1 / 16

Skin Value Analysis

Skin Value Analysis . From “radial.dat” : Pdew point= 5899.3Psia The value that makes layer 1 and layer 2 reach dew point pressure at the same time is: S=250 Thus it’s not the expected value of S≈ 80that gives this result ( why? ) For S=250, Pdp is reached after around 450 days.

lilike
Download Presentation

Skin Value Analysis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Skin Value Analysis • From “radial.dat” : Pdew point= 5899.3Psia • The value that makes layer 1 and layer 2 reach dew point pressure at the same time is:S=250 • Thus it’s not the expected value of S≈ 80that gives this result (why?) • For S=250, Pdp is reached after around 450 days. • Even if they reach Pdp at the same time, the depletion of layer 1 and 2 after dp is NOT the same after dew point (normal?). • It’s not possible to reach a plateau period for gas for such skin value.

  2. Simulation Results(Plots) • I tried to plot some vectors to illustrate my previous comments related to skin value. • I didn’t manage to plot on the same graph vectors from different layers (1 and 2). I already asked Silvya and she does not know how to do it with SensorView.Maybe I could ask Faiz or Alek how to do it? • We are really limited with the vectors than can be plot with SensorPlot/SensorView; Could I use Sensor2Excel or StrExcel instead? (or something else?)The main point is to keep it “automatic”. Otherwise I could take the results and paste it in Excel in order to plot CGR for instance. • See plots

  3. Pressure: Layer 1 ; S1=0 BHP limit reached after 5000days BHP limit is reached in layer 1 after 5000days

  4. Pressure: Layer 2 ; S1=0 BHP in layer 2 is around 3000 Psia (much higher than BHP limit)

  5. Pressure: Field ; S1=0 BHP average for the whole field falls to 2000 Psia

  6. Pressure: Layer 1 ; S1=250 With such a skin value, BHP in layer 1stays higher than 3500 Psia (i.e. does not reach anymore BHP limit as for S=0) With such a skin value, BHP in layer 1stays higher than 3500 Psia With such a skin value, BHP in layer 1stays higher than 3500 Psia Dew point pressure is reached in layer 1 around 450 days of depletion Dew point pressure is reached in layer 1 around 450 days of depletion Dew point pressure is reached in layer 1 around 450 days of depletion Dew point pressure is reached in layer 1 around 450 days of depletion

  7. Pressure: Layer 2 ; S1=250 BHP in layer 2 STILL stays around 3000 Psia. Almost no effect of S1=250 due to “LNX” assumption (However final BHP is a little lower to satisfy target gas rate) Dew point pressure is reached in layer 2 around 450 days of depletion (same time as layer 1)

  8. Pressure: Field ; S1=250 BHP average for the whole field falls to 3500 Psia (much higher than 2000Psia for S=0)

  9. GOR: Field ; S1=0 Classical shape of GOR for 2 layers LNX reservoir (showing changes in layers contribution to GOR over time)

  10. GOR: Field ; S1=250 Linear increase of GOR over time.The peak value of 16000Mcf/d is below the peak value of 20000Mcf/d for S1=0 Linear increase of GOR over time.The peak value of 16000Mcf/d is below the peak value of 20000Mcf/d for S1=0 Linear increase of GOR over time.The peak value of 16000Mcf/d is below the peak value of 20000Mcf/d for S1=0

  11. Qoil/Qgas: Field ; S1=0 Plateau period is maintained around 2500 days at 25000Mcf/days

  12. Qoil/Qgas: Field ; S1=250 No plateau period is maintained. With such high skin the well can’t deliver 25000Mcf/days.

  13. Optimization (1): for target rate of 25000 Mcf/day • As expected with previous plots and comments, the optimum value for NPV is not for S=250 (not when layer 1 and 2 reach Pdp at the same time). • NPV max (Global!) is reached forS=5.625The increase in NPV value compared to S=0 is negligible! • However as showed on next slides, it is possible to find a couple (S,D) to maximize NPV (Local maximum) by almost factor 10 compared to (S=0;D=0).

  14. NPV Optimization (Target rate=25000 Mcf/day): Variable: S

  15. NPV Optimization (Target rate=25000 Mcf/day): Variables: (S ; D)

  16. Optimization (2): for target rate of 25000 Mcf/day • How to know when we have reached the optimum value? • I remember that when you showed me the optimization process, there were different colors for the different values of the objective function. How to display this option? • I don’t see any physical meaning behind a local maximum such as: (15.234; 0.003952)? • I am really unsure of the consistency of these results and I don’t understand phenomena behind this tremendous increase in NPV? • How to plot the optimization results to get the shape of NPV versus (S;D)? As we have 2 variables the plot is a “surface”?

More Related