bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Water-Desaturation Technique and Stress on Laboratory Measurement of Hydraulic Properties of Tight Sandstones
Authors: Chowdiah P. 
Published: December 2007

Summary
Mercury porosimetry on unconfined sample chips and effective-gas-permeability measurements with evaporation used as the desaturating mechanism are two of the most common core-analysis measurements for tight sands. Data obtained with these two techniques have been compared with data on gas/water capillary pressure and effective gas permeability along a true drainage path at in-situ net confining stress. Results show that confining stress can have a significant effect on capillary pressure. Also, the use of evaporation to desaturate samples yields effective gas permeabilities much smaller than those obtained under true drainage conditions, suggesting that the evaporation method results in a pore-water distribution similar to that in an imbibition process.
Geologic and Engineering Implications of Production History From Five Mesaverde Wells in Central Piceance Creek Basin, Northwest Colorado
Authors: Chancellor R. E. , Johnson R. C. 
Published: December 2007

SummaryFive gas wells completed in low-permeability rocks of the Upper Cretaceous Williams Fork and Iles formations in the central part of the Piceance Creek basin, northwest Colorado, have been on continuous production for about 2 years. A general comparison is made between these wells and the Dept, of Energy 's Multiwell Experiment (DOE MWX) wells about 30 miles [48 km] to the southeast. The five wells were completed with gelled KC1 water/sand fractures in various intervals over a 3,000-ft [910m] section of largely fluvial and paludal rocks of the Williams Fork and Iles formations of the Mesaverde group. Flow has apparently stabilized at low flowing tubing pressures at a rate of 30 to 125 Mcf/D [0.84 to 3.5 × 103 m3/d] per well, with minor water and variable condensate volumes. On the basis of production information to date, attempts to select intervals with better-than-average effective permeabilities by state-of-the-art techniques were not successful. The study points out several important differences in the Mesaverde group between the area of the five wells and the MWX site. Formation temperatures are higher and levels of thermal maturity are lower in the area of the five wells than at the MWX site. High formation pressures were encountered in the lower part of the Williams Fork and Iles formations at the MWX site, while thus far, only near normal to slightly below normal pressures have been encountered in the Mesaverde group in the area of the five wells. Gas shows and gas production characteristics in the area of the five wells appear to be related in part to the availability of gas-generating source rocks. Gas shows are sparse in the upper 1,000 to 1,700 ft [305 to 520 m] of the Williams Fork formation, where good source rocks are uncommon. Gas shows generally occur in only the upper parts of sandstones in this interval, suggesting that discrete gas/water contacts (GWC 's) are present. Completion attempts in this interval are commonly hindered by higher-than-average volumes of formation water. In contrast, almost continuous gas shows occur throughout the remainder of the Williams Fork formation and underlying Iles formation, where good source rocks are abundant. Discrete GWC 's are rare in this interval. Completions in this part of the section are capable of sustaining continuous gas production. The differences in the Mesaverde group between the MWX site and the area of the five wells point out the need to expand the MWX data base to include other gasproducing areas in the Piceance Creek basin.
Improvement of Hydraulic Fracture Predictions by Real-Time History Matching on Observed Pressures
Authors: Crockett A. R. , Willis R. M. , Cleary M. P. 
Published: December 2007

SummaryA new, fully integrated model of hydraulic fracturing can be used to compare measured and calculated pressures for parameter determination during the fracture treatment to improve the prediction of hydraulic fracture geometry. Sensor data obtained during the course of the treatment—such as wellhead flow rates, fracturing-fluid viscosity, and proppant concentration—are received directly by this model, which takes into account all the essential physical phenomena that influence the pressure response associated with hydraulic fracture growth. At any point during the treatment, the model can be rerun, faster than real time, changing reservoir and treatment parameters until the difference between calculated and measured wellhead or bottomhole pressure (BHP) histories is minimized. Updated predictions of final propped fracture geometry can then be made by running the model faster than real time, using the remaining treatment schedule as input and adopting the parameters that correspond to the best history match; these predictions may differ substantially from that of the job design, thus providing field personnel with an improved estimate of the final fracture geometry before the treatment is completed, while remedies can still be implemented.Results show history matches of the pressure response and associated fracture geometries for three treatments performed in the Travis Peak formation of east Texas and one performed on a coal seam in the Piceance Creek basin near Collbran, in western Colorado. In addition, this work is contrasted with previous efforts to deduce fracture geometry from pressure-response profiles.
A Note on the Duration of the Transitional Period of Responses Influenced by Wellbore Storage and Skin
Authors: Vongvuthipornchai S. , Raghavan R. 
Published: December 2007

SummarySeveral correlations are available for computing times at which storage effects can be considered to be negligible. The times given by these correlations are not in agreement principally because the criteria used to determine times for storage effects to become negligible are different. This paper clarifies the reasons for the differences and provides a unified treatment of the rules proposed in the literature. We show that correlations that specify the duration of the various flow periods depend on the manner in which the estimates are computed and on the tolerance used to obtain the estimate.A new correlation to determine the time for the start of the semilog straight line is presented. This correlation is based on the slope of the pressure trace and ensures that the slope of the semilog straight line will be correct within a specified tolerance.
A Drilling Reporting and Evaluation Data System
Authors: Woie Rune , Sirevaag Roald B. 
Published: December 2007

Summary
The BORE system is a drilling reporting and evaluation data system specially designed for drilling engineering. It reports drilling information from the rig site to the drilling department office and to license partners and authorities. The system provides valuable well information on previous drilling experience to be considered when new drilling activity is planned and in the daily follow-up of operations. The BORE system is easy to use and powerful for fast, complete data presentation when particular problems are considered and for special studies.
Core Preservation With a Laminated, Heat-Sealed Package
Authors: Hunt P. K. , Cobb S. L. 
Published: December 2007

Summary
A core preservation package was developed to maintain the reservoir characteristics of core samples and consequently to improve the quality of data obtained through laboratory core analyses. The package is a heat-sealable plastic/aluminum laminate similar to those common in the food-packaging industry.
The laminated core preservation package acts as an impermeable barrier to water vapor and gases, and is resistant to chemical alteration and degradation by core fluids. These performance characteristics result in effective core preservation by maintaining the fluid content of the core. Other advantages of the laminated package are that it is fast and simple to use and eliminates the cumbersome dip-coat step used in some core preservation methods.
Controlled experiments comparing core samples preserved by hot-dipping and those preserved with the laminated package were conducted. Warehoused core samples lost as much as 80% of their original water content during 2 years of storage when B-60 Hot Melt Peel Coat Type II™ preceded by aluminum foil and plastic wrap was used as the preservation package. Less than 10% moisture loss occurred over the same period of time when the new package was used. The hot-dip package also exhibited significant decay of the aluminum and plastic-wrap layers, whereas the laminate used to form the heat-sealable packages did not show any visible degradation.
Pseudocomponent Characterization for Hydrocarbon Miscible Displacement
Authors: Wu R. S. , Batycky J. P. 
Published: December 2007

Summary
A technique has been developed for lumping hydrocarbon pseudocomponents to simulate enriched-gas displacement processes. The proposed technique takes the reservoir temperature and the enriched-gas solvent compositions into account and then applies a mixing rule that proportions the molar- and weight-fraction weighting factors within the Peng-Robinson (PR) equation of state (EOS).
This technique was successfully applied to one condensate and three oil reservoirs by reducing the original multicomponent characterizations to only four pseudocomponents. The resulting oil characterizations matched the bubblepoint pressures, GOR’s, and atmospheric flash liquid and gas compositions. Also, solvent/oil phase behavior predictions at reservoir pressures—i.e., the accurate construction of the gas/liquid two-phase envelopes in pseudoternary diagrams—closely matched the multicomponent data. The mixing rule proportioning factor was found to be insensitive to pressure. For the condensate, the pseudocomponent pressure/temperature phase envelope representation matched the multicomponent representation. Finally, a match of the slim-tube displacement test data is presented for one oil as a further test of the technique’s validity.
Test of a High-Resolution Spectroscopy Logging Tool to Measure Chlorine in a Low-Salinity Reservoir
Authors: Neuman C. H. 
Published: December 2007

Summary
A series of tests was conducted to evaluate the usefulness of neutron-induced gamma spectra recorded by a detector cooled to the temperature of liquid nitrogen. These tests were conducted in an oil well that had been evaluated with core and other logging techniques. Results showed that measurements of carbon abundance were not accurate enough to enable useful estimates of oil abundance, but measurements of chlorine abundance could be used to estimate brine saturation if data were accumulated long enough.
The commercial logging equipment tested consisted of two different tools that combined a high-resolution detector with both chemical and 14-MeV pulsed neutron sources. Methods were developed to process and display the 4,000-channel spectra recorded. Use of the spectral data to measure chlorine abundance was developed by recording spectra at depths opposite formations containing saline and fresh water. Effects of brine in the casing were evaluated by recording spectra before and after brine in the casing was displaced by fresh water.
Predicted statistical uncertainty and variations between repeat runs indicated that a measurement of chlorine abundance that discriminates between 30 and 50 saturation units (s.u.) of oil requires 1-hour station measurements for 11,000-ppm brine. Chlorine abundances calculated from the spectral data were consistent with saturations measured from cores and openhole logs. Spectra of gamma rays from inelastic scattering of neutrons produced by a pulsed source had no detectable carbon peaks.
New Findings on Leak Resistance of API 8-Round Connectors
Authors: Schwind B. E. , Wooley G. R. 
Published: December 2007

Summary
This paper covers research funded by the API Production Research Advisory Committee (PRAC) on leak resistance of API 8-round connectors. It details the sensitivity of leak resistance to variations in makeup turns, pipe diameter, grade, and applied tension. Findings show that the leak resistance of the connector relative to pipe-body ratings increases with the number of makeup turns and decreases as diameter and yield strength increase. Finally, tension is found to lower leak resistance in a manner that renders hydrotesting insufficient for defining leak resistance in typical service conditions.
The Effects of Wellbore Storage, Skin, and Turbulence Intensity on Early-Time Transient Flow of Real Gas Through Porous Media
Authors: Oren Paul E. , Lee Robert L. , Tek M. R. 
Published: December 2007

Summary
This paper represents the first contribution in quantifying the effects of wellbore storage along with those of skin and turbulence intensity on deliverability from gas wells. A decay factor, WD, has been introduced to account for the contribution of sandface flow rate to early-time transient production from the gas wells. Generalized charts for type-curve studies on gas wells, based on pseudopressure and pseudotime concepts, along with wellbore storage, are presented with applications and support from field data.
Simulation of Pressure Buildup in a Multiphase Wellbore/Reservoir System
Authors: Winterfeld P. H. 
Published: December 2007

Summary
A pressure-buildup test is simulated in a system consisting of a wellbore and a reservoir and containing multiphase fluid. Wellbore flow is governed by conservation of matter and momentum, and reservoir flow by conservation of matter and Darcy's law. Finite-difference versions of the flow equations are solved on a discretized system. A single-phase example illustrates wellbore storage and wellbore fluid inertia shortly after shut-in. Two-phase examples illustrate phase redistribution, and one shows a "hump" caused by phases segregating. Buildup and other data from a field case are also matched.
Glenn Pool Surfactant Flood Pilot Test: Part 2—Field Operations
Authors: Bae J. H. , Syed E. U. 
Published: December 2007

Summary
A surfactant flood pilot test was conducted in a 20-acre [8.1 -ha], four inverted five-spot pattern in the Glenn Pool field. The field had been waterflooded and the pay zone, the Upper sand, was at a depth of 1,500 ft [457 m]. The crude oil had a viscosity of 4.0 cp [4 mPa-s] at a reservoir temperature of 95°F [35°C]. The process consisted of sequential injection of 35% PV of preflush, 10% PV of sulfonate slug, and 35% PV of polymer solution, followed by drive water. Injection operation was smooth; no injection well plugging was observed during sulfonate and polymer solution injection. On the other hand, production operation was somewhat hampered by plugging of producers. Low-equivalent-weight sulfonate precipitated out around the producers and contributed to the plugging problem. Solvent treatment corrected this situation effectively.
Although a large oil bank was observed in the two observation wells and all other observation-well behavior indicated a successful process performance, the total oil production was disappointing. About 63,000 bbl [104 m3] of incremental oil was produced. During the test, it was established through reinterpretation of existing data and a pulse test program that there was no clear separation between the Upper and Middle sands. The impermeable shale streaks separating these two zones were not continuous. The implication was that injected fluids were not confined in the Upper sand. This made the interpretation of field data very difficult.
PDC Applications in the Gulf of Mexico With Water-Based Drilling Fluids
Authors: Gault A. D. , Knowlton H. , Goodman H. E. , Bourgoyne A. T. 
Published: December 2007

SummaryThis paper presents the results of a recent study conducted to determine application and operating requirements for polycrystalline diamond compact (PDC) bits in the Gulf of Mexico. This study evaluated PDC-bit usage in Miocene sections of the Gulf of Mexico and has resulted in a saving of more than $1.4 million based on 22 bit runs. As a result of this study, operational guidelines for PDC bits were established and drilling costs per foot were significantly reduced. In addition, a relationship was found between shale reactivity, strength, and density. This proved to be an effective aid in bit selection and determination of hydraulic requirements and verified the results of the study.
Laboratory Drilling Performance of PDC Bits
Authors: Warren T. M. , Armagost W. K. 
Published: December 2007

Summary
A laboratory study of polycrystalline diamond compact (PDC) bit designs has generated data that give an insight into PDC-bit performance in the field. The tests reviewed in this paper include those for rate of penetration (ROP), torque response, hydraulic energy sensitivity, balling tendency, dull-bit performance, and bit performance after the removal of selected cutters. A total of four bit designs was tested. The designs included flat-faced profiles and parabolic profiles.
Numerical Simulation of Naturally Fractured Reservoirs
Authors: Sonier F. , Souillard P. , Blaskovich F. T. 
Published: December 2007

Summary
The most important and difficult aspect of modeling a naturally fractured reservoir is the correct calculation of the exchange of fluids between the matrix rock and the surrounding fractures. Several authors have published alternative techniques for handling this problem over the past few years. However, because each of these alternatives has some limitations, a new and more general technique has been developed. This new technique is used to simulate matrix/fracture exchange with special emphasis on the gravity forces included in the exchange terms. The exchange terms and the gravity forces within the exchange terms simulate the behavior of a single matrix block surrounded by fractures that may contain several different fluids. The gravity forces are internally calculated as functions of saturation. This technique has been incorporated into a new three-dimensional (3D), three-phase, fully implicit model for simulating fluid flow in a naturally fractured reservoir. The description of the porous medium might include highly fractured, microfractured, and nonfractured regions. Several examples explain the use of a new naturally fractured reservoir model and the essential differences between the new approach and those used in earlier naturally fractured reservoir models.
Fluid-Loss Mechanism for Gels and Suspensions
Authors: Medlin W. L. , Massé L. 
Published: December 2007

SummaryWe present a new model of fluid loss with wall building that applies to gelled fracturing and drilling fluids. Our model separates leakoff into two parts: an invasion phase and a wall-building phase. The invasion phase begins with Darcy flow, which carries residue into pore spaces near the rock face. This phase ends when sufficient residue has accumulated to allow the formation of a wall on the rock face. Once the wall has formed, it dominates the fluid-loss mechanism through its extremely low permeability. During the wall-building phase our model predicts a hyperbolic rather than a linear relation between leakoff volume and t. We made laboratory fluid-loss measurements for a variety of fluids and rock materials to test this model. We monitored effluent volume produced by flowing a gel or suspension through a fully saturated core sample. We found that the new model fit these measurements over periods of several hours, whereas the conventional Cw model did not. The Cw method can lead to large errors in fluid-loss estimates for long-term operations, such as massive fracturing and drilling. Our model requires the measurement of three leakoff parameters. We collected enough measurements to determine some general relations between these parameters and fluid and rock properties. These relations are discussed in terms of practical applications.
Earth Stress Measurements in the South Belridge Oil Field, Kern County, California
Authors: Hansen Kirk S. , Purcell W. R. 
Published: December 2007

Summary
Earth stress magnitudes in the South Belridge oil field, determined from integrated density logs and microhydraulic fracturing tests, indicate that the vertical stress is generally the intermediate principal stress, except possibly at the deepest zone tested (2,100 ft [640 m]), where it is approximately equal to the lesser compressive horizontal stress. Azimuth of the greater horizontal stress and of induced hydraulic fractures, as measured or inferred by several different techniques, is N15°E±15°.
Understanding and Controlling Corrosivity of Heavyweight Brines
Authors: Hudson T. E. 
Published: December 2007

Summary
This paper describes methods and technology for controlling the corrosivity of heavyweight brines. The conclusions are based on more than 5,000 corrosion data points generated in the laboratory and actual field use of the technology. Brines used in this study were single-, two-, and three-salt mixtures with densities varying from 8.4 to 19.2 lbm/gal [1007 to 2301 kg/m3]. Test temperatures and pressures varied from 100 to 500°F [38 to 260°C] and 1,000 to 10,000 psi [6.9 to 69 MPa], respectively. The tests varied in length from 1 to 90 days, and the tubing materials tested were 1008, J55, N80, and P110 steel.
Delineation and Evaluation of a North Sea Reservoir Containing Near-Critical Fluids
Authors: Neveux A. R. , Sakthikumar S. , Nolray J. M. 
Published: December 2007

SummaryA newly delineated reservoir in the North Sea Viking graben contains fluids that are at near-critical conditions. This paper presents a global approach for the delineation program, fluid correlation, and subsequent reservoir simulation studies. The delineation history and fluid sampling are detailed first. Fluid data correlation is presented, based on the use of an equation-of-state (EOS) program. Then, the compositional simulator, which provided satisfactory fluid representation for full-field studies and proved to be reliable and cost-efficient, is described.
TLP Production Risers for 1200-m Water Depth
Authors: Delgado J. H. , Erb P. R. , Moe G. 
Published: December 2007

Summary
A number of technically feasible alternative riser systems exist for tension leg platform (TLP) production systems in deep water. These include conventional steel, steel with added buoyancy, titanium, and carbon-fiber composite. The last three of these options provide substantial reductions in required riser tension for a 1200-m [3,935-ft] depth. For a minimum-size TLP, these reduced tensions translate into substantial reductions in fabricated steel weight. Replacing conventional top tensioners with a hard-mount or gimbal arrangement requires a relatively small increase in top tension, which would be balanced out by weight savings on the tensioning equipment. Operational concerns related to pressure and temperature changes must be addressed to ensure feasibility of the hard-mount or gimbal approach.
Chromium (III) Propionate: A Crosslinking Agent for Water-Soluble Polymers in Hard Oilfield Brines
Authors: Mumallah N. A. 
Published: December 2007

Summary
Reservoir heterogeneity and channeling have limited the success of many EOR projects because the injected fluids are preferentially transported through the path of least resistance. Current technology uses water-soluble polymers gelled with a suitable crosslinker to block, either partially or totally, channels and high-permeability zones. Most of the known gel systems are not usable in hard brines because the crosslinking chemicals are either incompatible or unstable in those brines.
This reports on the new chromium (III) (Cr+3) propionate gel system that was found suitable for in-depth, as well as near-well, gel treatments in both fresh water and hard brines. Laboratory coreflood testing of this gel system in various brines with hardness (calcium) levels up to 14,000 ppm resulted in high, long-lasting residual resistance factors (RRF’s). The stability and performance of Cr propionate in hard brines will extend gel treatments to reservoirs that have been excluded from consideration because fresh water was not available.