Analyzing Performance of

Transcription

1 Analyzing Performance of North American Shale Gas Resources 2013 SPE - GCS - Reservoir Technology Forum Rakesh R. Rai

2 NanoDarcy Rock Changes Everything G&G: Shale petrophysics, seismic, core analysis, microseismic fracture monitoring Engineering: transient flow lasts months or years versus hours or days Months to years for fracs to see nearest neighbors Years to Never for wells to see nearest offset wells Frac spacing reservoir dominated or completion dominated What can you learn from early production (transient flow)? Fracturing: how successful, how effective Must quantify uncertainties: to forecast, reserves bookings, optimal completion & well designs Hard to keep up with the drill bit 2

3 Shale Resource Drivers Shale well performance depends on OHIP Effective permeability (k) Effective fracture area (Af) Average fracture spacing (Ls) Drainage area (Ad) And is dictated by. Nature Reservoir Quality Rock Quality Nurture Well, completion design & efficiency Facilities & production philosophy Field development strategy Economic & Regulatory Constraints 3

4 Shale Gas Well Schematic XRV Well SRV 2X f Fractures nl s 4

5 Shale Well Performance Analysis Internal Linear Transient Flow Internal Depletion Flow Drainage Volume Depletion Flow External Linear Transient Flow n 1 STF t q t q t t qn j 2 n 1 p, n j p, n p, j 1 SPE

6 Frac Area Frac Spacing Min Perm Most-Likely Perm Max Perm Max Perm Feasible Range Analysis Max Spacing Feasible Range Max 2 k L s Most-Likely Spacing Min Spacing Max Area Most-Likely Area Fixed Af k Min Area Perm 6

7 Simple or Complex Fractures SPE

8 XRV Dominated SRV Dominated Semi-Analytical Shale Model J lt AR f n g ki icti Mscf B psi d gi gi 12 Internal Linear Transient Productivity Index J dep 1 kirn g Af Mscf B psi d gi gi Internal Depletion Flow Productivity Index External Linear Transient Productivity Index J A R k c Mscf SR n g i i t lt, ex 12 Bgi gi psi d External Depletion Flow Productivity Index J dep, ex 1 kirn g ASR Mscf B L psi d gi gi d SPE

9 Example Well Update 1 Update 3 Update 2 Update 4 SPE

10 Diagnostic Plots Linear Flow Diagnostic Plot Log-Log Diagnostic Plot 10

11 Asset Progression 11

12 Benchmarking Well Performance 12

13 Estimated Permeability P 10 Max Perm P 50 Max Perm P 50 Min Perm P 90 Min Perm SPE Better Wells 13

14 Interpreted Fracture xf Cluster efficiency % P 10 Max X f P 50 Max X f P 50 Min X f P 90 Min X f Better Wells 14

15 Reconcile Completion Microseismic Geomechanical Model 15

16 Shale Well Productivity Index Reconcile Drilling Higher Lateral Landing Middle Landing Lower Landing Number of Clusters 16

17 Woodford Field Development Planning Red Section Inner wells have 20% less productivity Inner wells drive economics Outer wells suggest larger spacing % More Proppant % Better Productivity % Higher Rate

18 Woodford Field Development Planning 8 wells initially planned per section reduced to 4-6 wells Increased completion cost offset by higher productivity wells Significantly higher NPV Planning cycle: Multiple months became <3 weeks 18

19 Review What are the key reservoir & completion properties impacting Shale well performance a) Reservoir permeability b) Fracture Area c) Hydrocarbon in place d) All of above 19