bluuebunny/crossref_metadata_2025_split huggingface dataset:
Viscosity and Phase Behavior of Petroleum Sulfonate Solutions in the Liquid Crystalline Region
Authors: Benton W. J. , Baijal S. K. , Ghosh O. , Qutubuddin Syed , Miller C. A. 
Published: December 2007

Summary
Aqueous solutions of two petroleum sulfonate surfactants, a pure sulfonate surfactant and one mixed with an ethoxylated sulfate surfactant, were studied with polarizing microscopy, polarized light screening (PLS), and viscometry. The same sequence of phases was seen with increasing salinity for the various surfactants—i.e., transformation from an isotropic micellar solution to a lamellar liquid crystalline phase to an isotropic phase that scattered light and exhibited streaming birefringence. Addition of calcium ions to the petroleum-sulfonate/ethoxylated-sulfate mixtures led to the same basic sequence of transformations, but the effect of calcium was about 11.5 times as great as that of sodium on a molar basis. Many small crystalline particles were also observed when calcium was present.
A cone-and-plate viscometer was used to measure the apparent viscosity of the various solutions. A maximum in apparent viscosity was always found in the transition region between a dispersion of spherulitic liquid crystalline particles in an aqueous phase and a single liquid crystalline phase. The maximum occurred whether the transition was brought about by changes in salinity, divalent cation concentration, oil content, or other compositional variables. Apparent viscosity generally decreased with increasing temperature, although dependence on temperature was not monotonic at high salinities.
Apparent viscosity decreased with increasing shear rates and was time-dependent at a given shear rate. At low salinities, apparent viscosity generally decreased with time. At high salinities, apparent viscosity frequently increased with time.
MWD: A Case Study in Applying New Technology in Norwegian Block 34/10
Authors: Teige T. G. , Undersrud E. , Rees M. 
Published: December 2007

Summary
Developments in measurement while drilling (MWD) technology have led to the successful operation of a multisensor, negative-pulse telemetry system in the Norwegian sector of the North Sea. This paper describes the MWD system and discusses its application on three wells drilled in Block 34/10 and its advantages over a more conventional drilling program. Particular attention is paid to Well 34/10-20, where the simultaneous drilling, logging, and hole-opening of the 26-in. [66-cm] tophole section was performed for the first time.
We believe that as multisensor MWD systems become more reliable, substantial savings in rig time and increased drilling control and rig safety will result.
Characterization of Pore Space by Quantitative Image Analysis
Authors: Ruzyla K. 
Published: December 2007

Summary
A quantitative image analysis system has been configured for characterizing pore space of reservoir rocks. The technique can be applied to a magnified image of a rock thin section or polished section. With this system, numerous accurate measurements of porosity, pore size, shape, and internal rock-surface area can be obtained and easily summarized as distributions of pores. This quantity and quality of information is not attainable with conventional thin-section point-count techniques. Porosity values obtained by image analysis are in agreement with those obtained from core-plug analysis.
Porosity, Permeability, and Pore Structure of the Tight Mesaverde Sandstone, Piceance Basin, Colorado
Authors: Soeder D. J. , Randolph P. L. 
Published: December 2007

SummarySpecial core analyses on 44 tight Mesaverde sandstone samples from the U.S. DOE Multiwell Experiment (MWX) were combined with petrographic investigations to relate the porosity and permeability of the cores to the pore structure of the rocks. Core analysis was performed on 1-in. [2.54-cm] -diameter horizontal plug samples with a computerized steady-state-flow measuring device that routinely measures gas flow rates with a resolution of better than 10−6 std cm3/s.All samples were selected from intervals expected to be gas-productive on the basis of wireline well logs and were taken from the portion of the interval that showed the lowest gamma ray log response. The core plugs were measured for dry permeability to gas, relative permeability at various water saturations, porosity to gas, and PV compressibility. Petrographic samples were taken directly off the plug ends and were analyzed with both an optical microscope and a scanning electron microscope (SEM). The petrographic study was explicitly directed toward observing the flow paths and pore structure deduced from the core analysis data.Petrographic observations revealed that the pore geometry of tight sandstone falls into three general categories: grain-supported primary pores, secondary solution pores connected by narrow intergranular slots (the most common pore structure in the Mesaverde), and matrix-supported grains. Reservoir properties measured from core analysis correlated fairly well with the observed pore geometry and showed trends associated with various depositional environments in the formation.
An Improved Method for Viewing Micropore Systems in Rocks With the Polarizing Microscope
Authors: Gies R. M. 
Published: December 2007

Summary
Blue dye, mixed with epoxy resin and used to impregnate rock thin-sections to reveal porosity, is replaced by a fluorescent dye, rhodamine B. Incident-light illumination is provided by a special attachment available for polarizing microscopes. The intense autofluorescent-light response makes even the smallest micropores and microfractures visible in sharp detail.
Mathematical Modeling of a Gravel-Pack Logging Tool
Authors: Boyce James R. , Carroll James F. 
Published: December 2007

Summary
This report discusses a sophisticated mathematical model of a gravel-pack logging tool that has a gamma ray source and a single gamma ray detector. We use a generalized Monte Carlo computer code, called MCNP, to model photon transport in three-dimensional (3D) geometries. Our approach includes a technique called variance reduction, which both reduces computational time and increases the precision of the results.
The mathematical model is verified by comparison of calculated results with measurements made in laboratory simulations of gravel-pack completions. Laboratory measurements reported previously1 included a wide selection of fluids of various materials and densities, several screens, tubings, and two casing sizes. Comparison of the modeling results with experimental data reveals excellent agreement, giving a high level of confidence to the model.
This study had three major objectives: (1) to expand our understanding of the physical processes involved, (2) to verify and to interpret the laboratory data, and (3) to provide a method by which tool responses can be obtained for a variety of borehole and gravel-pack conditions not measured in the laboratory. Thus, we were able to develop a generalized interpretation method that predicts downhole conditions as a function of tool response. A field example showing this interpretation procedure is presented.
Particle Transport in Viscous and Viscoelastic Fracturing Fluids
Authors: Acharya A. (Ruma) 
Published: December 2007

SummaryParticle settling velocity as related to fluid rheology in fracturing fluids is an important parameter in the determination of the final distribution of propping agent in a fracture. This paper describes theoretical and experimental analyses that account for viscous and elastic properties of the fluid to predict proppant settling characteristics and reviews existing theoretical models used to correlate proppant settling data.A closed-form expression for the terminal settling velocity of a single particle as derived from an approximate analysis is compared with experimental data and with data from the literature. The theoretical results are combined with the experimental data to obtain a correlation that is useful in the prediction of the settling velocity of a particle in viscous fluids at an intermediate Reynolds number.
PDC Bit Performance for Rotary, Mud Motor, and Turbine Drilling Applications
Authors: Black A. D. , Walker B. H. , Tibbitts G. A. , Sandstrom J. L. 
Published: December 2007

Summary
During laboratory drilling tests at simulated downhole conditions in shale, the performance of a polycrystalline-diamond-compact (PDC) bit was measured over a wide range of rotational speeds covering rotary, positive-displacement-motor (PDM), and turbine drilling applications. Tests were conducted at a constant borehole pressure with a standard water-based mud. Rate of penetration (ROP), torque, and mechanical horsepower at the bit were determined as functions of rotational speed, bit weight, and flow rate. From the test results, the cost benefit of higher rotational speeds achieved with PDM and turbine drilling was examined in terms of break-even costs relative to rotary drilling.
Bulk CO2 Removal Achieved Through Membrane Separation
Authors: Dinello M. S. , Narayan R. S. , Patton C. J. 
Published: December 2007

Summary
A pilot CO2 recovery system was installed in a major west Texas field to confirm the operation and performance of commercial-size coated hollow-fiber membrane gas separators. Data were gathered to verify predicted membrane performance on the basis of earlier demonstration tests. Such parameters as feed pressure, temperature, and CO2 content in the feed gas were evaluated. Removal of CO2 from a casinghead gas stream containing 40 to 80 vol% CO2 was successfully demonstrated with minimum pretreatment of the feed gas. The data taken compared favorably with predicted performance curves based on earlier demonstration unit results.
Development and Application of a Shear-Ram Tubing-Head System for Increased Offshore Platform Safety
Authors: Elkins Hugh L. , Adamek Frank C. 
Published: December 2007

Summary
Concurrent drilling and production operations on offshore platforms increase the potential for blowouts and subsequent fires. Present wellhead and Christmas tree designs address the potential for production equipment to resist flame impingement for limited exposure periods, but new technology is required to eliminate the source feeding the flame.
A new concept incorporates a blowout preventer (BOP) shear-ram system permanently installed in the wellhead to shear and to seal the tubing in the event of an emergency. Wellhead equipment and BOP systems provide a tandem hanger system that incorporates metal-to-metal sealing and tubular support, tubular shearing, fish retrieval, and tieback re-entry capability.
This report details the design, manufacture, installation, and full-scale laboratory testing that successfully confirmed the ability of the shear-ram tubing-head system to suspend, tie back, shear, and seal 7-in., 32-lbm/ft [17.8-cm, 47.6-kg/m] N-80 tubing at 5,000-psi [34.47-MPa] maximum service pressure.
A Parametric Study of the Effects of Coal Seam Properties on Gas Drainage Efficiency
Authors: Remner David J. , Ertekin Turgay , Sung Wonmo , King Gregory R. 
Published: December 2007

Summary
A parametric study is conducted to investigate the effects of reservoir properties on gas drainage efficiency. It is found that when a coal seam is opened to production, the gas desorption and production rates increase to a maximum value and then decline. The magnitude of the early desorption peak was found to be a function of (1) the ability of the micropore matrix to supply gas to the macropore system, and (2) the coal seam's conductivity to water. The desorbing gas was observed to create a localized, high-gas-saturation bank in the area enclosed by the pressure transient. The gas bank provided an internal pressure maintenance to the reservoir, while it decreased the relative permeability to brine. This created a competing effect with respect to water production. Because water removal strongly influences the pressure decline and, consequently, the desorption rate, a unique production mechanism was observed.
The study explored the interference effects on gas and water flow in multiple-well systems. It was found that the pressure drawdown caused by the multiple wells enhanced the desorption of gas into the macropore system and caused a positive interference effect on the gas flow rate. The water rate, however, encountered the more conventional negative interference effect.
Discrimination of Crude Oil and Water in Sand and in Bore Cores With NMR Imaging
Authors: Blackband S. , Mansfield P. , Barnes J. R. , Clague A. D. H. , Rice S. A. 
Published: December 2007

Summary
Nuclear magnetic resonance (NMR) imaging techniques were used to study the mobile proton content in prepared samples containing mixtures of crude oil, water, and sand. The measured proportions of viscous crude oil agree well with the actual values. Discrimination of light crude oil and water was demonstrated by proton chemical shift differences. A bore core sample also was examined and gave clear images from its oil content.
Clear Brine Drilling Fluids: A Study of Penetration Rates, Formation Damage, and Wellbore Stability in Full-Scale Drilling Tests
Authors: Doty P. A. 
Published: December 2007

Summary
The performance of CaCl2/CaBr2 clear brine fluid was compared with that of lignosulfonate-water-based and oil-invert-emulsion-based fluids in a series of full-scale laboratory drilling tests. Sandstone and shale rock samples were drilled with a clean CaCl2/CaBr2 brine, a solids-contaminated CaCl2/CaBr2 brine, a water mud, and an oil mud, all at 13-lbm/gal [1558-kg/m3] density. Penetration rates were measured under various conditions of weight on bit, fluid flow rate, and differential wellbore/pore pressure. Drilling fluid filtration into the sandstone was measured under both drilling and circulating (nondrilling) conditions. After drilling, 2-in. [5.08-cm] radial cores taken from the sandstone specimens were studied for permeability damage caused by the drilling fluids. In a separate test, shale specimens were exposed to circulating drilling fluids to examine wellbore stability effects.
Delta Flow: An Accurate, Reliable System for Detecting Kicks and Loss of Circulation During Drilling
Authors: Speers J. M. , Gehrig G. F. 
Published: December 2007

Summary
A system to monitor drilling-fluid flow rate has been developed that detects kicks and lost returns in floating, fixed-platform, and land-based drilling operations. The system uses flowmeters that monitor the flow rates of drilling fluids entering the borehole through the standpipe and leaving the well through the return flowline. These readings are processed in a computer-based, data-acquisition system to form a filtered delta-flow signal that identifies the occurrence of downhole fluid gains or losses. The system is designed to trip an alarm when a gain or loss exceeds 25 gal/min [1.6 dm3/s], even in a floating drilling environment. This sensitivity will generally keep gains or losses to less than 5 bbl [0.8 m3].
A Study of Mineral/Alkali Reactions—Part 2
Authors: Mohnot S. M. , Bae J. H. 
Published: December 2007

Summary
In a study of alkalinity loss by interactions of alkali with minerals and reservoir sands, static tests were conducted with high concentrations of NaOH and a variety of minerals, mineral mixes, and reservoir sands at high temperature. Reactions lasted up to 2 months in some cases. Solutions were analyzed for pH and titratable alkali, silicon, and other elements. The reacted alkaline solution from a reservoir-sand/alkali reaction was used for interfacial tension (IFT) and contact-angle measurements and for sandpack oil-recovery tests.
Alkalinity loss was greatest for kaolinite and gypsum; moderately high for montmorillonite, illite, dolomite, and zeolite; moderately low for feldspar, chlorite, and fine quartz; lowest for quartz sand; and insignificant for calcite. Alkalinity loss was dominated by chemical reactions for kaolinite, by dissolution/precipitation equilibria for gypsum and dolomite, by ion-exchange and silica dissolution for montmorillonite, and by ion exchange and chemical reaction for illite. The alkalinity loss by multimineral mixtures and reservoir sands agreed reasonably well with the sum of contributions by individual minerals. The contribution by highly reactive minerals was disproportionate to their weight fraction and was found empirically. The contributions by other minerals (not very reactive or ion-exchange-dominated) were approximated proportionately to their weight fractions. For reservoir sands, identifying exposed minerals and estimating their exposed surface areas by scanning-electron (SEM) and thin-section microscopy with several samples were important.
In an attempt to determine the influence of dissolved species from reaction, reacted alkali after sand/alkali contact was tested for contact angle, IFT, and oil recovery for a U.S. gulf coast reservoir system. More oil-wet (quartz) conditions were found with reacted alkali than with fresh alkali with one oil sample, and highly oil-wet conditions were found with both fresh and reacted alkali for another oil sample. Minimum IFT values were slightly lower, and no detrimental effects of dissolved species on oil recovery were observed.
A Study of the Reduction of Brine Permeability in Berea Sandstone With the Aluminum Citrate Process
Authors: Parmeswar Ravi , Willhite G. Paul 
Published: December 2007

Summary
A systematic study of permeability modification of Berea sandstone by the injection of alternate slugs of polymer and aluminum citrate is described. The research included brine permeabilities from 10 to 300 md. Results of treatments with Pusher 700™ showed that permeability reduction was limited to the front end of the core (0 to 4 in. [0 to 10 cm]). The effective mobility of the treated region was so low that in-depth treatment of the remainder of the core was prevented. The amount and distribution of permeability reduction is related to both polymer and aluminum retention. The retention of aluminum was found to be a nonequilibrium process, varying with flow rate and thus residence time in the core. Aluminum was retained in large quantities in Berea core in the absence of polymer. Changing the treatment sequence to aluminum citrate/brine/polymer/brine yielded in-depth treatment of cores 12 to 48 in. [30 to 121 cm] in length. Both magnitude and persistence of permeability reduction were comparable to or better than those obtained with the combination process. Permeability increased with distance from the core inlet in most runs. This is believed to be caused by nonuniform distribution of retained aluminum.
An Experimental Study of Waterflooding From a Two-Dimensional Layered Sand Model
Authors: Ahmed Gulfaraz , Castanier Louis M. , Brigham William E. 
Published: December 2007

Summary
The effect of flow rate on oil recovery by waterflooding is studied with a two-dimensional (2D), layered sand model that allows visual observation. The model consists of three communicating layers of equal thickness of water-wet sand with the permeability ratio of 2 :4 : 1 from top to bottom. Three white mineral oils of viscosity 15, 30, and 150 cp [15, 30, and 150 mPa · s] have been used for immiscible liquid/liquid displacement under constant pressure drops covering a range of flow rates.
The changes in flow regimes in the various layers are observed with respect to the variations in pressure drop across the model. The effects of capillary imbibition, gravity segregation, and viscous pressure gradient are observed and an attempt is made to calculate the instantaneous crossflow. Crossflow of oil from the tight layers to the most-permeable layer increases the intermediate oil recovery for a given volume of water injected. Oil recovery increases somewhat with a decrease in flow rate and considerably with a decrease in oil viscosity. Slow flow rates produce higher recovery but may not be feasible in the field for economic reasons.
For M &gt; 1, viscous crossflow contributes very slightly to oil recovery until the time of breakthrough of water from the most-permeable layer. After that, the viscous crossflow increases and creates a secondary oil stream close to the interfaces of the most-permeable layer. The additional oil is produced until the least-permeable layer also breaks through. A sequence of slow flow rate followed by a fast flow rate is shown to improve oil recovery for a given volume of water injected, and this occurs within a reasonable experimental time frame. The slow flow rate is set from a criterion of stable displacement in the most-permeable layer based on stability analysis, and the fast flow rate is based on the maximum pressure the model can take.
The effect of variation in interfacial tension (IFT) on the displacement behavior was also studied. IFT is reduced from 35 to 4 and 0.5 dynes/cm [35 to 4 and 0.5 mN/m], respectively, by addition of two surfactants to the injected flood water. These IFT ranges are not sufficiently low to increase oil recovery from interfacial effects. The two surfactants influenced the recovery behavior differently.
Reducing Gravel Pack and Formation Dissolution During Steam Injection
Authors: Watkins D. R. , Kalfayan L. J. , Watanabe D. J. , Holm J. A. 
Published: December 2007

Summary
Gravel-packing sand and formation minerals dissolve in the hot alkaline water injected with steam. This dissolution is believed to cause gravel-pack failure and other production problems. This paper describes the use of ammonium salts in reducing dissolution by reducing the pH of generator effluents from values of 11 and greater to between 9 and 10. These salts, such as ammonium chloride and ammonium nitrate, do not significantly change feedwater pH. Both laboratory and field test results are presented.
This paper also presents a brief summary of other methods proposed to prevent gravel and formation dissolution. In addition, the need for more information about the role of silica dissolution in causing production problems is discussed briefly.
Effect of Oil Production Rate on Performance of Wells Producing from More Than One Horizon
Authors: Tempelaar-Lietz W. 
Published: December 2007

Abstract
The performance of a two-horizon depletion-type reservoir produced through combination wells is analyzed. By introducing some simplifying approximations it has been possible to obtain formulas which are easy to handle. Only ordinary differential equations are used, and the development of the analysis can he followed without difficulty by the non-specialist. A rigorous analysis has been made of this problem. It has been found that the approximations introduced in the simplified analysis are fully justified and that errors seldom will be more than 2 per cent.
The report shows the effect of the rate of withdrawal upon the relative depletion of the two horizons. Numerical examples are given.

Introduction
In its simplest form an oil reservoir consists of a Continuous, homogeneous body of porous and permeable rock, enclosed at the top and the bottom by impermeable material. The flow of fluid through such a reservoir has been the subject of numerous papers, and the mathematical analysis of well performance, pressure build-up, etc., has reached a high degree of refinement. One of the basic assumptions introduced into these analyses is the homogeneity of the reservoir. In non-homogeneous reservoirs, these computations still can be carried out satisfactorily, provided small irregularities in the physical properties of the rock are distributed in a random fashion.
The flow equations are derived as solutions of the continuity equation, and their solutions are dependent upon the assumption of many constant factors in the reservoir: permeability to oil, compressibility of the reservoir fluid, viscosity saturation, etc. When these are assumed to be constant, the continuity equation can be solved rigorously. When these assumptions do not hold and corrections are introduced, it becomes very difficult and often impossible to solve analytically.