bluuebunny/crossref_metadata_2025_split huggingface dataset:
State-of-the-Art Modeling for Unconventional Gas Recovery
Authors: King Gregory R. , Ertekin Turgay 
Published: December 2007

Summary
A series of mathematical and numerical developments that simulate the unsteady-state behavior of unconventional gas reservoirs is reviewed. Five major modules, considered to be unique to the simulation of gas reservoirs, are identified. The inclusion of these models into gas reservoir simulators is discussed in mathematical detail with accompanying assumptions.
Improved Prediction of Wet-Gas-Well Performance
Authors: Oudeman Pieter 
Published: December 2007

Summary
A series of field tests on liquid loading of gas wells demonstrated that various types of behavior could be encountered in such wells. On the basis of the test results, an improved model for predicting the performance of gas wells producing liquids was formulated. This model takes into account multiphase reservoir performance and the vertical flow performance of the tubings for wet gas. It provides improved estimates for gas deliverability and the remaining life of watering-out gas wells, compared with common methods that calculate "critical" conditions at a single point (usually the wellhead) in the tubing string.
North Sea Experience With Aluminum Drillpipe
Authors: Tarr Brian A. , Graham Iain A. 
Published: December 2007

Summary
Aluminum drillpipe was used to drill the first five directional wells from a North Sea platform. A comparison with steel drillpipe showed that the operational problems of using the aluminum drillpipe outweighed the benefits in the directional wells drilled. Therefore, steel drillpipe was specified for subsequent, similar platform wells.
Sour-Gas Sweetening During Offshore Drillstem Tests—A Case History
Authors: Casselman Robert L. 
Published: December 2007

Summary
This case history details the use of Sulfa-Check®, a sour-gas sweetener, on two exploratory well drillstem tests (DST's) offshore California. Also included is a brief description of the Sulfa-Check process and comments on future plans. This case history is intended to show that Sulfa-Check can be applied effectively in a sour-gas offshore DST. It will show Sulfa-Check's performance on each of the exploratory wells and explain the solutions initiated to mitigate problems incurred in subsequent DST's. This information is presented for future operators' use in preparing an economical and safe sour-gas DST.
Optimizing Sandstone Acidization
Authors: Ponce da Motta Eduardo , Plavnik Benjamin , Schechter R. S. 
Published: December 2007

Summary
The treatment of sandstone formations with mixtures of HF and HCI to remove formation damage is a widely practiced stimulation method; however, little attention normally is given to process optimization. This paper presents a procedure design that minimizes the total acid volume required to remove damage from a fixed-zone, near-wellbore region. To account for differences in formation mineralogy, a single laboratory coreflood experiment with field cores is necessary but more are recommended. The optimization method relies on scaling this experiment to a radial-flow geometry, where acid flux rates may differ substantially from those used in the single core test. Changing the injection rate is shown to result in a minimum acid volume at an optimum injection rate, and this optimum is found for a specific example.
Scale Formation in Reservoir and Production Equipment During Oil Recovery: An Equilibrium Model
Authors: Haarberg Torstein , Selm Ingrid , Granbakken Dag B. , Østvold Terje , Read Peter , Schmidt Terje 
Published: December 2007

Summary
This paper presents a reliable model for the solubility products of scale-forming minerals. Our model solubilities are in relatively good agreement (±5% to 10%) with the most reliable solubilities in aqueous solutions of up to twice the seawater concentration at temperatures of 20 to 150°C and pressures up to 40 MPa. An equilibrium model for the reactions responsible for scale formation is developed. The CO2 equilibria between the gas, oil, and water phases and in the water phase itself are considered. By combining a hydrodynamic model for the transport of water through an oil reservoir during waterflooding with the proposed equilibrium model, we can estimate the amount of precipitate formed in the reservoir.
Field Applications of PHPA Muds
Authors: Kadaster A. G. , Guild G. J. , Hanni G. L. , Schmidt D. D. 
Published: December 2007

Summary
Mud systems with partially hydrolyzed polyacrylamide polymer (PHPA) are used worldwide and have proved effective and versatile for inhibiting troublesome shale formations. We made significant changes in the generally recommended compositions for these systems and developed a systematic approach to applying them. The most significant changes are (1) the constant maintenance of 1.0 lbm/bbl [2.9 kg/m3] PHPA (active) on the basis of materials balance and the supplemental addition of PHPA to account for its loss and degradation, (2) tightly controlled fluid loss, and (3) selective use of seawater and NaCl for inhibition.
Determining the Productivity of a Barrier Island Sandstone Deposit From Integrated Facies Analysis
Authors: Sharma Bijon , Honarpour M. M. , Jackson S. R. , Schatzinger R. A. , Tomutsa Llvlu 
Published: December 2007

Summary
Two crossplot techniques, based on core-calibrated resistivity, porosity, and gamma ray (GR) logs, are described that distinguish barrier island sandstones from genetically different nonbarrier sandstones in the Muddy sandstone reservoir in Unit A of Bell Creek field, Montana. The barrier island sandstones are separated further and grouped into two log facies, one consisting of highly productive facies (foreshore, shoreface, etc.) and the other, a less-productive facies (lower shoreface). The distinct crossplot pattern for each facies group is due to similar petrophysical properties of each facies group resulting from deposition within a unique depositional setting.
Fluid production results from primary, secondary, and two EOR pilot projects indicate that in the barrier island reservoir at Bell Creek, the distribution of facies, with their characteristic reservoir properties and heterogeneities, dominates primary production, waterflood-sweep efficiency, distribution of residual oil saturation, and the performance of the chemical EOR pilot projects.
Hydrocarbon Type Identification With MWD Neutron Porosity Logging: A Case Study
Authors: Slmms G. J. , Koopersmlth C. A. 
Published: December 2007

Summary
Measurement-while-drilling (MWD) information accurately defined gas, oil, and water in an offshore field. Basic MWD and wireline formation evaluation data compare favorably. A cost saving of $130, 000 was realized when MWD information was used instead of wireline data on one well. In the future, MWD logs may serve as the primary evaluation data on routine development wells in similar fields.
Development and Validation of Equation-of-State Fluid Descriptions for CO2/Reservoir-Oil Systems
Authors: Negahban Shahin , Kremesec V. J. 
Published: December 2007

SummaryThis paper discusses the required data, methodology, and validation for developing equation-of-state (EOS) fluid descriptions for the vaporizing-CO2/reservoir-oil systems. Validation of the EOS description is shown by an ability to predict additional first-contact data and slim-tube performance over a wide range of pressures covering both immiscible and multiple-contact-miscible (MCM) conditions. Slim-tube performance is predicted with a fully compositional simulator that uses a physical dispersion formulation. The relative permeability curves and dispersivity of the slim tube were measured and honored during all simulations.
Observations and Correlations for Immiscible Viscous-Fingering Experiments
Authors: Pavone Didier 
Published: December 2007

Summary
We studied immiscible two-phase flow instabilities in porous media under drainage conditions. The objective of our experiments was to improve our understanding of viscous fingering so that we could avoid it or at least account for it in flow simulations. This paper first presents the molding technique used to observe and measure viscous fingering in large, 3D, natural consolidated porous samples. Moldings of 16 flows showed instabilities that looked like fingers and stable displacements behind the unstable front. We correlated breakthrough recovery, mean local saturation, finger volume and width, pressure drop, and saturation profiles with dimensionless numbers. Three kinds of displacements occurred: stable displacements, with macroscopic viscous fingering, and displacements with both macroscopic and microscopic viscous fingering. Finally, we determined linear ID relative permeabilities.
Influence of Texture on Steady Foam Flow in Berea Sandstone
Authors: Ettinger R. A. , Radke C. J. 
Published: December 2007

Summary
An understanding of texture, or bubble-size, evolution is paramount for modeling foam flow in porous media in that fine textures may impart large flow resistances. Bubble size, in turn, is determined by complicated lamella creation and decay processes. We study, for the first time, the quantitative role of bubble size in the steady flow of strong foam through a 0.8-μm2 Berea sandstone. Inlet and outlet textures are determined from photomicrographs taken of bubbles flowing through specially designed visual cells. Concurrent measurements of pressure and liquid-saturation profiles by microwave attenuation are acquired for gas velocities from 1 to 3 m/d and foam qualities from 70% to 90%, A simple, 1D foam population-balance model is outlined to quantify the observed flow and texture behavior. Agreement between the proposed model and the new bubble-size and flow data is adequate. The population-balance method proves to be a useful tool.
Insight Into Sulfate in High-Salinity Producers and Selection of Scale Inhibitor
Authors: Hamouda Aly A. 
Published: December 2007

Summary
Several squeeze treatments in the Ekofisk field have tested various squeeze parameters, such as the overflush volume and the displacement means to maximize the scale squeeze life time, to prevent the formation of downhole scale cost-effectively. Scale may form when incompatible waters are mixed or the physicochemical parameters of the fluid (temperature, pressure, and chemical composition) change. This paper presents experience gained from treatment of high-salinity produced water on the Tor platform (2/4E) in the Norwegian sector of the North Sea, which has a total-dissolved-solids (TDS) content of about 200, 000 mg/L, compared with the typical average of about 70, 000 mg/L in some other Ekofisk fields. The high-salinity water requires extra care for predicting the scaling tendency, inhibiting scale formation, and preventing upsets in the downstream production facilities, like the oily-water treatment system. The high content of calcium and iron ions present in the produced water makes it even more difficult to treat. Because the scale inhibitor selected is nearly always a compromise, no one single laboratory test can determine the best scale inhibitor. This paper, however, discusses an approach for examining the sulfate-scale-inhibition efficiency with a reference to field experience for both down-hole and topside treatments.
Portable Piston Gas Prover for Field Calibration of Flowmeters
Authors: Ting V. C. , Haipine J. C. 
Published: December 2007

Summary
This paper describes a newly developed, unique piston-gas-prover system and its advantages for on-site gas flowmeter calibration to improve measurement accuracy. The gas prover was tested at a natural gas flow calibration facility and at the Colorado Engineering Experimental Station Inc. (CEESI) to demonstrate its measurement performance, repeatability, and accuracy. The piston prover, with a design similar to that of an existing piston liquid prover, is bidirectional and uses a special piston to move gas through a calibrated section of known volume. It is constructed to perform on-site calibration of such flowmeters as gas turbine or orifice meters at operating conditions. The unit can easily be set up in series with a field meter for calibration. Less than 4 in. of water pressure drop is required to operate the piston through the calibrated section.
In the evaluation tests, a master turbine meter was calibrated on unprocessed natural gas. Test results show turbine pulse-count repeatability to be ±0.05%. The accuracy of the piston prover was also checked in series with an air calibration system at CEESI. This study showed that on-site calibration of a gas metering device can be conducted successfully with a portable piston-gas-prover system to improve flow measurement accuracy.
Cone Breakthrough Time for Horizontal Wells
Authors: Papatzacos Paul , Herring T. R. , Martinsen Rune , Skjaeveland S. M. 
Published: December 2007

SummaryRecovery from an oil zone underlying a gas cap, overlying an aquifer, or sandwiched between gas and water can be improved by repressing the coning problem through horizontal-well drainage. Literature methods to predict coning behavior are limited to steady-state flow conditions and determination of the critical rate. The results in this paper are based on new semianalytical solutions for time development of a gas or water cone and of simultaneous gas and water cones in an anisotropic infinite reservoir with a horizontal well placed in the oil column. The solutions are derived by a moving-boundary method with gravity equilibrium assumed in the cones. For the gas-cone case, the semianalytical results are presented as a single dimensionless curve (time to breakthrough vs. rate) and as a simple analytical expression for dimensionless rates &gt; ⅓. For the simultaneous gas- and water-cone case, the results are given in two dimensionless sets of curves: one for the optimum vertical well placement and one for the corresponding time to breakthrough, both as functions of rate with the density contrast as a parameter. The validity of the results has been extensively tested by a general numerical simulation model. Sample calculations with reservoir data from the Troll field and comparison with test data from the Helder field demonstrate how the theory can be used to estimate the time to cone breakthrough and its sensitivity to the uncertainties in reservoir parameters.
A Procedure to Shut Off High-Pressure Water Flows During Primary Cementing
Authors: Mitchell Richard K. , Salvo Gregory S. 
Published: December 2007

Summary
Shutting off high-pressure water flows and achieving good cement bonding during primary cementing has long been a problem experienced by operators. Corrosion, casing leaks, excessive water production, and contamination of freshwater aquifers have led to costly workover operations throughout the oil field, especially within the Permian Basin. Remedial cementing jobs are often expensive and unsuccessful when primary cementing techniques fail. Therefore, a cost-effective, engineered method for cementing off these water flows was developed. This paper describes the cementing techniques, well-control criteria, well preparation, and data evaluation. Use of new and existing cementing practices provided the flexibility necessary to handle variable well conditions. Preplanning, evaluation of produced waters, compatibility studies, and proper slurry design helped to eliminate poor cement jobs in many areas. If one works closely with service and rig personnel, the procedure can be accomplished quite effectively, even on wells in which unexpected water flows are encountered. Examples of the procedure are documented with proven field results under variable conditions.
Two-Phase Compressibility Factors for Retrograde Gases
Authors: Rayes D. G. , Piper L. D. , McCain W. D. , Poston S. W. 
Published: December 2007

Summary
The two-phase compressibility factor should be used in material-balance calculations for rich-gas-condensate systems. This paper presents a correlation for estimating this factor from field data. The correlation, which is based on 67 fluid-depletion studies with C7+ concentrations ≥4 mol% also applies to rich gases with large amounts of CO2, H2S, and N2. The correlation gives an average error of 3.66% but may result in larger errors for some rich gases.
Numerical Evaluation of Single-Slug, WAG, and Hybrid CO2 Injection Processes, Dollarhide Devonian Unit, Andrews County, Texas
Authors: Lin E. C. , Poole E. S. 
Published: December 2007

Summary
This paper summarizes a numerical evaluation of the effectiveness of applying the conventional single-slug and water-alternating-gas (WAG) CO2 injection processes and an innovative hybrid process at the Dollarhide Devonian Unit, Andrews County, TX. The hybrid process consists of the injection of an initial slug of CO2 followed by WAG CO2 and water injection. The study shows that a properly designed hybrid injection process may have the potential to improve CO2 flood oil recovery.
Converting Wells in a Mature West Texas Field for CO2 Injection
Authors: Power Michael T. , Leicht Monte A. , Barnett Kerney L. 
Published: December 2007

Summary
This paper deals with the planning, special equipment considerations, and operations necessary to convert 163 water injection wells to CO2 injectors that will function through at least the end of the century. The paper is divided into two parts: planning and engineering (wellhead, packer, and tubular selection) and procedural operation highlights (fishing, openhole cleanout, casing evaluation and repair, stimulation, liner running, wellhead replacement, packer setting, and the reworking of tubulars). A case-history approach was used to analyze the success or failure of the various methods and techniques used in this project. All 165 wells were converted as of March 29, 1989.
CO2 -Foam Fracturing With Methanol Successfully Stimulates Canyon Gas Sand
Authors: Craft J. R. , Waddell S. P. , McFatridge D. G. 
Published: December 2007

Summary
Successful stimulation using CO2 foam with methanol has revived the economically marginal Canyon gas-sand reservoir of Sterling County, TX. Field experience in the Conger (Penn) field demonstrated that CO2 foam (1) lessened the water required in the fluid and (2) provided a gas assist to help remove water and lower interfacial tension (IFT). The low pH of the fluid, combined with additional clay stabilization, iron control, and enhanced water recovery additives, proved helpful in initial well response and subsequent performances. Since the CO2-foam fracture treatments were administered, production from Sterling County Canyon gas sands met or surpassed initial rates, even though formation pressure in the field declined 33.2%.
Stimulation is essential for commercial production in these sands. However, water blockage, caused by stimulation, was encountered in designing an effective completion technique for a tight formation with reduced bottomhole pressure (BHP). Production in tight, low-pressure gas wells can be completely blocked if formation pressure does not exceed the capillary pressure increase caused by injected fracture fluid. Original stimulation techniques consisted mainly of gelled-water fracture treatments containing 65, 000 lbm of 20/40-mesh sand with a maximum concentration of 2½ lbm/gal. In many cases, several weeks of swabbing were required to ensure continuous flow. After the fracture treatments, about 40% water recovery was realized throughout the field. This paper discusses CO2-foam fracture treatments and job design and presents case histories from several Conger (Penn) field CO2-foam fracture treatments.
Effect of Solvent Viscosity on Miscible Flooding
Authors: O'Steen B. L. , Huang E. T. S. 
Published: December 2007

Summary
This paper presents experimental results for tertiary miscible displacements in strongly water-wet Berea cores. Floods with both continuous solvent and simultaneous solvent/water injection were studied at ambient conditions. Three solvent/oil systems are compared: heptane (0.4 cp) displacing mineral oil (6 cp), tagged heptane displacing heptane, and tagged mineral oil displacing an equal-viscosity mineral oil (6 cp). Saturation profiles from microwave absorption measurements and production histories are presented. The experimental results show that the manner in which residual oil is mobilized and propagated depends on solvent/water injection ratio, oleic/water-phase viscosity ratio, and fractional-flow hysteresis.
A Mathematical Model of In-Situ Gelation of Polyacrylamide by a Redox Process
Authors: Todd B. J. , Willhite G. P. , Green D. W. 
Published: December 2007

Summary
Recent displacement data conclusively show that the initial permeability reduction during in-situ gelation processes does not result from a bulk gelation of the injected fluid. This paper presents a filtration-based model that correctly accounts for all physical phenomena occurring during in-situ gelation displacements.
Use of Pulsed-Neutron Capture Logs To Identiffy Steam Breakthrough
Authors: Masse P. J. , Gosney T. C. , Long D. L. 
Published: December 2007

Summary
Identification of steam-breakthrough zones in a stacked sand/shale sequence with variable lateral continuity is difficult. Such identification, however, would allow the modification of field operations to enhance recovery through improved vertical sweep and heat injection. Twenty pulsed-neutron capture (PNC) logs were run to identify the steam-breakthrough zone(s) in a seven-pattern area of Mobil's Middle Expansion (MIDX) Steamflood Project in the South Belridge field. These PNC data were combined with data from recent replacement wells and a detailed geologic analysis. Evaluation of this combined information allowed identification of potential steam-breakthrough zone(s), and operations were modified to reduce and eliminate steam breakthrough.
Removal of Oil, Grease, and Suspended Solids From Produced Water With Ceramic Crossflow Microfiltration
Authors: Chen A. S. C. , Flynn J. T. , Cook R. G. , Casaday A. L. 
Published: December 2007

Summary
Results of studies of two onshore and two offshore pilot plants that use ceramic crossflow microfiltration (CCFM) to separate oil, grease, and suspended solids from produced water are discussed. The method is capable of producing permeate quality with &lt;5 mg/L (detection limit) of dispersed oil and grease and &lt;1 mg/L of suspended solids.
OILMUD: A Microcomputer Program for Predicting Oil-Based Mud Densities and Static Pressures
Authors: Peters E. J. , Chenevert M. E. , Alhamadah A. M. 
Published: December 2007

Summary
OILMUD* is a program for predicting the densities and hydrostatic pressures in oil-based mud columns at high pressures and temperatures. The program uses multiple-linear-regression analysis on experimental data to calculate the densities and static pres sures for diesel-oil-based mud and for four less-toxic mineral-oil-based muds. This menu-driven, easy-to-use program runs on an IBM personal computer and compatible systems. It can be used by a drilling engineer to estimate downhole densities and pressures during drilling on the basis of surface measurements or to plan the mud program for a new well.