tubular goods, the near impossibility to get surface equipment made from forgings; these and many other factors have caused industry to set new and different priorities. About two years ago it was determined that to meet the energy goals for the present and future, it would be necessary to drill deeper wells in search of production. In doing this the geophysicists projected that we could meet new problems and hostile environments.
Energy seeking companies and independents have several deep wells in the planning stage.
Optimizing the Development of a Giant Deepwater Multireservoir Oil Field through Reservoir Simulation
Authors: Corbishley D. W. , Guedes S. S. , Pinto A. C. C. , Corá C. A. 
Published: December 2007

Abstract
Reservoir simulation can be a cost-effective tool for helping to optimize the development scheme and minimize economic risk for practically any hydrocarbon reservoir. Simulation of giant deepwater fields can require an increased level of model sophistication, as in many cases there are multiple reservoirs, and planning for a large number of production and injection wells connected to various platforms over large distances. Risk analysis is important, as much of the development planning is based on a limited acquired database. This extended abstract presents a summary of the modeling techniques employed for such a field: Marlim Sul, offshore Rio de Janeiro, Brazil.
Comparison of the Performance of a Discrete Fracture Multiphase Model With Those Using Conventional Methods
Authors: Kim Jong Gyun , Deo Milind D. 
Published: December 2007

Abstract
Results from a new multiphase discrete fracture model are compared to simulation results using a variety of homogenization methods. A 2-D random fracture network is used as an example. The discrete-fracture model has been developed as an alternative to the dual porosity models. It will be difficult to capture the features of the fracture network using dual porosity models. At low permeability contrast (between the matrix and the fracture), as expected, the new model showed symmetric water advance in a water flood simulation. At high permeability contrast, features of the fracture network became critically important with great deal of oil bypassing at higher flow rates. The results also showed that even though specific, mathematically rigorous homogenization captures the fracture network features, especially at fine resolution, the results are vastly different from the discrete-fracture model.