bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Integrated Technique for Production Data Analysis (PDA) With Application to Mature Fields
Authors: Gaskari R. , Mohaghegh S. D. , Jalali J. 
Published: December 2007

Summary
The most common data that engineers can count on, especially in mature fields, is production rate data. Practical methods for production data analysis (PDA) have come a long way since their introduction several decades ago and fall into two categories: decline curve analysis (DCA) and type curve matching (TCM). DCA is independent of any reservoir characteristics, and TCM is a subjective procedure.
State of the art in PDA can provide reasonable reservoir characteristics, but it has two shortcomings: First, for reservoir characterization, the process requires bottomhole or wellhead pressure data in addition to rate data. Bottomhole or wellhead pressure data are not usually available in most of the mature fields. Second, a technique that would allow the integration of results from hundreds of individual wells into a cohesive fieldwide or reservoirwide analysis for business decision making is not part of today's PDA tool kit.
To overcome these shortcomings, a new methodology is introduced in this paper that has three unique specifications:
It does not "require" pressure data, bottomhole or wellhead (but it can make use of it, if available, to enhance accuracy of results). It integrates DCA, TCM, and numerical reservoir simulation or history matching (HM) to iteratively converge to a near unique set of reservoir characteristics for each well. It uses fuzzy pattern recognition technology to achieve fieldwide decisions from the findings of the analysis.
Scale Inhibitor Squeeze Treatments Deployed From an FPSO in a Deepwater, Subsea Fields in the Campos Basin
Authors: Bogaert P. , Berredo M. C. , Toschi C. , Jordan M. M. , Frigo D. M. , Morgenthaler L. , Bryson B. , Afonso M. 
Published: December 2007

Summary
This paper describes field experience and lessons learned from scale control operations in a deepwater subsea development in the Campos Basin, Brazil; specifically, from bullheading scale-inhibitor squeezes from the FPSO host, along the production flowlines, into four low-watercut, horizontal subsea wells, completed with sand control.
The relatively small number of high-cost, highly productive wells, coupled with a very high barium-sulfate scaling tendency upon breakthrough of injection water, meant that not only was effective scale management critical to achieve high hydrocarbon recovery, but even wells at low water cuts were deemed to be at sufficient risk to require squeeze application.
Use of conventional, water based squeezes have been known to cause significant damage to productivity in low-watercut wells, including those showing a fines-migration tendency, as was the case here. Hence, on the basis of risk mitigation, supported by an extensive program of laboratory testing, it was decided that for the initial treatments, only the mainflush would be water based, with a mutual-solvent preflush and marine-diesel overflush.
Other key challenges associated with treating from the host included the remote location of the wells, the potential to form hydrates, the cleanliness of the lines along which the treatment would pass, the achievement of effective placement over a long producing interval, as well as the need to deploy the chemical package via a support vessel adjacent to the FPSO. All had to be managed because of the high cost and low availability of a deepwater rig that could deploy the treatments directly to the subsea wellheads.
This paper will explore in detail the issues associated with inhibitor-squeeze deployment in deepwater, subsea fields, many of which are currently being developed in the Campos basin, Gulf of Mexico, and West Africa, and are a good example of best-practice sharing from another oil basin.
Theoretical and Experimental Studies of Rate-Dependent Two-Phase Immiscible Flow
Authors: Allen F. R. , Puckett D. A. 
Published: December 2007

Summary
Theoretical predictions are obtained with both Eulerian and Lagrangian methods for calculating saturation profiles in two-phase immiscible displacements in the presence of capillary pressure effects. The one-dimensional (1D) simulator WFLOOD is described with Lagrangian and Eulerian options for refined calculations of saturation distributions throughout all stages of a linear core flood. WFLOOD calculations are presented to demonstrate typical waterflood performance in a 1-m [3.3-ft] core with two different capillary-pressure functions at high and low flow rates.
Steady-state and dynamic brine/tetradecane displacement experiments are described with Clashach sandstone cores that have radioactive ferrocene in the oil phase to measure saturation by a new nucleonic method. Some of the nonuniform character of these cores has been revealed by measurements.
The PORES reservoir simulation model is used for a theoretical analysis of the experiments in which the nonuniform initial saturation distributions must be represented. It is shown that PORES, used in conjunction with measured steady-state relative permeabilities and measured static capillary pressure data, reproduces the time-dependent saturation profiles to within the accuracy of the measurements at high and low flow rates. The Lagrangian treatment in WFLOOD provides a theoretical benchmark that defines the levels of numerical dispersion present in the PORES Eulerian finite-difference calculations.
A theoretical analysis is used to derive a constraint on the form of krw(dpc/dSw), as a function of Sw, which is valuable when capillary pressure functions Pc = Pc(Sw) are chosen for numerical modeling of immiscible displacements.
Percolation Theory of Two-Phase Relative Permeability
Authors: Heiba A. A. , Sahimi Muhammad , Scriven L. E. , Davis H. T. 
Published: December 2007

Summary
This paper uses statistical concepts, some borrowed from the percolation theory of disordered media, to develop a theory of two-phase relative permeabilities in regimes in which one phase is strongly wetting. Inputs to the theory are a network model of pore space, the distributions of pore-throat radii, and functions that relate pore-throat conductance and volume to its radius. The theory with a network model of pore space and several simple statistical distributions of pore dimensions, is found to predict all observed trends in two-phase relative permeabilities of systems in which one phase is strongly wetting. Moreover, the inputs to the theory can be adjusted to fit experimental data closely.
Determining Fracture Orientation From Pulse Testing
Authors: Tiab Djebbar , Abobise Edwin O. 
Published: December 2007

Summary
This paper presents a procedure for determining a complex orientation of a vertical fracture and the formation permeability from pulse testing. Generalized correlations relating the quotient of dimensionless response amplitude and dimensionless cycle period (ΔpD/ΔtcycD) to dimensionless time lag are presented. The correlations can be used for analyzing pulse-test pressure response at an un-fractured observation well resulting from pulsing a vertically fractured active well. Detailed procedures for the design and analysis of pulse testing of a vertically fractured well are presented.
New Oil Mud Passes Environmental Tests
Authors: Hinds Aston A. , Clements William R. 
Published: December 2007

Summary
In recent years, there has been a substantial incréase in the use of oil-based drilling fluids. This widespread use results primarily from the ability of oil muds to handle a variety of potential drilling problems. They have excellent thermal stability, can tolerate solids, salts, and acid-gas contamination, and provide excellent borehole stability. The major concern about oil muds has been their toxicity, especially in regard to marine life when used offshore. Current regulations prohibit the discharge of oil muds and unwashed cuttings offshore.
This paper discusses the performance characteristics of a new, nontoxic oil-mud system. This system employs a nontoxic-mineral seal oil as the base fluid. The emulsifiers are formulated to give minimum toxicity while retaining the excellent temperature and contaminant stability normally associated with invert-emulsion drilling fluids.
The Relationship of Thickening Time. Gel Strength, and Compressive Strength of Oilwell Cements
Authors: Sabins Fred L. , Sutton David L. 
Published: December 2007

Summary
A previous investigation1 of the effect of thickening times on early compressive-strength and gel-strength development has been expanded to include a wider range of well conditions, a greater variety of slurry types, and a more thorough evaluation of static gel strength.
No positive relationship between thickening time and the onset or the rate of static-gel-strength development could be found. With few exceptions, all slurries tested developed values greater than 48 Pa [100 lbf/100 sq ft] gel strength in less than 20 minutes. Data presented show that times needed to develop a specific static gel strength are more closely related to the type of slurry than to thickening time. A calculation method is given for estimating shutdown factor from static-gel-strength data.
New data confirm that 12- and 24-hour compressive strengths are not significantly reduced by reasonable increases in thickening time. The maximum single-stage cement interval without an unreasonable waiting-on-cement (WOC) time for specified compressive strength has been redefined in terms of interval temperature differences.
The Remote-Controlled, Multiangle Bent Sub for Drilling Trajectory Control and Corrections
Authors: Boulet J.G. , Morin P.E. 
Published: December 2007

Summary
A downhole, adjustable, multiangle bent sub, called Telepilote, has been developed for remote control of the wellbore path on a real-time basis without changing the general bottomhole assembly (BHA) configuration. Different modes of actuation for changing the bent sub correspond to different types of construction. The tool is available in 6 3/4-, 7 3/4-, 8-, and 9 1/2-in. [17.1-, 19.7-, 20.3-, and 24.1-cm] nominal sizes. It can be set at six positions, from zero (or straight position) to a maximum angle position of 2 deg. 2 deg.30', or 3 deg. according to nominal sizes. The main construction features and different drilling applications are presented. In addition, the T-3000 Telepilote is described, which features the Telehydrocom (THD) actuator system. This system makes an immediate, direct hookup in the drillstring between the sub and all survey instruments, including measurement-while-drilling (MWD) systems, possible.

Introduction
Worldwide application of directional drilling methods proves that drilling the complete trajectory of a given hole proves that drilling the complete trajectory of a given hole size requires BHA changes. These can be achieved in either rotary drilling or downhole motor drilling with fixed-angle bent subs for controlling and correcting the two basic complementary directional parameters: drift angle and azimuth. Accurate controls and corrections of azimuth are impossible in rotary drilling, while methods with downhole motor and fixed-angle bent subs do not permit the optimization of the drift angle for the hole permit the optimization of the drift angle for the hole profile. Therefore, the application of a downhole deviation profile. Therefore, the application of a downhole deviation tool that is adjustable from the surface makes directional drilling more efficient, saves time, and is more accurate. Such equipment will extend current standard methods for directional control.
The Telepilote is associated with a turbine in a downhole motor. It allows drilling of the complete buildup zone and of the constant-drift-angle zone with the same BHA by a modification of only the multiangle-bent-sub angle from the surface. Thus the need of a round trip either to install an angle sub for the kickoff or to change the BHA is eliminated. A wide variety of applications are foreseeable because of the remotely controlled variable configuration from surface, which can respond to a large variety of worldwide drilling programs and formations with accuracy and efficiency.
Critical Water-Free Production Rates and Gravity-Drainage Rates for Multiwell Systems
Authors: Lehner F. K. 
Published: December 2007

Summary
A formal analogy with plane potential flow is established for the steady or semisteady free-surface flow of a compressible reservoir fluid in horizontally bounded reservoirs or reservoir sections where the permeability is allowed to vary with depth. This leads to simple analytical estimates of critical (maximal) water-free production rates in the presence of bottomwater or of gravity-drainage rates in the presence of a gas cap for single wells and multiwell systems. Reservoir fluid compressibility is shown to have little effect on these rates in most practical situations.
Laboratory Drying Procedures and the Permeability of Tight Sandstone Core
Authors: Soeder Daniel J. 
Published: December 2007

Summary
Core analysis of identical, side-by-side samples of Rocky Mountain tight sandstone indicates that laboratory drying technique strongly affects the measured core permeabilities to gas. Samples dried to constant weight at 140°F [60°C] in a vacuum oven or in an unhumidified conventional laboratory oven have significantly higher permeabilities than identical samples dried to constant weight at 140°F [60°C] under 45% relative humidity. Drying the samples maintains the proper hydration states of swelling (smectite) clays present in "dry" gas-bearing tight sands in the ground. Drying in an unhumidified oven removes this hydration water, causes the clays in the flow paths to collapse, and increases the permeability of the core. This clay damage is irreversible. We recommend that Rocky Mountain tight sands be dried in a controlled-humidity chamber at 140°F [60°C] under 45% relative humidity until the samples reach stable weight. This drying technique will remove all free pore water while maintaining the proper hydration state of swelling clays. Cores dried with this procedure will reflect more accurately the properties of actual tight gas sand reservoirs.
New Skin and Wellbore Storage Type Curves for Partially Penetrated Wells
Authors: Kuchuk Fikri J. , Kirwan Paul A. 
Published: December 2007

SummaryAn analytic solution is derived for the transient pressure behavior of a partially penetrated well when wellbore storage and skin effects are significant. New type curves, generated by this solution, enable the engineer to analyze well test data from partially penetrated wells and to discriminate between near-wellbore damage and pseudoskin caused by partial penetration.
Analysis of Fractured Wells Producing at High Flow Rates Using Late-Time Data
Authors: Guppy Kern H. 
Published: December 2007

Summary
This paper presents a method for analyzing late-time data for high-flow-rate wells that cause turbulent flow within the fracture. Fracture conductivity has been determined on the basis of early-time pressure data. The pseudoradial flow period, however, can be used to check the fracture conductivity by identifying the semilog straight line and by determining the total skin factor. Late-time analysis will increase the confidence in the fracture conductivity. In small fractures, early-time data may not be long enough to calculate fracture conductivities. In these cases, late-time data are the only option available for calculating these fracture parameters.
In high-flow-rate wells, the calculated fracture conductivity is significantly lower than the true fracture conductivity. Methods have been presented for correcting these apparent values to obtain the true fracture conductivity. We have found that early-time correlations cannot be used to correct apparent fracture conductivities obtained in the late-time analysis. This is because the flow regime has changed significantly between the early and late periods. Examples are presented that use either both early- and late-time data or only late-time data for determining the true fracture conductivity.
Electromagnetic Wave Resistivity MWD Tool
Authors: Rodney Paul F. , Wisler MacMillan M. 
Published: December 2007

Summary
This paper is an overview of the development of a 2-MHz [2×106-cycle/sec] measurement-while-drilling (MWD) resistivity logging tool. This tool uses propagating electromagnetic waves rather than the pseudostatic fields of its low-frequency counterparts. The basic theory of operation is presented along with a discussion of the factors that affect tool response and the compromises that led to the specific embodiment. Field data are presented from which a comparison is made between this tool and wireline tools. It is seen that it is often possible to obtain a direct reading of true formation resistivity, Rt, with this tool.
An Efficient Finite-Difference Method for Simulating Phase Segregation in the Matrix Blocks in Double-Porosity Reservoirs
Authors: Gilman J. R. 
Published: December 2007

Summary
An efficient finite-difference method is presented for simulating unsteady-state multi phase flow in the matrix blocks (primary porosity) of naturally fractured systems or other reservoirs that have two different porosities. The scheme obtains pressure and saturation distributions in the matrix blocks (rather than average values) by dividing the matrix into subdomains. The method is an extension of the double-porosity concept in which fractures are the continuum for fluid flow and the matrix rock is the primary storage medium that acts as a source term to the fractures. Examples show that this subdivision results in different recoveries from the conventional double-porosity models when phase segregation in the matrix blocks is important to the recovery mechanism.
In this formulation, the fracture medium is the major flow path to the wellbore with the matrix subdomains as source terms. The matrix subdomains can be connected to each other or to the fractures in any way desired to conform to the physics of the reservoir. This approach lends itself to an efficient scheme for reducing the system of flow equations to the same structure as conventional single-porosity simulators. The method is presented for a fully implicit, one-dimensional (1D), two-phase (oil/water) simulator.
Use of Capillary-Pressure Data for Rapid Evaluation of Formation Damage or Stimulation
Authors: Amaefule J. O. , Masuo S. T. 
Published: December 2007

Summary
Foreign fluids and/or entrained solids introduced during various phases of well development reduce the intrinsic reservoir productivity by blocking the effective flow path. Oil/gas recoveries, therefore, can be enhanced significantly if better quality control is established for all well treatment fluids by assessing rock/fluid and fluid/fluid compatibilities before field use.
A capillary-pressure method, developed for evaluating the formation damage or stimulation potential of well treatment fluids, uses relative changes in pore-entry pressure, shape of the capillary-pressure curve, and residual wetting-phase saturations as measures of damage or stimulation in core plugs exposed to various treatment fluids.
Surfactant Flooding Carbonate Reservoirs
Authors: Adams Wilton T. , Schievelbein Vernon H. 
Published: December 2007

Summary
Some of the most difficult yet most attractive EOR targets are found in the west Texas carbonate reservoirs, where tertiary recovery is complicated by characteristically very low permeability coupled with high hardness and salinity of the reservoir brine. This paper presents data obtained in two well-pair surfactant floods undertaken in the San Andres formation, Bob Slaughter Block, Hockley County, Texas.
To provide the most data in the least time, a close well spacing and relatively large production/injection ratios were used. For each well pair, a different surfactant system was developed, tailored to resist the local aquifer brine salinity and hardness. Consequently, neither system required a preflush. Each test consisted of a large slug of surfactant, followed by biopolymer, fresh water, and formation brine, together with appropriate nonadsorbent tracers. The large slug sizes were intended to allow subsequent designs to be made by interpolation rather than extrapolation. The data provided by these tests demonstrate that (1) low-permeability carbonate reservoirs can be chemically flooded, (2) polymer can be injected and propagated in these reservoirs without any biodégradation, (3) these systems can mobilize tertiary oil effectively at a chemical consumption near that observed in the laboratory, and (4) two-well tests can provide a quick field evaluation of surfactant systems proposed for large-scale use.
A Postflood Evaluation Test of the North Burbank Surfactant/Polymer Pilot
Authors: Lorenz P. B. , Trantham J. C. , Zornes D. R. , Dodd C. G. 
Published: December 2007

Summary
In a follow-up evaluation to a surfactant/polymer pilot in the North Burbank field of Osage County, OK, a test program was designed to determine the relative importance of the various detrimental factors—heterogeneity, crossflow, ion exchange, and partitioning—that lead to nonconformance and degradation of surfactant and polymer slugs. A diagnostic well was drilled within the drainage area of one of the best producing wells for tertiary oil. The location was selected because (1) there was good communication between the injector and producer in this quadrant, (2) it was close to an injector and probably would be swept by injected chemicals, and (3) simulation suggested that a well at this location could encounter several zones swept by surfactant, polymer, and fresh water. Rock, brine, and oil samples were taken and analyzed for sulfonate, polyacrylamide, alcohol, calcium, and residual oil. Comparisons were made with core analyses on adjacent wells at the start of the project and with fluids produced from them.
Chloride and residual oil were low, indicating that the region had been swept and oil displaced. Sulfonate and alcohol were surprisingly high. Surfactant and cosurfactant were segregated, and the slug was markedly displaced toward the Type II+ direction from optimality. No polyacrylamide was detected in the brine or on the rock, suggesting a change in flow patterns that diverted polymer around the region so that sulfonate and alcohol were not fully displaced. These observations indicate that the performance of the pilot was influenced by both heterogeneity and degradation of the chemical slug.