bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measuring Oil Flow Rates Using Standard Oil-Gas Separators
Authors: De Wit H.P. 
Published: December 2007

Abstract
Methods are described of measuring flow rates and total liquid produced from oil wells using standard oil-gas separators. These methods are now used for normal production controls in several fields by Compania Shell de Venezuela.
The development of the weight-type metering separator used for well gauging of foamy crude during the past four years is described.
The object of this type of metering is to increase both frequency and accuracy of well gauging in the field and, at the same time, to reduce labor costs and capital investment on new installations.

Introduction
For continuous optimum production in an oil field, frequent and reliable individual well gauges, in addition to accurate bulk production measurements, are essential.
In those fields which have a large number of wells, however, because of restricted manpower it is not always possible to realize either the accuracy or the frequency of well gauging necessary for the most efficient running of the field.
All metering systems on the market based on the volume principle are not very suitable for our types of heavy viscous crudes because too much gas stays trapped in the oil and results in inaccurate readings.
In an attempt to improve the accuracy of well gauging operations, while at the same time reducing manpower and installation costs, experiments were initiated during 1954 to ascertain whether this could be achieved satisfactorily by counting and registering automatically on a chart the number of filling stages over a certain period of time of a standard vertical separator of known dimensions. A method was finally developed whereby it is possible to record the time to fill a vertical separator between predetermined levels and, at the same time, to record the weight of crude in each filling stage on a differential pressure chart, thus allowing the average throughput of crude through the separator to be calculated.
To date, this method has proved satisfactory and is used with success for both well gauging and bulk measurement of crude in block stations.
Installation of the Central Production Facilities Deck for the Mokoko-Abana Field, Cameroon
Authors: Gatto A. W. 
Published: December 2007

Summary
Summary. To reduce development costs at the Mokoko-Abana field, all production equipment was installed in deck units during fabrication and the equipment was precommissioned in,the contractors’ yards before loadout. The 5,000-ton [4500-Mg] central production facilities deck, however, exceeded lifting capabilities of available marine equipment, so a unique installation technique was developed that uses tidal changes and rapid barge ballasting to lower the completed deck onto a specially designed jacket.
High-Temperature Sand Consolidation
Authors: Friedman R. H. , Surles B. W. , Kieke D. E. 
Published: December 2007

Summary
A sand consolidation system has been developed that is stable to wellbore temperatures of 700°F [371°C]. Two improvements in technique have contributed to this development. First, a controlled quantity of catalyst is adsorbed on the sand. Consequently, consolidation occurs only on or very near the sand grains, resulting in a high-permeability consolidation. Second, the reaction is driven to completion by avoiding, insofar as possible, the adverse effect of water. The resin used for the consolidation is a very viscous derivative of furfuryl alcohol that requires a diluent to make it injectable. The diluent used to reduce viscosity is a hydrolyzable ester. The diluted fluid, which is still more viscous than water, displaces much of the water present in the pore space. During the catalyzed consolidation, water produced by the polymerization is removed by reaction with the diluent (hydrolysis of the ester). The high-molecular-weight polymeric consolidation is better able to resist the high temperatures encountered in steam-displacement producing wells. Adaptation of the technology has been made so that the process can also be used in low-temperature wells. Because of the catalysis method, long shelf life is guaranteed for the consolidating formulation.
Simulations of Naturally Fractured Reservoirs
Authors: Dean R. H. , Lo L. L. 
Published: December 2007

Summary
This paper describes a three-dimensional (3D), three-phase, black-oil model being used to simulate naturally fractured reservoirs. The program is fully implicit and can perform single-porosity, dual-porosity, or dual-permeability computations. Sample simulations are presented to illustrate the differences between the three computational techniques. Single-porosity recoveries are much larger than the recoveries predicted by the dual techniques. The dual-permeability, primary-depletion recoveries are very similar to the dual-porosity, primary-depletion recoveries, while the dual-permeability waterflood recoveries are significantly larger than the dual-porosity waterflood recoveries.
Pseudocapillary pressures are generated from fine-grid, single-matrix block studies. The pseudocapillary pressures are then used in the dual-porosity simulations to account for fluid distributions in the matrix and fracture systems.
Chemical Equilibrium Models: Their Use in Simulating the Injection of Incompatible Waters
Authors: Bertero L. , Chierici G. L. , Gottardi G. , Mesini E. , Mormino G. 
Published: December 2007

Summary
One of the problems encountered in waterflooding projects is scale formation caused by chemical incompatibility between potential injection waters and reservoir brine. Chemical compatibility evaluation through laboratory experiments on cores at reservoir conditions is of limited value because only first-contact phenomena are reproduced. A numerical model is presented that couples a reservoir-fluid-flow/thermal-equilibrium simulator with a chemical-equilibrium computer code. This model, AGIPS, enables us to calculate the evolution in time of the amount of scale formed at any point in the reservoir and inside the wells when changes occur in the temperature of the injected water and when the injection water mixes with reservoir brine. Moreover, the model calculates temperature and pressure profiles in the reservoir, together with their evolution in time, taking into account the permeability reduction caused by scale formation. Results are presented for the chemical-equilibrium code validation by matching experimental data on scale formation in mixtures of incompatible waters. An example is also given of the use of AGIPS in simulating a five-spot waterflood where incompatible water is injected.
Effect of Oil Composition on Minimum Miscibility Pressure—Part 2: Correlation
Authors: Orr F. M. , Silva M. K. 
Published: December 2007

Summary
A new correlation for CO2 minimum miscibility pressure (MMP) is proposed and tested. The correlation is based on experimental evidence that extraction of hydrocarbons from a crude oil depends most strongly on the size of the hydrocarbon molecules. Thus, an oil rich in hydrocarbons that are efficiently extracted should show a lower MMP than a heavier oil. The only crude-oil data needed for use of the correlation are a carbon-number distribution, which can be obtained easily by chromatography. The density of CO2 at the MMP is correlated against a weighted-composition parameter. The MMP of any oil at a given temperature is estimated as the pressure required to yield that CO2 density. The effects of contaminants in CO2 can be estimated easily by calculating the pressure required to give a mixture density equal to that required for pure CO2.
Correlation accuracy was tested by comparing predicted and measured MMP's for 35 oils. The proposed correlation produces MMP estimates accurate to within about 10% for most oils. Comparison of correlation predictions with those of other commonly used correlations indicates that the proposed correlation is significantly more accurate, particularly for recombined oils.
Laboratory Evaluations and Field Testing of Silica-CMHEC-Cement Mixtures
Authors: Rust C.F. , Wood W.D. 
Published: December 2007

Introduction
The discussion which follows represents a report on laboratory evaluations and field testing of silica-carboxymethyl hydroxyethyl cellulose (CMHEC)-cement mixtures. While the major part of the laboratory work reported, and all of the field tests, were carried out in Mobil Oil Co.'s operations in Venezuela, the work received its impetus at the Magnolia Petroleum Co. Field Research Laboratory (now Socony Mobil) in Dallas, a Mobil affiliate. Laboratories of other companies have been active in this area of cementation methods, although very little data are available in the literature.
Extensive laboratory tests, involving the use of a high-temperature consistometer in conjunction with high-temperature curing baths, have indicated that at temperatures exceeding 250°F oilwell cements of all types develop undesirable properties. These tests show that at elevated temperatures compressive strengths retrogress and become dangerously low near a temperature of 300°F. This fact is illustrated in the upper part of Fig. 1, which represents a plot of compressive strength vs time for an oilwell Class E cement at various temperatures. This figure shows that at 180°F compressive strengths build up and remain essentially constant with time. At 260°F, high strengths are realized early but pass through a maximum and then decline. At 320°F, the maximum compressive strength is reached in less than 24 hours and is much lower than at the lower temperatures.
This is not the only detrimental factor which affects the properties of a cement cured at high temperatures. Fig. 2 illustrates that corresponding increases in permeability accompany the strength retrogression. At 320°F, the permeability of this sample increased from 4 X 10(–6) to 2,780 X 10(–6) darcies.
Fortunately, these deficiencies can be corrected by the use of proper amounts of silica. The lower part of Fig. 1 shows the effect on compressive strength when 35 parts of silica are added to 100 parts of Class E cement. For a curing temperature of 180°F, maximum compressive strength is obtained more slowly but reaches the same order of magnitude as in the case of neat cement. For a temperature of 260°F, an increase in compressive strength is realized, with no evidence of subsequent retrogression apparent. At 320°F, an initial strength is observed which is not only satisfactory but which, for all practical purposes, remains constant. The effects on the water permeability of adding 22.5 parts of silica to 100 parts of Class E cement are shown in the lower right-hand portion of Fig. 2. The water permeability decreased with curing time and is much lower than in the case where no silica was used.
A New Test for Determination of Individual Layer Properties in a Multilayered Reservoir
Authors: Ehlig-Economides Christine A. , Joseph Jeffrey 
Published: December 2007

Summary
Many wells penetrate several layers, and flow from each layer is often commingled during production or injection. The behavior of pressure transients for layered systems has been studied in detail for two types of systems: (1) layers that are separated by impermeable barriers (no formation crossflow) and (2) layers that communicate in the reservoir. In this work, the general problem of n homogeneous layers, in which any two adjacent flowing layers may or may not be crossflowing in the formation, is solved analytically. Properties, including permeability, porosity, layer thickness, the wellbore skin factor, and the vertical permeability between crossflowing layers, are distinct for each flowing layer. Wellbore storage effects are also included, and solutions are provided for both infinite-acting and bounded systems.
The key to finding the individual layer properties in a given reservoir lies in the interpretation of the transient flow rates from each layer following a change of the total flow rate for the well. Pressure transients are also used in the analysis. The limiting forms of the analytic solution are used to identify certain characteristic patterns in the flow-rate transients that provide the means for determining the individual layer properties.
The methods used in this analysis are entirely new. An example of the interpretation method is provided.
Distribution and Permeability of Stylolite-Bearing Horizons Within a Lower Cretaceous Carbonate Reservoir in the Middle East
Authors: Koepnick R. B. 
Published: December 2007

Summary
Stylolites and related pressure-solution features occur in many carbonate reservoirs. They are seams of insoluble residue that record the removal of rock by pressure dissolution. Stylolites may limit reservoir continuity by forming barriers or impedances to fluid flow. This core-based study documents both the distribution of stylolites and the variable impact of stylolite-bearing horizons on reservoir continuity for a Lower Cretaceous carbonate reservoir in the Middle East.
The Effects of Mud Rheology on Annular Hole Cleaning in Directional Wells
Authors: Okrajni Slavomir S. , Azar J. J. 
Published: December 2007

Summary
The effects of field-measured mud rheological properties on cuttings transport in directional well drilling were studied experimentally. Water and bentonite/polymer muds were used, and angles of annulus inclination ranging from 0 to 90° from vertical. Experimental data were processed to express the cuttings transport quantitatively through annular cuttings concentration (vol%) at steady state.
Three separate regions of hole inclination can be identified regarding cuttings transport: 0 to 45°, 45 to 55°, and 55 to 90°. The effect of laminar flow dominates cuttings transport in low-angle wells (0 to 45°). In high-angle wells (55 to 90°), the effect of turbulent flow predominates. In the range of intermediate inclination (45 to 55°), turbulent and laminar flow generally have similar effects.
In laminar flow, higher mud yield values and yield-point/plastic-viscosity (YP/PV) ratio provide better cuttings transport. The effect of mud yield value is significant in the range of 0 to 45° hole inclination and becomes small or even negligible in the range of 55 to 90°. The effects of mud yield value and YP/PV ratio are more significant for lower annular fluid velocities. In turbulent flow, the cuttings transport was generally not affected by the mud rheological properties.
Postanalysis of Abnormal Cementing Jobs With a Cementing Simulator
Authors: Smith R. C. , Beirute R. M. , Holman G. B. 
Published: December 2007

Summary
Postanalysis often cannot be applied because of lack of prediction and real-time performance data. Proper postevaluation includes collection of actual job performance data and comparison with predicted cementing performance. A comprehensive cementing simulator is required that accounts for fluid properties, well geometry, changing displacement and mud return rates, and the free-fall effect. Such a simulator has been used successfully in the design of many cementing operations and quite frequently in actual jobs to monitor the progress of the operation. In this paper, case histories are presented to show how this model and on-site measurements can be used for postevaluation of cementing jobs that did not perform as predicted. Two examples illustrate job problems caused by a restriction either in the annulus or in the casing; a third case points out problems associated with use of improperly calibrated pressure gauges during a cementing job.
Steady-State Tar/Water Relative Permeabilities in Peace River Cores at Elevated Temperature
Authors: Closmann P. J. , Waxman M. H. , Deeds C. T. 
Published: December 2007

Summary
On the basis of Peace River bitumen/brine flow experiments at elevated temperatures, tar relative permeability/saturation relations vary depending on the previous thermal history of the tar. The relative permeability curve for thermally unaltered tar is shifted toward the region of low water saturation, while that for thermally altered tar is closer to the Leverett oil permeability curve for water-wet unconsolidated sands. Oil permeability values for deasphaltcd tar lie at saturations intermediate between those of the thermally altered and unaltered tar.
Gas Reservoir Decline-Curve Analysis Using type Curves With Real Gas Pseudopressure and Normalized Time
Authors: Fraim M. L. , Wattenbarger R. A. 
Published: December 2007

SummaryA normalized time has been developed that linearizes the rate decline vs. normalized time for a gas reservoir producing against constant wellbore pressure during (external) boundary-dominated flow. This allows type-curve matching of the exponential decline curve for a reservoir with any shape. Values of G, kgh, and kg/ϕ can be determined from this type-curve match. It was determined that gas reservoir depletion plotted vs. actual time does not match exponential, harmonic, or hyperbolic decline curves, and future performance can lead to overestimates of reserves and future rate.
A New Technique for the Evaluation of Shale Stability in the Presence of Polymeric Drilling Fluid
Authors: Lu Cheng-Fa 
Published: December 2007

Summary
A quantitative evaluation technique for shale stability in a polymeric medium has been developed with a rheological method. The storage modulus of a shale pellet immersed in a drilling fluid is used to predict the shale-inhibitive properties of the fluid. Polymer concentration, molecular weight, carboxyl sUbstitution, and KCI concentration are important parameters affecting shale stability.
Acoustic Determination of Producing Bottomhole Pressure
Authors: McCoy James N. , Podio Augusto L. , Huddleston Ken L. 
Published: December 2007

Summary
This paper discusses the acoustic determination of producing bottornhole pressure (BHP). Two different techniques are presented for wells that have liquid above the formation and gas flowing upward through the gaseous liquid column. One technique involves the acoustic measurement of the liquid level and the casing-pressure buildup rate when the casinghead valve is closed. When these data are used along with an empirically derived correlation given here, the gradient of the gaseous liquid column in the annulus can be obtained. This technique offers a reasonably accurate procedure for determining the producing BHP of a well by acoustic means. The second method involves two acoustic measurements. A backpressure valve is used in the casing head to depress and to stabilize the liquid level at two positions while the well is produced at a constant rate. The gradient of the gaseous liquid column is then calculated and extrapolated to the formation depth.
This paper discusses results from the field testing of numerous wells where the actual gradients of gaseous liquid columns were measured in a variety of casing/tubing sizes, oil gravities, gas flow rates, and pressures.
Influence of Shear History at Bottomhole Temperature on Fracturing-Fluid Efficiency
Authors: Harris P. C. , Penny G. S. 
Published: December 2007

SummaryThe effects of downhole environmental conditions on fracturing-fluid rheology and leakoff were evaluated in a flow loop at simulated fracture conditions. Linear and crosslinked gel fluids were subjected to shear rates of 50 to 100 seconds−1 past core for 4 hours at temperatures of 75 to 250°F [24 to 121°C].Nonlinear effects commonly observed with crosslinked gel fluids diminished as the fluid was sheared. Shearing for 30 minutes to 4 hours at 100 seconds−1 before a fluid-loss test was run resulted in leakoff following square-root-of-time behavior. Spurt loss increased for crosslinked gel fluids as the fluid degraded, whether by enzyme or oxidative mechanism. The leakoff coefficient decreased slightly with time under shearing conditions. Although the polymer was breaking, the absolute amount of polymer available for deposition did not change.The apparent viscosity of fluid remaining within the fracture was also investigated. During initial fluid leakoff, polymer was concentrated as a gel filter cake at the fracture face. Once an equilibrium filter-cake thickness was achieved, however, fluid loss to the formation resulted in an increase in the polymer concentration in the remaining fluid and hence an increase in apparent viscosity.
Inverse Lumping: Estimating Compositional Data From Lumped Information
Authors: Schlijper A. G. , Drohm J. K. 
Published: December 2007

Summary
Many methods of characterizing reservoir fluids thermodynamically yield equation-of-state (EOS) models with a large number of components. For simulation studies, this detailed compositional model is subsequently replaced by a simplified model in which compositions are described with a limited number of groups or pseudocomponents. This paper discusses methods of translating group (pseudocomponent) compositions into detailed component compositions, a procedure that will be referred to as "inverse lumping." Inverse lumping can be used to calculate phase properties in the group (pseudocomponent) model. This eliminates the need to construct ad-hoc property correlations. Another application would be to inverse lump the well streams as predicted by the simulator so that the results can be used in a fully compositional separator-system simulator.
Some Case Histories of Remedial Work Resulting from Water Tracer Surveys
Authors: Ford Walter O. 
Published: December 2007

Abstract
Use of water tracer surveys to improve the over-all performance of waterfloods has long been recognized. Remedial work to water injection wells is becoming more important as the ratio of secondary reserves to primary reserves increases. While the proper use of tracer surveys does not necessarily mean a workover after every survey, too little significance is often given surveys where they could be of real productive use. This paper lists several case histories where tracer surveys were run and properly analyzed, resulting in thoughtful remedial work. What actual effect this remedial work had on production in the immediate area it also shown, when available.
Introduction
During the past 10 years, waterflood operators have tended to rely more on the use of quantitative water injection profiles. Though there are several different types and methods being used today to obtain this quantitative information, this paper will not discuss their principles or merits; rather, the assumption is made that quantitative water injection profiles can be run by a variety of service companies. Concern over what can and has happened from this point is the basis of this paper. This work was undertaken to present evidence from actual case histories where water tracer surveys were used, relied upon and found capable of being highly informative and of utmost practical value. During the search for such histories, an effort was made to stay away from examples where evaluation of remedial work could only be done at the injection well. Instead, examples are sought where direct production results confirmed proper water tracer survey evaluation of injection well remedial work, regardless of its success. This had a tendency to lead the author away from any but the most positive cases-where any cause for production changes, other than the success or failure of the remedial work, was extremely remote. Case History 5 is somewhat of an exception to this aim.
Case History 1
This case history was taken from a dolomite flood in which a northwest-southeast breakthrough system had been indicated (Fig. 1). Well 63 was converted to water injection in March, 1964. By June, 1964, Well 124 started to increase in water production with no increase in oil production (Fig. 2). This trend continued until Well 124 was producing over 100 BWPD and very little oil (2 to 3 B/D).
JPT
P. 791ˆ