bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reversible Invert Emulsion Drilling Fluids: A Quantum Leap in Technology
Authors: Patel A. D. 
Published: December 2007

Summary
A novel, invert emulsion fluid useful in the drilling, completion, and workover of subterranean wells has been invented. The new invert emulsion drilling fluid can readily and reversibly be converted from an invert, i.e., water-in-oil emulsion, to a regular, i.e., oil-in-water emulsion, and back to the original invert emulsion using an acid-base chemical switch. The surfactants used in the reversible invert emulsion fluids are strong invert emulsifiers in the presence of lime. However, the same surfactants become regular emulsifiers in the presence of water-soluble acid. The reversible emulsion property of these surfactants allows the drilling fluid to be changed from an invert emulsion to a regular emulsion at different stages of the drilling/completion operation. During the drilling stage, the drilling fluid can be an invert emulsion achieving all the performance benefits associated with oil-based muds (OBMs). During the completion stage and afterwards, the emulsion can be reversed by adding water-soluble acid, thus providing excellent filtercake cleanups, improved production in an openhole completion, better cementing, and efficient cuttings cleanup and waste minimization. The reversible system is simple and easy to run without any exotic changes in current operations or other additives than those commonly used in OBMs. The reversible drilling fluid is versatile and relatively inexpensive and versatile, especially as compared to new, exotic fluids on the market today. The reversible feature allows the mud to achieve performance, production, minimal environmental impact, and cost control. The paper discusses the overall impact of reversible invert emulsion technology in meeting the environmental and functional requirements of drilling operations. The laboratory data show that this system can provide drilling performance similar to OBMs at various oil/water (O/W) ratios, mud weights, and in the presence of commonly encountered contaminants. This paper compares the new reversible fluids with previous state-of-the-art invert emulsion drilling fluids. These new stable, reversible invert emulsion drilling fluids can readily be reversed to regular emulsions using inorganic acids such as hydrochloric acid or organic acids such as citric acid. The paper discusses the application of reversible emulsion technology on efficient removal of filter cake and improved production in openhole horizontal well completions. The environmental impacts of this system on washing and disposal of drilled cuttings are discussed.
Can We Sample the Complete Geological Uncertainty Space in Reservoir-Modeling Uncertainty Estimates?
Authors: Massonnat G. J. 
Published: December 2007

Summary
The method by which the space of uncertainty should be sampled in reservoir models is an essential point of discussion that can have a major impact on the appraisal, development and economics of hydrocarbon fields.
Usually, uncertainty is assessed by way of many realizations of a given stochastic model with fixed parameters but this does not adequately sample the complete geological uncertainty space and it underestimates the uncertainty.
To improve the uncertainty assessment, in this article we propose a classification and hierarchy of the sources of internal reservoir architecture uncertainty.
The impact of the different levels and sources of uncertainty on elements such as original hydrocarbons in place or final recovery is quantified.
In this article we demonstrate that decisions as significant as stationarity, organization of reservoir heterogeneity, choice of the global statistics and variogramme range are of prime importance in relation to the other parameters. Furthermore, we also prove that the relative importance of any parameter in assessing the uncertainty depends on the type of result—volumetric or dynamic—on which the uncertainty calculation is computed.
Uncertainty of the global mean provided by hard data is assessed using sampling techniques.
The coefficients of variation obtained from many field cases allow a comparison between the different distributions. It lends support to the hierarchy of the sources of geological uncertainty into six levels.
The evolution of this uncertainty with the quantity of hard data, wells, and the quality of knowledge, zoning, has been quantified using synthetic models and a field case.
Both a general function for the decrease of uncertainty with the quantity of the data, and a possible increase—for some parameters—of uncertainty estimates with knowledge development are demonstrated herein.
Detailed Response of Some Rock Targets to Jets from Lined-Cavity Shaped Charges
Authors: Austin Carl F. , Pringle J. Kenneth 
Published: December 2007

Abstract
The U. S. Naval Ordnance Test Station has a continuing program of applied research in rock and earth dynamics. One aspect of this program has been the investigation of rock masses subjected to jet attack from lined-cavity shaped charges. The detailed testing of rock response has been carried out in air using dry bulk targets of sufficient size to preclude gross target fracturing during penetration. Overcoring methods have then been used to remove the penetration area to permit section in g and studying the hole walls. During these tests two distinct modes of penetration wall response were observed. One mode is well illustrated by coarse-grained silicate rocks which yield penetrations with severe adjacent grain damage plus significant compaction and stored energy, which is slowly released by failure of the hole walls. The second mode is illustrated by limestone, which gives virtually no megascopic damage adjacent to the hole and which is stable following penetration. Under proper conditions, however, the limestone samples consistently yield liner-metal and liner-metal-oxide filled fractures adjacent to the penetration. Tests were also performed which permitted evaluation of the effect of gross target fracturing during penetration, and evaluation of the concept of rock density as a criterion of penetration depth.
Introduction
The mechanisms of jet formation by various configurations of lined-cavity shaped charges and of penetration in metallic targets have been extensively reported in the technical literature. Jet penetration into rock and earth materials has been investigated in conjunction with mining uses and a considerable body of technical literature established on the petroleum industry applications of shaped-charge phenomena. Examination of these many publications reveals that the details of the response of rock targets to the jet penetration process are not well known. The studies reported in this paper were performed to establish the detailed response of rock targets in air to jets from lined-cavity shaped charges and, as such, do not necessarily represent down-hole, well phenomena. The rocks selected for testing are representative of broad groupings of geologic materials that occur in bulk on the earth's surface, but only the general materials applicable to the petroleum industry are discussed. Although the igneous rocks, per se, are of minor interest to petroleum engineers, these rocks are occasionally important reservoir rocks. Furthermore, the igneous rocks, despite their limited occurrence as reservoir rocks, offer a wealth of pertinent data on general rock behavior. The behavior of igneous rocks is also believed to be representative of the behavior of dense, hard, low porosity silicate rocks in general. Quartzites, strong sandstones and many metasediments are believed to belong in this grouping of materials.A set of standard definitions of penetration effects must be established in order to permit a useful discussion of jet penetration phenomena.
JPT
P. 41^
A Field Streaming - Potential Experiment
Authors: Gondouin M. , Hill H.J. , Waxman M.H. 
Published: December 2007

Abstract
Streaming-potential experiments were conducted within the Muddy- and Dakota-sandstone interval of a Denver basin well. Analysis of the data shows that, for this case, streaming potentials opposite sands were higher than those opposite shales when the mud was fresh. Streaming potentials opposite shales, however, were of sufficient magnitude to be important in SP interpretation. They were linearly dependent upon pressure differential, and they increased with mud filtrate resistivity. The magnitude of streaming potentials opposite sands was influenced by the characteristics of the original mud cake formed at the time of drilling. Use of mud samples taken at the time of logging may not always be satisfactory for determining streaming-potential corrections. Both the streaming and electrochemical potentials were found to be affected by the previous history of the borehole system. Following a change in mud characteristics, several days were required for SP stabilization. This was, in part, due to the mud cake acting as an imperfect shale membrane.

Introduction
Laboratory investigations by Wyllie, Salisch, Moore, Sen Gupta and Bannerjee, and Hill and Anderson have shown that streaming potentials developed across mud cakes deposited on permeable filter beds are of sufficient magnitude to be critically important in SP interpretation. Streaming potentials across shales have been reported by Schenck, Gondouin and Scala, and Hill and Anderson. The magnitude of the shale streaming potentials obtained by Schenck and by Gondouin et al led these authors to conclude that in many cases the shale streaming potential would approximately equal the mud-cake streaming potential. Hill and Anderson, however, obtained somewhat lower magnitudes of shale streaming potential. The field experiment described in the present paper was a cooperative project carried out by the respective operations and research departments of Schlumberger Well Surveying Corp., Shell Development Co. and Shell Oil Co. The primary objective of the experiment was to determine in the borehole the streaming-potential behavior of both shales and mud cakes under conditions approaching, as nearly as possible, those normally encountered in logging practice.

METHODS AND EQUIPMENT

WELL
A Muddy- and Dakota-sandstone well in the Denver basin was chosen for the experiment. Both sandstones were water-bearing and, since reservoir pressures in these sandstones are abnormally low (gradient of approximately 0.25 psi/ft), it was expected that studies of streaming potential could be conducted from low-pressure differentials (approximately 200 psi) to about 2,000 psi by bailing mud from the hole, filling up and then applying wellhead pressure.
JPT
P. 305^
First Pacific Coast Permanent Drilling Island Modified to Allow Drilling of 70 Wells
Authors: Pyles E.E. 
Published: December 2007

The first permanent drilling island constructed on the Pacific Coast is now being modified to provide surface locations for the drilling of a total of 70 wells, The small circular Monterey Oil Co.- The Texas Co. filled island, 1 1/2 miles offshore from Seal Beach. was originally designed for the drilling of only three wells. Now, through the construction of a raised floor to provide additional cellars, this small island is expected to provide adequate surface drilling sites from which to develop the lease.
When this modification has been completed, about the end of this year, the little island will provide probably the densest concentration of drilling sites anywhere in the world.
The circular island is 75 ft in diameter and is located in 45 ft of water. A rectangular wharf 74 ft by 51 ft extends shoreward from the island. A group of four pipelines connects the island to a separation and shipping center onshore. Nine wells have been drilled from the island to date, and the tenth one is now being drilled.
The outer rim of the island is formed of interlocking sheet steel piling driven into the ocean floor to a depth of 15 to 20 ft. The interior is filled with rock and sand. A series of parallel reinforced concrete beams across the island carries the working load. Each beam is supported by a line of wood piling. The reinforced concrete floor rests on the beams and sand fill. The construction of the raised floor above the original concrete floor is now in progress. Through this addition the island, which was once considered supplemental only, will become a very valuable surface property from which to develop the extensive oil reservoir. The operators have spend approximately $750,000 in connection with island construction.

Early History of the Lease
In 1944 the Marine Exploration Co., one of the predecessors in interest of Monterey Oil Co. and The Texas Co., obtained rights to drill for oil offshore at Seal Beach by obtaining state lease which was the predecessor of the present State Lease PRC 186.1. This lease begins at the Seal Beach shoreline and extends 3 miles seaward. The drilling of the first two wells was done from a land location in the City of Long Beach, County of Los Angeles, 2.500 ft inland front the water's edge.
Application of the p'D Function to Interference Analysis
Authors: Djebbar Tiab , Anil Kumar 
Published: December 2007

A technique for analyzing interference test data is presented that employsthe time rate of pressure change - the pD' function. Thisfunction exhibits a maximum value of 0.736 at atD/rD2 of 0.25 for an idealline-source well. Several field examples are included to demonstrate theapplication of this technique in determining transmissibility (kh/µ) andstorage (fch) between a well pair.

Introduction
It has been pointed out that interference tests1 may be run withgreater ease and may take less time than pulse tests2,3 to developin-situ reservoir properties such as transmissibility (kh/µ) and storage(fch). An interference test consists of recording the transient pressureresponse at an observation well caused by a constant rate change at some sourcewell. The pressure response can help determine formation continuity, fracturesorientation, and areal average transmissibility and storage between a wellpair.
Interference pressure data can be analyzed by (1) least-squares regressionanalysis coupled with a two-dimensional single-phase compressible-fluidreservoir simulator4,5 and (2) type curve matching6,7techniques. A rapid hand analysis method1 requires the recognitionof the maximum slope line on pressure response ?p vs. time curve plottedon a rectangular coordinate paper. This slope is used to determine thetransmissibility (kh/µ). The intercept of this line on the time scale isused to obtain storage (fch) between the well pair.
The slope of the line gives the maximum value of the time rate of change ofpressure at the observation well. This maximum slope occurs at the inflectionpoint of the ?p vs. time curve. The time to reach this maximum slope ofinflection point is also a characteristic of the system and, therefore, can beused to determine the storage (fch) between the well pair. The examplespresented in this paper will illustrate this technique.
In view of the above, it is necessary to develop the behavior ofpD' at an observation well due to a constant-rate source wellfor a proper understanding of interference test behavior. The wellbore storageeffects are assumed to be negligible at this source or active well. This ispresented in the next section in terms of dimensionless quantities forsimplicity. In later discussion, equations in oilfield units are used.
It is emphasized here that the pD' function has been usedbefore in petroleum literature for water influx8–10 and wellborestorage11,12 calculations. Further, pD' behaviorhas been employed in detection of reservoir boundaries.13–15 Theseapplications will not be discussed in this report.
High-Rate Foam Fracturing: Fluid Friction and Perforation Erosion
Authors: Harris P. C. , Pippin P. M. 
Published: December 2007

Summary
Foam fracturing treatments pumped down 3.5 to 4.5 in. tubing at up to 80 bbl/min have presented problems in control and execution. Wellhead pressures used to predict net entry pressure can give erratic results in the absence of good knowledge of bottom-hole pressure. Since nitrogen ( N2) delivery rates are pressure sensitive, errors in bottomhole pressure estimation control problems with both rate and foam quality. Perforation erosion, if unaccounted for, can signal a need for increase in rate to maintain bottomhole pressure.
We used a laboratory study of foam in laminar and turbulent flow and a series of field experiments with bottomhole gauges to calibrate foam friction pressure in tubulars at very high rates. To measure viscosity of foam fluid with N2 at 1,000 psi, we used a small-scale, flow loop viscometer that could be applied in both laminar and turbulent flow. Foam parameters included foam qualities from 25 to 80% N2, and guar concentrations from 0 to 40 lbm/Mgal. The effect of surfactant concentrations from 0.2 to 1.0% were also studied.
Field foam treatments pumped at high foam rates were equipped with bottomhole real-time transmitting gauges. Step-rate tests were performed on both neat foam and sand-laden foam to calculate friction pressures. Actual friction pressures from these treatments were compared with pressures based on laboratory data. The laboratory correlation can predict tubular friction accurately for foam fluids up to very high foam rates.
In several of the treatments, small perforations were used in an attempt to provide limited entry stimulation. With the bottomhole-gauge data, we were able to assess the effects of perforation erosion due to changes in sand concentration.
Case History of Reservoir Subsidence and Wellbore Damage Management in the South Belridge Diatomite Field
Authors: Dale B. A. , Narahara G. M. , Stevens R. M. 
Published: December 2007

Summary
Production of fluids from the shallow, thick, and low-strength Diatomite reservoir in the South Belridge Field has resulted in reservoir compaction, surface subsidence, and numerous well failures. The most severe subsidence problems occurred while the field was under primary recovery, prior to implementation of waterfloods for pressure support. Consequently, a significant number of wells in the field have incurred casing damage, which proportionately limits the utility of these wellbores for continued production and routine wellwork operations. The nature of casing damage varies significantly depending on the location in the field, however casing shear ("kinks") generally produces the most severe problems in retaining full wellbore utility since it limits tool passage (e.g., packers, scrapers, etc. ) and is not economical to repair using conventional milling tools.
Since the mid-1980s, surveillance has been in place to monitor and assess the magnitude and progression of surface subsidence, reservoir compaction, and wellbore damage in Exxon's operations of Section 19 in the South Belridge Field. The surveillance includes the use of ground elevation markers and a variety of production logs—several of which involve novel application and log interpretation. These data subsequently were used to develop and verify hybrid geomechanics and wellbore geometric models for assessing casing damage, identifying well operability and wellbore utility limits, and forecasting the remaining wellbore life from which a reservoir management plan and wellbore management operational strategies were established. A key ingredient in the implementation of this plan and operational strategies involved a cooperative tool development with a major oil tool service company to repair casing kinked wellbores as an alternative to re-drilling wells.
In this article we provide a case history that describes the various synergistic reservoir and wellbore management activities designed to effectively mitigate subsidence-induced operational problems and the accompanying field benefits resulting from their implementation.
Steam Injection Project in Heavy-Oil Diatomite
Authors: Murer A. S. , McClennen K. L. , Ellison T. K. , Larson D. C. , Timmer R. S. , Thomsen M. A. , Wolcott K. D. 
Published: December 2007

Summary
A steam injection project was conducted in diatomite containing heavy, biodegraded oil (12°API, ∼3,000 cp) in the South Belridge field, Kern County, California. The diatomite interval tested (the San Joaquin, Etchegoin, and Belridge diatomites) underlies an active steamflood in the sandstone of the Tulare formation. Initially, the test was to determine the viability of cyclic steam recovery from an unpropped, steam fractured completion in the diatomite. Four standard steam cycles were completed, with sluggish oil recovery [oil–steam ratios (OSR) were less than 0.1]. The well was then hydraulically fractured and propped. Two additional steam cycles were completed that had considerably greater oil recovery (OSR&gt;0.2). The project was then configured for steamdrive by drilling a closely spaced producer. The new producer was initially completed with a propped hydraulic fracture and cycled once. The original cyclic producer was converted to continuous injection, and a two-well steamflood was operated for more than 1 year. During the steamflood, heavy oil was mobilized and response has been continuous. The configuration of the "pattern," with only one producer, results in poor capture efficiency. The performance of this incomplete pattern has been, as expected, poor (&lt;0.1 OSR), but steam injection is shown to be a promising recovery technique for the heavy oil diatomite. The process is applicable to California diatomites, or any other high porosity, low permeability, shallow reservoirs that contain a significant concentration of heavy oil.
Sedimentation in Emulsions of Water Petroleum
Authors: Tipman Edward , Hodgson Gordon 
Published: December 2007

Introduction
An appreciable number of the oil fields in Western Canada are accumulations of heavy black oils in more or less unconsolidated sandstones. When the crude oils are produced by conventional means, they are frequently contaminated with both sand and oilfield water. The water is usually present as emulsified water, and the sand and other solid material are suspended in the emulsions.
The presence of the solid material in the crude oils is troublesome and, in general, little is known about the behavior of suspended solid particles in emulsions. The Stokes equation describes the behavior of suspended particles in homogeneous fluids in terms of particle size, density differential, and fluid viscosity. In the case of an emulsion, particle size and density differential introduce no difficulties, but considerable doubt centers around the viscosity term.
For crude oil emulsion the Simha equation and the data presented by Fukushima and Ichimura show a non-linear dependence of the viscosity ratio on the water concentration. While it is undoubtedly reasonable to use these data for predicting the viscosity of a specific emulsion, and while it is equally reasonable to expect the calculated viscosity to predict the settling rate of a solid spherical particle in the emulsion by means of Stokes equation, there seems to be no direct evidence that this calculation is indeed sound for describing the settling rates of solid particles in emulsions of water in crude oils.

Procedure
A direct approach to the problem was thus indicated. Laboratory equipment was designed and built for the direct determination of the rate-of-fall characteristics of solid particles in emulsions of water in oil. Although the apparatus incorporated the basic design of conventional falling-ball viscometers, the study was concerned directly with the rate-of-fall characteristics of particles in emulsions, rather than with the viscosity of the emulsions as such.