After the Shale-Gas Multi-Stage Frac –Recovering Valuable Operating Information on the Flowback. George E. King 17 November 2009 SPE Horizontal Well Stimulation Workshop. Why Bother with Flowback Analysis?. Information Available for Frac Design Well Spacing and Orientation - PowerPoint PPT Presentation
The following discussions contain certain “forward-looking statements” as defined by the Private Securities Litigation Reform Act of 1995 including, without limitation, estimates, expectations, plans and goals regarding Apache’s production, reserves, financings, acquisitions, exploration and exploitation prospects, energy prices, operating costs, and results of operations. Such forward-looking statements involve estimates, assumptions and uncertainties. No assurance can be given that Apache’s expectations or goals will be realized, and actual results may differ materially from those expressed in the forward-looking statements. CORPORATION After the Shale-Gas Multi- Stage Frac –Recovering Valuable Operating Information on the Flowback George E. King 17 November 2009 SPE Horizontal Well Stimulation Workshop
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The following discussions contain certain “forward-looking statements” as defined by the Private Securities Litigation Reform Act of 1995 including, without limitation, estimates, expectations, plans and goals regarding Apache’s production, reserves, financings, acquisitions, exploration and exploitation prospects, energy prices, operating costs, and results of operations. Such forward-looking statements involve estimates, assumptions and uncertainties. No assurance can be given that Apache’s expectations or goals will be realized, and actual results may differ materially from those expressed in the forward-looking statements.
CORPORATION
After the Shale-Gas Multi-Stage Frac –Recovering
Valuable Operating Information on the Flowback
After the Shale-Gas Multi-Stage Frac –Recovering
Valuable Operating Information on the Flowback
George E. King17 November 2009
SPE Horizontal Well Stimulation Workshop
George E. King17 November 2009
SPE Horizontal Well Stimulation Workshop
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CORPORATIONCORPORATION
Why Bother with Flowback Analysis?Why Bother with Flowback Analysis? Information Available for Frac Design
Well Spacing and Orientation
Perf Cluster Spacing, Offset, Shot Density
Optimum Injection Rates, Max Pressures
Sand Size and Schedule
Production
Make a 50% Difference in Stable Production?
Reduce Produced Water by 50 to 90%
Warning Signs
Information Available for Frac Design
Well Spacing and Orientation
Perf Cluster Spacing, Offset, Shot Density
Optimum Injection Rates, Max Pressures
Sand Size and Schedule
Production
Make a 50% Difference in Stable Production?
Reduce Produced Water by 50 to 90%
Warning Signs
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CORPORATIONCORPORATIONScope of the talkScope of the talk
Limited to gas shales stimulated by slick water fracs
Touching lightly on:
Frac Pressure / Rate / Loading response,
Chemical and RA Tracers,
Microseismic (near real time),
Flowback Volume & Salinity Measurements
Production Logs
Production Rate and EUR
The information available from a frac, its flowback and the ensuing production is often confusing, because so many variables are in play.
Limited to gas shales stimulated by slick water fracs
Touching lightly on:
Frac Pressure / Rate / Loading response,
Chemical and RA Tracers,
Microseismic (near real time),
Flowback Volume & Salinity Measurements
Production Logs
Production Rate and EUR
The information available from a frac, its flowback and the ensuing production is often confusing, because so many variables are in play.
Not all the formation is the same…..Not all the formation is the same…..
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CORPORATIONCORPORATIONPore Micro-Fracture PassagesPore Micro-Fracture PassagesOpening natural fractures takes ~ 60% of the stress to break the rock.
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CORPORATIONCORPORATIONLook at the PiecesLook at the Pieces
Why does flowback matter?
Shale wells that recover frac load water too rapidly strand water in the microfractures – permeability to gas is reduced.
At least one cause is capillary pressure – a control on water movement in the smallest fractures.
Why does flowback matter?
Shale wells that recover frac load water too rapidly strand water in the microfractures – permeability to gas is reduced.
At least one cause is capillary pressure – a control on water movement in the smallest fractures.
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CORPORATIONCORPORATIONCapillary Forces – in fractures?Capillary Forces – in fractures?Note that capillary pressure is increasing as initial load is recovered & saturation of water in the pore (or micro-fracture) is decreasing.
Capillary pressure increases sharply in smaller pores (and smaller fractures).
Effects of capillary forces will be less for fractures than pores but will still be a factor limiting recovery of water from a highly fractured flow system.
Initial – high rate, tracers & micro-seismic. Follow up?Next – shorten the frac and make it wider…….
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CORPORATIONCORPORATION
Sequential Fracs, rate by M-S activity, Xf not yet modified by sand slugs
<5% of points below BarnettWell made ~ <50 bwpd
Next Step – Optimize the RateNext Step – Optimize the Rate
W/Xf = 1
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CORPORATIONCORPORATIONSingle Fracs – Reaching too Far?Single Fracs – Reaching too Far?
W/Xf = 0.7
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Zipper Frac - generally
good complex fracture
coverage.
Sequential Fracs – Barnett, Western Parker Co.Sequential Fracs – Barnett, Western Parker Co.
W/Xf = 2
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CORPORATIONCORPORATION
Well /Stage Width of Flow Path
Cloud
Xf (frac half length)
H (total height events)
Frac Complexity Index W/Xf
Primary frac
Second frac
Cluster Direction
T1 stage 1 1370 930 301 1.5 N 42 E S 38 E N 16 ET1 stage 2 1374 659 425 2.1 N 61 E S 39 E N 5 ET1 stage 3 1056 555 338 1.9 N 56 E N 83 E N 9 ET1 stage 4 1129 636 501 1.8 N 17 E S 48 E N 7 ET1 stage 5 1016 735 422 1.4 N 46 E S 38 E N 83 ET1 stage 6 1211 577 523 2.1 N 45 E S 39 E N 59 ET1 stage 7 755 571 509 1.3 N 53 E S 36 E S 89 ET1 stage 8 1025 549 364 1.9 N 42 E S 44 E N 78 E
T2 stage 1 1615 767 288 2.1 N 45 E S 43 E N 47 ET2 stage 2 1845 1014 306 1.8 N 45 E S 45 E N 89 ET2 stage 3 1175 913 340 1.3 N 45 E S 54 E S 74 ET2 stage 4 1228 763 448 1.6 N 51 E S 42 E N 67 ET2 stage 5 866 662 492 1.3 N 51 E S 64 E N 6 ET2 stage 6 855 668 499 1.3 N 36 E S 35 E N 9 ET2 stage 7 621 665 314 0.9 N 48 E S 52 E N 38 ET2 stage 8 1040 980 273 1.1 N 58 E S 51 E N 55 ET2 stage 9 1110 681 252 1.6 N 78 E S 40 E S 80 ET2 stage 10 971 677 254 1.4 N 45 E S 39 E N 43 E
Comparison of Frac Spread and Fracture Direction
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CORPORATIONCORPORATION
Tracer tagged sands are used periodically to analyze proppant breakdown points and
near well communications.
Tracer tagged pad & frac waters determine:• which intervals are broken down in each
of the perf clusters• which intervals are flowing back first;
41
598
0
1480
1935
2295
2620
3490
not g
iven
0
200
400
600
800
1000
1200
1400
Stage 1Stage 4
Stage 7
Stage 1
Stage 2
Stage 3
Stage 4
Stage 5
Stage 6
Stage 7
Stage 8
?
• which continue to flow with time;
• which stay open compared to prod
log.
Tracers – What broke down, what produced back?Tracers – What broke down, what produced back?
