SPE Distinguished Lecturer Program

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1 SPE Distinguished Lecturer Program Primary funding is provided by The SPE Foundation through member donations and a contribution from Offshore Europe The Society is grateful to those companies that allow their professionals to serve as lecturers Additional support provided by AIME Society of Petroleum Engineers Distinguished Lecturer Program 1

2 Unconventional Frac Jobs for Unconventional Reservoirs What Should You Be Concerned About? Jennifer L. Miskimins, Ph.D., P.E. Petroleum Engineering Dept. Colorado School of Mines Society of Petroleum Engineers Distinguished Lecturer Program 2

3 Outline of today s presentation Purpose Unconventional reservoirs Fluids, proppants, and transport Growth complexity Hydraulic fracturing for reservoir management Conclusions 3

4 WHY should you be concerned? Unconventional reservoirs (UCR s) are just that - unconventional UCR s are increasing forming our reserve/resource base around the world Extrapolation of conventional techniques to UCR s is risky Combination of considerations 4

5 Conventional vs. Unconventional Unconventional resources accumulations that are pervasive throughout a large area not significantly affected by hydrodynamic influences require specialized extraction technology SPE-PRMS, 2007 Holditch,

6 Today s presentation focuses on Shale gas (is a shale a shale?) Nano-Darcy permeability (10-9 ) High quartz or carbonate content Tight gas What is tight? Micro-Darcy permeability Low perm oil Various lithologies 6

7 Slickwater Fluid Systems Minimal polymer loading Polyacrylamide friction reducers 1 10 cp fluid system Carrying capacity reduced F = Must minimize damage due to the initial low permeability CD k f kx w f Courtesy of Stimlab 7

8 Retained Permeability With Gel Residue Stimlab,

9 Lightweight/Smaller Proppants Use of lower viscosity fluids = difficult to carry high proppant concentrations Velocity is the transport mechanism, not viscosity Function of fracture width, Reynolds numbers, densities of proppants and fluids, diameters of proppants 30/50 and 40/70 sizes common 9

10 Particle Transport (From Patankar, 2002 and Kern, Perkins, and Wyant, 1959) 10

11 Example 1 Bank Placement 0:08 sec 0:35 sec 0:58 sec 1:26 sec Courtesy of Stimlab 11

12 Example 2 Erosion of Bank 0:01 sec 0:10 sec 0:38 sec 0:50 sec 12 Courtesy of Stimlab

13 Complexity of Growth Remember that fracturing is always the path of least resistance How complex is complex? 3D is no longer really 3D 13

$8 ppg cement Laboratory experiments laminated block before hydraulic fracturing (28 cm$

14 Lyons sandstone Polyurethane base adhesive bond 15.8 ppg cement Lyons sandstone Unbonded interface 16.2 ppg cement Lyons sandstone Epoxy 15.8 ppg cement Laboratory experiments laminated block before hydraulic fracturing (28 cm X 28 cm X 48 cm) Athavale and Miskimins, 2008 After hydraulic fracturing notice the complexity for this simple system 14

15 Treatmen t Well Receivers Monito r Well From the lab to the field multiple stimulation stages in horizontal wells From SPE

16 Reservoir Management/Development Reservoir characterization 16

17 Reservoir Characterization Diagnostic injection tests Presence of natural fractures Reservoir pressure Pressure Derivative Pressure (psi) Permeability Process zone stresses G-Function dp/dg GdP/dG Pressure 0 G-Function Analysis 17

18 Young s Modulus vs. Poisson s Ratio 2.60E+07 Middle Woodford Upper of Lower Woodford Upper Woodford Lower of Lower Woodford 2.40E E+07 Brittle 2.00E+07 E (psi) 1.80E E E E+07 Ductile 1.00E v From Aoudia et al,

19 Reservoir Management/Development Reservoir characterization Well spacing acres (4-8 hectares) Need to maximize contact area Low permeability Minimal drainage area 19

20 10-ac spacing 3D view of wellbore penetrating fluvial bodies Body types penetrated as a function of well-spacing densities Modified from Anderson, 2004

21 Microseismic Events, Side View From Mohammad and Miskimins, 2010 Well D1; Stages

$hydraulic fracture model results (proppant$ concentration, lb/ft 2 ) superimposed

22 Well D1, Stage 1 Microseismic side view with hydraulic fracture model results (proppant concentration, lb/ft 2 ) superimposed Microseismic plan view From Mohammad and Miskimins,

23 Piceance Basin, Western Colorado, USA 23

24 S-Curve Development From

25 Centralized fracturing equipment location Multiple well pads (16 wells per pad) From Miskimins, 2009 Large diameter, welded surface lines 25

26 Shale Gas Reservoir Drainage Drainage Areas Horizontal well system Vertical well system 26

27 Reservoir Management/Development Reservoir characterization Well spacing acres (4-8 hectares) Need to maximize contact area Low permeability Minimal drainage area Reorientation 27

28 Reorientation Theory Courtesy Devon Energy 28

29 Conclusions Hydraulic fracturing for UCR s requires combinations of considerations UCR s represent a wide variety of reservoir types and designs must address these differences Materials, complexity, reservoir management The learning curve can be shortened by studying other successful applications 29

30 Thank you for your time! 30

31 SPE Distinguished Lecturer Program Primary funding is provided by The SPE Foundation through member donations and a contribution from Offshore Europe The Society is grateful to those companies that allow their professionals to serve as lecturers Additional support provided by AIME Society of Petroleum Engineers Distinguished Lecturer Program 31

The SPE Foundation through member donations and a contribution from Offshore Europe

Primary funding is provided by The SPE Foundation through member donations and a contribution from Offshore Europe The Society is grateful to those companies that allow their professionals to serve as