bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reservoir Evaluation and Completion Results From a Horizontal Well in the Mancos B, Douglas Creek Arch, Northwest Colorado
Authors: Middlebrook M. L. , Branagan P. T. , Hill R. E. , Kukal G. C. , Peterson R. E. , McDonald T. S. , Aslakson J. K. 
Published: December 2007

ABSTRACT
The Gas Research Institute (GRI) initiated a data acquisition and analysis project in 1990 with the goal of evaluating the applicability of horizontal well completions In various gas-productive reservoirs. One of the target gas reservoirs in this study was the Mancos Β interval of the Mancos Shale located in the Southwest Rangely Field in northwest Colorado. The overall objectives of the project were to determine reservoir characteristics from a vertical well, model the reservoir, design an appropriate horizontal well completion and compare the production economics of the horizontal well to the economics of the standard vertical well completion.
Data were initially acquired from a vertical well completion in the Mancos Β to evaluate the extent and strike of natural fractures, in-situ stress magnitude and direction, log-derived reservoir characteristics, pre- and post-frac production rates and hydraulic fracture dimensions. A horizontal well was subsequently designed to intersect the interpreted primary set of natural fractures in the Mancos Β. The horizontal well was air-drilled and intersected approximately 1,500 ft of the Mancos Β "main porosity zone."
Borehole image log data indicated that no significant natural fractures were intersected by the horizontal wellbore. A 4-1/2-in. liner was cemented in the well to facilitate hydraulic fracturing after only minimal gas was produced from the open-hole during a 3-week production test. Reservoir modeling and economic forecasting indicated that 2 hydraulic fracture treatments over the 1,500-ft interval would be the most economical. Two fracture treatments were attempted but both resulted in screenouts during the early sand stages. The early screenouts were believed to be directly related to the higher than normal in-situ stresses that were observed during breakdowns and injection tests. Due to the limited vertical extent of natural fractures and the lack of vertical permeability, horizontal well completions in this area of the Mancos Β reservoir do not appear to be a viable completion alternative to hydraulically fractured vertical wells.
NORM Cleaning and Disposal Using Closed-Loop Hydroblasting or Solvent Bath and Underground Injection System
Authors: Lowe D. J. 
Published: December 2007

ABSTRACT
In 1987, BP Exploration (Alaska) Inc. (BPX) began surveying its facilities on the North Slope of Alaska to test for the presence of Naturally Occurring Radioactive Material (NORM). Only one occurrence of NORM in a heat exchanger bundle from a gathering center was found to contain NORM scale at that time. Recent declines in crude oil production from the North Slope oil fields have increased daily quantities of produced water to over 40 million gallons in the Prudhoe Bay Field alone. Regular NORM surveys have continued since 1987 because increases in NORM are generally correlated to increased water production.
In anticipation of a future need for an economical and environmentally sound solution for NORM disposal, BPX and ARCO Alaska, Inc. (ARCO), Co-Operators of the Prudhoe Bay oilfield, began discussions with regulatory agencies and environmental groups to provide a regulatory framework for NORM disposal. The focus of the discussions was to educate both the environmental community and the regulators on the occurrence of NORM, disposal alternatives, and the relative health risks of NORM handling and disposal, compared to other commonly understood health risks faced by our society. This approach created an environment in which rational discussion and decision making prevailed, and ultimately led to approval to dispose of NORM materials either in Class Π wells or in cement slurries to be used in well abandonment procedures. In 1992, BP began disposal of NORM materials via injection after five barrels of the materials were removed from a NORM scale contaminated heat exchanger during cleaning.
This paper discusses the decision making process and the geologic conditions which make NORM disposal via injection the most logical solution for NORM disposal in Northern Alaska. The procedures for NORM removal, processing, and injection are also discussed.
Disposal of Naturally Occurring Radioactive Material From Operations on Federal Leases in the Gulf of Mexico
Authors: Rutherford G. J. , Richardson G. E. 
Published: December 2007

ABSTRACT
This presentation will address the Minerals Management Service (MMS), Gulf of Mexico Outer Continental Shelf (OCS) Region's Letter to Lessees and Operators (LTL) concerning removal and disposal of produced well solids that contain naturally occurring radioactive material (NORM), disposal options for NORM by offshore operators of Federal leases, and data gathered from NORM disposal applications.
Disposal of produced well solids containing NORM from operations on Federal leases in the Gulf of Mexico will continue to be a concern for operators and for the regulating Federal agencies. On December 11, 1991, the MMS's Gulf of Mexico OCS Region sent an LTL concerning removal and disposal of well solids that contain NORM. The LTL provides interim guidelines to monitor closely the disposal of well solids containing NORM and to assist in the collection of data to establish regulations necessary for NORM disposal. The LTL contains disposal criteria and requirements for applications, sampling, testing, and recordkeeping. An operator's disposal options may include encapsulating material in abandoned wells, injecting material into depleted reservoirs, and cleaning material for overboard disposal. Overboard disposal of produced well solids is limited to material that meets National Pollution Discharge Elimination System (NPDES) standards and contains very low levels of NORM, i.e., dose equivalent rates of less than 25 microroentgens per hour above background levels.
Environmental Aspects of Oil and Gas Acquisitions and Divestitures
Authors: Dodson C. J. 
Published: December 2007

ABSTRACT
Environmental issues in the oil and gas exploration and production industry continue to grow and become more complex. As the domestic industry is reshaped through acquisitions and divestitures, the associated environmental issues become a major factor in this evolutionary cycle. An understanding of the environmental aspects of a transaction and the timely and complete management of them will greatly assist in a successful transfer of assets for both the buyer and seller. Early identification of the environmental aspects of the acquisition/divestiture and involvement by the key personnel in their management should prevent those costly surprises from a governmental agency or a court at a later date.
The Use of Geophysical Surveys for Conductive Groundwater Plume Assessment During Remediation
Authors: Dalton M. S. 
Published: December 2007

ABSTRACT
Surface geophysical surveys (electromagnetic) were used to reduce the cost, and increase the effectiveness of the assessment and remediation of a conductive ground water plume in Michigan. Following the release of an estimated 50 bbl. oil and 800 bbl. brine from a pipeline rupture, an inexpensive electromagnetic (EM) geophysical survey was performed to help define the areal extent and configuration of impacted ground water. Test borings, monitor wells, and an interceptor drain system were installed based on the results of the EM survey. Remediation is being accomplished by pumping impacted ground water from the drain and injection of the purged water into a Class IIR secondary recovery injection well.
Throughout remediation, quarterly EM surveys have been used to demonstrate progress. Over the three year remediation period, the chloride concentration in the most contaminated monitor well has been reduced by 99.7%, from 68,000 to 200 milligrams/liter (mg/l). The highest apparent conductivity in the plume has been reduced by 84.5%, from 290 to 45 millimhos/meter (mmho/m).
The Environmentally Sensitive Contract
Authors: Fachin G. M. , Fachin Gary M. 
Published: December 2007

Abstract
An analysis of the application of selected environmental laws and regulations to onshore exploration and production activities and of how such laws and regulations compel new contractual provisions. Aspects of the federal Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), federal Resource Conservation and Recovery Act (RCRA), and California air pollution control program along with judicial interpretations are examined.
Southeast Lost Hills Hydraulic Fracturing Stimulation of the Antelope Shale Zone: Case History
Authors: Martinez A. D. , Marquez M. R. , Shotts K. D. 
Published: December 2007

ABSTRACT
This paper presents a case history of the hydraulic fracturing stimulations applied to the Antelope Shale (AS) zone in the Southeast Lost Hills (SELH) Field located in Lost Hills, CA. Over 100 wells have been stimulated in this low permeability naturally fractured reservoir since 1979. The hydraulic fracture treatments have been refined to their current empirically "optimized" design.
Results are presented concerning production response vs. sand volume placed and the effect of various proppant sizes on production and job success. In addition, results are given from the use of inter-stage pressure bombs hung below bridge plugs for determination of inter-zonal communication during treatments. Also, the paper discusses the developed perforating schemes and their effect on zone coverage, and the identification of reservoir depletion in various infill wells exemplified by lower fracture gradients.
Interference Pressure Behavior in Stratified Reservoirs
Authors: Hatzignatiou D. G. , Ogbe D. O. 
Published: December 2007

ABSTRACT
In this paper semi-analytical solutions for interference testing in a two-layer reservoir are presented. The two layers may or may not be separated by a semi-permeable shale barrier. The solutions are derived assuming that (i) pressure equilibrium existing in the more permeable layer, due to its high vertical permeability, allows only radial flow in this layer, and (ii) the radial flow in the tighter layer is negligible due to the permeability contrast between the two layers. The upper reservoir boundary condition allows the modeling of either a no-flow or a constant pressure upper reservoir boundary which can be used to represent a gas cap. Wellbore storage and skin effects are considered at both active and observation wells. The dimensionless pressure and pressure derivative solutions are obtained for both layers at the observation well and for the producing layer at the active well.
The results obtained indicate that the interference pressure behavior in a stratified reservoir with vertical crossflow taking place from the supporting layer to the producing layer is affected significantly by the transmissibility ratio of the two layers, the properties of the shale barrier separating the two layers, and the skin and wellbore storage at both active and observation wells. It is shown that depending on the magnitude of the wellbore storage at the active and/or observation well, the early time interference pressure behavior may be masked making proper interpretations of early-time pressure transient test data difficult.
Faulting: A Major Control on Fluid Flow and Production Performance, Prudhoe Bay Field, Alaska
Authors: Kay E. A. , Bodnar D. A. , Cazier E. C. 
Published: December 2007

ABSTRACT
During 15 years’ development at Prudhoe Bay, some wells have been drilled near, or inadvertently through, faults, often resulting in impaired well performance. This paper provides examples of fluid movement through and along faults using open and cased hole logs, and production data. Where data exist, faults can be shown to be transmissible where reservoir juxtaposes reservoir. Data from recently drilled wells show pressure communication across major faults. Highly transmissible fault planes allow rapid movement of water or gas to the perforated intervals of production wells. Other problems result from drilling through fault zones including lost circulation, adverse hole conditions causing poor wireline log data and inadequate primary cementing. The majority of wells are unfaulted in the reservoir section, but with continued infill drilling, targeting new wells to avoid faults becomes increasingly difficult. The importance of accurate structural mapping tied to well data, therefore, cannot be overstated.
Determining Wellbore Pressures in Cement Slurry Columns
Authors: Prohaska Michael , Ogbe D. O. , Economides M. J. 
Published: December 2007

ABSTRACT
This work discusses the major factors affecting the pressure drop in the cemented annulus which are filtration from the wellbore into permeable layers, shrinkage of the slurry due to hydration, and changes in the rheological properties of the slurry. A model for determining wellbore pressures in cement slurry columns is presented. It accounts for the depth-dependent or placement history-dependent behavior of the gel strength evolution. Experiments conducted in the laboratory demonstrate that static gel strength development is a function of temperature, pressure and shear rate. Results show that large differences in wellbore pressures can be obtained when the depth-dependent characteristics of gel strength are neglected in wellbore pressure loss calculations.
Simulation Study of Steam-Assisted Gravity Drainage Process in Ugnu Tar Sand Reservoir
Authors: Kamath V. A. , Sinha Sandeep , Hatzignatiou D. G. 
Published: December 2007

ABSTRACT
A two-dimensional numerical model of the steam-assisted gravity drainage process with a pair of horizontal wells (SAGD) is developed for heterogeneous, layered tar sand reservoirs. As a case study, this model is applied to Ugnu reservoir to study the effect of heterogeneity on the growth of steam chamber and the process performance.
A detailed simulation study is conducted to determine the effect of various reservoir parameters such as porosity, permeability, initial mobile water saturation, Dykstra-Parson’s permeability variation, reservoir anisotropy and shale barriers on the SAGD process performance in Ugnu reservoir. Also, the effect of process parameters such as steam injectivity, steam quality, steam temperature, horizontal well length, vertical and lateral well spacing is studied.
Rapid Evaluation of the Impact of Heterogeneity on Miscible Gas Injection
Authors: King M. J. , Blunt M. J. , Mansfield M. M. , Christie M. A. 
Published: December 2007

ABSTRACT
To predict and manage petroleum production there are two challenges: (i) to generate and utilise tremendous detail in our reservoir description (ii) to recognise that the majority of this detail is uncertain. Techniques, therefore, are necessary to assess uncertainty while making predictions of oil, water, and gas production. We demonstrate that by using a mixture of old and new techniques (streamlines and fine grid simulation) that we obtain the speed of the first while retaining the rigor and accuracy of the second. The method is applied to the rapid evaluation of the impact of reservoir heterogeneity on miscible gas injection.
Sensitivity of Oil Recovery to Grid Size and Reservoir Description in Fluvially Dominated Deltaic Facies
Authors: Haajizadeh Masoud , Begg S. H. 
Published: December 2007

ABSTRACT
We address the question of what grid-size is necessary to adequately simulate oil recovery from a variety of heterogeneous facies found within a fluvial-deltaic system. We start by generating geological models of core-plug-scale poro-perm heterogeneities based on a geological understanding of the spatial distribution of lithotypes within a facies. This fine scale distribution is then re-scaled to different reservoir simulation grids which coarsen both horizontally and vertically. The finest simulation grid was such that the effect of re-scaling was negligible and thus the simulation model was almost an exact representation of the "true" reservoir. Equivalent homogeneous models, using the global effective properties of the fine-scale reservoir description, were also run. This enabled us to compare purely numerical effects with the effects of re-scaling the heterogeneous description. Waterflood and gasflood simulations were then run on each grid.
For the heterogeneous systems considered, the coarser grids under-estimated recovery - by up to 16%. Also, for the homogeneous models, waterflood recovery always decreased as the grid coarsened; gasflood recovery was relatively insensitive to block size. Further, recoveries were always higher in the heterogeneous model compared to the homogeneous model at any given grid size.
Finally, recovery and PI were grossly under-estimated at gridblock sizes that were approximately the same as that of significant heterogeneities - finer or coarser grids did a better job. The global effective permeability of the re-scaled grid was much lower for these inadequate grid sizes. Global effective permeability can thus be used to assess grid adequacy with respect to heterogeneity prior to performing simulations.
Use of Coiled Tubing for Abandoning Shallow Thermal Wells, South Belridge Field, Kern County, California
Authors: Fram J. H. , Eberhard M. J. 
Published: December 2007

Abstract
This paper details the use of coiled tubing for spotting cement plugs without a workover rig present, during abandonments of 100 shallow, thermal wells in the South Belridge Field. This method decreased the cost of this portion of the abandonment operation by $2000 per well. The paper describes why multiple well abandonment programs are common in thermal fields. The requirements for effective abandonment in thermal fields are also covered. Workover rig and coiled tubing abandonment methods are discussed and compared. The methodology used for selection of an effective and less expensive thermal abandonment cement slurry is outlined. This paper shows that if operating, service company and regulatory agency personnel work together, the cost of abandoning wells can be substantially decreased without decreasing the effectiveness.
Low-Pressure Gas Injection To Enhance Production in a Pressure-Depleted Reservoir at Elk Hills Oil Field, California
Authors: DeRose W. E. , Ottaviani W. L. , Harris B. R. 
Published: December 2007

Abstract
A low pressure gas injection pilot was implemented in the Shallow Oil Zone Reservoir of the Elk Hills Field (Naval Petroleum Reserve #1 in California) to investigate the technical feasibility and economic viability of injecting gas for pressure assistance.
This paper highlights various aspects of the gas injection project including the use of perfluorocarbon tracer to detect gas movement, the value of geologic sublayer mapping, and the need for a multi-mode monitoring program.
Pilot results are reported in terms relative to initial expectations based on volumetric calculations and reservoir modelling. Furthermore, project objectives and strategies related to reservoir communication and optimum depletion pressure are also reported.
Since the success of this project was predicated on a unique, synergistic working relationship among the principals, a portion of this paper addresses the merits of such a relationship.
Petroleum Engineering Nineties Style: Caroline Major Sour Gas Condensate Project
Authors: Harvey P. A. , Coppes J. L. , Webb R. J. , Lebiadowski G. P. 
Published: December 2007

ABSTRACT
This paper Is an introduction to the sub-surface aspects of the $1 billion Caroline sour gas condensate development. Technical aspects concerning reservoir geology and fluids, well performance and depletion strategy are reviewed.
The Caroline field contains 60 bcm (2.1 tcf) of liquid-rich gas containing 35% H2S. Production is from the high deliverability Swan Hills reservoir at a depth of 3800 m (12400 ft). The nature of the reserves and their proximity to rural population centers impacts the planning process.
The theme of the paper is that hydrocarbon development planning in the 1990's and beyond is constrained due to the legitimate concerns of the local and broader public. In the Caroline example, there was minimal well testing prior to start up as a result of these concerns. Still, a strong consultative effort resulted in an effective use of the data for planning purposes. These efforts determined an appropriate scope for the project which was started up on time and on budget. With limited production data available up front, Caroline is not unlike a major offshore project. The challenge for marketers, builders, operators and sub-surface technical specialists was to provide and execute a development plan and depletion strategy for the project that would meet the needs of both the owners and the affected parties.
A Tight Gas Field Study: Carthage (Cotton Valley) Field
Authors: McCain W. D. , Voneiff G. W. , Hunt E. R. , Semmelbeck M. E. 
Published: December 2007

Abstract
INTRODUCTION
Evaluation of the need for infill drilling in complex, low-permeability, gas reservoirs requires the application of advanced technology. Use of typical engineering tools such as conventional decline curve analysis, conventional pressure transient analysis, and single layer reservoir descriptions often create inaccurate results and misleading conclusions. Despite the accuracy of advanced analysis techniques, these techniques are typically not performed on a well-by-well basis in field-wide studies because the cost cannot be justified. As a result, accurate conclusions, valid for all areas of a field, are not obtained.
In this paper we present a practical means of applying advanced analysis techniques to an entire field. We describe a powerful statistical method for dividing the reservoir into areas of like productive behavior. This method provides an unbiased means of comparing well performance, selecting areas for advanced analysis, and defining the areal locations where specific conclusions apply. Emphasis is placed on incorporating a sound geological and petrophysical description, and evaluating the consistency of reservoir descriptions developed through independent geological and reservoir engineering techniques.
This analysis technique was used to evaluate the infill drilling potential of the Carthage (Cotton Valley) field in east Texas. The Carthage field, discovered in 1968, is a thick, layered, low-permeability gas reservoir underlying 250,000 acres in Panola County, Texas. See Fig. 1. At the time of this study, there were approximately 900 wells producing 400 million cubic feet and 300 barrels of condensate per day. The Carthage Cotton Valley sand has been classified as "tight gas" by the FERC. Prior to this study, there were three periods of intense drilling activity corresponding to authorizations of 640-, 320-, and 160-acre drilling densities. Carthage is currently experiencing a fourth active drilling period, in which numerous wells are being drilled on 80-acre spacing in selected areas of the field.