CORING METHODS
Porosity, permeability, grain density, and mineralogy of reservoir rocks are important elements in a reservoir description. We can estimate these properties from well logs or measure them from rock samples in the laboratory. The rock samples are obtained by cutting a piece of rock from the well bore; the process is called coring.

Conventional cores are cut using a specialized subassembly at the bottom of the drill string. This consists of a coring drill bit (usually a diamond bit), a core barrel to hold the recovered core, and fingers in the core barrel to hold the core in place while the coring assembly is pulled out of the hole. At the surface, the core is retrieved from the core barrel and placed in transport boxes, which are transported to a laboratory for further study.

If coring while drilling is impractical, small cores can be taken on wireline using a sidewall core gun or a sidewall rotary coring tool. The sidewall core gun uses black powder explosives to fire a steel bullet into the rock adjacent to the tool. The hollow bullet captures a small piece of rock that is pulled to the surface by the tool. Such guns can recover up to 48 samples in one trip in the hole. Depth control is monitored using a gamma ray log to correlate to previous logs run in the well.


        
Coring assembly on bottom of drill string and coring bit

The rotary coring tool uses an electrically driven  diamond bit to drill a small core from the formation adjacent to the tool. Several cores can be taken at different depths before the tool is brought to the surface.

     
Rotary core drill on wireline                  Sidewall core gun with steel bullets     

       
Core slab, core plug, full diameter, and whole core definition               Core photo of slabbed core                 


Taking core plugs for horizontal and vertical rock properties requires care and attention to dipping beds, fractures, lithology variations, and porosity heterogeneity.  Do NOT high-grade the selection of core plugs by choosing only good porosity points - this will not provide useful information to control petrophysical evaluations, reserves, productivity or other performance calculations.


CORE CLEANING METHODS
Before measuring porosity and permeability, the core samples must be cleaned of residual fluids using solvents, then thoroughly dried. There are numerous lab techniques available to do this. Most methods also provide the oil and water saturation of the core samples on an “as-received” basis.

The number of cycles or amount of solvent which must be used depends on the nature of the hydrocarbons being removed and the solvent used. Often, more than one solvent must be used to clean a sample. The solvents selected must not react with the minerals in the core. Toluene and benzene are most frequently used to remove oil and methanol and water is used to remove salt from interstitial or filtrate water. The cleaning procedures used are specifically important in special core analysis tests, as the cleaning itself may change wettability.

The core sample is dried to removing connate water from the pores, or to remove solvents used in cleaning the cores. When hydratable minerals are present, the drying procedure is critical since interstitial water must be removed without mineral alteration. Drying is commonly performed in a regular oven or a vacuum oven at temperatures between 500C to 1050C. If problems with clay are expected, drying the samples at 600C and 40 % relative humidity will not damage the samples.

Direct Injection of Solvent

The solvent is injected into the sample in a continuous process. The sample is held in a rubber sleeve thus forcing the flow to be uniaxial.

 

Centrifuge Flushing

A centrifuge which has been fitted with a special head sprays warm solvent onto the sample. The centrifugal force then moves the solvent through the sample. The used solvent can be collected and recycled.
 

Gas Driven Solvent Extraction

The sample is placed in a pressurized atmosphere of solvent containing dissolved gas. The solvent fills the pores of sample. When the pressure is decreased, the gas comes out of solution, expands, and drives fluids out of the rock pore space. This process can be repeated as many times as necessary.

 

Soxhlet (left) and Dean-Stark (right) extraction apparatus

 

Soxhlet Extraction

A Soxhlet extraction apparatus is the most common method for cleaning samples, and is routinely used by most laboratories. As shown in the illustration, toluene is brought to a slow boil in a Pyrex flask; its vapors move upwards and the core becomes engulfed in the toluene vapors at approximately 1100C. Eventually, water within the core sample in the thimble will be vaporized. The toluene and water vapors enter the inner chamber of the condenser, the cold water circulating about the inner chamber condenses both vapors to immiscible liquids. Recondensed toluene together with liquid water fall from the base of the condenser onto the core sample in the thimble; the toluene soaks the core sample and dissolves any oil with which it come into contact.

When the liquid level within the Soxhlet tube reaches the top of the siphon tube arrangement, the liquids within the Soxhlet tube are automatically emptied by a siphon effect and flow into the boiling flask. The toluene is then ready to start another cycle.


A complete extraction may take several days to several weeks in the case of low API gravity crude or presence of heavy residual hydrocarbon deposit within the core. Low permeability rock may also require a long extraction time.

 

Dean-Stark Distillation-Extraction

The Dean-Stark distillation provides a direct determination of water content. The oil and water area extracted by dripping a solvent, usually toluene or a mixture of acetone and chloroform, over the plug samples. In this method, the water and solvent are vaporized, recondensed in a cooled tube in the top of the apparatus and the water is collected in a calibrated chamber (Figure 2.1b).

The solvent overflows and drips back over the samples. The oil removed from the samples remains in solution in the solvent. Oil content is calculated by the difference between the weight of water recovered and the total weight loss after extraction and drying.


Vacuum Distillation

The oil and water content of cores may be determined by this method. As shown in Figure 2.2, a sample is placed within a leakproof vacuum system and heated to a maximum temperature of 2300C. Liquids within the sample are vaporized and passed through a condensing column that is cooled by liquid nitrogen.

Summary

The direct-injection method is effective, but slow. The method of flushing by using centrifuge is limited to plug-sized samples. The samples also must have sufficient mechanical strength to withstand the stress imposed by centrifuging. However, the procedure is fast. The gas driven-extraction method is slow. The disadvantage here is that it is not suitable for poorly consolidated samples or chalky limestones.

Distillation in a Soxhlet apparatus is slow, but is gentle on the samples. The procedure is simple and very accurate water content determination can be made. Dean-Stark method crushes the sample, so it cannot be used for other purposes, but accurate oil, water, and pore volumes can be determined.  However, if clay bound water is present some or all of it may be driven off, adding to the water recovered from the pore space.

Vacuum distillation is often used for full diameter cores because the process is relatively rapid. Vacuum distillation is also frequently used for poorly consolidated cores since the process does not damage the sample. The oil and water values are measured directly and independently of each other.


CORE POROSITY  DEFINITIONS
Porosity is an intrinsic property of reservoir rocks and indicates the storage capacity of the reservoir. It is used as a primary indicator of reservoir quality, and along with a few other factors, to calculate hydrocarbon volume in place, and recoverable reserves. Petrophysicists use core porosity values to help calibrate porosity derived from well log data.

Bulk Volume of a Rock = Grain Volume + Pore Volume
        1: Vb = Vg + Vp

Porosity = Pore Volume / Bulk Volume
       2: PHIt = Vp / Vb 

OR: Porosity = (Bulk Volume - Grain Volume) / Bulk Volume
         3: PHIt = (Vb - Vg) / Vb

Note that "V" in this Chapter stands for Volume, not Velocity. These volumes are usually reported in cubic centimeters (cc).

The properties Vb, Vg, and Vp can be measured in the lab on full diameter core or on smaller core plugs drilled from the whole core, or from sidewall percussion or sidewall rotary cores. Whole core is best in heterogeneous reservoirs and in low porosity reservoirs.

                                                                                                                                                                       MEASURING BULK VOLUME (Vb)
There are 3 ways to measure bulk volume:
      s. direct measurement of the dimensions of a regular solid
      b. fluid displacement using Archimedes Principle
      c. fluid displacement using calibrated container (pycmometer)

DIRECT MEASUREMENT:  Bulk Volume = Pi * Length * Radius squared
        4: Vb = PI * L * D^2 / 4

This method is less accurate due to the roughness of the surfaces of the solid and imperfections in shape.


ARCHIMEDES METHOD
This technique utilizes the Archimedes’ principle of mass displacement in a liquid (buoyancy):
        a. The core is first cleaned, dried, and weighed in air (WTdry)
        b. The core sample is then saturated with a wetting fluid and weighed (WTsat)
                 (the core may be coated with paraffin to prevent evaporation)
        c. The sample is then submerged in the same fluid and its submerged weight is measured (WTsub)
        d. The bulk volume is the difference between the last two weights divided by the density of the fluid.
        e. The porosity  is the difference between the first two weights divided by the density of the fluid.

Bulk Volume = (Weight in air (saturated) - Weight submerged) / Density of Fluid
        5: Vb = (WTair - WTsub) / DENSfl
        6: Vg = (WTdry - WTsub) / DENSfl
        7: Vp = (WTsat - WTdry) / DENSfl
        8: PHIt = (WTsat - WTdry) / (WTsat - WTsub) = Vp / Vb

Bulk Density = Saturated Weight / Bulk Volume
        9: BulkDens = WTsat / Vb

If clays are present and sample is maintained at a high humidity (not over dried), this last equation gives PHIe, not PHIt.

Laboratory measurements using this technique are very accurate.


CALIBRATED DISPLACEMENT METHOD
The bulk volume can be determined also by the volume of the displaced fluid. Fluids that are normally used are  water, which can easily be evaporated afterwards, and mercury, which normally does not enter the pore space in a core sample due to its non-wetting capability and its large interfacial tension against air.

Bulk Volume = Volume of Displaced Fluid = Weight Displaced Fluid / Density Displaced Fluid
       10: Vb = WTdisp / DENSfl

Laboratory measurements using this technique are very accurate.

EXAMPLE:
    WTdry = dry weight in air = 16.0 gm
    WTsat = weight of saturated sample in air = 20.0 gm
    WTcoated = weight of dry sample coated with paraffin = 20.9 gm (density of paraffin = 0.9 gm/cc)
    WTsub = weight coated sample immersed in water at 70 °F = 10 gm (density of water = 1.0 gm/cc)
Determine bulk volume
      Weight of paraffin = WTcoated - WTsar = 20.9 - 20.0 = 0.9 gm
      Density of Parrafin = 0.9 gm/cc
      Volume of paraffin = WTpar / DENSpar = 0.9 / 0.9 = 1.0 cc
      Weight of water displaced = WTcoated - Wtsub = 20.9 - 10.0 = 10.9 gm
      Volume of water displaced = 10.9 / 1.0 = 10.9 cc
      Volume of water minus displaced-volume of paraffin = 10.9 - 1.0 = 9.9 cc
      Bulk volume of rock = 9.9 cc


 MEASURING GRAIN VOLUME (Vg)
There are 3 ways to measure grain density in the lab:
        a. assume a grain density, compare to dry weight
        b. displaced fluid method
        c. Boyle's Law

ASSUMED GRAIN DENSITY
Determine Vg from the dry weight of the sample and the rock grain density (2.65 gm/cc for quartz grains). This method is not very accurate if grain density varies due to varying mineralogy.

Grain Volume = Dry Sample Weight / Grain Density
        11: Vg = WTdry / DENSMA

DISPLACED FLUID METHOD
A more accurate approach is to use the displaced fluid volume. First the core plug is measured to obtain its bulk volume, as described earlier  Then the sample is crushed to eliminate all porosity and weighed (WTgr). A glass tube filled with water, called a pycnometer to confuse novices, is weighed (W1), then the crushed rock is placed in the tube (still filled with water), and weighed again WT2). The difference in weights gives the volume of displaced fluid.

Displaced Volume = Crushed Sample Weight + Water-filled tube Weight  - Combined Weight
        12: Vdisp = (WT2 - WT1)

Grain Volume = Displaced Volume / Water Density
        13: Vg = Vdisp / DENSwater

Porosity = (Bulk Volume - Grain Volume) / Bulk Volume
        14: PHIt = (Vb - Vg) ' Vb

If clays are present and sample is maintained at a high humidity (not over dried), this last equation gives PHIe, not PHIt.

Grain Density = Dry Weight in Air / Grain Volume
        15: GrainDens = WTdry / Vg

EXAMPLE:
    WTdry = Weight of dry crushed sample in air = 16.0 gm,
    WT1 = Weight of pycnometer filled with water at 70 °F =  65.0 gm
    WT2 = Weight of pycnometer filled with water and crushed sample = 75.0 gm
Calculate grain volume
    Volume of water displaced = 16.0 + 65.0 - 75.0 = 6.0 gm
    Grain Volume = 6.0 / 1.0 = 6.0 cc
Calculate porosity
    Bulk volume of the sample = 9.9 cc, from previous example
    Total porosity = (9.9 - 6.0) / 9.9 = 0.394 fractional porosity (39.4%)

BOYLE'S LAW METHOD
An alternate grain volume method makes use of Boyle’s Law.

This gas transfer technique involves the injection and decompression of gas (Helium, CO2, or N2) into the pores of a fluid-free (vacuum), dry core sample. Either the pore volume or the grain volume can be determined, depending upon the instrumentation and procedures.

To determine grain volume using ideal gas law at constant temperature:
   a. connect two cells of known volume, Vcell1 and Vcell2
   b. close valve between cells, apply pressure P1 to cell 1
   c. place dry core sample in cell 2, seal and evacuate cell 2 
   d. open valve and measure pressure P2


Boyle's Law apparatus to measure grain volume Vg

          16: V2 =  P1 * Vcell1 / P2
Since V2 = Vcell1 + Vcell2 - Vg And Vtotal = Vcell1 + Vcell2
Then  17: Vg = Vt - Vf
 

MEASURING PORE VOLUME
In previous sections pore volume Vp was derived from volumetric methods based on weight and density. Semi-direct measurement of porosity can also be attempted.

BOYLE'S LAW METHOD
Pore volume measurements can be done by using the Boyle’s Law model, where the sample is placed in a rubber sleeve holder that has no void space around the periphery of the core and on the ends. Such a holder is called the Hassler holder, or a hydrostatic load cell. Helium or one of its substitutes is injected into the core plug through the end stem.


Boyle's Law apparatus for determining porosity

          18: V2 =  P1 * Vcell1 / P2
Since V2 = Vcell1 + PHIe
Then  19: Vp = V2 - Vcell1
 

 FLUID SUMMATIONS METHOD
This technique is used to measure the volume of gas, oil and water present in the pore space of a fresh or preserved (peel-sealed) core of known bulk volume. The volumes of the extracted oil, gas, and water are added to obtain the pore volume and hence the core porosity.

DEAN-STARK CORE ANALYSIS METHOD
This method is used in poorly consolidated rocks such as tar samds and involves disaggregating the samples and weighing their constituent components. Samples are usually frozen or wrapped in plastic to preserve the contents during transport. In the lab, the still frozen cores are slabbed for photography and description, then samples are selected and weighed.

Samples are then heated and crumbled to drive off water, and weighed again. The weight loss gives the water weight. Solvents are used to remove oil or tar. The sample is weighed again and the weight loss is the weight of oil. The matrix rock is separated into clay and mineral components by flotation, dried and weighed again, giving the weight of clay and weight of the mineral grains.
      20: WTwtr = WTsample - WTheated
      21: WTtar = WTheated - WTminerals&clay

By dividing each weight by its respective density and adjusting each result for the total weight of the sample, the volume fraction of each is obtained. Porosity is the sum of water plus oil volume fractions  Because the bound water in the clay is driven off by the drying sequences, this porosity is the total porosity.
      22: VOLwtr = WTwtr / DENSwtr / WTsample
      23: VOLtar = WTtar / DENStar / WTsample
      24: PHIcore = VOLwtr + VOLtar

<== Dean-Stark laboratory apparatus

Assuming clay bound water is driven off by heating and drying, then PHIcore equals total porosity. From comparison to log analysis results, it appears that some clay bound water remains in many cases, so PHIcore lies between total and effective porosity from log analysis.

Example of Dean-Stark porosity (dots) showing that it is less than total porosity
 from logs (black curve) due to incomplete drying of clay. Trying to match log
 porosity directly to core may be futile in many cases. Scale is 0.50 to 0.00. ==>


TAR MASS FROM CORE LISTINGS
If not provided on the core listing, the equivalent value of tar mass from core analysis is derived from porosity, oil saturation, and an assumed oil density:
     25:  Wtar = PHIcore * Star * DENStar
     26:  Wwtr =  PHIcore * Swtr * DENSwtr
     27:  Wrock = (1 – PHIcore) * GR_DENScore

Where:
  Star = tar volume relative to pore volume
  Swtr = water volume relative to pore volume
  PHIcore = volume of water + valume of tar
  Wtar = tar mass fraction
  Wwtr = water mass fraction
  Wrockcore = rock mass fraction

 

PHIcore Star Swtr Vol Tar Vol Wtr GR_ DEN WT Tar WT Sand WT Wtr WT Rock Tar Mass Wtar Wtr Mass Wwtr Rock Mass Wrock
frac frac frac frac frac kg/m3         frac frac frac
0.306 0.301 0.699 0.092 0.214 2.650 0.092 1.839 0.212 2.143 0.043 0.099 0.858
0.271 0.236 0.764 0.064 0.207 2.650 0.064 1.932 0.207 2.203 0.029 0.094 0.877
0.279 0.306 0.694 0.085 0.194 2.650 0.085 1.911 0.193 2.189 0.039 0.088 0.873
0.244 0.304 0.696 0.074 0.170 2.650 0.074 2.003 0.168 2.246 0.033 0.075 0.892
0.298 0.217 0.783 0.065 0.233 2.650 0.065 1.860 0.233 2.158 0.030 0.108 0.862
0.273 0.298 0.702 0.081 0.192 2.650 0.081 1.927 0.191 2.199 0.037 0.087 0.876

If saturations (or pore volume) are known, as well as core porosity, all other terms can be calculated. Some core analysis reports do the math for you, some do not.
 

Since GR_DENScore represents a mixture of quartz and shale, this value should vary with shale volume. However  shale volume is never reported on core analysis, so the composite grain density from the rock sample is used. If grain density is not recorded in the core analysis, we must assume a constant of  2650 Kg/m3 or lower.


FLUID VOLUMES FROM CORE LISTINGS
If not provided on the core listing, the equivalent value of tar volumes from core analysis are derived from porosity, tar mass fraction, and an assumed oil density:
     27: Star = Wtar / (PHIcore * DENStar)
     28: Swtr = Wwtr / (PHIcore * DENSwtr)
OR 29: Swtr = 1.00 - Star

Where:
  Star = tar volume relative to pore volume
  Swtr = water volume relative to pore volume
  PHIcore = volume of water + valume of tar
  Wtar = tar mass fraction
  Wwtr = water mass fraction
 

PHIcore Star Swtr Vol Tar Vol Wtr GR_ DEN WT Tar WT Sand WT Wtr WT Rock Tar Mass Wtar Wtr Mass Wwtr Rock Mass Wrock
frac frac frac frac frac kg/m3         frac frac frac
0.306 0.301 0.699 0.092 0.214 2.650 0.092 1.839 0.212 2.143 0.043 0.099 0.858
0.271 0.236 0.764 0.064 0.207 2.650 0.064 1.932 0.207 2.203 0.029 0.094 0.877
0.279 0.306 0.694 0.085 0.194 2.650 0.085 1.911 0.193 2.189 0.039 0.088 0.873
0.244 0.304 0.696 0.074 0.170 2.650 0.074 2.003 0.168 2.246 0.033 0.075 0.892
0.298 0.217 0.783 0.065 0.233 2.650 0.065 1.860 0.233 2.158 0.030 0.108 0.862
0.273 0.298 0.702 0.081 0.192 2.650 0.081 1.927 0.191 2.199 0.037 0.087 0.876

If tar mass fraction and water mass fraction are known, as well as core porosity, all other terms can be calculated. Some core analysis reports do the math for you, some do not.


POROSITY FROM MICRO CT SCANS
Porosity is directly calculated from high resolution digital images such as those shown below. This calculation is the ratio of the number of voxels that fall into the pore space (black and dark-gray) to the total number of voxels in a 3D image. The task of separating the pores from grains in such 3D objects is called image segmentation.  The main technical challenge in image segmentation is the gradual transition from dark to light shade of gray at the edges of the pore space. Proprietary image-processing algorithms are used, which   include statistical analysis of the gray-scale images. As a result, the pore space is accurately separated from the mineral matrix and the porosity is computed. Source: www.ingrainrocks.com.
 

   
    Clean sand 39%                            Tight sand 5%                 Poorly sorted 12%            Silty Shale 8%
                                Black = Porosity,  Grey = Matrix Grains,  White = Heavy Minerals


SAMPLE CORE ANALYSIS REPORT


Samples of core analysis and core description plots, with a few of the posible histograms and crossplots that can be made.

02181815W4

#23708

731011

 

NOTE: Accumap has Kvert in K90 Column

S#

Top

Base

Len

Kmax

K90

Kvert

Poros

GrDen

BkDen

Soil

Swtr

Lithology

 

feet

feet

feet

mD

mD

mD

Frac

Kg/m3

Kg/m3

frac

frac

 

1

3499.19

3500.17

0.98

742.0

0.0

180.0

0.283

0

0

0.129

0.448

SS VF-F

2

3500.17

3501.16

0.98

1196.0

0.0

694.0

0.297

0

0

0.123

0.450

SS VF-F

3

3501.16

3502.17

1.02

622.0

0.0

266.0

0.276

0

0

0.111

0.520

SS VF-F

4

3502.17

3503.16

0.98

223.0

0.0

50.5

0.271

0

0

0.129

0.479

SS VF-F

5

3503.16

3503.88

0.72

837.0

0.0

171.0

0.278

0

0

0.110

0.504

SS VF-F PY

6

3503.88

3504.57

0.69

407.0

0.0

113.0

0.287

0

0

0.118

0.466

SS VF-F

7

3504.57

3504.67

0.10

 

0.0

0.0

0

0

0

0

0

SH

8

3504.67

3505.26

0.59

514.0

0.0

365.0

0.253

0

0

0.151

0.398

 

9

3505.26

3505.49

0.23

100.0

0.0

2.6

0.201

0

0

0.134

0.358

SS VF-F SH INC

10

3505.49

3505.98

0.49

401.0

0.0

120.0

0.254

0

0

0.143

0.268

SS VF-F SHBKS

11

3505.98

3506.96

0.98

478.0

0.0

302.0

0.282

0

0

0.131

0.471

SS VF-F

12

3506.96

3507.88

0.92

431.0

0.0

100.0

0.243

0

0

0.156

0.399

SS VF-F CARB INC

13

3507.88

3508.47

0.59

777.0

0.0

556.0

0.277

0

0

0.119

0.389

SS VF-F

14

3508.47

3508.87

0.39

831.0

0.0

383.0

0.275

0

0

0.136

0.422

SS VF-F CARB BK

15

3508.87

3509.88

1.02

413.0

0.0

262.0

0.281

0

0

0.132

0.440

SS VF-F

16

3509.88

3510.87

0.98

604.0

0.0

425.0

0.277

0

0

0.131

0.323

SS VF-F SH INC

17

3510.87

3511.88

1.02

320.0

0.0

35.1

0.229

0

0

0.146

0.422

SS VF-F SH INC

18

3511.88

3512.87

0.98

616.0

0.0

437.0

0.239

0

0

0.103

0.354

SS VF-F

19

3512.87

3513.79

0.92

259.0

0.0

62.0

0.261

0

0

0.073

0.418

SS VF-F

20

3513.79

3514.38

0.59

320.0

0.0

26.8

0.219

0

0

0.096

0.441

 

21

3514.38

3515.07

0.69

431.0

0.0

82.5

0.236

0

0

0.119

0.387

SS VF-F

22

3515.07

3515.16

0.10

 

0.0

0.0

 

 

 

 

 

SH PY

23

3515.16

3516.18

1.02

969.0

0.0

628.0

0.270

0

0

0.044

0.492

SS VF-F

24

3516.18

3516.77

0.59

837.0

0.0

634.0

0.280

0

0

0.042

0.501

SS VF-F

25

3516.77

3517.46

0.69

556.0

0.0

201.0

0.273

0

0

0.050

0.531

SS VF-F CARB INC

26

3517.46

3518.28

0.82

706.0

0.0

338.0

0.262

0

0

0.046

0.487

SS VF-F

27

3518.28

3519.07

0.79

502.0

0.0

377.0

0.238

0

0

0.079

0.494

SS VF-F CARB INC

28

3519.07

3519.99

0.92

1136.0

0.0

183.0

0.263

0

0

0.063

0.501

SS VF-F

29

3519.99

3520.58

0.59

825.0

0.0

291.0

0.265

0

0

0.052

0.563

 

30

3520.58

3521.46

0.89

1346.0

0.0

706.0

0.274

0

0

0.055

0.516

SS VF-F

31

3521.46

3522.48

1.02

389.0

0.0

102.0

0.246

0

0

0.064

0.450

SS VF-F/M CARB INC

32

3522.48

3523.47

0.98

165.0

0.0

11.9

0.219

0

0

0.058

0.408

SS VF-F/M CARB INC

33

3523.47

3524.48

1.02

586.0

0.0

66.0

0.219

0

0

0.082

0.411

 

34

3524.48

3525.47

0.98

1035.0

0.0

395.0

0.244

0

0

0.051

0.391

SS VF-F

35

3525.47

3526.48

1.02

514.0

0.0

187.0

0.199

0

0

0.073

0.360

 

36

3526.48

3527.47

0.98

526.0

0.0

89.0

0.205

0

0

0.046

0.481

SS VF-M

37

3527.47

3528.16

0.69

1375.0

0.0

208.0

0.216

0

0

0.042

0.548

SS VF-M PY CARB

38

3528.16

3528.88

0.72

287.0

0.0

95.0

0.207

0

0

0.066

0.462

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Arithmetic Averages

0.78

618.8

0.0

240.7

0.253

0.0

0.0

0.095

0.443

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

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