bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Method of Perforating Casing Below Tubing
Authors: Lebourg M.P. , Hodgson G.R. 
Published: April 2012

Abstract
The introduction in the field of a new type well completion called for the setting of tubing open-ended in the well before perforating the casing. This paper describes a new perforating tool of the shaped charge expendable type, small enough to pass through tubing and powerful enough to perforate the casing. The perforations are produced at an angle and are large enough for optimum production. Performance of this tool in targets and under various well conditions is described.
Very often no lifting equipment will be available at the well. In some cases, pressure will exist in the well at the time of the perforating operation (workover wells or multiple trip perforation); therefore, new equipment and new technique for the perforating operation were devised. This paper describes this equipment and technique, particularly casing collar recording, sheave support, and cable pull-down device, this last item being necessary for wells under pressure. Results obtained with this tool in the field are given.

Introduction
One of the key requirements for the introduction in the field of a new method of permanent well completion was the development of a new perforating method involving the use of a perforating gun small enough to go through tubing and with enough penetrating power to perforate the casing satisfactorily.
The equipment described in this paper was basically designed to go through open-ended two-in. tubing and to perforate 5?-in. casing. The equipment is illustrated in accompanying figures.

New Completion Method
With the new permanent type well completion, the production string of casing is run and cemented through the potential producing zone. Open-ended tubing is then run into the well and used to replace the drilling fluid with oil or water. The amount of the oil or water "cushion" can be varied according to the expected bottom hole pressure. Thus, if desired, the hydrostatic head can be greater, equal to, or less than the expected pressure within the zone to be perforated.
Mud having been displaced, the tubing is then positioned so that the end is above the zone to be perforated.
Effect of Pressure and Temperature on Oil-Water Interfacial Tensions for a Series of Hydrocarbons
Authors: Hassan M.E. , Nielsen R.F. , Calhoun J.C. 
Published: April 2012

Abstract
An apparatus was constructed for the measurement of interfacial tensions over a range of temperatures and pressures. This apparatus utilized the pendent drop method, and resembles in construction similar apparatus recently described in the literature and in use in some petroleum research laboratories. The interfacial tensions of benzene, propane, n-pentane, n-hexane, n-octane, and iso-octane against water were measured at temperatures ranging from 26? to 82? C and at pressures ranging from 1 to 204 atm. Values of interfacial tensions for the benzene-water system and their variations with temperature and pressure are generally in good agreement with values of previous investigations.
The data in all cases showed a slight decrease of interfacial tension with pressure at constant temperature in the range studied. The effect of pressure became less as the pressure was increased, with an indication of a reversal of the effect at higher pressures. There was a decrease of interfacial tension with temperature at constant pressure in all cases, as would normally be expected. This rate of decrease became greater the higher the temperature.
A general equation is presented for the interfacial tensions as a function of pressure and temperature over the range studied, and the constants calculated for each system. A definite trend was found in the effect of molecular weight on the interfacial tension at a given temperature and pressure, for the homologous series from propane to n-octane. Data for n-decane from the literature fitted well into this trend.

Introduction
It has been recognized for many years that surface forces play an active part in the production history of an oil reservoir as well as in determining the amount of unrecoverable oil. The magnitudes of these forces are governed by the values of the interfacial tensions. These vary greatly with composition, pressure, and temperature. The effect of composition is greater than that of pressure and temperature over the ranges normally encountered. In fact, because of the variety of compounds present in a crude, no attempt has yet been made to correlate crude composition with its surface tension or with its interfacial tension against water. The amount of dissolved methane greatly affects the surface properties of an oil, and there are "surface-active" compounds in crudes which have a much greater effect on boundary tensions than do equal amounts of hydrocarbons.
Relationship of Drilling Mud Resistivity to Mud Filtrate Resistivity
Authors: Patnode H.W. 
Published: April 2012

Abstract
The effect of suspended solids on the resistivity of slurries is discussedand the relationship between drilling mud resistivity and mud filtrateinvestigated. It is concluded that it is erroneous to substitute mudresistivity for mud filtrate resistivity in electric log calculations. Arecommendation is made that both the bud resistivity and the mud filtrateresistivity be determined when electric logs are run.

Introduction
The electric log is influenced not only by the resistivity of the drillingmud in the borehole at the time of logging but also by the resistivity of thedrilling mud filtrate.
Sherborne and Newton investigated the relationship of mud resistivity to mudfiltrate resistivity and concluded that, "The resistivity of the mud inmost cases closely approximates that of its filtrate," and "In fact, with the exception of Aquagel and its filtrate, the figures for any particularmud and filtrate are almost identical." Present practice is to determineonly the drilling mud resistivity and apply this same value to calculationsinvolving the mud filtrate. The purpose of this study is to reexamine thefactors governing the relationship between mud resistivity and mud filtrateresistivity.

Effect of Borehole Fluid on the Electric Log

Resistivity Log
The resistivity log may be modified by the resistivity of the borehole fluidin two different ways:The apparent resistivity of a formation may be different from the trueresistivity of the formation because of the flow of some current through thedrilling mud in the borehole. Therefore the resistivity of the mud is animportant factor.The apparent resistivity may differ from the true resistivity, if aformation is invaded by mud filtrate, because of displacement by the mudfiltrate of some of the interstitial fluid in the formation. In this case theresistivity of the mud filtrate rather than the resistivity of the mud is theimportant factor.

Self Potential Log
The self potential arises, in part, from electrochemical effects resultingfrom the interaction of connate waters in porous formations and the fluid inthe borehole. A theory of the electrochemical component of the self potentialin boreholes has been recently set forth by Wyllie. In the above equationresistivities have been substituted for activities of the ions in the fluids.It is therefore apparent that the resistivity of the mud filtrate is morenearly representative of the activities of the ions than is the resistivity ofthe mud. However, it is possible that in some instances the ionic activities ofcations from certain clays may contribute to the total cationic activity of thedrilling fluid to such an extent that the mud resistivity is more nearlyrepresentative of the activities than the filtrate resistivity. This isparticularly the case when the resistivity of the mud is less than theresistivity of the mud filtrate.
In addition the apparent self potential may be influenced by the resistivity ofthe drilling mud because of current flow through the borehole.
T.P. 2512
Semiautomatic Power-Operated Drilling Machinery
Authors: True Martin E. , Stone Bert L. 
Published: April 2012

Abstract
To cope with the problems encountered when drilling at greater depths and toreduce the amount of physical effort required on the part of drilling crews inmaking round trips, a new type of semiautomatic power-operated drillingmachinery has been developed which permits round trips to be made without thedrill pipe being touched by hand. This equipment consists of hydraulicallyoperated tongs which perform the stabbing, spinning, and tonging operations, and two power-operated racking units mounted in the derrick for carrying thepipe to and from the center of the hole and positioning it on the mat and inthe rack. With this equipment all of the operations of the various units arecontrolled remotely by manipulation of hydraulic valve levers and electricswitches.

Introduction
As horsepower rises to meet the demand for deeper drilling, it is necessaryto increase the weight of surface drilling equipment. Also, the duration ofrepetitive operations in making round trips to change bits is greatly increasedwith depth. Harder formations encountered at greater depths reduce bit liferapidly, resulting in more frequent round trips and in some instances more timeis consumed in changing bits than in drilling.
Since the introduction of the first rotary employed to drill for oil in 1895there has been relatively little change in the general procedure for making up, breaking out, stabbing, and racking drill pipe in making round trips to changebits. The conventional method of making round trips with the drill piperequires that drilling crews lend strenuous physical assistance to manuallyoperated tools.
Although many new devices have been developed to improve efficiency, increase speed of making round trips, improve safety, and reduce the amount ofphysical effort required in handling drill pipe, it is considered a vitalnecessity to substitute automatic or semiautomatic power-operated machinery formany of our more or less manual operations if extremely deep drilling is to becarried out successfully on a production basis in the same manner as ourshallower drilling of today.
T.P. 2543
Capillary Pressures - Their Measurement Using Mercury and the Calculation of Permeability Therefrom
Authors: Purcell W.R. 
Published: April 2012

Abstract
An apparatus is described whereby capillary pressure curves for porous mediamay be determined by a technique that involves forcing mercury under pressureinto the evacuated pores of solids. The data so obtained are compared withcapillary pressure curves determined by the porous diaphragm method, and theadvantages of the mercury injection method are stated.
Based upon a simplified working hypothesis, an equation is derived to showthe relationship of the permeability of a porous medium to its porosity andcapillary pressure curve, and experimental data are presented to support itsvalidity.
A procedure is outlined whereby an estimate of the permeability of drillcuttings may be made with sufficient accuracy to meet most engineeringrequirements.

Introduction
The nature of capillary pressures and the role they play in reservoirbehavior have been lucidly discussed by Levrett, Hassler, Brunner, and Deahl, and others. As.a result of these publications the value of determiningcapillary pressure curves for cores has come to be generally recognized withinthe oil industry. While considerable attention has been directed toward thesubject in an effort to provide a reliable method of estimating percentages ofconnate water, it has been recognized that capillary pressure data may prove ofvalue in other equally important applications.
This paper describes a method and procedure for determining capillarypressure curves for porous media wherein mercury is forced under pressure intothe evacuated pores of the solids. The pressure-volume relationships obtainedare reasonably similar to capillary pressure curves determined by the generallyaccepted porous diaphragm method. The advantages of the method lie in therapidity with which the experimental data can be obtained and in the fact thatsmall, irregularly shaped samples, e.g., drill cuttings, can be handled in thesame manner as larger pieces of regular shape such as cores or permeabilityplugs.
Based upon a simplified working hypothesis, a theoretical equation will bederived which relates the capillary pressure curve to the porosity andpermeability of a porous solid, and experimental data will be presented tosupport its validity. This relationship applied to capillary pressure dataobtained for drill cuttings by the procedure described provides a means forpredicting the permeability of drill cuttings.
T.P. 2544
Methane Hydrate at High Pressure
Authors: Kobayashi Riki , Katz Donald L. 
Published: April 2012

Abstract
The conditions at which methane and water form solid hydrates have beenextended from 4,000 to 11,200 pounds per sq. in. The curve at high pressure hadbeen in doubt because of Villard's report of a critical decompositiontemperature. The paper explains the nature of the hydrate curve at highpressure and its dependence on fluid phase behavior. Extropolation of themethane hydrate curve indicates a pressure of 40,000 pounds per sq. in. willcause hydrates to form at a temperature of 100' F.

Introduction
The conditions under which natural gases form hydrates when liquid water ispresent have been studied by several investigators up to pressures of about4,000 pounds per sq. in. The early work by Villard on hydrates of methane andethylene, ethane, and propane included references to critical decompositiontemperatures of the hydrates. Villard's work raised the question as to whetherthe pressure-temperature curve for methane-water hydrate continued above atemperature of 70.7?F. or whether this was the maximum temperature at whichhydrates would form.
This paper extends the experimental data on methane hydrate to 11,200 poundsper sq. in. A discussion of phase relations in the hydrate region for thehydrocarbons and of the methane-water system at high pressures isincluded.

Previous Work
Villard suspected that methane hydrates could not be formed at temperaturesabove 21.5?C. (70.7?F.) irrespective of the pressure of the liquid-vaporsystem. However, he was limited in his studies by his apparatus in 1888 topressures not greater than 300 atmospheres (4,410 pounds per sq. in.) so thatthere has remained some doubt as to the existence of such a maximum temperaturein this region.
For the case of ethylene hydrates, however, Villard does specifically state theoccurrence of what he terms a "critical temperature for the decompositionof the hydrates."
T.P. 2579
Reservoir Performance of a High Relief Pool
Authors: Burtchaell E.P. 
Published: April 2012

Abstract
A method is presented for evaluating the effect of gravity drive upon thereservoir performance of a high relief pool. Conventional forms of reservoiranalysis do not consider the alterations in the basic material balance datacaused by gravity segregation of reservoir fluids. A procedure is outlined forstructurally weighting physical and chemical data for use in the materialbalance equation. It is demonstrated how actual pool performance data can beutilized to evaluate the future reservoir performance of a gravity drivepool.

Introduction
Conventional reservoir engineering procedure is inadequate for the analysisof an oil pool which has considerable structural relief, steep dips, and goodpermeability development. In pools of this type, gravity drainage has animportant part in the movement of oil to the wells and the effects of gravityon the overall pool performance should be included in any analysis of reservoirbehavior. Many engineers have the opinion that the force of gravity in themovement of oil is not important until the later life of a pool. Probably thebasis for this belief is that gravitational effects may not be readilydiscernible until a pool is nearing depletion. This would be especially truefor pools not having a high degree of structural relief and permeabilitydevelopment. Actually the effects of gravitational forces are at a maximum whenthe pool pressure is high, for during this period the hydrostatic head of theoil column is at a maximum and the viscosity of the oil is at a minimum.
Oil recoveries from pools having favorable gravity drive characteristics mayequal or even exceed recoveries which might be expected from waterdisplacement. Field evidence indicates that in some reservoirs gravity drivehas resulted in recoveries greater than that which could have been expectedfrom gas expansion or water drive. Unfortunately, the possible effects ofgravity drive on pool performance have been underestimated and other reasonshave been sought to explain the high recoveries obtained. There areunquestionably many reservoirs to which the principles of gravity drainage canbe effectively applied.
It is the purpose of this paper to illustrate one method whereby gravitydrive is included in the reservoir analysis of an oil pool. A hypotheticalpool, typical of many California reservoirs, is used as an example. As used inthis paper, "gravity drive" is defined as the overall effect ofgravitational influences on the recovery of petroleum from the reservoir;"gravitational segregation" as the gravity separation of oil and gaswithin the reservoir; and "gravity drainage" as the downward movementof oil as caused by the force of gravity.
T.P. 2645
The Effect of Well Spacing and Drawdown on Recovery From Internal Gas Drive Reservoirs
Authors: Loper Raymond G. , Calhoun John C. 
Published: April 2012

Abstract
Theoretical calculations for the decline of pressure and the variation ofinstantaneous producing gas-oil ratio with increased cumulative production havebeen made for reservoir systems under various producing drawdown values and forvarious spacings. These variables have been included by a modification of previously published techniques. Thisconsists essentially of utilizing a radial system flowing gas and oil in asuccession of steady state calculations. The results of the calculations do notshow any variation in the predicted behavior of the internal gas drivereservoir when either the drawdown or the spacing are changed.

Introduction
The prediction of performance on an internal gas drive reservoir has beenpresented by various authors. These predictions are in the form of a pressuredecline and an instantaneous producing gas-oil ratio as a function ofcumulative oil withdrawal. In making these predictions a basic assumption hasbeen that the saturation of the reservoir is uniform throughout at any time, orthat the pressure differential imposed on the reservoir system is zero. Becauseof these assumptions the validity of such predictions has been questioned.Their application to actual systems, where saturations are not uniform andwhere producing differentials exist, has been a hazardous procedure.
The authors cited have used different methods of approach to the derivation ofequations for making their predictions and for arriving at a solution of bothequations, but basically the same relationships are utilized in each case. Inall instances the instantaneous producing gas-oil ratio is calculated from theequation:
(Equation 1)
In utilizing this equation an average reservoir pressure and an averagereservoir saturation must be known. Predictions can be made, therefore, onlyfor the conditions of a uniform reservoir saturation and a uniform reservoirpressure.
This restriction of requiring a uniform oil saturation can be resolved byapplying two-phase steady state flow for the radial system to the reservoir'shistory. Radial steady state flow is defined when the ratio of phases flowing, the pressures imposed, and the dimensions of the system are fixed.
T.P. 2592
The Relation Between Electrical Resistivity and Brine Saturation in Reservoir Rocks
Authors: Dunlap Henry F. , Bilhartz Harrell L. , Shuler Ellis , Bailey C.R. 
Published: April 2012

In connection with electric log interpretation it is important to know thevalue of the saturation exponent. For example, if in a given reservoir it isfound that the resistivity is three timcs the resistivity observed when thereservoir is 100 per cent saturated with water, this fact would be interpretedas indicating a water saturation of 33 per cent if the saturation exponent were1 and a water saturation of 64 per cent if the saturation exponent were2.5.

Experimental Method
In the work to be described it was assumed that reservoir conditions aremost nearly obtained when core plugs are desaturated by the capillary pressuretechnique referred to in numerous places in the literature, as for example, inBruce and Welge's paper. In this technique the core, saturated 100 per centwith brine, is placed in contact with a ceramic disc permeable to brine but notto the displacing medium for the displacement pressures used. Pressure is thenapplied to the displacing medium and brine forced out of the core through theceramic disc. Fig. 1 shows the core plug in place in the cell in whichresistivity and saturation measurements are made. Fig. 2 shows the schematicelectrical diagram used to make resistivity measurements on the core plug. Afour-electrode type circuit is used, employing a Hewlett-Packard model 400A, ACvacuum tube voltmeter. The 60-cycle AC current through the core is adjusted to1 milliampere and measured by noting the voltage drop across the calibrated100-ohm resistor. The voltages appearing at probes 1, 2, 3, and 4 are thensuccessively measured. Voltage drops across the top, center, and bottomportions of the core are obtained by subtracting the voltages appearing atsuccessive probes. This technique avoids any polarization or other high contactresistance phenomena which may develop at the current input electrodes.Resistances which may develop between the core and the probes, and which aresmall compared to the 1-megohm input impedance of the vacuum tube voltmeterwill obviously not affect the measurements appreciably. Any very appreciableresistances which may develop at any of the probe wires are detected andallowed for by inserting a 1-megohm resistor in series with the voltagemeasuring probe. If the probe resistance is actually zero, the new voltagemeasured after insertion of the 1-megohm resistor will be approximatelyone-half of that previously measured- since the input impedance of the vacuumtube voltmeter is itself 1 megohm. If any appreciable probe resistance hasdeveloped, the new voltage is found to be appreciably greater than one-half ofthe previously measured voltage.
T.P. 2711