SPESociety of Petroleum Engineers

SPE 21510

Comparative Study of Microcomputer-Based GasFlow ComputersM. Seghier* and A.L. Podia, * U. of Texas, and WW. Dunn, Remote Operating Systems'SPE Members

Copyright 1991, Society of Petroleum Engineers, Inc.

This paper was prepared for presentation at the SPE Gas Technology Symposium held in Houston, Texas, January 23-25, 1991.

This paper was selected for presentation by an SPE Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper,as presented, have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material, as presented, does not necessarily reflectany position of the Society of Petroleum Engineers, its officers, or members. Papers presented at SPE meetings are subject to pUblication review by Editorial Committees of the Societyof Petroleum Engineers. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgmentof where and by whom the paper is presented. Write Publications Manager, SPE, P.O. Box 833836, Richardson, TX 75083-3836 U.S.A. Telex, 730989 SPEDAL.

Abstract

A laboratory investigation was undertaken to evaluateand compare the performance of various microprocessor-based gas flow meters. A total of 45 tests were performedwith both steady- and unsteady-state flow regimes tosimulate field conditions.

In general, the differences in cumulative volume obtainedwith the seven types of metering systems studied were in therange of 2 to 7%, with the mode being between 3 and 4%.In particular, the study revealed that under unsteady-stateconditions the turbine meters agreed reasonably well, i.e.,less than 3% percent deviation in cumulative volume, withthe orifice plate devices.

Data sampling rates were examined and found to have apronounced effect on unsteady-state flow measurements.also, bearing in mind the generally high cost of pressuresensing elements, instantaneous values of flowing anddifferential pressure across the orifice were affected withrandomly generated errors in order to investigate the effecton cumulative flow, and thus quantify the degree oftransducer accuracy necessary to measure flow under a givenset of conditions.

IntrOduction

The objective of this research was the evaluation of theperformance of four different gas flow measurement systemswhen installed in series in a metering run by measuring theflow of compressed air at variable rates from 35 to 905mscf/d.

The flow meters tested consisted of two gas turbinemeters and two standard orifice plate meters which wereconnected to various data recording devices includingcommercially available gas flow computers, a standard threepen chart recorder, and a general purpose data acquisitionsystem.

References and illustrations at end of paper.

,

291

Real field conditions were simulated by allowing a widespectrum of flow conditions to occur. Results from thevarious meters were compared mutually as well as withresults integrated from recorder charts, which were used as acommon reference. Further insight was gained in terms ofthe effects that higher sampling rates and larger errors haveon the calculated total volume.

Experimental System

The laboratory system used for this study is representedschematically in Fig. 1. The Ingersol Rand compressor wasgenerally operated at a discharge pressure between 90 and100 psig for variable flow rates.

Flow was controlled at the inlet metering run whichconsists of a 2-inch Camco orifice plate holder and meteringtubes outfitted with a temperature sensor, a static pressuretransducer, and stacked differential pressure transducerswhich are fed to the inputs of gas flow computer FC#1.Regulation of flow rate was accomplished with manuallyoperated flow control valves located downstream themetering run.

The majority of the tests were undertaken by flowingdirectly from this metering run into the production separator( 4 x 10 ) and from there to the test metering run. The backpressure in the separator and the test metering run wascontrolled by the regulator at the outlet of the meteringsystem and was varied over the range of 5 to 90 psig inorder to cover the broadest possible range of turbine meterTFC#2 allowed by the compressor system.

Also included in this experimental setup -but not shownin Fig.l- is a fully completed 500 ft deep test well whichwas used to simulate multi-rate flow tests, i.e., unsteady-state flow conditions.

2 ARATIVE STUDY OF MICRO-PROCESOOR-B!\SED GAS FI.DW UTERS SPE 21510

Test Meterin~ Run

From the separator gas flowed through turbine meterTFC#l, then through the Daniel Senior Orifice Plate holderand meter tubes and finally through turbine meter TFC#2.TFC#l includes the turbine body and separate transducerssensing line pressure and temperature. The signals are fed toa microprocessor-based flow computer which displays inputvariables, flow rate and cumulative volume.

The signals from the orifice plate differential pressure,flowing pressure, and flowing temperature were paralleled tofour measuring systems:

1. Three pen circular chart recorder( subsequently referred to as CHART)

2. Flow computer FC#2 with integral transducers3. Flow computer FC#3 with integral transducers4. FLUKE data acquisition system

This arrangement allowed the comparison of fourcalculated flow rate values using a single set of inputparameters from common sensing elements.

TFC#2 displays flow rate, pressure, temperature andcumulative volume as calculated by an integralmicroprocessor. For these laboratory tests it also providedanalog output signals of flowing pressure, temperature andinstantaneous flow rate. These signals were fed to theFLUKE data acquisition system for better monitoring ofexperiments and future comparison with values acquiredmanually from the LCD display of TFC#2.

Data Acquisition

For each experiment a major portion of the data wasacquired manually and some automatically through theFLUKE system. Real time was used as the correlatingparameter between various meters and instantaneous valueswere recorded as displayed at that time.

Continuous recording of the orifice plate parameters onthe circular chart was done for the 24-hour clock setting.Thechart recording was also used as a means of quality controlof experimental conditions and when anomalies wereobserved on the charts the run was terminated and the datawere discarded.

Automatic data acquisition was limited to TFC#2'Ssignals and to the orifice plate differential and flowingpressures using the FLUKE data acquisition system whichconsists of a programmable front-end (2400B) and a hostcomputer (1752A). Scanning of analog channels and 16 bitAID conversion were undertaken by the 2400B using adown-loaded Pascal-coded program and the data weretransmitted to the host upon request. A total of five voltageinput variables were scanned and averaged over five cycles(approximately one second) before being transmitted to thehost program for conversion to engineering units andincorporated into a flow calculation program. Overall cycletime of this flow computation and data storage program wasapproximately four seconds.

Flow Computations

These were undertaken by the host computer andinvolved calculating flow rate from the orifice plate signals,accumulating total flow, and accounting for the analog datareceived from TFC#2.The orifice plate flow calculation is an

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adaptation of the AGA3 calculation procedure with air beingthe gas flowing through the system.

Flowing pressure, temperature and instantaneous flowrate were recorded in a disk data file and processed so as toobtain an integrated value of cumulative volume from thevalues of the instantaneous rate.

The flowing pressure and the differential pressure acrossthe orifice were measured using a set of independentRosemount transducers and input to the AGA3 gas flowcalculation program in order to determine the corresponding.instantaneous flow rate. In this calculation the flowingtemperature was obtained from TFC#2. The compressibilityfactor was fixed to equal 1.0, which is the same assumptionmade in TFC#2.

The data acquisition program is fully interactive and itsexecution is controlled with menus from the touch sensitivescreen. At the beginning of a test the pertinent data isrequested and entered by the operator. This is followed bythe experiment checklist to insure that the necessary steps areundertaken in the proper order. Data is then acquired, thecalculations performed in real time and the results are printedon the data logger and stored on disk. The experiment isterminated by the operator when a representative flow periodhas elapsed.

Flow Tests

A total of 45 flow tests were undertaken to cover theuseful range of TFC#2's operating pressures obtainable withthe available laboratory facilities. Test duration ranged froma minimum of 15 to 60 minutes depending on the flow rate.Table 1 represents a map of the flow conditions tested.

This series of flow tests included both steady-state andvariable flow rate conditions. A second series of testsdesigned to simulate gas well testing conditions wasundertaken using the test well. Flow rates were increasedfrom zero to maximum using the adjustable choke so as tosimulate a multi-rate flow test. The duration of these testswas typically of the order of 90 minutes.

Tests were carried out at specific metering run pressuresin order to cover the useful range of TFC#2. At 90 psig linepressure the range is from 100 to 1700 mscf/d while at thelowest tested pressure of 5 psig the range is from 19 to 300mscf/d.

The general procedure for the unsteady-state flowexperiments was to begin the test at the lowest flow rate,establish stabilized conditions and then begin recording data.After adequate time (depending on flow rate) cumulativeflow was totalized and the rate increased to a new level. Thisprocedure was continued so as to cover the desired range.

During these tests the performance of the orifice meterwas monitored closely. When necessary the orifice platediameter was changed before the start of a test to insure thatdifferential pressure levels were within the AGA guidelines.

Discussion of Results

The results of the various experiments are divided basedon the type of flow that was maintained during the testsequence. For the steady-state tests, a stabilized flow ratewas maintained during the major portion of the flow test.Cumulative flow results however include the time periodduring which the flow was started from zero and the timeperiod during which the flow was shut-in. Typically thistime interval corresponds to a small percentage of the

SPE 21510 M. SIDHIER, A. PODIO AND W. W. DUNN 3

duration of the test so that its effect on the values is minor.Table 2 presents the results of cumulative flow for all thetests at steady state flow conditions as a function of meteringrun pressure and nominal flow rate.

To compare the performance of the various flw met~rsand gas flow computers it was necessary to deCIde whIchwas to be used as a reference. The CHART was opted for asthe reference owing to its commonplace utilization in the gasindustry.

The common parameter used to compare results was thecumulative volume. This comparison was performed foreach set of tests run under the same line pressure. Smallvariations in instantaneous rate and the extreme difficulty ofmonitoring all the meters.simultaneously at a giv~n ~stantprecluded comparing the Instantaneous flow rates Indicatedby each meter.

Steady-State Flow Tests

The results are presented both in tabular form ~a?le 2)and some graphically (Figs. 2-8). In all cases the IndIcatedflow rate is the NOMINAL rate for the test and not theinstantaneous rate. The reported cumulative volume fromeach meter was obtained as follows:

TFC#2 Difference of LCD readouts before and aftertest.

FC#2 Difference of hand-held terminal readoutsbefore and after test.

FC#l Cumulative flow readout, reset to zero beforetest.

FLUKE: Result of integration of instantaneous flowrates from AGA-3 procedure.

FC#3 Difference of LCD readouts before and aftertest.

TFC#l Difference of LED readouts before and aftertest.

CHART: Result of integration of three-penrecorder charts.

It is worth noting that FC#3, one of the gas flowcomputers provided for this experimental study, ~asprogrammed such that the digital display .of th~ cumulat~vevolume had a resolution of 1 mscf. WhIle thIS resolutIonmay be adequate for field measurements over long ~riods oftime, it was clearly inadequate for the short duratIOn testsundertaken in the laboratory. However the results arereported here for complet~ness and also because the rawdata include values of Instantaneous rate, pressure,differential pressure and temperature.

The three-pen recorder charts were integrated by aprofessional company specializing in gas measurementaudits. Also in this case the values, although com~uted to agreater resolution, were reported in the computer prmtouts tothe nearest mscf. It was therefore necessary to re-computethe cumulative flow, using the integration results an~ theappropriate coefficients, to obtain values to 1 scfresolutIOn.

The performance of all the meters ~d for all flow te~ts iscompared in Figure 2 to the cumulauve volume obtal~edfrom the circular charts. It can be seen that although pOIntsfall on both sides of the equality line there appears to belarger deviations above the line (the dash~d lines represent a10% band) indicating that the tendency IS for the charts tounder-estimate the cumulative volume.

The performance of the FC#2, or~fice base~ flowcomputer is shown in Figure 3. Ge~erally Its vol~II!-e IS closeto the chart's cumulative.The pOInts that exhIbit a large

293

deviation correspond to conditions of flow pulsations whichresulted in a painted chart. The deviat~ons between th~smeter's cumulative volume and the chart s are presented InFigure 4. The majority of the deviations are positive whichindicates that the flow computer generally accounted for alarger volume than the circular charts.

The performance of the TFC#2 turbine gas flowcomputer indicated in Fig. 5 shows that relative to the charts,TFC#2 generally underestimates the cumulative volume. Thetrend seems to be fairly consistent since the departure of thepoints from the line increases as the cumulative flowincreases. Increasing the flow-line pressure from 10 to 90psig appears to increase the deviation. Figure 6 prese~tsthese deviations as a function of pressure and cumulatIvevolume.The majority are negative showing that thisparticular meter has a tendency to under estimate the flowrelative to the circular charts.

Since TFC#1 and TFC#2 are basically equivalent, it is ofspecial interest to compare their performance. Figure 7 is aplot of the % difference in cumulative volume calculated bythese two flow computers. For most cases they differ by lessthan 3% at all pressures and over the range of rates. TFC#2seems to consistently under estimate the flow, indicating abias probably caused by a zero offset in the transducers.This unit has integral pressure and temperature sensorswhich were calibrated at the factory and used as received.

Because the difference in readings between any twometers might vary with the total flow measured and with thepressure level of the metering run, it was necessary toinvestigate this eventuality by expressing the differencebetween the cumulative volumes indicated by the charts andthe other meters as a percentage and plotting this differenceversus reference cumulative volume for all the line pressurestested. These results are presented in Figs. 6 through 8.Figure 6 shows that TFC#2 is probably consistently biasedtowards a more conservative estimate of the flow. Inaddition there appears to be an increasing deviation withincreasing line pressure. The difference between TFC#2 andthe reference charts is of the order of -7 % at 10 psig. As thepressure increases the deviations increase. In a few cases at90 psig the deviations become very large 25-30 %. In thesecasfts the compressor discharge pressure pulsated between90 and 100 psig resulting in a painted chart and an underestimate of the flow by standard integration. The flowcomputers on the other hand were able to track the linepressure accurately.

Unsteady-state Flow Tests

A series of tests was undertaken to simulate conditionswhere the flow rate varied periodically with time about anaverage value. These tests were designed to reprod~ceconditions which would be found in the field under surgIngconditions such as production from gas-lifted wells, gasdistribution to intermittent gas-lift networks, surging oilwells, long flow-lines, etc.

Measurements were undertaken at line pressures of5,20,30 and 40 psig with flow rates ranging from 27 to 380mscf/d. At each pressure two tests were run. The pressuredrop across the orifice plate oscillated between 2 and 25inches H20 for one test, and between 49 and 90 inches H20for the other. The frequency of the oscillations wasapproximately between 0.5 and 1.5 cycles per minute.

4 CDn>ARATIVE STUDY OF MlrnoPROCESOOR-BASED GAS FLOW CDn>UTERS SPE 21510

The duration of each test varied from 30 to 90 minutes.Figure 8 shows a copy of a circular chart for a typical test.The following summarizes the test conditions:

Line Pressure Flow Rate Range Test Numberpsig msef/d

----------------- ------------------ ----------------

5 27-155 385 160-211 39

20 75-196 4020 196-285 41

30 164-301 3530 237-323 3630 82-230 37

40 80-257 4240 250-350 43

Test No. 35 was the first test of the series and wasconducted in a slightly different manner by adjusting the rateto short (5 minute) constant flow intervals in a relativelyrandom pattern. A visual inspection of the unsteady-stateflow charts -commonly referred to as "painted" charts-reveals laboratory flow conditions that are commonlyencountered in the field.

Whereas flow instability was deliberately created duringthe unsteady-state flow tests, it was not so for the series ofsteady-state tests run with a line pressure of 90 psig. In thelatter, the high frequency oscillations of the flow rate wereattributed to the nature of the compressor pressure regulationsystem.

Table 3 summarizes the results of the unsteady-state flowtests and Figure 9 shows a comparison of the flowcomputers' cumulative volumes compared to those obtainedfrom chart integration. The deviation bars correspond to +/-10%. The majority of the values are within this envelope,except those corresponding to FC#3 which is the meter witha display resolution of 1MCF.

Effect ofData Samplinli Rate

The cumulative flow is obtained from integration of theinstantaneous flow rate as computed from the values of linepressure, line temperature and differential pressure for theorifice plate meters. For the turbine meters the cumulative isgiven by summation of pulses converted to flow frominstantaneous readings of line pressure and temperature. Inboth cases the pressure and temperature readings are taken atspecific time intervals which vary from system to system.

The data from tests No.29, 42 and 43 were used toinvestigate the effect of the sampling rate on the value of thecalculated cumulative flow. As discussed earlier, thepressure data from the differential pressure, line pressureand line temperature were acquired by the FLUKE dataacquisition system at a rate of approximately 4 seconds persample. The values for a complete test were continuouslystored on a disk fIle. The data on this file were subsequentlyre-processed to calculate the cumulative flow for the test. Aprogram was written which would process these datarepeatedly, each time increasing the time betweenconsecutive readings. The Irrst time the cumulative wascalculated using all the data points, then using every otherdata point, then using every third data point, and so on. Thisis equivalent to increasing the sampling rate from 4 seconds,

294

to 8 seconds, to 12 seconds, etc..., up to a maximum of 240seconds, which corresponds approximately to the period ofvariation of the flow rate for these tests. Figure 10 is a plotof about one cycle of the flow rate as a function of time fortest No. 42. The flow rate is oscillating between 4000 and11000 mscf/hr with a period of approximately 240 seconds.This period represents only a minute portion of the totalduration of Test No. 42 which was of 100 minutes. On thesame figure is superimposed a plot of the cumulative valueof the flow obtained by repeated integration of the data atdifferent sampling periods. The filled circles in Fig. 10represent the actual cumulative volume based on theinstantaneous actual sampling rates. The empty circlesindicate the cumulative volume as computed with imposedand increasingly longer sampling times. Note that forsampling times up to about 80 seconds, the measured andcomputed values coincides almost exactly. These oscillationsincrease as the sampling period increases to 240 seconds. Asexpected, due to the periodic nature of the flow rate thecumulative calculated at intervals that correspond tomultiples of even fractions of the flow rate period (T/2, T/4,T/8 or 120,60 and 30 seconds) yield values very close tothe actual ones. Figure 11 shows a similar behavior for theresults obtained from test No 10 which covered a higherrange of flow rates.

These results indicate that it is very important to knowthe characteristics of the flow if one is to decide on anadequate data sampling frequency for computation of thecumulative flow. To investigate the effect further the datafrom Test No. 29 was analyzed in a similar fashion. Thiswas a steady-state test at a line pressure of 90 psig and aflow rate of 114 msef/d. The metering run's line pressure isvery close to the compressor's discharge pressure set pointof 100 psig, so that it was possible to observe the cycling ofthe flow controller. Figure 12 shows that the flow rateoscillates at about 475 scf/hr with a period of about 20seconds. Sampling at 4 second intervals will yield 5 samplesper cycle. As the sampling interval is increased to 240seconds the periodic nature of the function becomes apparentwith ever-increasing deviations.

Error Analysis

The effect that measurement error on both flowing anddifferential pressure measurements across an orifice plate hason total flow was investigated. Actual data stored for agiven test such as flowing pressure (P), differential pressure(M'), temperature, and real time were re-processed to obtainthe total volume by integration after modifying the raw databy introducing deviations of the values. These deviationswere intended to simulate the effect of bot random and biaserrors..

The error on each variable (P and M') was computed as apercentage of the transducer's full scale, i.e., for the flowingpressure transducer,

Perror = Pactual +/- error% x (100 psia) + 100and for the differential pressure transducer,

M'error =f1Pactual +/- error %x (150 in Hg) + 100The program used a random number generator to

determine the sign and the value of the deviation to beapplied to a given set of instantaneous values of theparameters.Fig. 13 shows a typical behavior of thecalculated cumulative volume as the range of error on P andM' varies. The horizontal line represents the computedvolume without the deviations. Note that up to about 5-6%

SPE 21510 M. SffiHIER, A. PODIO AND W.W. DUNN 5

error the difference between the correct volume and theaffected volume is minimal. As the error range increases asignificant deviation is observed. Note that repeating thiscalculation will yield different values due to the randomnature of the deviations. Also, at each data point thedeviations of P and ~P are not the same. Random errors arerelated to the overall error band of the transducers used in aparticular application. These results seem to indicate that aslong as the errors are random their effect is minimal. Theredoes not seem to be a major advantage in using highprecision transducers vs.normal instrumentation devices thatexhibit error bands of less than +/- 1% of full scale.

On the other hand, the effect of an error bias, zero shift,was simulated by applying a constant deviation to the rawdata and integrating the instantaneous volumes. Againdeviations were expressed in terms of % FS of the respectivetransducers. The results are shown in Figure 14 where theworst case scenario is illustrated ( P and ~P errors of thesame sign). The errors in cumulative volume increase rapidlyeven for small deviations. This indicates the importance offrequent checks of the transducer zeros to insure accuratemetering.

Conclusions

For the majority of the tests the differences incumulative flow obtained from the seven types ofmeasurements were in the range of 2 to 7% with the meanbetween 3 and 4%. In some instances deviations as large as20 to 25% were observed.

Turbine meter TFC#2 consistently yieldedconservative estimates relative to the other meters. This isprobably due to differences in the pressure transducercalibration since the deviation appeared to be related to theflow-line pressure level.

During unsteady-state tests the turbine meters'estimates of cumulative flow agreed within less than 2%difference from each other and within less than 3% deviationfrom the orifice plate gas flow computer. This indicates thatthe turbine meters can be used with equal confidence insteady- as well as unsteady-state applications.

In unsteady-state flow the data sampling rate has apronounced effect on the cumulative flow calculation. Forthe tests conducted in this study the fastest sampling andinstantaneous flow calculation rate was about 4 seconds.Increasing this rate resulted in steadily increasing deviationsof the calculated cumulative volume from the actual one.

To insure accurate flow metering the accuracy oftransducers should be as high as economically justifiableHowever the results clearly show that even small errors intransducer zero (bias errors) cause cumulative volumedeviations much larger than the corresponding randomerrors.

Acknowledgements

This research was sponsored by the Remote OperatingSystems company of San Antonio Texas through SponsoredResearch Contract No. 26-6802-05.

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II

TABLE 1- FLOW TEST CONDITIONS

Line Pressu Test Numbe Flow Rate Flow Mode DatePsi MSCF/D

5 38 160-211 Unsteady 12/21/885 39 27-155 Unsteady 12/21/8810 14 35 :steaay ~fn~~10 15 67 Steady10 16 113 Steady 1217/8810 17 198 Steady 1217/8810 18 328 Steady 12/8/8820 40 196-285 Unsteaay ~~~~20 41 75-196 Unsteady30 19 500 Steady ~~~30 20 250 Steady30 21 310 Steady 12/9/8830 22 312 Steady 12/9/8830 23 311 Steady 12/9/8830 30 198 Steady 12/14/8830 31 147 Steady 12/14/8830 32 114 Steady 12/15/8830 33 77 Steady 12/15/8830 34 52 Steady 12/1618830 35 164-301 Unsteady 12/1618830 36 237-323 Unsteady 12/19/8830 37 82-230 Unsteadv 12/19/88

~g 42 80-257 Unsteady ~~~~~43 250-350 Unsteady40 44 304 Steady 1/10/89

~g 1 210 :steaay ~W~~2 187 Steady50 3 138 Steady 1lI15/8850 4 93 Steady 11/22/8850 5 79 Steady 11/23/8850 6 362 Steady 11/28/8850 7 817 Steady 11/28/8850 8 754 Steady 11130/8860 45 ::rrn SteadY 131lS970 9 904 :steady 1!/3.!'~~70 10 618 Steady 11/30/8870 11 408 Steady 12/1/8870 12 191 Steady 12/1/8870 13 96 Steady 12/2/88

~ 24 316 :steady ~~:~~25 315 Steady90 26 192 Steady 12/12/8890 27 153 Steady 12/12/8890 28 114 Steady 12/13/8890 29 114 Steadv 12/13/88

, I

BPE 21510

TABLE 2 - CUMULATIVE FLOWP TEST FLOW CHART TFCl/l TFC#2 FLUKE FCI/l FCI/2 FCI/3

PSIG NO. MSCF/D SCF SCF SCF SCF SCF SCF SCF10 14 3~ 720 733 730 789.1 761 770.1 100010 15 67 2310 2284 2250 2337 2311 2342.7 200010 16 113 3924 3811 3720 3907.9 3854 3876.5 400010 17 198 7634 7564 7450 7810.6 7680 7742.7 700010 18 328 10804 10246 10120 10643 10502 10541 11000

30 22 312 8995 8915 8800 8963.5 8969 9114 900030 23 311 11645 13235 13050 13360 13329 13544 1400030 30 198 5625 5448 5340 5484 5553 5640 500030 31 147 2950 3044 2990 3031 3110 3116 300030 32 114 3164 2800 2750 2818 2808 2881 300030 33 77 1854 1772 1750 1775 1697 1820 200030 34 52 1105 1022 1080 1111 1088 1120 100030 21 310 3217 3006 2960 3108 3032 3070 300030 20 250 5482 5356 5280 5308 5414 5468 600030 19 500 11476 11244 11110 11418 11459 11591 11000

4U 44 304 5219 6370 6414 6517 6603 7000

50 1 210 4266 4200 4440 4400 400050 2 187 4318 4000 4335 4197 400050 3 138 4576 4370 4798 4550 4586.5 400050 4 93 3752 3740 4204.6 3969 3916 400050 5 79 2470 2190 3919.2 2259 2295 200050 6 362 16005 15170 16602.6 15450 16000 1600050 7 817 19753 18670 20700.9 19286 19541.5 2000050 8 754 14340 15210 15406.1 15614 15835 15000

60 45 316 6750 6958 6891 7009 7000

70:0

904 177Bj 18100 19000 18527 18891 1900070 618 11857 11880 12000 12224 12537.5 1200070 11 408 9573 9340 10000 9416 9848.4 1000070 12 191 3599 3360 4000 3413 3516.5 400070 13 96 1874 1910 2000 2087 1999.4 2000

:: 24 315 7211 9554 9150 9461 9591 9887 1000025 315 4125 3757 3620 3750 3814 3915 400090 26 192 3639 4881 4730 4935 4979 5122 500090 27 153 3386 3280 3190 3261 3347 3395 300090 28 114 3567 3603 3470 3592 2493 3769 400090 29 114 1589 1552 1500 1549 1080 1629 2000

TABLE 3 - CUMULATIVE FLOW, UNSTEADY STATE

rESTNc FLOW CHART TFCl/1 TFal2 FLUKE FC#1 FCI/2 FCI/3MSCF/D SCF SCF SCF SCF SCF SCF SCF

38 27-155 3744 4191 4140 4340 4290 4275 400040 196-285 5593 5210 5140 5249 5274 5328 500041 75-196 3129 2977 2940 3043 3002 3033 300035 164-301 9910 9907 9760 9898 10004 10122 1100036 237-323 6142 6050 5950 6838 6100 6187 600042 80-257 13459 12754 12660 12918 13157 1300043 250-350 14220 14093 13930 14244 14504 1500037 82-230 3586 3390 3450 3574 3525 3580 300039 27-155 2027 2024 2050 2189 2160 2109 3000

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