bluuebunny/crossref_metadata_2025_split huggingface dataset:
Net Pressure Fracture Design
Authors: Poulsen Don K. 
Published: December 2007

ABSTRACT
By substituting net pressure values for the fluid mechanics of typical fracture growth calculations, numerical models for calculating fracture growth from these pressures, using any of three popular fracture width equations, have been developed. One model uses expected net pressure behavior, ideally obtained from a similar treatment in an offset well, to predict fracture growth for design calculations. A second model uses collected pressures and injection or flowback rates to calculate fracture dimensions over time, allowing fracture behavior to be monitored during a treatment or analyzed afterward.
The governing equations for these models were examined under specific conditions, leading to guidelines for interpreting fracturing pressures under a variety of conditions.
And, by considering fluid mechanics, as well as fracture mechanics and a volume balance, expected pressure behaviors for power-law fluids in all three fracture geometries have been determined.
Slug Testing for Pumping Wells
Authors: Kabir C. S. 
Published: December 2007

ABSTRACTThis paper proposes a variation of ‘slug test’ for sucker-rod pumping oil wells. Application of slug testing simply expedites the buildup process. A slug test is conducted by admitting a slug of reservoir liquid such that the hydrostatic head of the wellbore liquid column balances the reservoir pressure; that is, the well kills itself. Bottomhole pressures (BHP) monitored in such a test have been routinely analyzed by the hydrologists and petroleum engineers alike over the past 35 years.Although a slug test is typically associated with a new well, the same concept can be extended to pumping wells producing for years. A variation of slug test can be conducted on a pumping well by leaving the casinghead valve open and recording pressures either downhole or by using the acoustic method. The data so gathered lends itself to slug test interpretation.An analysis of wellbore storage phenomenon arising from flow of a two-phase gas/liquid mixture is presented. The analysis shows that a slug test would allow the pressure buildup process to occur much faster than the conventional buildup method wherein a surface shut-in is required. Two tests conducted on the same well by the two methods, using downhole recorders, demonstrate the value of the proposed method. Reservoir parameters computed from the two tests are in very good agreement; thus, lending credence to the method proposed.
Scale Inhibitor Evaluations and a Mechanism of Inhibition of Sparingly Soluble Salts
Authors: Tomson Mason B. , Matty J. , Oddo J. E. 
Published: December 2007

Summary
Scale deposited within production systems associated with high volumes of produced brine can pose serious problems to the operator both in field economics or in the total loss of production. Seven barrels of oilfield brine are produced for every barrel-equivalent of energy obtained in the United States each year and with the advent of enhanced recovery methods, this ratio can be as high as thirty or fifty to one.
Many inhibitors have been in use for over fifty years, but no quantitative explanation for their effectiveness has been available. A general theory of inhibitor effectiveness and mechanisms of action are presented and two mechanisms based on diffusion rates are proposed with associated equations.
Many scale inhibitors are currently on the market primarily based on phosphonates, copolymers or polymaleates. An inhibitor evaluation apparatus developed at Rice University has gained wide acceptance in the petroleum industry and will be described. The results of inhibitor evaluation tests in various brine systems will be discussed in conjunction with the theory of inhibitor effectiveness. Results are presented for CaSO4 and CaCO3.
Continuously Gelled Diesel Systems for Fracturing Applications
Authors: McCabe M. A. , Terracina J. M. , Kunzi R. A. 
Published: December 2007

ABSTRACT
An efficient system of running gelled diesel stimulation fluid has been developed which allows continuous treatment and requires no pregelling or batch mixing. Continuous gelling while pumping is possible with this unique system, which is a combination of phosphate ester chemistry and computer-controlled metering incorporated in a mobile trailer or preblender. Operational and environmental advantages have been reported after field applications of this system.
Stimulation treatments using gelled oil as the fracturing fluid have been routine for many years. Most of these treatments have been performed by batch mixing gelled oil in storage tanks before pumping it into the formation. This, however, can result in costly waste of premixed gel should the job be cancelled or terminated prematurely. The system discussed in this paper gels the fracturing fluid while it is being pumped downhole, to eliminate the disposal problems associated with batch mixing;
The preblender is capable of mixing at 10 to 40 bbl/min and metering two liquid additives (phosphate ester gellant and activator) into the diesel. The automated equipment can be used to vary the concentrations of the additives, gel viscosity, or job volume in realtime at any point during the job without wasting gel.
Environmental and operational advantages of running gelled diesel continuously include (1) no left-over gel in tank bottoms to dispose of after the job, (2) pre-gelling time saved, (3) operators pay only for materials actually used during the job, and (4) elimination of the difficult task of withdrawing highly viscous, batch-mixed gels from storage tanks.
In Alaska, several wells have been hydraulically fractured using the technique. The diesel-based gel is found to be preferable to water-based gel systems in areas where temperatures can reach well below the freezing point. The equipment of this system is also designed to withstand arctic conditions.
This paper describes the fluid system as well as the equipment design and metering criteria for the continuous gelled oil system. Field application cases of this system will also be presented.
Chaos: A Source of Miscible Viscous Fingering Instabilities
Authors: Fanchi John R. , Shank G. Deane , Christiansen Richard L. 
Published: December 2007

SUMMARY
Previous theoretical researchers successfully generated viscous finger patterns by assuming a randomly distributed boundary condition in their numerical models. Our objective is to identify a natural source of the randomness that underlies their success. A source of fluid flow instability is discerned by viewing fingering as a chaotic (nonlinear dynamical) phenomenon.
We begin by showing that miscible displacement models can be expressed as nonlinear generalizations of the linear convection-dispersion equation. A nonlinear dynamical analysis technique is used to study the stability of the nonlinear system. Detailed study of several ID and 2D cases illustrates the applicability of the stability analysis.
Importance, Genesis and Recognition of Fracture Permeability in Fruitland Coalbed Methane Reservoirs of the Northern San Juan Basin, Colorado and New Mexico
Authors: Close Jay C. , Mavor Matthew J. , McBane Richard A. 
Published: December 2007

Abstract
Fracture permeability is inferred to be the most important influence on productivity of natural gas from commercial Fruitland Formation coalbed methane reservoirs in the Cedar Hill, Northeast Blanco Unit, and Ignacio Blanco fields of the northern San Juan Basin of Colorado and New Mexico. Reservoir deliverability in these areas with significant coalbed methane resources and reserves is less influenced by thickness, depth, completion technique, and measured and inferred pressure and formation damage.
Cleats (coal fractures) in cores from four northern San Juan Basin Gas Research Institute Fruitland evaluation wells in these fields formed during coalification in strain fields imparted as a result of Early Tertiary Laramide and Late Tertiary-Recent Rio Grande Rift regional tectonic episodes. These cleats are not the result of sedimentary compactional folding. The presence of discrete, very thin interbedded layers of Fruitland coal and non-coal ("ash") lithotypes with different respective rock mechanical properties favored brittle deformation of coal layers. Many commercial Fruitland wells are located in areas with extremely minor true structural flexure (folds), which indicates cleat permeability is largely a function of coal composition.
Knowledge concerning fracture permeability will influence further delineation and development of northern San Juan Basin Fruitland coalbed methane resources and reserves. The following procedure for qualitative recognition of areas with greater Fruitland permeability prior to drilling is suggested. 1. Preliminary collection and analysis of reservoir description and supporting geological and engineering data from in-house files and public literature should be completed. 2. The geologic setting of available acreage should be determined through interpretation of stratigraphic and structural maps and cross sections. 3. Favorable locations within acreage blocks should be delimited through interpretation of a). available drill stem test data, and b). gas and water production rate maps and data with respect to completion techniques and formation damage. 4. These areas of interest should be analyzed to find potential drilling locations by finding specific sites that a). required higher Fruitland drilling mud density to prevent blowouts using mud logs, drilling records and mud density maps, and b). have Fruitland coal waters with relatively low total dissolved solids (salinity) and chlorine ion concentrations. 5. Once a drilling location has been selected, potentially producible coal zones can be determined a). through identification of coal intervals with densities between 1.2 and 1.75 g/cc on open hole high resolution density logs, and b). by identification of coal intervals with drilling mud invasion through interpretation of micrologs and resistivity log suites from offset wells.
Prediction Of Pore Pressure From Penetration Rate
Authors: Combs George D. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
This paper was prepared for the 43rd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Sept. 29-Oct. 2, 1968. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
A general equation for penetration rate in shales is formulated, and the constants in the equation evaluated by a regression analysis of penetration rate data from six Offshore Louisiana wells. The correlation assumes that penetration rate is proportional to weight on the bit, rotary speed, and a hydraulics term, each raised to a fixed power. A penetration rate normalized for changes in these variables is found to decrease with increasing differential pressure and with increases in a tooth wear index. The drillability of shales defined as the drilling rate at some standard operating condition decreases with increasing depth but increases when the pore pressure increases because of the reduced compaction.
Prevention of Paraffin Well Plugging by Plunger-Lift Use
Authors: Narvaez C. , Ferrer A. A. 
Published: December 2007

Abstract
This paper describes a field project currently in progress in Corpoven's Anaco District, Eastern Venezuela. Corpoven S.A. an operating affiliate of Petroleos de Venezuela (PDVSA) has experienced production difficulties with paraffin deposition in natural flow and gas lift wells. A series of field tests were therefore devised to evaluate specialized plunger lift applications in problem wells. The objective of these tests was to investigate lifting techniques that would minimize existing paraffin removal costs involving wire line mechanical scraping of depositions in the production tubing and hot diesel fuel injection for solidified wax removal. During 24 months of continuous field testing, results indicated the possibility to keep affected wells on production using a plunger lift piston to dynamically remove precipitated wax in a relatively short cycle operation. Usefull production life between workovers has been dramatically increased while operating costs were correspondingly reduced. Response has been very positive in wells where various field options involving plunger lift technology have been completed. The method will have been extended to 17 additional wells by the end of 1990. Preliminary results to date indicate a similar success rate to that of the previous tests.
Refracture Stimulations in the Norge Marchand Unit: A Case Study
Authors: Branch G. A. , Drennan K. M. 
Published: December 2007

Abstract
This paper presents the results of a restimulation workover program in the Norge Marchand Unit performed during the past seven years. Upon initial completion these wells were fractured with Ottawa sand. It was suspected that a loss in fracture conductivity had occurred as a result of the proppant crushing due to the high closure pressure (7000 psi). In an effort to improve the fracture conductivity, the wells were refractured using intermediate strength proppant. The use of pressure buildup tests to select restimulation candidates improved the likelihood of having a successful treatment. The successful refractures resulted in an average increase of 50 B0PD and 98 MB0 additional reserves per well.
The Next Generation of Foam: A Field Study of Northwestern Oklahoma Foam Fracturing
Authors: Toney F. L. , Mack D. J. 
Published: December 2007

Abstract
Foams have been used as hydraulic fracturing fluids for over twenty years. Their primary usage is in reservoirs that are under-pressured and/or water sensitive. Nitrogen was the gas initially used as the internal phase. Later, carbon dioxide became more widely accepted and provided better load recovery and production.
Now, a third generation of foams has been developed. Nitrogen and carbon dioxide used simultaneously as the internal phase has shown to further improve load recovery and production rates.
This paper will present a brief review of foam fracturing procedures and mathematics, monitoring hardware and software requirements, rigging up and safety requirements. The majority of the paper will center on foam fracturing treatments performed on low permeability reservoirs in Northwestern Oklahoma. A comparison of past and present treatments and production rates utilizing operator supplied logs and production data will be presented. Overall, the new Binary Foam treatments have shown to be beneficial from a treatment application viewpoint. Advantages include (reduced screenouts), increased load water recovery, decreased flaring time due to lack of pipeline acceptable gas and improved production rates.
Analysis of Fann Model 50 for Fracturing Fluid Rheology
Authors: Gdanski R. D. , Harris P. C. , Lord D. L. , Reidenbach B. , Shah S. N. 
Published: December 2007

Abstract
Rheological measurements of a typical delayed titanium crosslinked hydroxypropyl guar (HPG) fluid were made with crosslinking reactions occurring under controlled shear rates (40, 120, and 170/sec) and heating rates (4 and 8°F/min and preheated bath). Five different bobs were used, showing the effect of gap width and percentage of total fluid within the gap. Some bob-cup combinations allowed the gel plugs formed in low shear rate conditions to easily circulate back into the gap and influence subsequent fluid viscosity. Other combinations allowed little circulation or had minimal plugs. As a result of this study more accurate fluid rheology measurements can be made with the Fann Model 50 viscometer if a realistic thermal and shear history are used, along with a bob-sleeve combination which maximizes the fluid contained within the gap and minimizes circulation of gel plugs back into the gap. Application of the findings in this work will help reduce the large differences typically observed between laboratories testing crosslinked fluids.
An Engineering Interpretation of Seismic Data
Authors: Pennebaker E.S. 
Published: December 2007

ABSTRACT
The reflection seismograph has long been the most important means for obtaining subsurface information prior to drilling. Interpretation of the seismic data is normally made by geophysicists to define subsurface structure. However, considerable information of great value to the drilling engineer is also contained in the seismic information. This paper discusses how the drilling engineer can use these data to estimate depth and magnitude of subsurface formation pressures, predict gross changes in lithology, and warn of possible drilling problems. Techniques are also presented for predicting relative drillability and fracture gradients in rank wildcat areas.
The predictive techniques described have been used with good results over a wide area along the Texas Gulf Coast including Continental Shelf locations and might possibly be applicable to any sedimentary basin.
INTRODUCTION
The only means of obtaining subsurface information other than from drilling is by geophysical prospecting. Although the seismograph has been used by geophysicists and geologists for many years to help define subsurface structure, it is only recently that engineers have begun to discover useful applications.
One of these applications is the use of routine seismic field data to predict both the depths to abnormal pressure formations and approximate pressure magnitudes.1 The predictive method results from the fact that velocities between subsurface reflecting layers can be obtained from seismic field data using well known geophysical techniques. Differences in interval velocities between these layers can be used to develop an average interval travel time (reciprocal of interval velocity) profile, which is in effect an acoustic log averaged over fairly long (500' - 1000') vertical intervals.
Analysis of numerous well velocity surveys revealed a close correlation between interval velocity (interval travel time), and factors such as lithology and degree of rock compaction and that interval travel time varies exponentially and predictably with depth. Departure from this normal trend signifies abnormal pressure or gross lithologic changes.
Utilization of Submersible Pump Systems in Southwestern Venezuela
Authors: Torres G. J. 
Published: December 2007

Abstract
The use of submersible pumps was first introduced to Venezuela in the state of Barinas during 1958. This area of operations is currently assigned to Corpoven S.A., an operating affiliate of Petroleos de Venezuela. Corpoven's Barinas District is made up of two areas. Barinas and Apure which produce some 105 MBPD, 45 MBPD of which is dependant on electrically driven submersible pumps installed in 35 wells. Crude from these wells reflect highly undersaturated reservoirs with oil gravities ranging from 18-30 deg. API and solution gas oil ratios of 50 to 200 SCF/STB. The primary production mechanism present in virtually all reservoirs is a strong water drive that maintains bottom hole pressures at relatively constant levels.
Sedimentary facies for the Barinas reservoirs indicate highly compacted sands interspersed with cementi tious material, while the Apure area reservoirs are characterized by compacted sands with little or no cementitious content.
The present work seeks to identify and document Corpoven's operational experiences and results in the utilization and operation of downhole electro-submersible pumps. Special attention will be drawn to the handling of produced BS&W (sand/sediment), as well as to the problems encountered with calcareous (Ca2C03) deposits. The unique effects of up and down thrusts on pump impellers will be cited, along with the resulting variations caused to well production by pump frecuency changes enacted to reduce maintenance down time and extend useful pump life. Operational procedures regarding preventative maintenance to the well's electrical power supply, and the resulting sand deposition between pump impellers and diffusers during this down time will also be analyzed.
Predicting Skin Effects Due to Formation Damage by Fines Migration
Authors: Ohen H. A. , Civan F. 
Published: December 2007

Abstract
Among the important issues concerning formation damage assessment and control studies are to understand and describe effectively the physicochemical and hydrodynamic factors controlling near wellbore damage during well development and reservoir exploitation. The problem is twofold. First, the mechanisms responsible for formation damage require complicated mathematical models. Second, it is difficult to simulate near wellbore flow conditions in a laboratory core flow test.
In a paper presented previously, effort has been made by the authors to solve the first problem. The present work is aimed at providing solutions to the second problem. Laboratory core data and the Ohen and civan model have been employed to determine the parameters that control formation damage for given rock / fluids systems and operating conditions. A mathematical technique has been developed to scale the laboratory response to near wellbore conditions-thereby simulating the actual radial flow conditions that exist in the near wellbore region. The radius and permeability of the damaged zone are computed as functions of exposure time of the zone of interest to the damaging fluids. A factor, herein referred to as the skin factor, is computed as a measure of the overall effect of formation damage on productivity or injectivity.
The major benefit of this work is the ability to design drilling and completion operations to optimize the time the pay zone is exposed to the damaging fluid. The validity of the model has been demonstrated in an earlier publication. A typical example is presented in this study to demonstrate the capability of the radial flow simulator to assess formation damage in the near wellbore region. The simulator presented in this study can be used in the design of well development and reservoir exploitation programs with reduced formation damage as well as cleanup operations.
Application of Electric-Driven Reciprocating Compressors for Low-Pressure Gas Well Compression
Authors: Elmer W. G. 
Published: December 2007

Abstract
The installation of electric motor driven reciprocating compressors was chosen instead of gas engine driven integral reciprocating compressors for eight Oryx Energy Company operated gas wells in Harper County, Oklahoma. The three main reasons for this decision were lower initial investment, decreased maintenance and downtime, and consideration of future emission regulations. Design choices for the electric driven compressors are presented.