Copyright 2000, Society of Petroleum Engineers Inc.

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AbstractCrystal Modifier chemicals have been successfully applied inseveral areas of the world to control deposition of paraffinwaxes in production strings, pipelines, and refinery storagefacilities. However, the use of these chemicals requires thatthey be protected from cold weather to prevent them fromfreezing, thus making them impossible to pump. Therefore,the practices of hot oiling and hot watering remain the mainmethods of paraffin wax remediation. Over the past two yearsadvances in the technology of crystal modifier formulationhave succeeded in producing modifiers that are suitable foryear-round application. This new technology has made itpossible to compare the effectiveness of crystal modifiersversus hot oiling and hot watering for a large sampling ofproduction areas. Three large and geographically distant areasof production, previously on hot oiling and hot wateringprograms, were placed on a program of solvent cleanup andcontinuous and batch treatment with crystal modifier products.Case histories for these three fields are presented in this paper.Additionally some theoretical topics are also coveredincluding the description of paraffin crystal modification andits affect on the behavior of crude oil fluids.

BackgroundThe problem of wax build-up in production areas, pipelines,and refinery storage areas continues to be a major problem foroil companies, and traditional methods of treatment such ashot oiling and hot watering are still employed by a majority ofthese companies. Although much has been written about thenegative effects of these treatments1, the prevalence of thesemethods indicate that the advantages of alternate methodshave not yet been adequately or satisfactorily proven.

Hot oiling has a well-deserved reputation for freeing suckerrods, down-hole pumps and, in some cases, evenreestablishing lost production. Although many papers havebeen written citing thermodynamic data refuting the notionthat sufficient heat capable of removing paraffin damage issupplied deep within the well, the fact remains hot oiling freessucker rods, and pumps. It is this fact that continues to drawoilfield workers to the hot oiler time and time again.

Hot OilingIt is true that in many oilfield processes heat is essential to theeffectiveness of a treatment; wax is melted by heat, andemulsion resolution is aided by heat. However, the amount ofheat supplied per unit volume is also important even crucial tothe realization of these effects. When it comes to waxes, thedistance one wax molecule is separated from anotherdetermines the amount of heat required to melt a specificmolecular weight wax. Thus, if wax molecules are dilutedwith low molecular weight compatible solvents, the amount ofheat required to disrupt their co-crystallization is diminished.The cumulative effect of solvency and temperature determinethe combining tendency of waxes or emulsions. Therefore, themelting point of diluted waxes can be very much lower thanthat of the pure wax. Many of the thermodynamic modelsreport the melting point of waxes retrieved from pulled tubingstrings, but these deposits have lost much of the lower solventfractions and, therefore, exhibit much higher melting points.

A large number of hot oiling procedures are conductedusing oil produced from the wells they are used to treat. Thispractice is questionable, since the wax deposits they areintended to remove were produced from these same oils.Obviously the wax carrying capacity of these oils is low ordeposits would not occur. Solutions of wax and oil can bethought of as becoming saturated at a given temperature. Butbecause there are several different molecular weight fractionsof waxes present within a given crude oil, many saturationpoints can be observed over a large span of temperature. Thissituation results in different molecular weight wax depositsbeing found at varying depths within a well. Thus, highermolecular weight waxes tend to deposit in areas of the wellwith elevated temperatures (e.g., the bottom), while lowermolecular weight fractions tend to deposit at lowertemperature regions within the well (e.g., increasingly

SPE 63123

Oilfield Paraffin Treatments: Hot Oil and Hot Water Compared to Crystal ModifiersJR Becker, Unichem Division of BJ Services Company

2 JR Becker SPE 63123

shallower depths). When wells are hot oiled, the area of thewell receiving the greatest amount of heat is the upper-mostlevel. As the hot oil contacts the casing and tubing a gooddeal of heat is transferred to these surfaces, and the lowermolecular weight waxes are melted and carried downwardwithin the well. The deeper the hot oil proceeds the lower itstemperature becomes, thereby, reducing its wax carryingcapacity. From the above discussion, it can be seen thatsolvency and heat are effective methods of removing waxwhen the quantity used is sufficient to solvate or melt thewaxes present.

Hot WateringHot water and hot water surfactant combinations wereintroduced to provide an alternative to hot oiling. Plain hotwater treatments cannot provide the solvency that hot oilingcan; consequently surfactant packages are frequently added toaid in the dispersion of wax into the water phase. Again adegree of separation of wax molecules is achieved by addingthe surfactant, but the extent of the separation is much reducedfrom that achieved during hot oiling. Hot water surfactantcombinations produce very large water wet particles of waxthat resemble coffee grounds. These particles often causetreating battery upsets by collecting at the interface betweenthe separated water and oil. The resolution of water wetwaxes requires substantially greater amounts of demulsifierthan the two phase water and oil normally handled by heatertreaters. Because of the greater heat capacity of water, theamount of heat reaching the bottom of the well may be slightlygreater than that obtained in the hot oiling method. However,the non-existent solvency possessed by water greatly reducesthe wax carrying capacity of water. Although the addition ofsurfactants or dispersents to the water helps in wax removal,the reduced wax particle separation distance acts to opposeany added temperature benefits.

SolventsVarious aromatic and aliphatic solvents have been used withvarying degrees of success to remediate wax damage in wells.This procedure is used without the added benefit of heat, andrelies mainly on the superior wax carrying capacity of thesolvent. Solvents that have high wax carrying capacitiesachieve separations closer to the molecular level than in eitherthe hot oiling or hot watering methods. The saturationphenomenon mentioned above is still operative, and thesolvent at various temperatures accommodates varyingamounts of different molecular weight waxes. Thus thequantity of solvent required to dissolve a given quantity ofwax is generally several multiples of the wax present.Frequently, surfactants and/or dispersents are added to thesesolvents to aid in the dispersion of the waxes. These solventscan benefit from increased temperatures, but generally theonly heat assisting them is the resident heat within the well.

Crystal ModifiersCrystal modifiers are special chemical structures producedsynthetically to interact with forming wax aggregates. They

usually consist of structures that have segments incorporatedin them that interact with the forming wax crystals. Theseproducts act at the molecular level to alter the tendency of waxmolecules to accumulate on each other, thereby reducing thecapability of paraffin wax to network within the oil.2 Thisability to act at the molecular level makes them truly effectiveat concentrations in the parts per million. While hot oil, hotwater, and solvents are required at concentrations that aremultiple quantities of the wax concentration. Since theseproducts behave similarly to the waxes they inhibit (e.g., theyco-crystallize with the wax), they also exhibit relatively highmelting points. Traditionally, high melting points have madethe use of these products difficult or impossible in areas wherewinter temperatures drop below 40o F. Until just recently (thelast two years), the physical characteristics of these chemicalsseverally limited their use during colder times of the year.Thus traditional methods of hot oiling and hot watering havecontinued as the methods of choice for the field operators.

Combining MethodsCrude oils that contain sufficient paraffin waxes to causedeposition generally owe this deposition tendency to a narrowmolecular weight range of wax.2 Since variable molecularweight waxes exhibit differing saturation at varioustemperatures, a narrow deposition temperature is usuallyobserved. Crystal modifiers operate on a molecular level byaltering the morphology of forming paraffin wax aggregates. 3

Because of this, it is necessary for them to be added at atemperature above the saturation temperature of the formingwax crystals. These temperatures are most often availablewithin the well, but in some instances they are not. Thus, theeffectiveness of crystal modifiers could be enhanced by theprovision of additional heat. Since hot oiling can provide heatto a well, and oils commonly used are from the sameproducing formation, addition of a crystal modifier to hot oilcould be a mutually beneficial proposition.

Field Conditions and Crystal ModifiersPrimitive and harsh conditions prevalent in a large percentageof producing areas of the world frequently preclude measuresrequired to shelter or heat the modifier chemicals. Thus a moreadvantageous method for providing modifier chemicals for usein these harsh environments requires that the physicalhandling characteristics of the modifier be altered. Alterationof the physical characteristics of crystal modifier blends is nota simple matter, since the activity of the chemical depends onits structure. Changing the modifiers basic chemical structureto enhance its physical properties under cold conditions is notan option. Furthermore, many of the methods of dilution andadditions of winterizing solvents used in demulsifer,corrosion, and scale treating formulation have been found tobe ineffectual. Therefore, different techniques must beemployed to produce winterized paraffin crystal modifiers.The end product of this modification must also be convenientto pump at temperatures down to –30o C, and stable toambient temperatures of up to 40o C. Formulations must be

SPE 63123 Oilfield Paraffin Treatments: Hot Water and Hot Oil Compared to Crystal Modifiers 3

quick to enter the oil phase, and be of sufficient concentrationto effectively treat the oil.

As mentioned above, the poor handling properties of thetypical paraffin wax crystal modifier chemical makes themdifficult to implement in the field. Given that a largepercentage of producing fields are located in areas with lessthan optimal prevailing temperatures for the implementationof these products, historical winter usage of these productsoccurs very rarely. This is ironic since the tendency of waxesto form in flow lines, and storage tanks is greatest during thewinter months. Although crystal modifiers are useful the yearround, they are needed most during the winter season.Producing companies prefer to avoid products that cannot beused throughout the year, and this is one reason they arereluctant to implement a program that must be altered aswinter approaches. Continuity of treatment and treatmentmethods builds confidence in treating programs, and as asuccessful program proceeds, the producers comfort levelincreases. Therefore, treating programs that are altered,because products are unsuitable for use during a particulartime of year, often cause the producer anxiety. Thus, thedevelopment of the winterized crystal modifier productscapable of all season use has been an important goal of severalspecialty chemical companies for a considerable time.

Winterization of Crystal ModifiersSpecific methods employed to produce acceptable winterizedparaffin crystal modifiers are presently pending patent;however, a general discussion of the concepts can beconducted. Given the requirements listed above, a method ofproducing suspensions of several existing crystal modifierchemicals was chosen. These methods consist of usingspecific solvated and non-solvated mixtures of various typesof paraffin crystal modifiers including maleic olefin esters,polymeric acrylate and methacrylate esters, and ethylene vinylacetate polymers and co-polymers. The concept choseninvolved a method to produce stable solid suspensions of theseactive crystal modifiers within a non-solvent external liquidmatrix. Normally aromatic solvent solutions of these modifiertypes form gels through macro-aggregate networking whensubjected to low temperatures. For this reason the externalliquid matrix must have a low pour point, and the internalsolid crystal modifier suspension must be incapable offorming aggregates with adjacent modifier particles.

Several different formulations are required to produce thedesired physical properties from the differing types of crystalmodifier chemistries. Frequently throughout the developmentof these products it was possible to reduce the pour point tothe desired temperature, but difficult to obtain sufficientlyhigh temperature stability. Consequently, an exhaustiveprocess of solvent and non-solvent screening was conducted toprovide the most stable suspensions of the different modifiers.Once the desired properties were obtained the product/s weretested on specific crude oils to determine their commercialeffectiveness.

Product ComparisonsThe laboratory setting is a good first screening ground forproduct effectiveness, since most of the variables expected tobe operative in the field can be controlled. The crystalmodifier solutions that might otherwise be solid under fieldconditions can be compared to the experimental suspensionversions of the same modifier chemical. This screening wasperformed with solution and suspension versions of each ofthe various chemicals. Extensive testing on a broad variety ofwaxy crude oils was performed to determine if any variabilityin effectiveness between the two types could be observed.ASTM D-97 pour point, cold finger deposition, cloud points,viscosity measurements, cooling curves, and crystal energyprofiles were run on several waxy crude oils and differences inperformance were noted.4 All the tests showed equaleffectiveness was exhibited by the solution and the suspensionversions of the modifier.

While laboratory performance is a good screening tool, thetrue test of performance can only be determined in actual fieldtrials. Consequently four field locations were chosen, andthree different winterized products were put on test to evaluatetheir winter handling properties and performance. Thelocations chosen were Kansas, West Texas, and South EasternTexas. Each provided winter temperatures appropriate forevaluation of the chemicals’ physical behavior andeffectiveness in treating existing paraffin wax problems.

Field Test 1The test field, located in the Big Springs area of West Texas,contains several wells with a history of paraffin wax problems.Historically, paraffin treatment of this field involved the use ofeither hot oil or hot water/surfactant methods to remove theparaffin wax build up in the tubing and flow lines. Thesemethods had come under scrutiny by the field operator, whojudged them to be marginally successful, since the frequencyof well shut-in and work-over jobs had increased in recentyears. The operator had expressed an interest in using crystalmodifiers as a means of addressing his paraffin wax problems,but he was also concerned about the handling properties ofthese products. The timing was right to introduce the newlydeveloped winterized crystal modifier products. A proposedtreatment program emphasizing the merits of the newlydeveloped products was delivered to the producer forconsideration. After some additional consultation it wasagreed between the treating company and the operator that anextended field trial (approximately 120 days) would berequired to determine if the crystal modifier program was trulyeffective.

Five wells producing from 4-6 barrels of oil and 7-60 barrelsof water per day and exhibiting tubing wax build-up and flowline problems were chosen to undergo a four-month minimumtrial period to assure a good comparison. The chosen wellswere cleaned using a solvent dispersant blend prior tobeginning the test to assure that a good comparison of wax

4 JR Becker SPE 63123

problem shut-in periods between the two methods could beconducted. Earlier laboratory testing indicated that severalwells in the test field responded favorably to a specific crystalmodifier chemistry. A product possessing this chemistry waswinterized as described above, and placed on five wells forevaluation. Two major criteria for the successful applicationof this product were:

1.) The modifier product must be capable of being pumped inthe winter months.

2.) The modifier product must reduce wax deposits in the welland transfer lines.

The assessment of product’s pumpability during the wintermonths would be accomplished by daily observations.Although some adjustments to the products originalformulation might be required, the products basic chemistrywould not be altered. The average winter (November-February) temperature for the Big Springs Texas area isreported to be 10-30oF (night) and 20-40oF (day). Althoughthese are average temperatures, much colder temperaturesmight be periodically observed. . The effectiveness of theproduct as a wax deposit reduction additive would bedetermined by changes in production, rod weight, pump motoramperage, pour point temperature, production rates, and flow-line pressures. The economic effectiveness of the product wasdetermined by comparison to the historical hotwater/surfactant treatment costs.

ResultsThe product remained fluid and pumped continuouslythroughout the mild winter of 1999, but periodic formulationadjustments were required. These adjustments were necessarysince the winter was relatively mild and the initial productexhibited some separation at higher temperatures (>70oF).Once the products’ elevated temperature separation problemswere resolved, periodic hand mixing requirements andfrequent observations were reduced.

After the second month on the modifier program, one of thewells was pulled to examine the sucker rod, tubing, and pump.The build-up of wax appeared to be minimal, indicating thatthe modifier product was performing effectively, and the wellwas put back in operation. Some test perimeters are presentedin Table I, and an economic analysis showing that the crystalmodifier program produced a cost saving of nearly ninethousand dollars ($8,836) for the five test wells over a four-month period is presented in Table 2 at the end of this paper.When these figures are averaged over a twelve-month periodand a one-time installation cost included, a nearly twentythousand dollar savings ($19,438) is projected. Thisinformation is presented in tables 3, and at the end of thispaper. As field testing of the original five wells continued toshow favorable results, the producer allowed the addition often wells to the crystal modifier treatment program. Assumingthe results obtained on the first five wells can be realized for

the additional ten wells, a projected saving of nearly seventyseven thousand dollars per year can be expected.

Field Test 2A large West Texas production area had been experiencingaccumulations of wax in a number of wells as primaryproduction methods were being replaced by secondary water-flood recovery. Wax accumulation resulted in frequent wellfailures and a significant reduction in production volume. Ashad been the practice over the years, hot oiling was employedto remove the accumulated wax. This method requires the useof specially constructed tank trucks equipped with high-pressure pumps and boilers capable of heating stock tank oil tohigh temperature and pumping it through the constricted areas.Over several years these treatments concentrated the highmolecular weight fractions of the accumulated waxes presentin the wells worsening the extent of the damage. As hot oilingdown hole began to receive attention as a negative method ofparaffin wax removal, several specialty chemical companiesbegan to employ the use of hot water and hot water/surfactantcombinations in place of stock tank oil. This method soonreplaced the hot oiling throughout this production area. Hotoil trucks were still employed to heat and pump the hot waterand hot water/surfactant combinations down hole to removethe wax damage. New problems associated with this practicebegan to appear as interface pads in dehydration units began toincrease and emulsion resolution was greatly diminished. Itwas at this point that this laboratory became involved inattempting to remedy some of these problems.

Although wax crystal modifiers had been successfully appliedto remedy wax problems for several decades by highly visibleand costly production operations such as those offshore, thewidespread use of these products had rarely been employed inmarginally productive fields. Several factors such as physicalproperties, high cost, and availability of these productsprevented their implementation as a means of controlling waxrelated problems. A major problem with the use of crystalmodifiers involved their tendency to become solid as theenvironmental temperature declined, thereby necessitatingspecial handling for their delivery to the problem areas.However, in this particular area well spacing and surfaceequipment configurations allowed for the placement of aspecial heat traced chemical storage facility. Thus, it waspossible to store the crystal modifier chemical at a centrallocation and conduct truck treating from this site.

The program began by conducting a thorough well clean-uputilizing aromatic solvent and aromatic solvent/surfactantcombinations. The solvent was placed in the wells insufficient quantity to cover the perforations, allowed to soakfor twelve hours and, where possible, circulated an additionaltwelve hours to remove the accumulated wax damage. Afterthe solvent cleaning of the well was complete and the waxdamage removed, it was placed on a periodic backsideinjection of crystal modifier via a truck treatment program.Since these wells were on a pump-off schedule (e.g., well

SPE 63123 Oilfield Paraffin Treatments: Hot Water and Hot Oil Compared to Crystal Modifiers 5

casing annular fluids are periodically reduced by automatedmethods) it was questionable that the crystal modifier wouldremain at an effective treatment level within the well. Pourpoint monitoring of these wells was conducted to determinewhether a depression of the pour point from the untreated oilsproduced was being realized. This testing indicated thatindeed the chemical was reaching the problem areas, and thatsignificant pour point reduction was being achieved.

ResultsPrior to the implementation of this program many of the wellsin this area were on a hot water/surfactant clean-up scheduleaveraging once every thirty days. After the implementation ofthe crystal modifier program, it is not uncommon to find thefrequencies decreased to once every one hundred and eighty tothree hundred and sixty plus days. Additionally, interfaceproblems experienced by down stream dehydration treatmenthave virtually disappeared. Over the past two years thistreatment program has expanded to the entire field, and theincidence of well failures has dropped from two or three amonth to zero over a two-year period.

Field Test 3A major pipeline company operating in South Eastern Texashad been experiencing wax deposition in the crude oil thatthey were transporting, and frequent pigging of the lineproduced significant amounts of wax. Although they had beentreating the line with a combination of solvent dispersent andlarge quantities of gasoline, they were disappointed with theresults. The quantities of solvent dispersant and gasoline wereextremely high, and storing gasoline presented a hazard theywere reluctant to continue. Discussions were conducted withthe operator of the pipeline, and a trial application of crystalmodifier was approved. Although the price of solventdispersant and gasoline are low, the quantities used weresignificant (e.g., solvent dispersent usage was over two-hundred gallons/day and gasoline usage nearly two-thousandgallons/day). The cost of crystal modifier on a per gallonbasis being substantially higher than the existing treatmentrequired that a significantly lower dosage be employed to treatthe crude oil. The required dose of crystal modifier was set atthirty parts per million or thirty gallons/day. This figure wasarrived at based on the economics of transporting the crudeoil, combined with laboratory tests that showed the product tobe effective at this low level.

ResultsThe crystal modifier used in this application is a winterizedproduct, since it must be applied to the pipeline throughout theyear. The product has been applied to the pipeline for a periodof over nine months, and the results have been shown to besuperior to those of the previous method of treatment.Periodic pigging of the line is conducted as a routineprocedure, and since the crystal modifier product has beenapplied the incidence of wax accumulation has fallensignificantly. Typical pigging procedures conducted prior tothe use of the crystal modifier invariably collected large

quantities of wax deposits that required disposal as hazardouswaste. Since, the implementation of the crystal modifier it israre to find any wax collected by the pigging operation. In therare cases wax is collected some event has been experiencedwhich explains the presence of wax. Such events include thechange of crude feed streams, and a chemical pump failure.The overall performance of the crystal modifier has beenshown to be vastly superior to the solvent dispersant gasolinetreatments conducted previously.

Field Test 4A large independent producer in Kansas had recentlypurchased a widely dispersed production region, anddiscovered that a large number of the wells in these fieldsproduced significant amounts of paraffin wax. It wasimmediately obvious that treatment of the wax problems hadto be undertaken to minimize the loss of production. Thetiming of the purchase was such that winter would soon be afactor in the choice of treatments employed in the area. Thusbids were sought, and selection criteria would be based on themost promising method of addressing the existing waxproblems. Many of those involved in the bid process offeredthe typical solvent dispersant packages that had beenemployed for many years. One company, however, couldprovide the more effective crystal modifier chemistry capableof withstanding the severe temperatures experienced in thewinter. This company was awarded the field and placement ofthe modifier took place. The broad expanse of this productionarea (over twelve thousand square miles) resulted in a verydifficult period for the service company. The initial productexperienced some difficulty due to pump failure and a newwinterize product was introduced.

ResultsSince the placement of the second winterized product theincidence of failure due to chemical pump failure has beeneliminated. Failure rates, due to paraffin wax buildup hadhistorically been high during the winter months (e.g., two tothree well failures per month). The program has beenunderway for a period of four months, and the failure rate hasdropped to one well during this period.

ConclusionsMuch has been said about the negative effects of hot oilingand hot watering, and much of it is true, but the fact remainshot oiling will continue to be used as long as it aids in wellworkovers. While it is true that solvent treatments and crystalmodifier applications afford a more efficient and safer methodof dealing with paraffin wax problems, these methods mightalso benefit from cooperation with hot oil companies. Routineaddition of crystal modifiers to hot oil treatments couldprovide a significant new tool in both the hot oilers andchemical companies kit. A major change in the paradigms ofboth the chemical company and hot oiler could serve to betterprovide for the oil company customer. After all many hotwater jobs are conducted with surfactants supplied by

6 JR Becker SPE 63123

chemical companies, why should this cooperation be limitedto hot water?

AcknowledgmentsThe work presented here is the result of a projects undertakenby three major oil companies, a major pipeline company andUnichem and is aimed at the resolution of field wax problemsin the Big Spring, Denver City, Hearne areas of Texas, and thesouthern Kansas region. The author would like to give thanksto Dora Galvan for her expert assistance in the development ofthese new products. Special thanks are due Jim CampbellDonald Reid, Jim Roberts, Rod Martin, Jerry Don Sweat, andMike Hill of Unichem for the tireless efforts they expended onthe products’ field application and monitoring.

References1. Mansure, A.J., Barker, K.M.: “Insights Into Good

Hot Oiling Practices”, SPE 25484, ProductionOperations Symposium, (March 1993) 689-694.

2. Becker, H.L. (J.R.), “Kinetic Model of Pour-PointPhenomena”, SPE 22830, 66th Annual TechnicalConference and Exihibition of the Society ofPetroleum Engineers Dallas, TX (October 6-9, 1991).

3. Asinger, F.: “Paraffin Chemistry and Technology,”Pergamon Press, (1967).

4. Becker, J.R., “Crude Oil Emulsions, Waxes, andAsphaltenes”, PennWell, (1997).

Well 1 Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12

Rod Weights 9838 10014 10003 9975 9828 Pat Vac 9790 9702Motor Amps 37 36 37 36 37 35 36 35 35 36 36 35 35 35 36Run Time / Hours 12:45 12:40 Pat Vac 14:37 11:30 11:02 9:10 11:08 11:14 10:45 10:41Production O / W 55 / 35 51 / 30 47 / 35 41 / 25Pour Point (degrees F) 22F 20F 3F (-)17F (-)30 F (-)34F (-)35F (-)6F (-)54F (-)17F (-)15F <(-)60F (-)27F (-)30F (-)27FFlowline Pressure 40 40 40 35 28 Pat Vac 28 25Ch Startup 12-29-98 12/15/98 12/17/98 12/22/99 01/06/99 01/13/99 01/20/99 01/27/99 02/03/99 02/11/99 02/17/99 02/24/99 03/03/99 03/11/99 03/17/99 03/24/99

Well 2 Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12

Rod Weights 14901 15158 14473 14550 14690 14690 14450 14550Motor Amps 51 52 51 52 51 51 51 51 51 51 51 51 51 52 51Run Time / Hours 6:09 9:33 8:20 9:15 8:31 8:34 13:29 9:27 9:32Production O / W 43 / 20 48 / 18 53 / 9 43 / 7 45 / 7Pour Point (degrees F) 8F 8F >(-)34F >(-)36F >(-)36F >(-)34F (-)44F (-)33F (-)54F <(-)60F (-)38F (-)32F (-)28F <(-)60FFlowline Pressure 40 40 40 40 40 40 40 30Ch Startup 12-16-98 ? 12/15/98 12/17/98 12/22/98 01/06/99 01/13/99 01/20/99 01/27/99 02/03/99 02/11/99 02/17/99 02/24/99 03/03/99 03/11/99 03/17/99

Well 3 Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12

Rod Weights 12657 12941 13054 12640 12560 12645 12490Motor Amps 52 51 52 52 51 51 51 51 50 51 51 51 51 50 50Run Time / Hours 9:44 9:55 10:06 11:41 9:45 11:25 10:13 10:12 10:00 9:56Production O / W 30 / 62 36 / 68 32 / 65 29 / 65Pour Point (degrees F) 18F 22F >(-)36F (-) 34 F >(-)36F (-)46F (-)64F (-)34F <(-)60F (-)36F <(-)60F <(-)60F <(-)60F (-)54FFlowline Pressure 50 50 50 43 43 45Ch Startup 12-30-98 12/15/98 12/17/98 12/22/98 01/06/99 01/13/99 01/20/99 01/27/99 02/03/99 02/11/99 02/17/99 02/24/99 03/03/99 03/11/99 03/17/99 03/24/99

Well 4 Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12

Rod Weights 15505 15514 15538 11940 11980 12000 12050Motor Amps 41 40 41 41 40 40 38 40 40 39 40 40 39 39 40Run Time / Hours 18:33 19:09 18:03 20:02 16:33 17:40 18:07 16:35 17:35 19:52Production O / W 52 / 57 51 / 55 63 / 86 48 / 85Pour Point (degrees F) 18F 18F (-)8F (-)10 F (-)34F (-)4F 21F 10F 12F (-)11F (-)29F 7F 14F (-)31FFlowline Pressure 50 50 50 35 35 42Ch Startup 12-30-98 12/15/98 12/17/98 12/22/98 01/06/99 01/13/99 01/20/99 01/27/99 02/03/99 02/11/99 02/17/99 02/24/99 03/03/99 03/11/99 03/17/99 03/24/99

Well 5 Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12

Rod Weights 10606 10625 10811 10860 10860 10861 10090Motor Amps 58 57 58 58 57 57 60 57 59 59 58 59 59 59 59Run Time / Hours 6:23 X 7:25 7:05 6:59 6:58 6:45 6:47 6:49 6:44Production O / W 23 / 62 23 / 63 24 / 72 22 / 63Pour Point (degrees F) 18F 22F 18F 4F (-) 18 F (-)8F 14F (-)8F 2F <(-)60F (-)58F (-)31F (-)14F <(-)60F 4FFlowline Pressure 40 40 40 40 X 40 45Ch Startup 12-31-98 12/15/98 12/17/98 12/22/97 01/06/99 01/13/99 01/20/99 01/27/99 02/03/99 02/11/99 02/17/99 02/24/99 03/03/99 03/11/99 03/17/99 03/24/99

Pre Test Baseline

Pre Test Baseline

Pre Test Baseline

Pre Test Baseline

Pre Test Baseline

Table I: Some measurements used to determine crystal modifier effetiveness

20

20

30

30

60

1

2

3

4

5

132

118

118

117

119

$ 5.43

$ 5.43

$ 5.43

$ 5.43

$ 5.43

Hot WaterTreatmentFrequency

Well Number

Days onModifier

$/dayModifier

TreatmentCost to Date

Hot WaterTreatments Skipped

Hot Water$/Treatment

Cost toHot Water Savings

$716.76

$640.74

$640.74

$635.31

$646.17

7

6

4

4

2

$543

$543

$543

$543

$543

$3,584

$3,204

$2,136

$2,118

$1,077

$2,867

$2,562

$1,495

$1,482

$430

Table 2: Four-month savings due to the implementation of a crystal modifier program

Chemical cost savings $8,836

Work-over rig and clean-up cost $15,175

Installation cost ( $10,188)

Total cost savings $13,823

Hot WaterTreatmentFrequency

Well Number

Days onModifier

$/dayModifier

TreatmentCost to Date

Hot WaterTreatments

Skipped

Hot Water$/Treatment

Cost toHot Water Savings

1 380 $5.43 $2,063 20 19 $543 $10,317 $8,254

2 366 $5.43 $1,987 20 18 $543 $ 9,774 $7,787

3 366 $5.43 $1,987 30 18 $543 $ 9,774 $7,787

4 365 $5.43 $1,982 30 12 $543 $ 6,516 $4,534

5 367 $5.43 $1,992 60 6 $543 $ 3,258 $1,265

Table 3: Twelve-month savings due to the implementation of a crystal modifier program

Chemical cost savings $29,625

Work-over rig and clean-up cost $45,524

Installation cost ( $10,188)

Total cost savings $64,961