DECLARATION OF CHRISTOPHER D. HAWKES, Ph.D., P.Geo.
`
`1. My name is Christopher D. Hawkes, Ph.D., P.Geo.
`I am an associate professor of Civil and
`knowledge of the statements below.
`Geological Engineering in the College of Engineering at the University of
`
`I have personal
`
`Saskatchewan.
`I was a co-author of a paper entitled "Minimizing Borehole Instability Risks
`2.
`in Build Sections through Shales" that I presented to the attendees of the 7th One(cid:173)
`Day Conference on Horizontal Well Technology that took place on November 3,
`
`1999 in Calgary, Alberta, Canada.
`I have reviewed a copy of the proceedings for the conference that is attached
`3.
`to my declaration and compared it to my own personal copy of the proceedings.
`The two appear to be the same, including the paper entitled "Production Control of
`Horizontal Wells in a Carbonate Reef Structure." The attached copy therefore
`
`appears to be a true and correct copy.
`To the best of my recollection, copies of the proceedings were distributed
`4.
`during check-in to each registered attendee of the conference, and this is how I
`received my copy of the proceedings. I have attended similar conferences before
`and after this one, and copies of those conference proceedings were distributed to
`attendees whep. they checked in. For that reason, I would expect to remember if
`the proceedings for this conference were distributed in a different manner.
`I estimate that at least 50 individuals attended the conference.
`I declare under penalty of the perjury that the foregoing is true and correct.
`
`5.
`
`6.
`
`\="eb.ICf )l..016
`Date
`
`Name (print):
`
`Page 1 of 127
`
`

`
`7th ONE-DAY
`CONFERENCE ON
`HORIZONTAL
`WELL TECHNOLOGY
`
`" Horizontal Well Technology
`Operational Excellence"
`
`Wednesday, November 3, 1999
`Telus Convention Centre
`Calgary, Alberta, Canada
`
`PRESENTED BY:
`
`• Canadian Section of the
`Society of Petroleum Engineers
`
`• The Petroleum Society of CJM -
`Horizontal Well Special Interest Group
`
`.42
`2
`9
`
`(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:20)
`
`SPE CIM
`Page 2 of 127
`
`

`
`The Petroleum Society of CIM - Horizontal Well Special Interest Group
`
`and
`
`The Canadian Section of the Society of Petroleum Engineers
`
`7th One Day Conference
`
`on
`
`HORIZONTAL WELL Technology
`
`Operational Excellence
`
`Wednesday, November 3, 1999
`
`Telus Convention Centre
`Calgary, Alberta, Canada
`
`(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:22)
`
`Page 3 of 127
`
`

`
`SPE/ClM 7th Annual One-Day Conference on Horizontal WelJ Technology
`Wednesday, November 3, 1999
`"Horizonta1 Well Technology Operational Excellence'·
`
`7:30am Check in
`
`7:55-8:00
`
`Conference Chairman's [ntroduction
`
`RickKry
`
`Imperial Oil Resources
`
`8:00-8:25
`
`8:25-8:50
`
`8:50-9:15
`
`9:15-9:35
`
`A New EOR Scheme for Thin Heavy Oil
`Reservoirs - Gas Pressure Cycling
`Numerical Simulation of an Innovative
`Recovery Process (VAPEX)
`Drilling Engineering Challenges in
`Commercial SAGO Well Design
`in Alberta
`Coffee Break
`
`MORNING SESSION 2:
`.. Drillin~ ,\dvanl'cs"
`1 9:35- 1o:oo
`I 0:00 - I 0:25
`
`Automatic Rotru·y Drilling Tools
`Demands of Multi-lateral Well Junctions
`
`K. Hutchence, S. Huang
`
`Saskatchewan Research Council
`
`R. Engelman
`
`R. Knoll
`K.C. Yeung
`
`GcoQoest Reservoir Technologies
`
`H-Tech Petroleum Consulting Inc.
`Suncor Energy lnc.
`
`I M. Buker
`R. MacDonald, D. Erickson
`
`I I Phoenix Technology Services Ltd.
`
`I
`
`Secure Oil Tools
`
`B. Bennion, B. Thomas
`
`Hycal Energy Research Laboratories Ltd.
`
`P. McLellan, C. Hawkes, Y. Yuan
`
`Advanced Geotechnology Inc.
`
`C. Marques de Sa, M. Rosolen,
`E. Brandao
`
`Petro bras
`
`Underbalanced Drilling-
`A Reservoir Design Perspective
`Minimizing Borehole fnstability Risks
`in Build Sections through Shales
`Predicting Cuttings Transport and
`Suspension Using a Viscoelastic
`Drilling Fluid in Extended Reach
`and Horizontal Wells
`
`10:25- 10:50
`
`10:50- J 1:15
`
`11 : I 5 - 1 I :40
`
`Page 4 of 127
`
`

`
`11:40 -
`
`l:IO
`
`Fibre optic new advances in horizontal
`well technology and production
`monitoring
`
`Dr. Alan D. Kersey
`
`Vice President - Technology Development,
`CiDRA Corporation (Wallingford, Connecticut)
`
`1:10-1:35
`
`l:35- 2:00
`
`2:00-2:25
`
`Applying Multilateral Well Technology to
`the Deep Foothills Area of Alberta
`
`R. Sanders, M. Shoup
`D. Themig
`
`M. Muir, W. Ellsworth
`J. Gray
`D. Themig
`
`R. Mottahedeh
`
`Production Control of Horizontal Wells
`in a Carbonate Reef Structure
`
`Case Study Comparison of Planned vs.
`Actual Drilling Results - Successful
`Mapping & Characterization of a
`Horizontal Injector Well in the Lower
`Halfway Sand Oil Reservoir,
`AEC West's Grand Prairie Halfway
`V Reservoir, Alberta (72-5W6)
`
`Mobil Oil
`Halliburton/Guiberson AVA
`
`Husky Oil Ltd.
`Allore Petroleum Managmcnt
`Halliburton/Guiberson AVA
`
`United Oil & Gas Consulting Ltd.
`
`2:25 - 2:50
`
`Production Enhancement of Prolific,
`Extended-reach Gas-lift Oil Wells
`
`R. Dunn, D. Yu, M . Tiss, D. Murphy
`D . Hahn
`
`PanCanadian Resources
`Adams Pearson Associates Inc.
`
`2:50-3:10
`
`Coffee Break
`
`.. Panel Discussion
`
`3: 10 -5:00
`
`(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:24)
`
`Page 5 of 127
`
`

`
`7th One Day Conference on HORIZONTAL WELL Technology
`November 3,1999 - Calgary, Alberta, Canada
`
`Presented by the Petroleum Society of CIM-Horizontal Well Special Interest Group
`and the Canadian Section of the Society of Petroleum Engineers
`
`SPE C I M
`
`Distinguished Panelists
`
`SADANAND(SADA) D.JOSHI
`
`Dr. Sada Joshi is the founder and President of JOSHI TECHNOLOGIES INTERNATIONAL INC of
`Tulsa, OK, an engineering consulting firm and an oil and gas producer. Well known for his pioneering
`work in horizontal well technology. Author of a best-selling book published in 1991, Sada is known for
`his formulae and equations for horizontal wells, as well as his involvment in over 160 worldwide field
`projects encompassing more than 1000 horizontal wells. He earned his Ph.D degree from Iowa State
`University.
`
`KEN NEWMAN, P.E.
`
`Ken Newman, P.E., is the founder and President of CTES, L.C. (Coiled Tubing Engineering Services)
`of Conroe, Texas. He is the inventor of the SmarTract wellbore tractor system, As a recognized
`authority on Coiled Tubing, he has authored many technical papers, magazine articles, and patents.
`He holds a masters degree in Mechanical Engineering from MIT and is a Registered Professional
`Engineer in the State of Texas.
`
`C.A. (KIP) PRATT
`
`Kip Pratt, P.Eng is Drilling Engineering Advisor for Shell Canada Limited. A drilling engineer at Shell
`for over 32 years, he has had drilling experience from the Mississippi Delta to the Mackenzie Delta.
`Since 1989, directly involved in many horizontal and Underbalanced Drilling projects in Canada and
`U.S.A. including short radius, slimhole re-entries, multilaterals, deep H2S horizontal wells, SAGID
`and SW-SAGD. Kip is a recognized authority in horizontal and extended reach drilling-completion
`projects. Amongst them: Midale, Peace River, House Mtn., Panther River, Waterton, Jumping Pound,
`Harmattan.
`
`LONG NGHIEM
`
`Dr Long Nghiem is currently Vice-President Research and Development, with Computer Modelling
`Group Ltd of Calgary. He joined the firm in 1977 and has been involved in the research, development
`and application of reservoir simulation technologies. He has authored over 50 papers on various
`aspects of reservoir modelling. He holds a Ph.D. degree in Petroleum Engineering from the University
`of Alberta and is a member of A.P.E.G.G.A.
`
`LEW HAYES
`
`Lew Hayes, P.Eng, is currently VP Operations at Petrovera Resources. He has been involved with
`in excess of 200 horizontal wells including several vertical and horizontal multilateral completions.
`Lew is a Petroleum Engineer graduate from Montana Tech in 1983. He has worked extensively in
`Canada with experience ranging from offshore east coast to deep sour Foothills drilling and
`completions.
`
`(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:25)
`
`Page 6 of 127
`
`

`
`7th One Day Conference on HORIZONTAL WELL Technology
`November 3,1999 - Calgary, Alberta, Canada
`
`Presented by the Petroleum Society of CIM-Horilontal Well Special Interest Group
`and the Canadian Section of the Society of Petroleum Engineers
`
`Message from the Chair
`
`SPE CIM
`
`Welcome to the 7th One-Day Conference on Horizontal Well Technology.
`
`On behalf of the Canadian Section of the SPE and the Petroleum Society, we are pleased to offer
`to the technical community a day of new ideas, case studies and analyses focussed on
`technology related to horizontal wells.
`
`The organizers, led by General Chairman, Rick Kry and the Technical Program Committee
`Chairman, K.C. Yeung, have enticed a selection of presentations, divided into four technical
`sessions: "Heavy Oil", "Drilling Advances", "Formation/Stimulation", and "Field Cases". They
`have arranged a luncheon presentation by Dr. Alan. D. Kersey, Vice President of CiDRA
`Corporation on fibre optic applications and potential. And to complete the program, a panel
`comprised of leaders in horizontal well applications and technology and representing business
`and technical perspectives, will discuss the latest advancements in horizontal wells, what is still
`needed and what are the likely breakthroughs in the future.
`
`Thank-you to each of the authors, speakers, panel members and organizing committee and
`technical committee volunteers who have taken time from their busy schedules to contribute to
`the success of this meeting. Enjoy the day and may it be productive for you.
`
`Dr. P. A. Kry
`Imperial Oil Resources
`General Chairman
`7th One Day Conference
`
`Page 7 of 127
`
`

`
`7th One Day Conference on HORIZONTAL WELL Technology
`November 3,1999 - Calgary, Alberta, Canada
`
`Presented by the Petroleum Society of CIM-Horizontal Well Special Interest Group
`and the Canadian Section of the Society of Petroleum Engineers
`
`Organization and Technical Program
`
`SPE; CIM
`
`Rick Kry
`K.C. Yeung
`Kenny Adegbesan
`Gil Cordell
`Lister Doig
`Con Dinu
`Fabio Diaz
`Brian Felty
`Norm Gruber
`Harry R. Hooi
`Ron McCosh
`Michael Olanson
`Bianca Palosanu
`Wes Scott
`Gurk Sarioglu
`Elena Tzanco
`Teresa Utsunomiya
`Chi-Tak Yee
`
`Imperial Oil Resources
`Suncor Energy Inc.
`KADE Technologies Inc.
`Canadian Hunter Exploration Ltd.
`PanCanadian Resources
`Husky Oil Ltd.
`Colulmbus Resources
`Triumph Energy
`Schlumberger-GeoQuest
`Numac Energy Inc.
`CenAita Well Services Inc.
`Audryx Petroleum Ltd.
`Merit Energy Ltd.
`Petroleum Society of CIM
`Petro-Canada
`ET Consulting
`PanCanadian Resources
`GravDrain Inc.
`
`Page 8 of 127
`
`

`
`7th One Day Conference on HORIZONTAL WELL Technology
`November 3,1999 - Calgary, AJberta, Canada
`
`Presented by the Petroleum Society of CIM-Horizontal Well Special Interest Group
`and the Canadian Section of the Society of Petroleum Engineers
`
`Sponsoring Organizations
`
`SPE CIM
`
`Platinum
`AGAT Laboratories
`CiDRA Corporation
`Import Tool Corporation Ltd
`JTI (Joshi Technologies International Inc)
`Outtrim Szabo Associates ltd
`Petroleum Recovery Institute
`Phoenix Technology Services Ltd
`Ryan Energy Technologies Inc.
`Schlumberger
`United Geo Com Drilling
`
`Gold
`Halliburton Energy Services
`Norwest Labs Energy Resource Group
`PanCanadian Limited
`Poco Petroleums Ltd
`Precision Drilling Limited Partnership
`
`Silver
`Baker Hughes Canada Company
`Northland Energy Corporation
`Petro-Canada
`Q'max Solutions Inc
`Union Pacific Resources Inc
`
`Bronze
`Core Laboratories Canada Ltd
`Directional Plus
`
`Page 9 of 127
`
`

`
`A New EOR Scheme for Thin Heavy Oil
`Reservoirs - Gas Pressure Cycling
`
`K. Hutchence, S. Huang -
`Saskatchewan Research Council
`
`THIS PAPER IS TO BE PRESENTED AT THE SEVENTH ONE DAY CONFERENCE ON HORIZONTAL WELL
`TECHNOLOGY, CALGARY, ALBERTA, CANADA, NOVEMBER 3, 1999.
`
`r Abstract
`
`infill horizontal
`It has been observed that an
`production well was much more productive after system
`~ re-pressuring by water than before. This has led to the
`'l simulation development of a proposed new enhanced oil
`f recovery scheme. The idea behind the pressure cycling
`/j scheme is to restore the reservoir's primary production
`~ conditions and to exploit them efficiently through the use
`{I of infill horizontal production wells. Primary production
`':! conditions are restored with good conformance by
`-~~ injecting produced gas, and then water, so as to re-
`I. saturate the reservoir oil by the time water injection raises
`pressure to around original reservoir pressure. The
`production phase of the cycle then follows. This process
`can be repeated several times (until it reaches the
`economic limit) while maintaining useful rates and
`amounts of production even in quite thin reservoirs (5 m).
`
`Introduction
`
`A considerable portion of Western Canada's heavy oil
`occurs in quite thin reservoirs (4 to 6 m). Much of the
`primary and secondary production has been done and so
`the need for effective enhanced oil recovery (EOR)
`methods is becoming urgent if production is to be
`sustained. Thermal methods would generally be
`inefficient because of the high heat losses inherent in thin
`1 reservoirs, and such methods are becoming increasingly
`li environmentally undesirable. By defaultthen, non-thermal
`~~ EOR methods must be considered.
`'
`
`Cost is a major factor in choosing a non-thermal method.
`Any EOR scheme involves putting a substantial amount of
`something down a well. It may also involve putting a
`hopefully small quantity of something expensive downhole.
`The least expensive, and most generally available, materials
`that can be injected are: water, air, and produced gas. There
`are few reasons for, and several for not injecting air if a
`combustion type of process is unintended. Methane or air
`flooding by itself is usually not useful and water injection is,
`of course, waterflooding. It is apparent that any new,
`potentially low cost, EOR process must involve some
`combination of the low cost materials. Water-alternating-gas
`(WAG) is one such process. Pressure cycling, the subject of
`this paper, is another such process.
`
`The Basis of the Pressure Cycling Process
`
`The WAG process would normally follow a waterflood.
`If a free gas saturation exists, the system is pressured up
`until the gas is compressed into solution. This is followed by
`gas injection, say, in the four corner wells of a five spot, until
`gas breakthrough to the producer. Gas injection is then
`discontinued and water is injected until the watercut
`becomes excessively high. The alternation of gas, then
`water injection usually can be repeated a few times before
`production becomes uneconomical. The appeal of WAG is
`that it should achieve good vertical conformance, in that the
`water would sweep the lower part of the formation and the
`gas the upper. Unfortunately areal conformance is less than
`excellent for all vertical well systems, and quite poor if a
`horizontal production well is used. Clearly a method that
`gives much better areal conformance would be desirable.
`
`Illustrations at end of paper.
`
`What was observed in connection with there-pressuring
`
`1
`
`(cid:51)(cid:68)(cid:74)(cid:72)(cid:3)(cid:20)(cid:20)
`
`Page 10 of 127
`
`

`
`for the WAG process is that wells produce substantially
`better after re-pressuring. The geometric arrangement of
`the study pattern was of four vertical wells at the corners
`of a square. The distance between vertical wells was 440
`m for historical reasons. For the WAG study of horizontal
`production wells, four vertical wells and a segment of
`horizontal well between them had been used. For
`comparison purposes a vertical infill well was also used
`in the center of the four original vertical wells. A
`comparison of the production from both horizontal and
`vertical wells, before and after re-pressuring by water
`injection, is shown in Figure 1. It may be observed that
`both the rates and amounts of production of either type of
`well were much improved. As was to be expected, the
`performance of the horizontal well was superior.
`
`The improvement in performance after re-pressuring
`can be shown to be primarily due to forcing gas back into
`solution in the oil rather than the increase in pressure, as
`such. One observation supporting this conclusion is, that
`re-pressuring with water beyond the pressure at which
`nearly all gas was
`forced
`into solution produced
`noticeably more water, but very little more oil. Re(cid:173)
`pressuring to pressures much below the gas re-solution
`pressure markedly reduced oil production. The second
`observation was that if repeated re-pressurings and
`productions were done without the addition of gas,
`production declined fairly quickly with successive cycles.
`Addition of gas prior to the water re-pressuring resulted
`in a much slower decline in productivity.
`
`The conclusion drawn from the above observations
`is that the pressure cycling scheme works by largely
`restoring the solution gas drive mechanism of primary
`production. Primary production is a generally well
`understood process, for which information is necessarily
`available for any reservoir to which the pressure cycling
`process might be applied. The production aspect of the
`pressure cycling process should therefore be known
`about beforehand. What remains to be clarified is the
`details of pressuring up and the timing of phases of
`operations.
`
`Optimization of Injection Phases
`
`The optimization of gas injection amount depends
`upon what stopping criteria are used for the production
`phase of the cycles. At first sight it might be supposed
`that measures such as rate of production or watercut
`might be used. It turns out that there exists what might be
`termed a natural stopping signal for production. It was
`
`observed, in a horizontal production well system, that if
`production for a cycle was carried on for sufficiently long,
`four gas-oil ratio (GOR) peaks were observable in the
`production. An example of these GOR peaks to the top of
`the fourth peak is given in Figure 2. Examination of the
`system at the times of these peaks indicated the origins of
`the GOR peaks to be the following. The pressure exerted by
`the water during re-pressuring is not uniform over the entire
`pattern. As a consequence some gas is moved sideways,
`and ultimately two small pockets of gas are formed near the
`center part of the horizontal well, which would require quite
`high pressure to force into solution. It is counterproductive to
`do so. Not compressing this small amount of gas into
`solution does result in a brief GOR peak very early in the
`production phase. The second GOR peak occurs when the
`production well reaches minimum bottomhole pressure
`(maximum gradients). The third GOR peak is observed to be
`associated with free gas saturation occurring all the way to
`the edges of the production pattern (maximum area of
`production). The fourth GOR peak is associated with free
`gas saturation reaching the bottom of the outer part of the
`pattern (maximum volume of production).
`
`If the production phase of the cycles is terminated too
`early, oil is produced from only the central portion of the
`pattern, and so areal conformance is diminished.
`If
`production is carried out too long, the lower regions of the
`pattern become excessively de-gassed. This condition is
`detrimental to production in any further cycles, as re-gassing
`the lower regions of the pattern seems to be quite difficult. A
`close to optimal termination criterion is to end the cycle at
`about the minimum between the third and fourth GOR
`peaks. This stopping condition has the advantage of being
`one that can be quite readily operationally observed.
`
`it can be
`the above stopping condition
`With
`demonstrated that there is an amount of injection gas that is
`optimal in several senses. The average rate of oil production
`showed a maximum, and the average watercut and amount
`of injected gas required to produce a unit of oil showed
`minima. These optima were fairly broad and all occurred at
`about the same amount of injected gas. The amount of gas
`required to achieve the optimal conditions was also that
`which resulted in the system being restored to about original
`reservoir pressure, when water injection had effectively
`pressured the gas into solution. With the gas being injected
`at a maximum pressure only slightly above original reservoir
`pressure, it was found that the same amount of gas was
`needed for several successive cycles. It is not presently
`known if re-pressuring to about original reservoir pressure is
`a very general optimization condition.
`
`2
`
`Page 11 of 127
`
`

`
`Effect of infill options
`
`The pressure cycling study evolved from an infill
`horizontal production well. Drilling such wells represents
`a substantial capital investment and so the question
`naturally arose of whether infill wells were really
`necessary for the pressure cycling process. The cases of
`no infill well, a vertical infill production well, and a
`horizontal infill production well were compared. The
`amounts and rates of production for the three cases are
`given in Figures 3 and 4 respectively. The results are
`reported on a per pattern basis (same production area)
`for all cases. This means, of course, that the horizontal
`well results are for just a segment of horizontal well
`contained in the square pattern. In reality a horizontal well
`would have productive end zones and would possibly be
`somewhat longer. In the no infill case there is only one
`half a production well per pattern.
`
`It may be noted that not very much is gained by using
`a vertical infill well. It is also quite clear that the horizontal
`infill well case gives much higher rates of production and
`a somewhat higher ultimate recovery than do the vertical
`production well cases. It is almost certainly necessary to
`drill horizontal wells to obtain economically attractive
`rates of production. This assumes that the heavy oil
`reservoirs exhibit normal darcian flow. In cases where a
`larger percentage of oil has been recovered in vertical
`well primary production, possibly due to wormholes, or in
`reservoirs with medium oil, vertical producers might
`provide acceptable rates.
`
`Comments and conclusions
`
`The research discussed above provides good reasons for
`believing the pressure cycling technique to have good
`potential as a EOR scheme in the difficult application of
`thin heavy oil reservoirs. It is, naturally, quite probable
`that application to less difficult situations would be more
`profitable. The pressure cycling scheme has the merit of
`simplicity, both in terms of what inputs are needed, and
`in terms of the process to be carried out. The inputs are
`water and produced gas which are reasonably available,
`require no special safety precautions, and are reasonably
`inexpensive. It is to be noted that the gas is not
`consumed. It is returned as the oil is produced. The
`production side of the process, being primary production,
`is readily understood, and the production limitations of
`needing to produce to the edge of the pattern but without
`de-gassing the oil are easily grasped.
`
`Research on pressure cycling at the Saskatchewan
`Research Council is continuing. Studies of thicker reservoirs,
`systems with bottomwater, and a range of viscosities all
`show positive findings. Work on how to fully optimize the
`pressure cycling process is also underway.
`
`3
`
`Page 12 of 127
`
`

`
`20000
`
`Horizo~tallnfill ~fter Wat~rflood I
`
`I
`
`.. /"
`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
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`
`6
`
`8
`
`10
`TIME, Years
`
`12
`
`14
`
`16
`
`18
`
`Figure 1. The Effect of Restoring Solution Gas Drive
`
`50
`
`---
`h ~
`\
`\
`\
`V\ >
`""'
`K
`\~ v
`
`Oil Rate
`
`1'-"VI
`
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`>-
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`
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`
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`
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`
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`
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`
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`
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`
`5500
`Time, days
`
`Figure 2. The Characteristic GOR Peaks
`
`4
`
`Page 13 of 127
`
`

`
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`Time, days
`
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`
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`Figure 3. Comparison of lnfill Option Productions
`
`8
`
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`
`Figure 4. Comparison of lnfill Option Production Rates
`
`5
`
`-
`
`Page 14 of 127
`
`

`
`Numerical Simulation of an Innovative
`Recovery Process
`(VAPEX)
`
`R. Engelman - GeoQuest Reservoir Technologies
`
`UNAVAILABLE AT TIME OF PRINTING
`
`Page 15 of 127
`
`

`
`Drilling Engineering Challenges
`in Commercial SAGD Well Design in Alberta
`
`R. Knoll - H-Tech Petroleum Consulting Inc.
`K.C. Yeung- Suncor Energy Inc.
`
`fHIS PAPER IS TO BE PRESENTED AT THE SEVENTH ONE DAY CONFERENCE ON HORIZONTAL WELL
`TECHNOLOGY, CALGARY, ALBERTA, CANADA, NOVEMBER 3, 1999.
`
`~BSTRACT
`
`Recently, the field pilots in Canada using SAGO (Steam
`1\ssisted Gravity Drainage) technology have generated
`sufficient positive response to encourage commercial
`scale development in the Alberta Oil Sands Deposits.
`This will be a very interesting time for drilling engineers,
`since SAGO well pairs present some unique design and
`:>perational challenges.
`
`This paper will attempt to review some of the drilling
`engineering challenges of generic SAGO well design in
`the Alberta setting, specifically, the need to cool the
`drilling mud to maintain hole stability, and the selection of
`slant or vertical intermediate hole section geometry.
`
`INTRODUCTION
`
`The Alberta Oil Sands deposits, located in the areas of
`Athabasca, Cold Lake and Peace River, are widely
`recognized for their tremendous resources (Figure 1 ).
`The Alberta Energy and Utilities Board (AEUB) has
`estimated that the potential ultimate volume of crude
`bitumen in place in Alberta to be some 400 billion cubic
`metres (2.5 trillion barrels). Of these,
`the ultimate
`potential amount of crude bitumen recoverable from
`Cretaceous sediments by in situ recovery methods is
`estimated to be 33 biBion cubic metres (200 billion
`barrels).
`
`About 80% of the bitumen in Alberta are contained in the
`Athabasca Oil Sands Deposits, where the in situ viscosity
`
`is over 1 million centipoise. The oil industry and Alberta
`government have been searching for in situ techniques to
`recover the bitumen economically. Significant amount of
`research and development and piloting effort have been
`spent on in-situ combustion, cyclic steam stimulation and
`steamflooding with limited success. Finally, with the
`advance in horizontal well technology, the Steam Assisted
`Gravity Drainage (SAGO) process was pioneered at the
`Underground Test Facilities (UTF) near Fort McMurray
`and has become the technology of choice for many new
`in-situ projects in Alberta. Some 39 SAGO well pairs have
`been drilled in Alberta to date. In the last two years, there
`are four announced new commercial in-situ development
`in the Athabasca Oil Sands, whereby SAGO is the
`selected recovery process. These projects are AEC
`Foster Creek, JACOS Hangingstone, Pan Canadian
`Christina Lake and Petro Canada Mackay River.
`
`These commercial scale projects will utilize parallel pairs
`of horizontal wells which are key to the SAGO process.
`The lower horizontal well is the producer and the upper
`horizontal well, which is placed several metres directly
`above the producer, is the steam injector (Figure 2). As
`steam is injected into the reservoir along the upper
`horizontal well, the steam rises in the reservoir and heats
`the force of gravity
`the bitumen. As the steam cools,
`enables the heated bitumen and condensate (water) to
`flow to the lower production well.
`
`The amount of steam injected and fluid produced depend
`on reservoir qualities such as permeability, porosity, water
`saturation; on operating constraints such as operating
`pressure and steam trap control temperature; and on the
`
`1
`
`Page 16 of 127
`
`

`
`length of the well. Some of the factors that determine the
`length of a well include geology and the pressure drop
`between the heel and the toe in the horizontal section.
`. The pressure drop in an injector is a function of steam
`volume, pressure and pipe size. Using a larger casing
`will reduce this pressure drop. The selection of the size
`of the liner and the intermediate casing is also influenced
`by the size of tubing and other instrumentation strings
`inside the casings. All the injection/production process,
`monitoring and manipulation demands have to be defined
`and addressed prior to considering the more typical
`drilling engineering issues. Thus, the optimization in the
`drilling design of SAGD wells requires dramatically more
`multi-disciplined team synergy than do vertical wells.
`
`(ERD)
`reach drilling
`SAGD wells are extended
`applications, where total length will be 3 to 8 times the
`true vertical depth (TVD). The well pairs require uniquely
`precise 3-D trajectory control, since the accuracy of well
`separation is a critical parameter in the SAGD process.
`Typically the reservoir will be a very shallow depth (150 to
`600 m TVD). Hole stability is a concern in drilling in the
`unconsolidated oil sands. Tight streaks and shale plugs
`in the reservoir and the erratic overlain glacial till deposits
`can complicate directional drilling capability. All these,
`and other aspects, present significant design and
`operational challenges to the well construction team.
`
`In the field pilots conducted to date, these challenges
`have been overcome with numerous
`technical and
`operational
`innovations.
`Pilot curves and magnetic
`vectoring for trajectory control, fibre optics for downhole
`instrumentation, expansion
`joints
`for
`tubular thermal
`distortion are examples. As the industry progresses from
`process validation
`(i.e., pilot)
`to commercial scale
`development, much more emphasis must be placed on
`the capital and operating costs of these wells. The well
`construction costs represent a significant portion of total
`project capital expenditures. The economic success of
`any commercial SAGD development will depend on how
`cost effectively the multi-disciplined team can address
`and overcome the design· and operational challenges of
`optimized well pairs.
`
`This paper will focus on two specific drilling engineering
`issues: the requirement for mud cooling and the choice of
`vertical vs. slant intermediate hole section geometry.
`
`MUD COOLING
`
`An extensive series of informal interviews with SAGD pilot
`operators revealed a spectrum of opinion in respect to the
`value added of mud cooling during drilling operations.
`The argument promoting mud cooling
`is
`relatively
`straightforward. The in-situ temperature of the typical
`
`SAGD reservoir is low. The "Cold Lake" type deposits will
`have reservoir temperature around 12-16 °C.
`The
`deposits of
`the more
`tar-like bitumen
`in
`the Fort
`McMurray region to the north tend to occur at a shallower
`depth and will have in-situ temperatures in the 7-10 °C
`range. While drilling, the fluid gains temperature due to
`the pumping action. The relatively hot drilling fluid will
`warm the near wellbore radius. The bitumen being
`heated along the well will thin, and this would lead to a
`reduction in the cohesive nature of the tar sand material.
`This may lead to a higher risk of hole instability, wellbore
`collapse and a host of other potential aggravations to the
`drilling operations. One can argue that mud chilling is an
`appropriate preventative maintenance step to reduce
`these hole trouble risks.
`
`However, a few experienced SAGD pilot operators claim
`mud cooling is expensive and inefficient, and question the
`"value added"