bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation Evaluation of Some Limestone Reservoirs With Particular Reference to Well Logging Techniques
Authors: Finklea Ernest E. 
Published: December 2007

Introduction
Evaluation of carbonaceous rocks as to their productive possibilities was for many years virtually impossible from electrical logs. True, many carbonaceous formations had sections of sufficient homogeneity and thickness that methods of interpretation normally associated with sands could be used with a fair degree of success. Unfortunately, the formations having the proper characteristics for such methods were the exception rather than the rule; hence, the log found little use except as a correlation tool.
In recent years many new logging tools have been presented to the industry with the result that under proper conditions it is often possible to arrive at a satisfactory interpretation of the carbonaceous beds traversed by the drill bit. The so-called "proper conditions" are the key to a successful approach to any logging program or interpretation. However, it is not to be concluded that in every instance the conditions can be controlled or anticipated to the extent that the logs obtained will lend themselves to a simple interpretations Too often the combination of Mother Nature and the limitations of even the latest well logging equipment will result in a log from which the logging experts can do little more than make an educated guess as to its interpretation.
The theory of the various logging devices and quantitative interpretations has been amply covered in the literature. This discussion will concern itself with the more common type of carbonaceous reservoir rocks and approaches that may be made toward their evaluation by means of various logging techniques.
Viewed strictly from a logging standpoint, the depth, lithology, porosity, fluid content, borehole diameter variations, and formation dips are the parameters that may be determined. Those that cannot be determined are permeability and, to a degree, the depth of invasion of the mud filtrate and the physical characteristics of the rock. All of these have been discussed in numerous papers; however, their importance to carbonate formation evaluation is such that it is felt time will not be wasted in reviewing some of the more salient points as related to the examples to be discussed.
A Decline-Analysis Technique Incorporating Corrections for Total Fluid-Rate Changes
Authors: Masoner Lance O. 
Published: December 2007

Summary
Decline analysis inherently assumes a constant total-reservoir-fluid rate in contrast to constantly varying rates in actual field operations. This paper provides an approach for determining decline constants under varying total fluid rates for secondary or tertiary oil recovery processes. It further enables forecasting oil and nonoil production performance under different total fluid rate strategies. The technique helps identify pseudosteady state flow periods when decline analysis techniques are valid. It distinguishes incremental from accelerated oil responses when a recovery process change, operating practices, or workover activity causes a total fluid rate change.
Analysis and Interpretation of Water/Oil Ratio in Waterfloods
Authors: Yortsos Y. C. , Choi Youngmin , Yang Zhengming , Shah P. C. 
Published: December 2007

SummaryAn important problem in water control is the identification of the dominant reservoir or production mechanisms. Recently, Chan (Chan, K.S.: "Water Control Diagnostic Plots," paper SPE 30775 presented at the 1995 SPE Annual Technical Conference and Exhibition, Dallas, 22–25 October) postulated that a log-log plot of the water/oil ratio (WOR) produced vs. production time may be used to diagnose these factors. In this paper we provide analytical and numerical results for a variety of waterflood conditions to explore this possibility.We show analytically that the late-time slope of the log-log plot can be related to the well pattern and the relative permeability characteristics, specifically the power-law exponent in the kro − Sw relationship or the reservoir heterogeneity. Analytical results are provided for the behavior immediately following water breakthrough. In certain simple cases (mobility ratio equal to 1, layered systems), analytical type curves can be derived. In the general case, we use numerical simulation to provide numerical type curves.The results are summarized in terms of the various power-law scalings in different time regimes and by a catalog of numerical type curves. They confirm the potential of WOR-time plots as diagnostic tools for reservoir analysis and characterization.
Performance Evaluation and Formation Damage Potential of New Water-Based Drilling Formulas
Authors: Argillier J. F. , Audibert Annie , Longeron Daniel 
Published: December 2007

SummaryFormation damage risks are well documented for standard mud formulations but they are poorly analyzed for new types of non-polluting muds. This paper describes extensive laboratory work aimed at evaluating the behavior of these new types of mud formulations. First, static and dynamic filtration experiments were conducted on paper filters and rock slices. Examination of mud cakes by means of cryo-SEM has permitted correlation of filtration behavior with the structural characteristics of both external and internal mud cakes. Then, the simulation of the full process of mud invasion in oil-bearing reservoirs was achieved by performing static and dynamic filtration experiments in a specially designed core-holder cell containing 40 cm long sandstone core samples. Cumulative filtrate losses and pressure drops across six sections of the core, while circulating the mud and back flushing the oil, were continuously monitored to evaluate the permeability damage. Damage arising from overbalanced conditions has been evaluated in terms of cake permeability, fluid loss characterization and reduction in oil permeability after mud exposure. For the three mud compositions tested here, the filtration process in high permeability sandstones is mainly controlled by external mud cakes. Damage is severe but an additional damage due to the trapped aqueous filtrate phase can strongly affect the oil relative permeabilities. This approach has given a complete behavior understanding of new water based drilling fluid formulations including evaluation of their performances, limits of use at high temperature and assessment of risks for different operational conditions.
Field Hydraulic Tests Improve HPHT Drilling Safety and Performance
Authors: Isambourg Patrick , Bertin D. L. , Brangetto Martial 
Published: December 2007

Summary
For the Elgin-Franklin UKCS fields, drilling of the high pressure/ high temperature (HPHT) phase is critical due to the narrow margin between formation pore and fracturation pressures. This problem is accentuated by the extreme temperature (up to 205°C— 400°F) and pressure (up to 1,200 bar—17,400 psi). A new generation of down-hole pressure while drilling (PWD) tools allows a better real-time monitoring of the bottom-hole pressure, but cannot withstand the extreme temperature of the entire HPHT phase. Furthermore, down-hole and surface pressures are dependent on complex hydraulic phenomena which make predictions challenging. Consequently, it was decided to perform hydraulic tests before drilling the HPHT section of the well 22/30c-G4 (first Elgin development well), in order to quantify the surface and down-hole pressures and temperatures on several operating conditions: circulating (with and without pipe rotation), tripping and flow check. Gelation tests, trapped pressure as well as pressure transmission tests were also performed. Objectives of these tests were to better understand some complex down-hole physical phenomena, to prepare practical guidelines, before drilling HPHT sections, to check reliability and accuracy of new real-time PWD tools, and to collect accurate well data for further hydraulic software packages validation or improvement. These procedures led to great benefits, both in terms of safety and performance, when drilling the HPHT phases of the well: results were considered as highly positive. This paper details down-hole measurement procedures and results, operational guide lines, tools performances, lessons learnt, and explains how to cope with sources of possible discrepancies between actual values and software predictions.
Evaluating the Transport of Solids Generated by Shale Instabilities in ERW Drilling
Authors: Martins A. L. , Santana M. L. , Campos Wellington , Gaspari E. F. 
Published: December 2007

Summary
The problem of cuttings transport in the inclined sections of extended reach wells (ERW) is a major concern in the oil-well drilling industry. This article presents an innovative time-dependent mathematical model, along with a computer implementation of it, which is based on the well-known two-layer model approach. An innovative feature of this model consists in the consideration of the added amount of solids that comes from the crumbling and cave-in of the wellbore. The unstable effects of this added amount of solids is taken into account through a variable representing the added volume of cuttings per unit time and length. A finite volume approach is used to solve the system of differential equations. The paper represents a first step on the integrated analysis of cuttings transport and wellbore stability problems.
Field Applications of ERD Hole Cleaning Modeling
Authors: Hemphill A. T. , Pogue Tom 
Published: December 2007

Summary
With the ever-increasing measured depths and horizontal displacements in extended-reach (ERD) wells, good hole cleaning remains a major challenge. Recently a hole cleaning model for fluids in laminar flow was presented to the industry. Since its introduction, the model has been used on many occasions to characterize hole cleaning efficiency in post-well analysis, evaluate fluid performance during the drilling of ERD wells, and to predict fluid rheological properties and pump output levels for optimum cleaning in prewell planning. In this paper, four field applications of the hole cleaning modeling in ERD and deviated wells are discussed. In these cases, the hole cleaning model was used to predict intervals of hole cleaning problems and identify certain ranges of fluid rheological properties that promoted good cleaning.
A Simplified Pore Size Distribution Apparatus
Authors: Bucker H.P. , Felsenthal M. , Conley F.R. 
Published: December 2007

Introduction
In the intensive analysis of core samples from oil reservoirs, there is a recognized need for pore size distribution data. Such data, if collected with adequate precision and in sufficient quantity, should contribute to a better interpretation of fluid flow phenomena than is now possible from a knowledge of permeability and porosity data alone. It is hoped, for instance, that pore size distribution data may eventually provide a useful aid for predicting whether a water flood, or other secondary recovery methods, will be successful in a given reservoir.
Apparatus for measuring pore size distribution by mercury injection at pressures ranging from 0 to 2,000 psi have been described in the literature. All of these apparatus are somewhat complex and fairly expensive. Furthermore, the calibration of some of the apparatus is not always easy. Great difficulty, for instance, was experienced in obtaining reproducible pressure-volume correction data for the mercury pump shown in one of the references. An apparatus was therefore developed which was less complicated and less expensive than those of previously described designs. This apparatus is, in some respects, an improved version of a previously described low pressure apparatus (maximum pressure 150 psi) which did not employ a mercury pump but instead used a precision bore glass tube for measuring the injected volumes.
Tests were performed with the apparatus from vacuum to 2,000 psi and it was observed that the apparatus furnished reproducible pressure-volume correction data. In addition, it was noted that the maximum correction was small, precision of measurement was high, and operation of the entire apparatus was relatively easy. Although the apparatus was designed exclusively for samples of 1 in. diameter and 1 in. length or smaller, it could be modified without much difficulty for larger samples, if desired.
Efficient Technique for Inversion of Reservoir Properties Using Iteration Method
Authors: Chu Lifu , Komara Moussa , Schatzinger R. A. 
Published: December 2007

SummaryIn light of the inverse solution theory, an efficient solution procedure has been developed to generate reservoir descriptions conditioned to statistics for rock properties, hard data, and dynamic data. The technique yields realizations for wellbore skin factors at each active well and porosity and permeability which honor a priori information and dynamic production data. The technique invokes inverse solution theory to construct the objective function and uses the gradient method to generate the maximum a posteriori estimates.Differing from the previous works, we derived and implemented a two-loop iteration method to perform the minimization. By using Krylov space-based methods to solve the linear part involved in the minimization, the explicit construction of the sensitivity coefficient matrix is avoided. Complexity analysis and computational results indicate the new algorithm is more efficient than several available methods due to the decrease of the number of the nonlinear iterations demanded for convergence.We also developed a modified procedure for computing realizations using the Chebyshev approximation of the decomposed a posteriori covariance matrix. In this way, the expensive computational cost of the construction and decomposition of the a posteriori covariance matrix is substantially reduced. When estimating multiple categories of parameters, which is the case in this study, our new procedure produces much more accurate results than the conventional Chebyshev method.
In-Situ Sand Consolidation by Low-Temperature Oxidation
Authors: Osman E. A. , Aggour M. A. , Abu-Khamsin S. A. 
Published: December 2007

SummaryLow-temperature oxidation (LTO) of crude oil has been investigated for its potential as a sand consolidation technique. Loose sand (20/30 mesh) saturated with crude oil (18 to 20° API) and brine was subjected to air injection at a low temperature (100 to 150°C) for a period of time (6 to 18 hours). The sandpacks developed compressive strengths ranging between 375 and 1,264 psi. The permeability loss due to consolidation was between 4.5 and 22%.It was found that higher oxidation temperatures reduced the consolidation time and increased the compressive strength; but had no effect on the magnitude of permeability loss. Heavier oils required less oxidation time, caused slightly larger permeability losses, but had an insignificant effect on compressive strength. The presence of clay enhanced the LTO reactions by shortening the oxidation time and increasing the amount of residue deposited on the sand grains. This greatly increased the compressive strength, but at the expense of larger permeability losses. When interstitial water was present with clay, the permeability loss was increased further while the compressive strength was slightly reduced. Acid treatment had no effect on the residue deposited on the sand grains.Experimental testing as well as two predictive models showed that this technique provides sufficient compressive strength to withstand sand-free, high-flow velocities and results in much smaller permeability losses compared with plastic consolidation.It is planned to test the consolidation process in one of the fields in the Middle East. Work is in progress to optimize the process parameters for the conditions of this field to be able to test the process on the first well by December 2000.
Application of Wavelet Transforms to Reservoir-Data Analysis and Scaling
Authors: Panda M. N. , Mosher C. C. , Chopra A. K. 
Published: December 2007

Summary
General characterization of physical systems uses two aspects of data analysis methods: decomposition of empirical data to determine system parameters and reconstruction of the system attributes using these characteristic parameters. Spectral methods, involving a frequency-based representation of data, usually assume stationarity. These methods, therefore, extract only average information and, hence, are not suitable for analyzing data with isolated or deterministic discontinuities, such as faults or fractures in reservoir rocks or image edges in computer vision.
Wavelet transforms provide a multiresolution framework for data representation. They are a family of basis functions that separate a function or a signal into distinct frequency packets that are localized in the time domain. Thus, wavelets are well suited for analyzing nonstationary data. In other words, a function or a discrete data set when transformed into a time-scale space using wavelets shows how it behaves at different scales of measurement. Because wavelets have compact support, it is easy to apply this transform to large data sets with minimal computations.
We apply wavelet transforms to one-dimensional and twodimensional permeability data to determine the locations of layer boundaries and other discontinuities. By binning in the time-frequency plane with wavelet packets, permeability structures of arbitrary size are analyzed. Wavelets are also applied to scaling up spatially correlated heterogeneous permeability fields.
Time-Lapse Seismic Monitoring and Dynamic Reservoir Characterization, Central Vacuum Unit, Lea County, New Mexico
Authors: Benson R. D. , Davis T. L. 
Published: December 2007

Summary
This article presents the results of a multidisciplinary, four-dimensional (4D) (time-lapse), three-component (3C) (multicomponent) seismic study of a CO2 injection project in vacuum field, New Mexico. The ability to sense bulk rock/fluid properties with 4D, 3C seismology enables characterization of the most important transport property of a reservoir, namely, permeability. Because of the high volume resolution of the 4D, 3C seismology, we can monitor the sweep efficiency of a production process to see if reserves are bypassed by channeling around lower permeability parts of the reservoir and the rate at which the channeling occurs. In doing so, we can change production processes to sweep the reservoir more efficiently.
A Long Range Lookahead for Oil and Natural Gas
Authors: Hedlund C.J. 
Published: December 2007

Introduction
We are living in what might be called the "Age of Mineral Energy". This is an era in which increased use of mineral energy is eliminating the drudgery of yesterday and providing a foundation for the technological progress of today and tomorrow.
We in the oil industry are fortunate to be playing a major role in the development of this significant era. The fluid fuels -oil and natural gas - are the most popular and most convenient all-around sources of energy. During 1955, close to 70 per cent of total energy consumed in the United States was supplied by oil and gas. Oil contributed 44 per cent and natural gas supplied 24 per cent.
Enthusiastic public acceptance of fluid fuels has made possible the rapid growth of the petroleum business. The industry itself has a right to be proud of the vigor and resourcefulness it has displayed in developing new sources of supply, new techniques, and new products. Along with success, however, new responsibilities have fallen upon us.
The industry has important responsibilities to its stockholders, to its employees, and to the public. This paper will treat its responsibility for long range supply. Energy is so basic to economic growth that the assurance of an adequate supply of liquid fuels over the years is one of our most important obligations.

Growth Continues with 1955 a New Record Year
We might first examine the historic growth in consumption of oil and gas to see the magnitude of the problem.
Petroleum consumption in the United States was nearly 8.5 million bbl daily in 1955, an increase of about 70 per cent over the less than 5 million bbl consumed in the first postwar year of 1946. It has exceeded by far the most optimistic outlooks made just after the war.
During the nine postwar years the population of the United States increased around 24 millions or 17 per cent. But in this same period the use of oil was growing by 70 per cent. Clearly, we must look beyond mere population growth to explain oil's expansion. The answer lies in the enormous increase which has taken place in petroleum consuming units such as oil burners and vehicles of all kinds.
Scaleup in the Near-Well Region
Authors: Durlofsky L. J. , Milliken W. J. , Bernath A. 
Published: December 2007

Summary
Scaleup techniques are commonly used to coarsen detailed geological models to scales more appropriate for reservoir simulation. These techniques typically generate upscaled permeabilities through solution of the local pressure equation, subject to some type of linear boundary condition. In the near-well region, coarse scale permeabilities computed in this manner may not adequately capture key features of the fine scale flow. In this article, we present a general method for computing accurate coarse scale wellblock transmissibilities and well indexes for vertical wells in two and three dimensions. The method is based on the solution of local well-driven flow problems subject to generic boundary conditions. Simulation results for two-dimensional systems indicate that the near-well treatment always provides improved predictions compared to those obtained using standard methods. In some parameter ranges, this improvement is quite substantial. Several three-dimensional models with vertical wells are also considered and improvement relative to the standard approach is achieved in all cases. Extension of the method to accommodate more general well configurations could result in significantly improved coarse scale simulations of nonconventional wells.
An Effective Matrix Diversion Technique for Carbonate Formations
Authors: Saxon Alan , Chariag Belgacim , Rahman M. R. Abdel 
Published: December 2007

Summary
The removal of formation skin damage from carbonate reservoirs is ordinarily accomplished by stimulation with hydrochloric acid. Uniform coverage of the zone being treated during matrix acidizing stimulations of carbonate reservoirs is an accepted1 requirement for successful treatment. However, the task of achieving efficient diversion and uniform zonal coverage is often difficult because of permeability heterogeneity within the treated interval.
In this article we describe a technique that has been used successfully to divert treating fluids in carbonate formations.
Enhanced Mechanistic Model and Field-Application Design of Gas/Liquid Cylindrical Cyclone Separators
Authors: Gomez L. E. , Mohan R. S. , Shoham Ovadia , Kouba G. E. 
Published: December 2007

Summary
An existing mechanistic model for prediction of the hydrodynamic flow behavior in a gas-liquid cylindrical cyclone (GLCC) separator has been enhanced. The main enhancement incorporated is a flow pattern dependent nozzle analysis of the cylindrical cyclone inlet for prediction of the gas and liquid tangential velocities at the GLCC entrance. Four typical field GLCC systems were designed for actual industrial applications using the proposed model. These include multiphase metering loop with both single-phase and multiphase flow meters, and pre-separation and full separation configurations. The field applications demonstrate the cylindrical cyclone capabilities and its potential impact on the petroleum industry.