Dykstra-parsons Coefficient (Vk)

This method used Log-Normal distribution of permeability to define the Coefficient of permeability Variation, Vk.

Let’s upload some Real Data to work on it.

data<-read.csv("C:/Users/Lenovo/Desktop/shahed1/karpur.csv",header=T)
summary(data)
##      depth         caliper         ind.deep          ind.med       
##  Min.   :5667   Min.   :8.487   Min.   :  6.532   Min.   :  9.386  
##  1st Qu.:5769   1st Qu.:8.556   1st Qu.: 28.799   1st Qu.: 27.892  
##  Median :5872   Median :8.588   Median :217.849   Median :254.383  
##  Mean   :5873   Mean   :8.622   Mean   :275.357   Mean   :273.357  
##  3rd Qu.:5977   3rd Qu.:8.686   3rd Qu.:566.793   3rd Qu.:544.232  
##  Max.   :6083   Max.   :8.886   Max.   :769.484   Max.   :746.028  
##      gamma            phi.N            R.deep            R.med        
##  Min.   : 16.74   Min.   :0.0150   Min.   :  1.300   Min.   :  1.340  
##  1st Qu.: 40.89   1st Qu.:0.2030   1st Qu.:  1.764   1st Qu.:  1.837  
##  Median : 51.37   Median :0.2450   Median :  4.590   Median :  3.931  
##  Mean   : 53.42   Mean   :0.2213   Mean   : 24.501   Mean   : 21.196  
##  3rd Qu.: 62.37   3rd Qu.:0.2640   3rd Qu.: 34.724   3rd Qu.: 35.853  
##  Max.   :112.40   Max.   :0.4100   Max.   :153.085   Max.   :106.542  
##        SP          density.corr          density         phi.core    
##  Min.   :-73.95   Min.   :-0.067000   Min.   :1.758   Min.   :15.70  
##  1st Qu.:-42.01   1st Qu.:-0.016000   1st Qu.:2.023   1st Qu.:23.90  
##  Median :-32.25   Median :-0.007000   Median :2.099   Median :27.60  
##  Mean   :-30.98   Mean   :-0.008883   Mean   :2.102   Mean   :26.93  
##  3rd Qu.:-19.48   3rd Qu.: 0.002000   3rd Qu.:2.181   3rd Qu.:30.70  
##  Max.   : 25.13   Max.   : 0.089000   Max.   :2.387   Max.   :36.30  
##      k.core            Facies         
##  Min.   :    0.42   Length:819        
##  1st Qu.:  657.33   Class :character  
##  Median : 1591.22   Mode  :character  
##  Mean   : 2251.91                     
##  3rd Qu.: 3046.82                     
##  Max.   :15600.00
head(data)
##    depth caliper ind.deep ind.med  gamma phi.N R.deep  R.med      SP
## 1 5667.0   8.685  618.005 569.781 98.823 0.410  1.618  1.755 -56.587
## 2 5667.5   8.686  497.547 419.494 90.640 0.307  2.010  2.384 -61.916
## 3 5668.0   8.686  384.935 300.155 78.087 0.203  2.598  3.332 -55.861
## 4 5668.5   8.686  278.324 205.224 66.232 0.119  3.593  4.873 -41.860
## 5 5669.0   8.686  183.743 131.155 59.807 0.069  5.442  7.625 -34.934
## 6 5669.5   8.686  109.512  75.633 57.109 0.048  9.131 13.222 -39.769
##   density.corr density phi.core   k.core Facies
## 1       -0.033   2.205  33.9000 2442.590     F1
## 2       -0.067   2.040  33.4131 3006.989     F1
## 3       -0.064   1.888  33.1000 3370.000     F1
## 4       -0.053   1.794  34.9000 2270.000     F1
## 5       -0.054   1.758  35.0644 2530.758     F1
## 6       -0.058   1.759  35.3152 2928.314     F1

Here we will find the distrirbutin of K (md),but first we should find the Frequency for each K and we will work on 100 samples to simplifed the resultant.

K_md<-kf$k.core
Vk<-tab1(K_md , sort.group = "decreasing", cum.percent = FALSE)

summary(Vk)
##              Length Class  Mode     
## first.line      1   -none- character
## output.table 1616   -none- numeric

Then after finding the Frequency we will find the Cumlative Frequency Distirpution for X-values then after that ploting K (md) with Cumlative Frequency Distirpution.

Cumlative_Frequency_Distirpution
## # A tibble: 807 × 4
##    k.core Frequency Num.samples cumulative_frequency
##     <dbl>     <dbl>       <dbl>                <dbl>
##  1 14225.         1           1                0.122
##  2 13545.         1           2                0.244
##  3 13034.         1           3                0.367
##  4 11842.         1           4                0.489
##  5 11117.         1           5                0.611
##  6 10860          1           6                0.733
##  7 10650.         1           7                0.856
##  8 10540          1           8                0.978
##  9  9898.         1           9                1.10 
## 10  9533.         1          10                1.22 
## # … with 797 more rows

Now we are Ready to plot our Graph

df = read_xlsx("C:/Users/Lenovo/Desktop/shahed1/shahed_al.xlsx")
model1 <- lm( df$k.core~ df$cumulative_frequency)
plot(df$cumulative_frequency,df$k.core,xlab="Cumlative Frequency Distirpution", ylab="K (md)")
abline(model1, lwd=4, col='Pink', untf=FALSE)

Now by using this relationship,

Vk= (K50-k84.1)/K50

we will be able to quantify Heterogeneity Index (HI)

Vk= (1591.2185-392.78)/1591.2185

Vk= 0.7531577

Therefore from this Value, we know that this reservoir is Extremely Heterogeneous.