World Oil - Modern Sandface Completion Practices Handbook

152 Pages·2000·7.803 MB·English

Modern Sandface
First Edition
Completion Practices
William K. Ott, P.E.
and Joe D. Woods
H A N D B O O K
A Supplement to World Oil
Publication of the World Oil Modern Sandface Completion Practices Handbookwas made possible by the
support of the following sponsors:
Premier Sponsors: Sponsors:
Baker Oil Tools Borden Chemical, Inc., Oilfield Products Division
BJ Services Company Cabot Specialty Fluids, Inc.
Core Laboratories Carbo Ceramics Inc.
Halliburton Energy Services Champion Technologies, Special Products Division
Reslink con-slot Screens International GMBH
Schlumberger Greig Filters, Inc.
Weatherford International Ltd. Grupo Royso, C.A.
M-I L.L.C.
Norton Proppants, Inc.
Red Wing Perforating Services L.L.C.
Smith Services, a Business Unit of Smith Interna-
tional, Inc.
STREN Company
TBC-Brinadd
Thru-Tubing Systems, Inc.
Tucan Petroleum Services, C.A.
Well Flow International
About the cover: Various methods for controlling sand
production in open- and cased- hole completions are
shown. Illustration was adapted from one appearing in
BP’s Frontiersmagazine, December 2001.
World Oil ®
Modern Sandface
Completion Practices
HANDBOOK
A treatise on reliable techniques to complete unconsolidated sandstone reservoirs
at the sandface (the physical interface between the formation and the wellbore),
using sand management and sand control methods.
William K. Ott, P.E., and Joe D. Woods
Published by
World Oilmagazine
Gulf Publishing Company
Houston, Texas
ABOUT THE AUTHORS
WILLIAM K. (BILL) OTT, P.E., is an independent petroleum consultant based in Houston, Texas, and founder
of Well Completion Technology, an international engineering consulting and petroleum industry training firm that
was established in 1986. Before consulting and teaching, Mr. Ott was division engineer for Halliburton’s Far East
region based in Singapore. Previously he was a research field coordinator for Halliburton in Duncan, Oklahoma. Mr.
Ott received his BS Degree in chemicalengineering from the University of Missouri (1972). He is a registered pro-
fessional engineer in Texas, and a 25-year member of SPE. He works regularly with and on wells requiring sand
control, principally in East Asia and South America. He has conducted technical petroleum industry courses
worldwide and written numerous technical papers relating to well completion and workover operations. Mr. Ott
teaches a Sand Control Technology course several times each year in the U.S., Canada, Southeast Asia and South
America. He can be reached via e-mail at: [email protected].
JOE D. WOODSis a Houston-based freelance writer and marketing consultant. He is founder of International
Pinpoint, a marketing and advertising consulting firm specializing in the petroleum industry. For twelve years,
Mr. Woods was director of marketing for Gulf Publishing Company. Mr. Woods has over 28 years of diversified
experience in the oil and gas industry. Previously he was vice president of marketing for GEO International Corp.,
a multi-division NYSE-listed oil field services firm, which grew rapidly in the late 1970s and early 1980s. He also
held key marketing-related positions with Halliburton Company in Duncan, Oklahoma, and Houston, Texas. In the
mid-1970s, he was instrumental in developing curriculum for the Modern Well Completion Practices School at the
Halliburton Energy Institute. Prior to that he was a marketing specialist with Texas Instruments. He has written and
produced hundreds of hours of employee and customer training materials in the petroleum and electronic indus-
tries. Mr. Woods has held memberships in AMA, BMA and PRSA, and has been an associate member of SPE and
a corporate representative member of SEG. A Distinguished Student at Texas A&M University, he received his
Bachelor's degree from the University of North Texas (1972). Mr. Woods can be reached via e-mail at:
[email protected].
ii
Acknowledgments
More than 20 companies sponsored the preparation of this handbook. The authors greatly appreciate this
sponsorship, and the technical and editorial assistance of these companies and numerous individuals. Without
their cooperation and the release of their data, the publication of this handbook would not have been possible.
In part, this work is a summary of technology already published by hundreds of others. That collective effort
is greatly respected, and it is hoped that the references cited are some measure of permanent recognition.
World Oil®
Modern Sandface Completion Practices Handbook
First Edition
US$95.00 per single copy
To order additional copies of this handbook or for educational and volume discounts,
contact the publisher at the address below.
Copyright © 2003 by Gulf Publishing Company, Houston, Texas. All rights reserved.
Printed in the United States of America.
This handbook, or parts thereof, may not be reproduced in any form
without permission of the publisher.
Gulf Publishing Company
P.O. Box 2608
Houston, Texas 77252
Phone: [phone]
www.gulfpub.com
Gulf Publishing Company and the authors have used their best efforts in collecting and preparing material for inclusion in this handbook, but do not warrant that
the information herein is complete or accurate. Errors and omissions, typographical, clerical and otherwise, can occur and this possibility exists in respect to any-
thing contained in this work. Gulf Publishing Company and the authors do not assume, and hereby disclaim, any liability to any person for any loss or damage
caused by errors or omissions related to this handbook whether such errors or omissions result from negligence, accident or any other cause. This applies to
product and service information, trademark information, directory listings, as well as all other matter contained herein.
iii
PREFACE
The business of completing oil and gas wells in unconsolidated sandstone reservoirs is continually changing with
new challenges, new methods and new technologies. Sand, when produced with hydrocarbons and water from
many wells, represents a costly problem for operators.
Cost effective solutions for controlling sand production are many, ranging from stand-alone screens to conventional
gravel packs to high rate water packs to frac packs and more. Most often operators elect to employ various sand
exclusion techniques when completing a well. In some areas, it may be more economical to employ sand manage-
ment techniques in an effort to minimize or delay expected problems such as formation erosion, sand fill, production
interruptions or even eventual wellbore collapse.
The true success or failure of a sand control application must always be measured against three related criteria:
• Stopping the movement and production of sand
• Maintaining maximum well productivity
• Paying for treatment costs and realizing a satisfactory return on investment within a reasonable period of time.
This handbook provides reliable techniques, updates industry methods and presents valuable new technologies
used to complete unconsolidated sandstone reservoirs. Numerous illustrations complement the text, and there is an
extensive list of references. The techniques and equipment described have been field-proven in thousands of oil
and gas wells around the world. Operators must know when to apply the different solutions. This book has been
prepared in an effort to provide the knowledge required for choosing the optimum solution.
iv
CONTENTS
Chapter One 1 Controlling Sand-Related Production Problems
1 Causes and Effects of Sand Production
3 Understanding the Reservoir
5 Productivity, Formation Damage and Flow Efficiency
7 Sand Management Techniques
9 Justification for Sand Control
10 Types of Sand Control
10 Drilling, Cementing and Completion Considerations
Chapter Two 13 Open-Hole Sandface Completions
13 Drill-In Fluids
Fluid Loss
Completion Considerations
Filter-Cake Removal
18 Stand-Alone Screens
Slotted Liners
Conventional, Prepacked and Premium Screens
Stand-Alone Completion Assemblies
24 Gravel Packing
Gravel-Pack Sand Sizing and Substitutes
Slotted Liner and Screen Design
Gravel-Pack Methods
Alternate Pathway Screen Option
38 Open-Hole Frac Packing
Chapter Three 43 Cased-Hole Sandface Completions
43 Completion Fluids
Use of Completion Fluids
Selection Criteria
Fluid Loss Control
49 Debris Removal and Mysteries
Displacement Procedures
Pump Rates and Pressure Calculations
51 Fluid Filtration
Filtration Guidelines
Relationship between Completion and Filtration
Filter Level Quality
Completion Fluid Filter Types
Filtration Quality Control
59 Perforating
Gun Design and Deployment Techniques
Detonation Methods
Well/Reservoir Characteristics
Perforation Clean Out
Special Perforating Techniques
Perforating Summary
70 Stand-Alone Screens
v
71 Gravel Packing
Perforation Prepacking
Water Packs
Slurry Packs
Well Productivity
Carrier Fluid Selection
Field Evaluation
Gravel-Pack Methods
One-Trip Perforate and Pack System
81 Frac Packing
Comparison of Frac Packs and Gravel Packs
Comparison of Frac Packs and HRWPs
Hydraulic Fracturing Concepts, Geometry and Rock Mechanics
Frac Fluids and Proppants
Pretreatment Testing
Frac-Pack Methods/Applications
97 Gravel-Packing Method Selection
Chapter Four 103 Surface Operations and Equipment
103 Surface Equipment and Techniques
Mixing and Blending Equipment
Pumping Equipment
Proppant Handling
Offshore Equipment
105 Monitoring and Control
Monitoring and Control Equipment
Design and Simulation
109 Evaluation Techniques
Gravel-Pack Evaluation
HRWP and Frac-Pack Evaluation
Chapter Five 113 Alternative Practices and Special Techniques
113 Rigless Sand Control Techniques
Chemical Methods
Mechanical Methods
118 Specialty Tools and Techniques
Wireline Gravel Pack
VibraPak
Multilaterals
Rod Pump and ESP Sand Control Techniques
Chapter Six 125 Next Generation Completion Technologies
Appendix One 127 Gravel/Proppant
Appendix Two 129 Graphic and Illustration Credits/Sources
Appendix Three 131 Contributor Profiles and Acknowledgments
133 Service/Supplier Directory
139 Index
vi
CHAPTER ONE
Controlling Sand-Related
Production Problems
Causes and Effects of Sand Production • Understanding the Reservoir
Productivity, Formation Damage and Flow Efficiency • Sand Management Techniques
Justification for Sand Control • Types of Sand Control • Drilling, Cementing and Completion Considerations
A
s the value of non-renewable sand is produced can be determined by unconsolidated rock surrounding a per-
hydrocarbon reserves and the the factors that affect the beginning of foration. After some sand is produced
costs of remedial work increase, sand production. These factors must from around a perforation tunnel, an
a renewed emphasis is being placed describe both the nature of the forma- arch is formed that has sufficient
on proper well completion techniques. tion material and also the forces that strength to support the weight of the
Maximum reliability and productivity cause the formation structure to fail. surrounding material. Under certain
are essential. These objectives are diffi- Strength of sandstone is controlled by: conditions, the production of a limited
cult to attain in unconsolidated sand for- • Amount and type of cementation amount of formation sand can be toler-
mations, which are always subject to material holding the individual grains ated to allow an arch to develop, after
structural failure. The sand production together which the production of formation sand
mechanism is exceedingly complex and • Frictional forces between grains ceases.3Figure 1.1 illustrates the con-
is influenced by every completion oper- • Fluid pressure within the pores of cept of a stable arch around a perfora-
ation. This handbook will summarize the rock tion; however, the stability of the arch is
the major problems encountered in • Capillary pressure forces complicated by the fact that the state of
unconsolidated sands, as well as current Several researchers have investigated stress surrounding the perforation is
techniques and technologies employed the type of failure that is likely to occur constantly changing due to changes in
in sandface completions. The techniques in sandstone. Work at Exxon1indicates flow rate, reservoir pressure, producing
and equipment described have been that the nature of a failed perforation water cut, etc.
field-proven in thousands of oil and gas tunnel is indicative of a shear failure
wells. Sand flow—and the multitude of that will occur when the compressive
inconveniences, production losses, and strength of the rock is exceeded. In
serious well damage it can cause—is addition, the Exxon work indicates that Fluid inflow
Cement
discussed with a view toward under- in weakly consolidated sandstones, a
standing fundamental causes and imple- void is frequently created behind the
menting early preventive measures. casing. Exxon concluded that the for-
mation’s compressive strength should
be a good indicator of sand production Perforation tunnel
Causes and Effects
potential, and that sand production will
of Sand Production
probably cause a void behind the casing
In highly unconsolidated formations, that can be filled with gravel pack sand
Sand grains
the production of formation fluids will during a gravel packing operation. under triaxial
loading
probably be associated with the produc- The mechanical failure of unconsoli-
tion of formation sand. In some situa- dated rock surrounding a perforation is Fluid inflow
tions, small quantities of formation analogous to the failure of a loose mate-
sand can be produced with no signifi- rial surrounding a tunnel in soft earth.
cant adverse effects; however, in most Terzaghi described the mechanism for Fig. 1.1. Geometry of stable arch
surrounding a perforation
cases, sand production leads to reduced load transfer surrounding a tunnel in
productivity and/or excessive mainte- such a situation2in 1943. As the mate-
nance to both downhole and surface rial over the tunnel yields, the stress Effects of Sand Production
equipment. Sufficient sand production originally held in the yielded material
The effects of sand production are
may also cause premature failure of the is relieved and transferred to the more
nearly always detrimental to the short
wellbore and well equipment. rigid material surrounding the tunnel.
and/or long-term productivity of a well.
However, a portion of the original
Although some wells routinely experi-
Nature of Sand Production stresses is supported by intergranular ence manageable sand production,
friction above the tunnel.
Conditions that can cause sand produc- these wells are the exception, not the
To a certain extent, the arching con-
tion and the probable condition of the rule. In most cases, attempting to man-
cepts used in tunneling apply to the
formation outside of the casing after age the effects of severe sand produc-
1
Modern Sandface Completion Practices
tion over the life of the well is not an operation must be performed cautiously formation material filling the perfora-
economically attractive or a prudent to avoid the possibility of sticking the tion tunnels will lead to a significant
operating alternative. inner string inside the production tub- increase in pressure drop across the for-
ing. If the production of sand is continu- mation near the wellbore for a given
Accumulation in surface squipment. ous, the clean-out operations may be flow rate.
If the production velocity is great required on a routine basis, as often as
enough to carry sand up the tubing, the monthly or even weekly. This will result
Causes of Sand Production
sand may become trapped in the sepa- in lost production and increased well
The solid material produced from a
rator, heater treater, or production maintenance cost.
well can consist of both formation
pipeline. If a large enough volume of
fines (usually not considered part of
sand becomes trapped in one of these Erosion of downhole and surface
the formation’s mechanical framework)
areas, cleaning will be required to equipment.In highly productive wells,
and load bearing solids. The production
allow for efficient production of the fluids flowing at high velocity and car-
of fines cannot normally be prevented
well. To restore production, the well rying sand can produce excessive ero-
and is actually beneficial. Fines moving
must be shut-in, the surface equipment sion of both downhole and surface
freely through the formation or an
opened, and the sand manually equipment leading to frequent mainte-
installed gravel pack are preferable to
removed. In addition to the clean out nance to replace the damaged equip-
plugging of the formation or gravel
cost, the cost of the deferred produc- ment. If the erosion is severe or occurs
pack. The critical factor to assessing the
tion must be considered. over a sufficient length of time, com-
risk of sand production is whether or not
If a separator is partially filled with plete failure of surface and/or down-
the production of load-bearing particles
sand, the capacity of the separator to hole equipment may occur, resulting in
can be maintained below an acceptable
handle oil, gas and water is reduced. For critical safety and environmental prob-
level at anticipated flow rates and
example, one cubic foot of sand in an lems as well as deferred production.
producing conditions.
oil/water separator with a two-minute For some equipment failures, a rig-
The factors that influence the ten-
residence time will cause the separator assisted workover may be required to
dency of a well to produce sand are the:
to handle 128 fewer barrels of liquid per repair the damage.
• Degree of formation consolidation
day. If the ratio of oil to water entering
• Reduction in pore pressure through-
the separator is one to one (i.e., 50% Collapse of the formation.Large
out the life of the well
water cut), the separator will deliver 64 volumes of sand may be carried out of
• Production rate
fewer barrels of salable oil per day. At the formation with produced fluid. If the
• Reservoir fluid viscosity
US$18/bbl, this adds up to US$420,480 rate of sand production is great enough
• Increase of water production through-
worth of oil per year that is not moving and continues for a sufficient period of
out the life of the well
through the separator. time, an empty area or void can develop
These factors can be categorized
behind the casing and can continue to
into rock strength effects and fluid flow
Accumulation downhole.If the pro- grow larger as more sand is produced.
effects. Each of these factors and their
duction velocity is not great enough to When the void becomes large enough,
role in the prevention or initiation of
carry sand to the surface, the sand may the overlying shale or formation sand
sand production is discussed in the
bridge-off in the tubing or fall and above the void may collapse into the
remainder of this chapter.
begin to fill the inside of the wellbore void due to a lack of material to provide
or casing. Eventually, the producing support. When this collapse occurs, the
Degree of consolidation. The ability
interval may be completely covered sand grains rearrange themselves to cre-
to maintain open perforation tunnels
with sand. In either case, the production ate a lower permeability than originally
is closely tied to the cementation of
rate will decline until the well becomes existed. This will be especially true for
the sand grains around the tunnels. The
sanded-up and production ceases. In sit- formation sand with a high clay content
cementation of sandstone is typically a
uations like this, remedial operations or wide range of grain sizes.
secondary geological process and, as a
are required to clean out the well and For formation sand with a narrow
general rule, older sediments tend to be
restore production. One clean-out tech- grain-size distribution and/or very little
more consolidated than newer sedi-
nique is to run a bailer on the end of clay, the rearrangement of formation
ments. This indicates that sand produc-
slick line to remove the sand from the sand will cause a change in permeabil-
tion is normally a problem when pro-
wellbore. Since the bailer removes only ity that may be less obvious. In the case
ducing from shallow, geologically
a small volume of sand at a time, multi- of overlying shale collapsing, complete
younger Tertiary sedimentary forma-
ple slick line runs are necessary to loss of productivity is probable. In most
tions. Such formations are typically
clean out the well. cases, continued long-term production
located in the Gulf of Mexico, Califor-
Another clean-out operation involves of formation sand will usually decrease
nia, Nigeria, French West Africa,
running a smaller diameter tubing the well’s productivity and ultimate
Venezuela, Trinidad, Egypt, Italy,
string or coiled tubing down into the recovery.
China, Malaysia, Brunei and Indonesia,
production tubing to agitate the sand The collapse of the formation is par-
among others.
and lift it out of the well by circulating ticularly important if the formation
Young Tertiary formations often
fluid. The inner string is lowered while material fills or partially fills the perfo-
have little matrix material (cementation
circulating the sand out of the well. This ration tunnels. Even a small amount of
2