1. INSTRUCTOR © 2017, John R. Fanchi
All rights reserved. No part of this manual may be reproduced in any form without the express written permission of the author.
© 2004 John R. Fanchi All rights reserved. Do not copy or distribute.

2. To the Instructor
The set of files here are designed to help you prepare lectures for your own course using the text Introduction to Petroleum Engineering, J.R. Fanchi and R.L. Christiansen (Wiley, 2017)
File format is kept simple so that you can customize the files with relative ease using your own style. You will need to supplement the files to complete the presentation topics.

3. WELL COMPLETIONS © 2017, John R. Fanchi
All rights reserved. No part of this manual may be reproduced in any form without the express written permission of the author.
© 2004 John R. Fanchi All rights reserved. Do not copy or distribute.

4. Outline Casing Cementing Types of Completions Perforating Workovers
Stimulation
Hydraulic Fracturing
Artificial Lift
Homework: IPE Ch. 10

5. CASING
© 2004 John R. Fanchi All rights reserved. Do not copy or distribute.

6. Well Completion Procedure to Prepare Well for Production
Decision: complete or plug & abandon
Issues to consider
Which formations should be isolated?
Open hole or cased hole?
Perforating design?
Stimulate? (if necessary)
Sand Control? (if necessary)
Test well?

7. Casing Design Keep hole from collapsing over its life
Complete production conduit from reservoir to surface
Protect shallow zones from heavy mud weights
Allow for future well stimulation
e.g. casing must withstand pressure of frac treatment

8. Wellbore

9. Wellbore Diagram for Vertical Well
Concentration
(ppm)
Fresh water
< 1,000
Brackish water
1,000 to 35,000
Brine
> 35,000
Source: Hyne (2012, pg 18)

10. Casing Strings Surface Surface + Production + Intermediate

11. CEMENTING

12. Cement Bond Log Uses acoustic signals to detect cement behind pipe
Determines quality of bond
good bond, poor bond, no bond
Determines top of cement
Requires interpretation, so user beware

13. TYPES OF COMPLETIONS

14. Types of Completions Cased Hole Open Hole Liners and Tiebacks
Tubingless
Dual zone and commingled zones

15. Sand Control
Suppose formation sand (e.g. from unconsolidated rock) flows into wellbore
Plugs pores and restricts or stops fluid flow
Increases damage to tubing
Causes surface equipment to sometimes plug up
Methods to Control Sand
Screening with gravel and metal screens
Chemical consolidation, e.g. resin coating
Frac Pacs
Sand control usually causes reduction in production rate

16. PERFORATING

17. Perforating Purpose of Perforating
Create passage for oil/gas to flow into wellbore
Position perforating gun
Blast holes through pipe and cement into target formation
Flow into wellbore
Source: accessed April 2013

18. Perforating Design
Hole size & shot density (holes per foot) are basic to design
e.g. 4 shots/foot is fairly dense
Design should include estimate of stimulation and production rates
Casing may be pre-perforated or slotted before running
Must design for intervals of interest

19. Formation Damage
Producing rock is altered in a way that reduces flow of hydrocarbons into wellbore
Types of Damage
Fluid damage
Drilling mud filtrate or other fluid fills pore space
Causes changes in perm and relative perm
Solids damage
Fines plug up pore spaces, e.g. mud cake
Scale buildup on perfs and in formation

20. WORKOVERS

21. Workover Repair or replace equipment Sucker rod string Downhole pump
Tubing
Cleanout well
Sand
Scale (salt)
Wax

22. STIMULATION

23. Well Stimulation Purpose: Increase productivity Methods
Explosive Fracturing
Acidizing
Hydraulic Fracturing

24. Acidizing Acid “soak” near wellbore can remove damage
Acid frac (deep penetration) in limestones
Limestone will dissolve
Create improved pathways; e.g. Middle East

25. Types of Acid HCL common Other types
Typically use about 1,500 gals of 15% HCl
Aids in frac after clearing perforations and borehole wall
Must be careful when producing spent acid
Excellent for dissolving lime scale buildup (CaCO3)
Other types
Citric – weak clean up acid
Hydrofluoric acid (difficult to handle; dissolves glass)

26. HYDRAULIC FRACTURING
Near Mansfield, TX

27. Orientation of three principal stresses
Wellbore Stress Sv Sv Sh Sh SH SH
Vertical
Horizontal
Orientation of three principal stresses

28. Directions of Sh and SH Borehole Breakout:
Determine direction of Sh using dipmeter and caliper logs in previously drilled wellbores
σhmax
σhmin
Plan View σv
Stress Orientation
Observe wellbore failure in direction of σhmin
σhmax is transverse to σhmin
Plan well azimuth in direction of minimum horizontal stress σhmin
σv > σhmax > σhmin

29. Gel Frac Gel fracs combine water and polymer
Thicken injected fluid so it can carry significant amount of proppants into formation
Injection pressure must exceed fracture pressure

30. Slick Water Frac
Slick water fracs combine water with a friction-reducing chemical additive
The additive allows water to be pumped faster into the formation.
Water fracs do not use any polymers to thicken so the amount of proppant used is significantly less than that of gels.
Slick water fracs work very well in low-permeability reservoirs
Injection pressure must exceed fracture pressure

31. Proppant Blend proppant (sand, beads, etc.) with water
Proppant stays in fracture to prevent it from closing (healing) after pumping ceases
Proppant must be strong enough not to collapse (or be crushed) under forces trying to heal fracture
Propped fracture becomes flow conduit
Propped frac should increase rate of fluid flow to producer

32. Approximate Closure Pressure Limits for Proppant Categories
Closure Pressure Limit, psi
Temperature Limit, ˚F
Sand
4,000 NA
Resin-Coated Sand
8,000
250
Intermediate Strength Ceramic
10,000
High Strength Ceramic
>12,000
© 2004 John R. Fanchi All rights reserved. Do not copy or distribute.

33. Water Production from a Shale Well
Influenced by
Formation rock and fluid
Fracturing fluid
Typical constituents
Suspended solids
Dissolved solids
Organics, e.g. hydrocarbons
Residual-fracturing-fluid chemicals
Disposition of produced water
Recycle
Disposal

34. Video Hydraulic Fracturing
Marathon Youtube video (6.5 mins)
Baker-Hughes Composite Plug Youtube video (7 mins)

35. Classification System for Fracturing Treatment Types
Fracture Treatment
Definition
(Types 1 to 6 transport proppant into hydraulic fracture)
1. Conventional
Use a gelling agent and one or more crosslinkers
2. Water Frac
Use a friction reducer, a gelling agent, or a viscoelastic surfactant
3. Hybrid
Use combination of friction reducer, gelling agent, acid-gelling agent, or crosslinker(s)
4. Energized
Incorporate an energizer, normally N2 or CO2, into base fluid to generate foam
5. Acid Frac
Use a gelled-acid base fluid to etch away formation rock and transport proppant
6. Gas Frac
Use a gas, normally propane, as base fluid to transport proppant
7. Matrix Acidizing
Use acid to etch away formation rock to increase oil or gas well productivity
Source: SPE , JPT (Mar 2014), pg. 110
© 2004 John R. Fanchi All rights reserved. Do not copy or distribute.

36. Typical Fracture Treatment
Pre-frac testing gives rate and pressure data
Pump job in stages
Lead in – no proppant mixed in
Followed by gelled water with proppant in low concentration – 1 or 2 ppg
Followed by more stages of gelled water with increasing concentrations of proppant
Tail in with high concentration at end up to 7-8 ppg

37. Planning the Job Determine type of fluid
Gelled, slick, foam, condensate, CO2.
Types of gelling agents, friction reducers, bactericides, corrosion inhibiters and other additives
May use foam, oil or condensate instead of water
Determine amount of water and proppant to be pumped
Rate of treatment – bbls / minute
Estimate rate and pressure needed to exceed frac gradient
Desired rate determines horsepower required
Consider safety, logistics and contingencies

38. Fracking may not be successful
Source: JPT (Mar 2014), pg. 87
© 2004 John R. Fanchi All rights reserved. Do not copy or distribute.

39. Fracture Treatment Issues
Size of Job
Small Job = 30,000 gals and 50,000 lbs proppant
Large job = 500,000 gals and 1,000,000 lbs proppant
Deep wells
Sand proppant can be crushed in deep treatments
Need special proppant (e.g. bauxite)
Should fluid be pumped down casing or tubing?
Typically casing ID > tubing ID
Casing gives better rate but at lower pressures
Tubing allows high pressures but low rate

40. Video Hydraulic Fracturing
Western Energy footage, 7.5 minutes
IPAMS
International Petroleum Association of Mountain States

41. Stimulation Guide Natural Completion
Stimulation not needed, e.g. undamaged, high quality rocks such as the Gulf Coast
Matrix Acidizing
Cleans up perforating debris & formation damage
Acid Frac
Primarily in limestones
Deep penetration (>100’ or more); etches out channels
Hydraulic Fracturing
Low permeability formations

42. ARTIFICIAL LIFT

43. Production Artificial Lift Common Methods
Useful when reservoir pressure unable to push oil to surface
Recognize need when oil rate declines unexpectedly
Common Methods
Pumping Unit
Submersible pump
Gas Lift
Time
Producing Rate
Projected
Actual
Is something wrong?

44. Factors that Impact Artificial Lift Reliability
Installation practices
Operating practices
Equipment qualification and testing
Material selection
Sizing and selection of equipment
New vs used equipment
Quality of manufacturing
Quality of completion
Fit for purpose design
Relationship between manufacturer, supplier, and vendor
Source: S. Noonan table, JPT, pg. 62, March 2015

45. QUESTIONS?

46. SUPPLEMENT