bluuebunny/crossref_metadata_2025 huggingface dataset:
Diamond Coring in the Rangely Field, Colorado
Authors: Christensen Carl  J.
Published: June 2014

This paper presents the development of diamond coring of the Weber sand sectionin the Rangely Field, Colorado. The description and operation of thediamond-coring equipment is included as well as the economics and resultsobtained by its use. Diamond coring is compared with the other methods used fordrilling the Weber sand. Two types of diamond coring are discussed. The firstand the one used most extensively is the regular 6 1/8 X 3 ?:-in. diamond bitand bottom hole 50'Ft barrel. The second type, which has also been usedsuccessfully by Stanolind, consists of a 4 13/16 X 2 11/32 in. cutting bit andreverse circulation coring equipment. The first type will be referred to asregular or conventional diamond coring while the latter type will be referredto as reverse circulation diamond coring.

Introduction

Diamond coring has been used for many years in mines, quarries, surface coringat dam sites, laboratory work, and so on, but, until recently, had never beenused very extensively in coring oil sands and other oil-bearing strata. It wasdemonstrated early in its development that hard formations could be cut rapidlyand that core recoveries far exceeded those obtained with conventional hardrock bits and quite often 100 pct recovery was obtained. However, the poorlyconstructed diamond-coring equipment and resulting high costs of early diamondcoring slowed down its progress.

Early in the development of the Rangely Weber field, Rio Blanco County, Colorado, the Rangely Engineering Committee selected key wells that were tocore the Weber section in its entirety. These cores were to be analyzed andvarious sections tested to gather sufficient information so that accuratereservoir studies could be made. The number of wells selected were kept at aminimum inasmuch as the productive Weber section, which is found at anapproximate depth of 6000'Ft, is thick, being as much as 600 to 700'Ft on topof the structure. The Weber section is also comparatively hard to drill. Forinstance, one well took 60 days to core 490'Ft of Weber sand with conventionalcoring equipment. It was noticed, however, that Core Laboratories diamond plugcutter could quickly cut a plug from one of these hard cores. This fact led tothe serious consideration of diamond coring the Weber sand.

The first diamond coring at Rangely was performed by Stanolind in August 1946and, although we experienced some difficulties, the results definitelyindicated that diamond coring would be successful at Rangely for coring theWeber sand. As more wells were cored and the equipment improved somewhat, diamond coring became less expensive than drilling the Weber sand with theconventional rock bit. In less than one year diamond coring has definitelyproved its usefulness in oil-field drilling operations in the Rocky Mountainarea where formations quite often drill very hard. The practice of spot coringin hard oil-bearing formations with conventional coring equipment is giving wayto diamond coring of the entire sections, thus giving an operator the completepicture.

T.P. 2301
Cathodic Protection of Steel Tank Bottoms by the Use of Magnesium Anodes
Authors: James J.R. , Featherly R.L.
Published: June 2014

The replacement or reconditioning of oil storage tank bottoms due to externalcorrosion is an expensive maintenance item to the oil industry.

Cathodic protection as a means of mitigating this problem has proved verysuccessful in the past few years.

One pipe-line company recently used magnesium anodes to cathodically protecttwo 55,000 bbl and two 20,000 bbl tanks. The tank bottoms were protected asindividual units with considerable factual data being taken on one of the20,000 bbl tanks. Twelve 60-lb anodes were installed about 2~ ft from the tankon approximately 17-~ft centers around the tank.

Previous installations and tests have shown that sufficient protection isprovided when the tank-to-soil potential using a copper-copper sulphatehalf-cell as a reference electrode is -0.90 volts at the edge of tank.

Potential measurements taken a few months after completing the installationindicated that the potentials were higher than were needed for protection.Resistors were then inserted in the individual anode circuits which increasedthe life of the anode installation and still provided adequate protection forthe structure.

All connecting pipe lines were then insulated from the tank. This limited theanode current strictly to the tank resulting in a greater degree of protectionwith a still longer anticipated anode installation life.

The corrosion of metallic structures in contact with soil or water has been avery serious and costly problem for centuries. The annual loss to our nation'spipelines alone is estimated at $200,000,000. Mitigation of this problem byvarious methods has been carried on quite successfully for a number of years.An electrical method called cathodic protection has been used with considerablesuccess to control corrosive influences on pipelines, tank bottoms, cablesheathing and other buried metal structures.

Corrosion of oil storage tank bottoms has been a serious problem among the oilindustries for years. In addition to damage costs and loss of oil, thereplacement of one tank alone represents several thousand dollars. Areconditioning program at periodic intervals was instituted by severalorganizations and found to be a very expensive process.

A few years ago two of the pipeline companies installed cathodic protectionunits at their tank farms the average current required for protection of thetank bottoms varied from 0.7 to 1.0 milliampere per square foot. The resultsindicated that adequate protection was obtained at a cost of approximately 10pct of the previous reconditioning program.

The total installation cost for this tank was less than $300 which amounts to$20 per year based on an expected installation life of 15 years. This figurerepresents an annual cost of one per cent compared to the cost of replacing thetank bottom.

T.P. 2202
An Improved Water-input Profile Instrument
Authors: Pfister R.J.
Published: June 2014

The development of a water-input profile instrument based on the introductionof brine and fresh water into an input well with the electrical location of theboundary developed between them is reported. Two methods are available in theuse of this instrument to measure the foot by foot water-intake rates of thevarious sand strata: the moving boundary method in which variable well borediameters can be determined and/or cancelled out and the constant boundarymethod. The type of results obtained and the relative advantages of each ofthese methods are described in detail.

Representative data are included covering the use of this instrument inexperiments involving selective acidizing, selective plugging, and selectiveshooting. In such experiments, this instrument has been used to diagnose theunfavorable distribution of water intake in input wells and also to determinethe effectiveness of the resultant treatments. The data included also serve toillustrate the type of problems which can be studied with this technique.

Introduction

For ten years or perhaps longer a number of progressive water-flood operatorshave felt the need for some method to measure the foot by foot water-intakerates of various strata in water-injection wells. The primary need is todiagnose unfavorable water distribution in various strata and to evaluate theeffectiveness of the corrective measures such as selective acidizing, selectiveplugging, and selective shooting. Previously described methods for obtainingthis type of data were not considered entirely adequate. The profile equipmentdescribed in this paper embodies the separate introduction of brine and freshwater into the well at carefully measured and controlled rates and theelectrical location of a sharp boundary developed between these fluids.

At present this instrument is a research tool of value in determining theeffect of various well treatments on an individual sand strata. Its primary usehas been on wells in which different sections require different treatments(e.g., wells with an open sand to be plugged and a tight sand to be acidized).It has, thus, made possible the determination of a rearrangement of the waterintake of a well. The instrument can also be used to direct the treatingmaterial into a given zone. In completing a well the less permeable sands areshot more heavily with nitroglycerine in order to equalize the water intakebetween the permeable and less permeable sands. The extent to which suchcorrective shooting has been successful can be determined by a water-inputprofile. The combined profile and well-bore diameters should also provide amethod for determining the direction and effect of various selective shootingtechniques.

T.P.2315
Location of Points of Water Entry in Oil Wells
Authors: Silverman D. , Brown A.R.
Published: June 2014

Equipment and methods for locating the points of entry of salt water into oilwells are described. These techniques make it possible to delineate accuratelythe top and bottom boundaries of water zones whether bottom water orintermediate zones of production. Data are given on tests by this survey methodon a number of producing wells. Complete results were obtained on wells showingwater percentages ranging from high values to as little as 10 pct salt water. Anumber of the wells tested were plugged back and the results are reported indetail. While not all the work-overs were successful, evidence, including theresults of reruns by this survey method, points to failure of the plug-backoperations. The data provided in the tests discussed show, contrary to generalopinion, that a large percentage approaching 50 pct of the wells showedintermediate water instead of bottom water. Furthermore, approximately a thirdof the wells tested showed multiple zones of water production. The equipmentcomprises a long pipelike assembly carrying 10 pairs of electrodes spaced aparta distance of 4 ft. A surface- controlled solenoid-operated switch is providedto connect each of the individual pairs of electrodes in turn to asingle-conductor steel-armored cable by means of which the conductivity of thefluid in the vicinity of each of the electrode pairs can be continuouslyrecorded at the surface. Any number of electrode pairs and any spacing can beused. This assembly is lowered on tubing and placed in position opposite thesection of the well to be studied. A conventional rod pump is used to producethe well for the survey. The pump inlet is placed below the lowest electrodepair. The well is conditioned by pumping out the salt water normally standingin the well and introducing fresh water into the annulus at the surface. Whenthe resistivity of the water standing in the well has been increased to asufficiently high value, the in flowing fresh water is stopped and the drawdown operation of the survey is started. As the fluid head is lowered bypumping, fluids flow into the well and the entry of salt water is indicated bythe change in resistivity of the fresh water opposite the zones of waterentry.

The process can be repeated as often as necessary with little effort andwithout moving any well equipment to be sure that the fluids produced from eachzone are representative of the true reservoir content.

Introduction

The oil industry has been concerned from its inception with the control offluids entering its wells. In order to effect the greatest economy of operationand to get the greatest economy of operation and to get the greatest totalproduction of petroleum liquids out of the ground, the flow of gas and watermust be controlled and often extensive workovers are planned and carried outfor this purpose. This has become even more important in recent years becauseof the need for the conservation of natural resources.

T.P. 2316
Wave Action on Structures
Authors: Munk Walter H.
Published: June 2014

Generation of waves by storms, and the transformation of waves in shallowwater by local bottom topography are briefly reviewed. A detailed descriptionof water motion in waves explains the nature and distribution of wave forces. Anumerical example dealing with forces and moments against vertical pilessummarizes the principles involved.

Introduction

The oil industry is moving into the open waters of the Gulf of Mexico. Thedesign and construction of offshore drilling rigs present a number of difficultproblems, among them problems involving the action of waves on fixed andfloating structures. This paper deals with our present knowledge of ocean wavesas it pertains to these problems, and the principles involved in computing waveforces against fixed structures. It is hoped that the more difficult casepertaining to floating structures can be discussed at a later time. None of theengineering aspects of the problem are entered upon in this paper, yet anunderstanding of the principles presented here should be helpful in thesolution of practical problems.

Nature of Wave Forces

Waves are capable of exerting almost unbelievable forces. During a gale, waves at the harbor entrance of Amsterdam Canal in Holland lifted a 20-tonconcrete block, which was resting on the bottom in 12ft of water, and depositedit on top of a pier which was 5 ft above the high water mark. At WickBreakwater in Scotland, a mass of large stones in cement and bound togetherwith iron rods, weighing 1350 tons, was broken loose and moved bodily! But oneneed not go to Holland or Scotland to find evidence of damage that waves arecapable of inflicting (Fig I and 2).

What is the mechanism by which waves are capable of exerting such enormousforces? To answer this, we must consider briefly the nature of wave motion.When a wind blows over a wheat field, waves appear to travel across the field, whereas the wheat itself remains rooted, slowly swinging back and forth.Similarly, in the case of water waves, the wave form travels swiftly over thewater surface, whereas the water particles oscillate back and forth, butscarcely advance. The speed of the wave form is called wave velocity, the speedof the water particles is called orbital velocity. This fundamental differencebetween wave velocity and orbital velocity was already recognized by Leonardoda Vinci. Orbital velocity is generally much slower than wave velocity exceptfor a breaking wave, a case which is of particular importance in theapplication to engineering problems.

T.P. 2322
Important Considerations in Marine Construction
Authors: Harris F.R. , Knox Harry Gard
Published: June 2014

This paper covers some of the problems presented to the oil industry in thedrilling of oil wells in the open waters of the Gulf of Mexico. The hazards, delays and relative costs of offshore drilling are reviewed and various formsof drilling platforms discussed.

The requirements of the offshore drilling rig are summarized together withthe principal items affecting the cost of construction. Sea waves and theirsize and characteristics as affecting offshore platforms are reviewed.

Drilling platforms are classified as fixed, or fixed and floating. Fixedplatforms of the conventional cofferdam and pile-supported type are discussedtogether with their good points and their limitations. The desirability ispointed out of eliminating as much offshore work as possible where operationsare subjected to constant and expensive delay and substituting therefor theprefabrication of structures ashore or in sheltered waters. Marked economy willcome with the standardization of offshore rigs and special means oftransporting them to the site.

Several types of structure which are partly pile-supported and partlybuoyancy-supported are discussed and their possibilities of future usefulnesscommented upon.

General Considerations

The predominant attribute of offshore drilling equipment is that it must beequal to the job in hand. We therefore give first thought to the matter ofadequacy.

In view of the probable depth of drilling, the investment involved and theper diem labor costs, it is assumed heavy modern drilling equipment will beemployed. In order to use such equipment efficiently, the working deck must beample in size and strength and supported so as to be relatively free frommotion and from green seas even in heavy storms. These requirements necessitatea high and rigid land-based support for the drilling rig and machinery withplenty of space for supplies, such as pipe, mud, water and fuel, with reservesfor days when transportation from shore is impracticable. In offshore rigs thecrew will be housed on board in comfortable quarters, probably air conditionedand equipped with a galley and refrigerated food storage.

An important consideration will be the ability to transfer stores and crewto and from the rig in all but the heaviest weather and the platforms must beprotected from the impact of supply vessels when alongside. It will beessential to maintain continuous communication with shore by radio or cable, not forgetting the possibility of a helicopter landing space for the transferof crew and light stores as well as a means of general communication. Whateverstructure is constructed must be secure from storms of hurricane force and asafe place for the operating crew to work. If the well comes in, the drillingrig will presumably be removed and a small but rugged pile-supported platformwill remain to carry the Christmas tree with safe working space around it. Itwill be protected from damage on all sides by buffer piles or dolphins.

It is assumed that the flowing oil will be piped to storage tanks in thevicinity of the well.

T.P. 2324
The Theory of Potentiometric Models
Authors: Muskat Morris
Published: June 2014

The detailed analogy between flow systems in porous media and thecorresponding potentiometric model systems is developed under conditions whereit may be desirable to take into account variable pay thickness, variableporosity, and permeability, and also the dependence of the fluid density onpressure. It is shown that in such models it is only necessary that theelectrolyte thickness be made everywhere proportional to the millidarcy-feet ofthe formation. In contrast to the iso-vol type model, previously suggested as abasis for the analogy, the porosity does not enter directly in the constructionof the model. It is introduced only in translating the electrical voltagegradient measurements into the equivalent fluid travel times. A discussion ofthis procedure is given.

Introduction

It is now some 50 years since it was pointed out that on the basis ofDarcy's law Laplace's equation must govern the steady state flow of homogeneousfluids through porous media. It is 16 years since the obvious implication ofthis fact, namely, that such steady state homogeneous flow systems in porousmedia could be simulated by electrical analogies, was first applied to problemsof practical interest with respect to oil production. In these initial studiesmajor emphasis was placed on the use of electrolytic models, made of blottingpaper, to give a direct and graphic history of the fluid particle motion inregular and infinite well networks. However, it was also noted there that thebasic requirement of the model was that it give a potential distributionsimilar to the pressure distribution in the flow system, and that from theelectrical measurement of the potential distribution the fluid particle motioncould be graphically or numerically determined. This was demonstrated byapplication to the fivespot infinite network, for which a conducting metallicsheet was used to establish the equipotential contours. As anticipated, thefluid particle motion computed from these contours agreed well with that givendirectly by the blotting paper model.

For irregular well distributions it was found more convenient to useelectrolytic bath analogs rather than metallic sheets. Several investigations, as applied specifically to cycling well patterns, have been reported with thesemodels, which have become known as "potentiometric models." However, the extremely laborious nature of both the electrical measurements by directprobing and the associated interpretive computations retarded the widespreaduse of these procedures. The electrical measurements can be accelerated byusing a four-probe electrode, which provides a means for simultaneouslydetermining the streamline paths along which the fluid particles must move andthe voltage gradients along these paths which are proportional to the fluidvelocities. With the increasing frequency of discovery of condensate pools, asdrilling depths are becoming greater, the applicability of the potentiometricmodel to production problems, and especially to the study of well patterns forcycling, has been given a fresh impetus.

T.P. 2490
A Critical Review of Methods Used in Estimation of Natural Gas Reserves
Authors: Gruy Henry J. , Crichton Jack A.
Published: June 2014

This paper discusses methods used in the estimation of natural gas reservesand the general conditions under which the various methods are applicable. Thefactors used in estimating natural gas reserves are reviewed. Errors which havebeen found to occur frequently are listed.

Introduction

The estimation of natural gas reserves has become of paramount interestbecause of the increasing importance of gas in the nation's economy. Gas is amost desirable fuel, a fact substantiated by the continued rise in the marketdemand. In addition, new uses for gas are being developed by the chemical, plastic, and associated industries, and plants are being built to make gasolinefrom natural gas. These are a few of the factors contributing to the importanceof the nation's natural gas reserves.

With the increased importance of gas there is an increase in the need forreliable estimates of the magnitude and availability of natural gas reserves.These estimates are being used currently:to determine which fields containsufficient available reserves to justify the construction of pipe-line outletsto serve particular markets;to design pipe lines necessary to serve thosefields adequately;to determine the location of industrial and chemicalplants;to finance the development of gas properties, and theconstruction of gas pipe lines;to determine fair and adequate depletion allowances anddepreciation rates;to justify applications for gas pipe lines beforevarious regulatory bodies;to determine the number of wells required toexploit the reserves most economically;to aid in establishing values forthe purchase or sale of gas properties, and for purposes of inheritance taxes;to determine equities under unitized operations;to provide a basisfor calculating the economics of gas-cycling operations.

History of Estimation of Natural Gas Reserves

The natural gas industry in the United States had its beginning during 1826when natural gas was used for lighting the city of Fredonia, N.Y. The firstnatural gas pipe line was a 25-mile wooden line constructed from hollowed logs, connecting West Bloomfield and Rochester, N.Y. There is no record of an attemptto estimate the gas reserve at West Bloomfield but an attempt was made todetermine the capacity of the well by measuring the time required to fill alarge balloon.

One of the earlier publications concerning estimation of natural gasreserves is the "Manual for the Oil and Gas Industry," published by theTreasury Department, United States Internal Revenue, in 1919.

T.P. 2402
Revaporization of Butane and Pentane from Sand
Authors: Weinaug C.F. , Cordell J.C.
Published: June 2014

A study of the behavior of retrograde condensation from gas mixtures wasmade in the presence and absence of sand in order to determine if the condensedliquid would revaporize in the presence of sand. Methane-butane andmethane-pentane mixtures that would form liquids by retrograde condensationwhen produced from a constant volume cell were used.

The methane-butane mixtures of similar composition were produced by threedifferent methods. The first two were charged into an empty cell and wereproduced in one case within a period of 9 hr and in the other within a periodof 3 days. The third mixture was charged to a sand-packed cell and producedwithin a period of 9 hr. The curves relating composition of the produced gas topressure obtained from these experiments show that equilibrium was maintainedas long as liquid was condensing. However, during the portion of the pressuredecline where the condensed liquid should be revaporizing, equilibrium wasmaintained only when the mixture was produced from the sand-packed cell.

The methane-pentane mixture is produced only in the presence of sand. Thedata obtained for this system also show that equilibrium is maintained at alltimes during the pressure decline.

These results indicate that revaporization is aided rather than prevented bythe fact that the condensate" wets the sand."

Introduction

The significance to the petroleum industry of the behavior of hydrocarbonsin the retrograde region is becoming increasingly important because a largepercentage of reservoirs being discovered today are of the gas-condensate type.The important characteristic of a gas-condensate reservoir is the retrogradecondensation of a liquid phase throughout the reservoir if the pressure isallowed to decline. In order to prevent the loss of this retrograde liquid insome of these reservoirs, they are "cycled"; that is, the materialproduced from the reservoir is processed to remove the heavier hydrocarbons andthe light fractions are returned to the reservoir to maintain the reservoirpressure. Another method of producing these reservoirs is pressure depletion.There are other methods but they are not in general use.

Although a large number of factors are involved in determining the optimummethod of producing a reservoir, only the problem of whether the retrogradecondensate resulting from pressure depletion will revaporize from sand atequilibrium conditions is considered in this paper. Also the data are limitedto the methane-n-butane and the methane-n-pentane systems at 100'F and one typeof sand.

Three types of tests were run in order to compare the revaporization ofretrograde liquid formed in a cell with that formed in a sand-packed cell, andto establish the effect of time.

T.P. 2467
Effect of Permeability Stratification in Cycling Operations
Authors: Muskat Morris
Published: June 2014

A general theory has been developed for the effect of permeabilitystratification on the efficiency of the gas-injection phase of cyclingoperations. It has been applied to three special types of permeabilityvariation; namely, exponential, probability, and linear. In the case of theexponential permeability distribution the effect of areal pattern sweepefficiency was also taken into account.

The exponential permeability distribution can be characterized by the ratioof the maximum to minimum permeability, which has been termed thestratification constant. Curves were calculated for the variation in total wetgas recovery and total gas throughflow, to give that recovery to variousabandonment limits of the wet gas content in the produced gas, as a function ofthe stratification constant. The cumulative wet gas recovery decreasesmonotonically as the stratification constant increases and is generally higherat the lower values of the wet gas content abandonment limits. The total gasthroughflow first rises to a maximum as the stratification increases, and thenultimately declines. The effect of the areal sweep pattern efficiency isrelatively minor as compared to that of the stratification constant, except inthe region of low values of the latter where the formation is substantiallyuniform.

The probability distribution can be characterized by a "variation"parameter varying from O to I as the formation changes from strict uniformityto extreme variability. The curves of total wet gas recovery and total gasthroughflow to different abandonment limits of wet gas content versus thevariation parameter have the same general characteristics as for theexponential permeability distribution.

In the linear permeability distribution the ratio of maximum to minimumpermeability also serves as a stratification constant index defining thedistribution. The curves of total wet gas recovery and gas throughflow to fixedabandonment limits versus the stratification constant are similar to those forthe exponential permeability distribution. However, for the higher values ofthe stratification constant the recoveries and throughflows do notasymptotically fall to 0 as in the latter, but approach constant valuesdetermined by the abandonment limit of wet gas content in the produced gas.

Introduction

It is becoming generally recognized that one of the most important factorsdetermining the economic feasibility of cycling operations is the arealcontinuity and permeability distribution of the producing formation. While theeffects of areal variations in permeability, porosity, thickness, and wellpattern on the sweep efficiency can be evaluated by electrical model studies, those due to permeability stratification require separate treatment: Severalstudies have been reported on the influence of permeability variations on thewet gas recovery by cycling. In these, however, discontinuous permeabilityvariations either have been assumed explicitly, or the analysis has beencarried through as if they were discontinuous.

T.P. 2494
A Viewpoint on Petroleum Engineering Education
Authors: Kaveler H.H.
Published: June 2014

Education is for the purpose of developing citizenship, and, if it ispursued for the additional purpose of preparing for a professional career, suchas engineering, it is also directed to developing a knowledge of essentialscience, aptitude for the application of science to practical situations, and aknowledge of the industrial art in which the engineer will be engaged. Theprocess of education required for engineering must of necessity extend beyondthe classroom into industry. For that reason, the education of engineers shouldbe divided as between the university and industry. Specialization inengineering should logically come as a result of experience in an industry. Thestudent cannot take the time in a university, and, the university cannot teachthe skills required to develop a specialist without sacrifice to the moreessential broad purposes of formal education.

In addition to talent in science, aptitude in the application of scientificfact, and knowledge of the industrial art, the engineer should possess certainpersonal qualities which are helpful in the pursuit of a professional career.Those personal qualities are: the ability to work as a partner in anenterprise, the ability to do jobs in a way whereby job performance is a meansof gaining experience and increased responsibility, the capacity to write andspeak in an understandable manner, and, a proper regard for the"significance of answers." These personal qualities may be of almostequal importance to academic accomplishments in the field of science.Development of such personal qualities are an essential part of the student'straining in the university and in industry. They can be developed effectivelythrough the leadership of instructors.

Compulsory Education

Nature played a mean trick on the human race when the evolutionary processfailed to develop in the individual a capacity to inherit knowledge. Wereknowledge transmissible in a cumulative manner from generation to generation, mankind would be by inheritance wise beyond measure within a few generations.Then there would be little if any need for a "system of education." Asmatters stand, however, all must suffer the burden of starting life at the"zero" level of learning from which station each rises depending uponindividual capacity to assimilate knowledge left of record by our predecessorsand the individual effort exerted to compensate for Nature's failure to endowthe offspring with intelligence.

In the United States some degree of education is generally regarded asessential and necessary. Therefore, all citizens are subjected by law to aneducational process covering the primary school age from six to sixteen years.Beyond the schooling required by law, many attend secondary schools, and beyondthat, schools of higher learning. Our standard of living is at a level thatpermits an increasingly large fraction of the population the opportunity to gothrough all of the formal educational process. As a result, education in thecolleges and universities has almost reached a mass production level.

T.P. 2382
Stuck Pipe Prediction and Avoidance: A Convolutional Neural Network Approach
Authors: Siruvuri C. , Nagarakanti S. , Samuel R.
Published: June 2014

Refining advanced technologies for successful completion of wells is paramount in high-risk, high-cost environments such as ultra-deep water. Challenges are still very much associated with extreme depths, high temperatures, and with the small differences between formation pore pressure and pressures that will unintentionally frac a formation. Drilling mud pressures outside this narrow range can readily lead to additional problems such as stuck pipe and wellbore instability.

Comparatively little research has been done to predict stuck pipe, and there are few references for quantifying estimates of force needed to free stuck pipe. Traditionally, stuck pipe problems are solved by using available standard methods and by post-sticking, ad hoc techniques. However, the real key to savings and success is in avoiding the risks leading to stuck pipe occurrences. If these risks are identified in advance, procedures can be set up to reduce the possibility of stuck pipe and, therefore, to reduce the costs associated with freeing stuck pipe.

This paper presents an application of neural network methods for understanding the causes of differentially stuck pipe. The method is proposed as a more effective prognostic tool than are currently available procedures. The methodology enables drilling industry personnel to estimate the risk of occurrence of stuck pipe not only during well planning procedure but also during drilling. A three layer feed-forward network with full connection topology between layers is used. Sigmoid type non-linear activation functions and an error, back propagation learning rule are used. The convolutional analysis of the model is based on the constraints of different drilling variables. The trained neural net is shown to be able to automatically detect variables of concern.

Extensive simulations have been carried out. The paper also includes three case studies of stuck pipe incidents from Gulf of Mexico where the neural network methodology successfully predicted pipe sticking and also suggested the procedure and forces necessary to free the pipe.
The effect of increasing grain size in biosand water filters in combination with ultraviolet disinfection
Authors: Frank Timothy E. , Scheie Matthew L. , Cachro Victoria , Muñoz Andrew S.
Published: June 2014

With sand less than 0.70 mm often difficult to source in the field, it is of interest to study larger grained sand for use in biosand water filters (BSF). This study examined how sand grain size affects biological sand water filtration and how the combination of biological sand filtration and ultraviolet (UV) disinfection affects drinking water quality. Two BSFs were built: a control with maximum grain size, dmax = 0.70 mm and an experimental with grain sizes ranging from 0.70 mm to dmax = 2.0 mm. Untreated water was passed through each BSF daily. Results show Escherichia coli and turbidity removal characteristics of the control and experimental BSFs were not significantly different from one another. Both BSFs produced water that met World Health Organization (WHO) drinking water guidelines for turbidity, and although E. coli reduction was over 98% for each BSF, a high initial bacteria concentration resulted in effluent levels above WHO guidelines. Subsequently, effluent from each BSF was placed in clear plastic bottles under UV light, after which water from each BSF met E. coli guidelines. The data yielded promising results for using larger sand in BSFs, but longer duration studies with more data points are needed.
Initial fluoride concentration and loading capacity in defluoridation with bauxite, gypsum, magnesite and their composite
Authors: Thole Bernard
Published: June 2014

One of the parameters that impact on fluoride sorption capacities of materials in water defluoridation is initial concentration. Water from various sources will have different fluoride concentrations; as such the employment of a particular media in defluoridation requires information on how the media will perform in different concentrations. Consequently, research was carried out to determine how initial fluoride concentrations in raw water affect capacity in defluoridation with bauxite, gypsum, magnesite and their composite, and to investigate the possibility of predicting loading capacity of their composite filter through initial fluoride concentration to optimize their application in defluoridation. The results showed that sorption capacities increased with increase in initial concentrations. However, higher starting concentrations resulted in larger residual fluoride concentrations; as such the benefit of large sorption capacities obtained was overshadowed. Polynomial relations of capacity (Cs, mg/g) and initial concentration (Co, mg/l), were obtained for bauxite and gypsum. Magnesite obtained a logarithmic relation for Cs and Co. A power relation was obtained between Cs and Co for their composite, Cs = 0.0328C1.20160. Approximation of capacities of this composite from initial fluoride concentrations was feasible. Water defluoridation has become important as a result of dental and skeletal fluorosis.
Gender mainstreaming in integrated rural water supply and sanitation project in Mzimba, Malawi
Authors: Mwamsamali O. K. K. , Mayo A. W.
Published: June 2014

Gender mainstreaming in the water sector in Malawi was analyzed using the Mzimba Integrated Rural Water Supply and Sanitation (IRWSS) project as a case in point. Information required for the study was obtained through interviews, administering a set of questionnaires and data collecting from existing documents. The results show that women in decision-making positions at head office of the Ministry responsible for water affairs only constitute about 11.1%. Assessment of the budget allocations has revealed that previously no budgetary allocations were made for gender issues, and that since the 2006/07 fiscal year about US$14,286 was allocated for gender mainstreaming. Women's involvement in local governance institutions and project activities in Mzimba is generally high. Most local water committees have 60% women and 40% men, whereas participation in project activities is highly rated at 97.2%. To improve gender balance, the Ministry responsible for water has to work with stakeholders in the education sector. Besides, great disparities still exist between men's and women's participation in water projects at a local level (97.2% for women) and a person's socioeconomic position greatly affects their inclusion in the local governance structures. Addressing these issues would, therefore, result in better gender integration in the water sector.
On the compressibility effects in mixing layers
Authors: Khlifi Hechmi , Lili Taieb
Published: June 2014

Previous studies of compressible flows carried out in the past few years have
shown that the pressure-strain is the main indicator of the structural
compressibility effects. Undoubtedly, this terms plays a key role toward
strongly changing magnitude of the turbulent Reynolds stress anisotropy. On
the other hand, the incompressible models of the pressure-strain correlation
have not correctly predicted compressible turbulence at high speed shear
flow. Consequently, a correction of these models is needed for precise
prediction of compressibility effects. In the present work, a compressibility
correction of the widely used incompressible Launder Reece and Rodi model
making their standard coefficients dependent on the turbulent and convective
Mach numbers is proposed. The ability of the model to predict the developed
mixing layers in different cases from experiments of Goebel and Dutton is
examined. The predicted results with the proposed model are compared with DNS
and experimental data and those obtained by the compressible model of
Adumitroiae et al. and the original LRR model. The results show that the
essential compressibility effects on mixing layers are well captured by the
proposed model.
Examining the Relationship between Sex and Motivation in Triathletes
Authors: López-Fernández Iván , Merino-Marbán Rafael , Fernández-Rodríguez Emilio
Published: June 2014

The present paper assesses the relationship between sex and motivation in triathletes utilising a multidimensional measurement of motivation in sports. Data were collected from 138 triathlon participants (age range 17–72 years): 95 men ( M = 36.7yr., SD = 10.7) and 43 women ( M = 34.6yr., SD = 9.9). Measures included the Sport Motivation Scale, a multi-dimensional measure to assess different types of athletes' motivations for practising their sport. Results showed a significant sex difference in amotivation, with women displaying lower scores; but amotivation scores were very low. The results were not dependent on competition level or age. Men and women competing at the international level in triathlon have similar motivational profiles.
Genetic Parameters of First Lactation Milk Yield and Fertility Traits in Brown Swiss Cattle
Authors: Şahin Aziz , Ulutaş Zafer , Yýlmaz Adkinson Asiye , W. Adkinson Robert
Published: June 2014

This research was carried out to estimate variance components and genetic parameters for first lactation milk yield (lactation milk yield, 305-day milk yield, lactation length, and dry period) and some fertility traits (calving interval, gestation length and number of services per conception) of Brown swiss cattle reared at konuklar state farm located in konya province, turkey. data were collected on milk yield traits of 3, 769 first lactation Brown Swiss cattle during the period from 1990 to 2008. Variance components, genetic parameters, breeding values, and genetic correlations were estimated using multiple trait derivative free restricted maximum likelihood (mtdfreml) fitting an animal model. Heritability estimates were 0.26, 0.25, 0.10, 0.06, 0.07, 0.06 and 0.03 for lactation milk yield (lmy), 305-day milk yield (305 dmy), lactation length (ll), dry period (dp), calving interval (ci), gestation length (Gl), and number of services per conception (nsc), respectively. Genetic correlations between milk yield and fertility traits ranged from 0.31 to 0.95 and phenotypic correlations ranged from –0.026 to 0.75. Breeding values were estimated and used to characterize genetic trends across the time period investigated. The results showed that the first lactation milk yield traits can be used as selection criteria for development of effective genetic improvement programme in turkish Brown swiss cattle. in addition, the results indicate the essential for scheming an effective schedule for growth of genetic variability to improve the milk yield traits of Brown swiss cattle in this farm by way of selection.
A New Species of Cleistes (Vanilloideae, Orchidaceae) from Colombia
Authors: Szlachetko Dariusz L. , Kolanowska Marta
Published: June 2014

A new species of Cleistes Lindl., C. lehmannii is described and illustrated based on Colombian material. The taxonomic affinities of the new entity are briefly discussed. The species is placed within a key to identification of the national representatives of the genus.
Two New Species of the Genus Govenia (Orchidaceae, Vandoideae) from Colombia
Authors: Szlachetko Dariusz L. , Kolanowska Marta
Published: June 2014

Two new species of Govenia Lindl. from Colombia are described and illustrated: G. plowmanii and G. renilabia. Their taxonomic affinities are briefly discussed, and information on the ecology and distribution of the new entities is provided. Both new species are placed within a key for identification of Colombian Govenia species.
Pregnancy in long QT syndrome with implantable cardioverter-defibrillator. A case report and review of the literature
Authors: Kutkiene˙ Sandra , Gumbiene Lina , Aganauskiene Juratę , Steponenienea Rima , Marinskisa Germanas , Aidietis Audrius
Published: June 2014

Implantable cardioverters-defibrillators have decreasedmorbidity and mortality as well as improved quality of life in patients with life-threatening cardiac arrhythmias and allowed an increasing number of young women to reach their reproductive years. New questions and tasks arise for medical professionals as to organize appropriate management of these patients, because little is known regarding the risk and outcomes of such pregnancies. The aim of this report is to describe our centre’s first experience of pregnancy and delivery management in patient with an implantable cardioverter-defibrillator as primary prevention of ventricular arrhythmias in congenital long QT syndrome.
La traducción como exégesis implícita: observaciones sobre la traducción al francés de los almanaques de Julio Cortázar
Authors: Ţăranu Ilinca
Published: June 2014

La obra de Julio Cortázar conoció un enorme éxito en Francia, y su recepción tan excepcional se debe en gran parte a la calidad de las traducciones al francés de sus obras. La traductora Laure Guille-Bataillon se encargó de la mayoría de las versiones francesas de los libros escritos por Cortázar, de modo que el nombre del autor argentino está prácticamente inseparable en Francia del nombre de su gran traductora. Nuestras observaciones en este artículo se refieren a un tipo de exégesis implícita que realiza Laure Guille-Bataillon a la hora de seleccionar los textos de Cortázar incluidos en sus libros-collage La vuelta al día en ochenta mundos (1967) y Último Round (1969) para realizar la versión francesa de un nuevo libro, Le tour du jour en quatre-vingt mondes (1980).
Essai de méthodologie pour le traitement lexicographique français – macédonien du nom propre employé figurativement
Authors: Aleksoska-Chkatroska Mirjana
Published: June 2014

Les recherches entreprises jusqu’à maintenant sur le nom propre en français nous permettent de mettre à profit les résultats auxquels ont abouti les rhétoriciens, les grammairiens et les linguistes pour un traitement lexicographique bilingue des unités lexicales et phraséologiques contenant des noms propres employés figurativement en français et macédonien. Dans cet article, nous essayons de distinguer l’ensemble des critères pertinents permettant au lexicographe de sélectionner et recenser ces unités, de proposer des solutions sur leur traitement et d’identifier les problèmes et les spécificités du nom propre.
The Color of Complexes and UV-vis Spectroscopy as an Analytical Tool of Alfred Werner's Group at the University of Zurich
Authors: Fox Thomas , Berke Heinz
Published: June 2014

Two PhD theses (Alexander Gordienko, 1912; Johannes Angerstein, 1914) and a dissertation in partial fulfillment of a PhD thesis (H. S. French, Zurich, 1914) are reviewed that deal with hitherto unpublished UV-vis spectroscopy work of coordination compounds in the group of Alfred Werner.
The method of measurement of UV-vis spectra at Alfred Werner's time is described in detail. Examples of spectra of complexes are given, which were partly interpreted in terms of structure (cis ? trans configuration, counting number of bands for structural relationships,
and shift of general spectral features by consecutive replacement of ligands). A more complete interpretation of spectra was hampered at Alfred Werner's time by the lack of a light absorption theory and a correct theory of electron excitation, and the lack of a ligand field theory for coordination
compounds. The experimentally difficult data acquisitions and the difficult spectral interpretations might have been reasons why this method did not experience a breakthrough in Alfred Werner's group to play a more prominent role as an important analytical method. Nevertheless the application
of UV-vis spectroscopy on coordination compounds was unique and novel, and witnesses Alfred Werner's great aptitude and keenness to always try and go beyond conventional practice.