ENCYCI6%)PAEDIA
`HYDROCARBONS
`
`ISTITUTO DELLA
`
`ENCICLOPEDIA ITALIANA
`FONDATA DA GIOVANNI TRECCANI
`
`1 of 25
`
`Exhibit 2014
`IPR2016-01517
`
`

`
`©
`ALL RIGHTS RESERVED
`
`Copyright by
`ISTITUDO DELLA ENCICLOPEDIA ITALIANA
`
`FONDATA DA GIOVANNI TRECCANI S.p.A.
`2007
`
`M.l.T. LIBRARIES
`
`
`
`
`
`MAR 3 I 2009
`
`Recaxven
`
`Printed in Italy
`
`Photolidm and priming by
`MARCHESI GRAFICI-IE EDITORJALI &p.A.
`Via Flaminia, 995/99? - 00189 Roma
`
`2 of 25
`
`Exhibit 2014
`IPR2016-01517
`
`

`
`Thlslnaultal muheomeetadbyoonvrismlwmuu 11 us. coda!
`
`W
`
`Upstream technologies.
`Novel well and production architecture
`
`computations necessary for their effective
`day-to-day use. All of the tremendous developments
`in all aspects of many different operations were
`focused on the same basic production scheme:
`developing. completing, and producing from a
`vertical well. Today, the art, science. and technology
`of drilling and completing a vertical well have
`reached a very high level of maturity.
`in spite of all efforts, however. production from
`some reservoirs proved highly challenging and
`beyond the existing capabilities of the industry. Even
`though large amounts of oil and gas were known to
`exist underground, the available techniques and
`production architectures were not sufficient to allow
`their economical exploitation. For example, the
`Austin Chalk formation in Central Texas was known
`
`to contain large volumes of hydrocarbon, but the
`productivity of wells drilled into it was random and
`unpredictable. For years operators grappled with
`trying to find a consistent suitable production
`scheme, but with very limited success. A similar
`situation existed in the Rospo Mare reservoir,
`offshore Italy in the Adriatic Sea, operated by Elf
`with Agip as a main partner. After a great deal of
`work, the collaborative efforts of Eli‘, Agip and
`lnstitut Francais du Pélrole led to the conclusion that
`production of this field required dilferent production
`architecture. They finally decided that the best way
`to produce from the fractured carbonate reservoir
`was by drilling a horizontal hole and intersecting the
`existing natural fractures in the formation.
`Even though horizontal drilling had been
`attempted in the 19-405, it had been completely
`abandoned as too cumbersome and inefficient. The
`
`general belief among experts was that many of the
`beneficial results of a horizontal hole could also be
`
`achieved by hydraulically fracturing a vertical well.
`In fact, theoretical developments had shown a direct
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`3 of 25
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`Exhibit 2014
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`*- 1.1 Introduction
`
`' over a century, the centrepiece of production
`.'tecture and associated technologies of the oil
`gas industry has been a vertical well. The
`uction philosophy has been quite simple: based
`.. the best available geological and geophysical
`locate the most likely underground spots for
`accumulation of oil and gas, drill a vertical hole.
`* and cement it to give it long life and to prevent
`tion of reservoir fluid into adjacent zones. The
`'ty of the initial wells were completed
`=-u ole along the producing zone to facilitate the
`period flow ofoil. But this model soon proved
`cause later production problems: excessive and
`I
`trolled water and gas flow accompanied by
`' drop in reservoir pressure and well
`a ctivity, lack of access to the zone in poorly
`lidated formations, and very limited remedial
`es and treatments to address flow problems.
`new technologies were developed by the oil and
`and other industries, the production schemes
`god to take advantage of the new developments.
`' I 1 the borrowed technologies are reservoir
`' w ring theories from hydrology, the use of
`- charges for perforation based on military
`2: ology, cementing materials from construction
`‘es, computer modelling and simulation from
`‘and aeronautical engineering, and many more.
`technologies developed by the industry itself
`also proved tremendously valuable in all phases
`rations. Notable among these are electrical
`, hydraulic fracturing, Logging While
`r g (LWD), 3D seismic, new drill bits, and
`I»
`terized on-site data acquisition systems.
`cation of these technologies required the
`lopment of new tools and equipment, materials.
`. e engineering know-how to perform
`
`
`
`H 3'"
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`It New DEVELOPMENTS: it-inner, rnansronr. SUSTAINABILITY
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`NEW UPSTREAM TECHNOLOGIES
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`correspondence between the two production
`methods. While horizontal drilling was an unknown
`territory with a very small basis of technical and
`operational support, hydraulic fracturing was a
`well-established and common practice in the
`industry, with all the required tools, equipment,
`materials and technologies in place. Lack of‘
`technical and operational support base for horizontal
`wells also meant scarcity of know-how, higher risk,
`and greater cost. In spite of these obstacles, it was
`decided to undertake the project, and thus began the
`next generation of production architecture, which is
`shaping the industry at the present time. The success
`of this pioneering effort has led to the development
`of an entirely new production architecture that is
`based on a horizontal well as its centrepiece. From
`the main bore multiple lateral branches are extended
`into the same or other reservoirs, thus substantially
`increasing contact with the hydrocarbon-bearing
`formation. Evolution of this system led to
`recognition that effective production management
`based on this complex scheme requires the ability to
`control and regulate flow from or into different
`branches, and thus recognition of the need for
`downhole flow regulators and intelligent wells.
`Since success of’ horizontal holes depends on much
`more accurate placement in the reservoir, new and
`advanced drilling and navigation systems had to be
`developed to augment the existing technology. Tools
`and techniques of reservoir description also had to
`undergo major changes to allow better definition of
`the distribution and flow of oil and gas. which led to
`downliole sensor technology development. To take
`full advantage of the above developments, one also
`needs hybrid simulators and decision-making
`processes to economically optimize fluid flow into
`or out of the reservoir. All of these procedures have
`led to the formation of a new frontier in oil and gas
`production, one that is likely to shape the future of
`oil and production.
`Below we review historical, technical and
`operational aspects of each of these technologies. In
`particular, the discussion covers horizontal holes,
`rnultilaterals, intelligent downhole flow regulators, and
`the technologies that enable their effective utilization.
`These enabling technologies include gcosteering,
`permanent downhole measurement devices, and novel
`completion techniques, among others.
`
`3.1.2 Horizontal drilling
`
`History of horizontal drilling
`The first modern horizontal holes were drilled
`
`in France: two in Lacq and one in Castéra-Lou
`
`(Giger et at, 1984). All ofthese were land wells.
`The main objective ofthe first two wells was to
`understand and develop the technology that was
`required for effective production of Rospo Mare
`reservoir. offshore Italy in the Adriatic Sea. The
`first two of these were drilled in Lacq Supérieur at
`the relatively shallow depth of around 2.000 F! (600
`m). The first well. Lacq 90, was drilled in 1979, and
`its horizontal section was 360 ft (108 m} long,
`completed with an un-cemented slotted liner. The
`next well, Lacq 9!, bad a horizontal section 1,120 it
`(336 in) long. Various completion techniques were
`tried in this well to isolate part of the well and to
`reduce flow of water. The third well, Castéra-Lou
`1 I0, was used to demonstrate the feasibility of
`drilling at a depth of9,l}00 ft (2,700 m} and to
`experiment with various completion techniques.
`This well penetrated l,O00 it of reservoir ( 300 m),
`with a 490 ft (14? n1) horizontal section. and
`produced at a rate of 440 bblld {barrels of oil per
`day) or 70 m3ld. its production was more than eight
`times higher than the neighbouring vertical wells,
`thus proving the viability of the concept.
`Rospo Mare, the next horizontal well, was
`drilled in the main target ofthe research. The
`formation is a carbonate with very low porosity
`where much of the oil is contained in natural
`
`fractures and vugs. The reservoir fluid is heavy oil,
`with AP] gravity of l 1° and viscosity of 300 of’. The
`vertical pilot hole was 9 5/8" f_about 24.4 cm) and
`the horizontal open hole was 8 U2" (about 21.6 cm)
`in diameter. The vertical location of the horizontal
`section was 230 ft (70 m) above the oilfwater
`contact. The horizontal section penetrated 2,000 ft
`(600 m) of the reservoir. This well produced 3,600
`bblfd (570 m3!d}, more than twenty times that of the
`other wells in the same field.
`
`The next major development in horizontal
`drilling was led by Maersk Oil & Gas in Dan field.
`Their main intent was also to improve productivity
`of the low permeability chalk. However.
`accomplishment of their production objectives
`required the creation of multiple fractures in the
`horizontal hole. To do this, they needed to
`successfully install and cement a liner in the
`horizontal section in order to isolate the well for
`
`multiple fracture treatments. Furthermore, creation
`of multiple fractures required new cementing
`techniques and materials for horizontal wells,
`highly specialized downhole tools. multiple trips,
`and several milling and cleaning operations, as well
`as specialized fracturing materials and techniques.
`All these issues were addressed and resolved
`
`through collaborative efforts between Maersk,
`l-lalliburton and Baker Oil Tools (Brannin er at'.,
`
`-
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`.
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`I
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`186
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`sncvctorastm or Hvoaotdl
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`4 of 25
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`Exhibit 2014
`IPR2016-01517
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`

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`
`the productivity index, J, is given by:
`7.03-1o*3 b,.’iI
`‘
`‘l’53)
`
`- q is the flow rate, stb/d (stock tank barrelfd); A
`"e drainage area of the horizontal well. R2; B is the
`" u.-: tion fluid volurne factor, rblstb (reservoir
`lfstock tank barrel);.,u is the oil viscosity. cP; It is
`drainage distance of horizontal hole in y direction,
`I H is the geometric factor; 1:, and k: are the
`eability in directions .1: and z, in ml) (where x, y,
`z are coordinates of a point in the reservoir); fig is
`average reservoir pressure in drainage volume, psi;
`
`1. Horizontal hole layout
`reservoir.
`
`-
`
`
`
`UPSTREAM TECHNOLOGIES. NOVEL-WELL AND PRODUCTION ARCHITECTURE
`
`0; Damgaard etal., 1992; Owens er al'., 1992}.
`._ result was a successful completion of long
`'
`and cernented horizontal holes with multiple
`- and substantially higher productions.
`In spite of this spectacular success, the growth of
`' ntal hole technology was relatively slow. It took
`— than a decade and many successes and failures
`_
`"fore the industry developed the required equipment,
`.. ‘ques, technologies and comfort—level to consider
`.. ' ontal drilling as a viable option for field
`iopment.
`
`_
`
`uctivity of horizontal wells
`Several dilferent equations have been developed
`computation of the productivity of horizontal
`, s. Because of the complexity of the problem, most
`Z-“these are approximations of the analytic solutions;
`' er, they are accurate for engineering
`putations.
`Babu and 0deh’s solution (1989) considers the
`- o-steady state flow. Assuming the reservoir
`u etry defined in Fig. 1, and that there is no
`_. anion damage, their solution for the flow rate q is
`..
`I by:
`q = 7.os- to-3s.fE(_s,,—p,,_,g
`B,-u(1n-"‘,'—'Q +1nc,.,— 0.75 +s,)
`
`p” is the average flowing bottomhole pressure, psi; r,,.
`is the wellbore radius, fr; 3,, is the skin resulting from
`partial penetration.
`The approximate expression for CH is:
`
`lnC,, 62sM£L 3+ H
`(n)2]_
`2 ’=_z1__n
`=
`
`—1n(sin%)—0.5 ln(%
`
`1.088
`
`where a is the drainage distance of horizontal hole in it
`direction, it; h is the drainage distance of horizontal
`hole in z direction, ft: x0 is the x coordinate of centre
`of well; 2,, is the z coordinate of centre of well.
`Denoting by L the length of horizontal hole, if L‘-b
`(fully penetrating well), then s_q=0. If L<£b, then the
`partial penetration skin, s3, is given for two special
`cases-
`In the first case:
`
`L :=- flit: ; °-75*’
`vikx
`Jky
`ti:
`
`where k_, is the permeability in direction y, then:
`
`SR = Ping + Pxy
`
`Pw=(%-)
`llnrw+0.25lnkz
`
`h
`
`k_,_
`
`.
`
`ln(s1n
`
`180°.-_» _
`
`h
`
`)
`
`1.84]
`
`P»=::”lf;[F(;:)+
`lF(iJ*-*2—*:i)+(e’r%L)ll
`
`where F denotes a function.
`
`Pressure computations are made at mid-point along
`the well length, y,m«d=(_y]+y2)/2. The values of
`-‘(L/26), Fl(4ymn+L)/lb] and Fl(4ym-rfilflbl in the
`above equations are computed by replacing y with the
`appropriate arguments in:
`
`F(y)= ~(y)[0.l45-+ iny -0.l37y2]
`_i
`_4y ..a,iL
`’’"2:;
`°'' y‘ W23;
`
`5
`
`F0’) :{2 -y)[0.l45 +lI1(2 -y)— O.l37(2 -y)]
`y=4.Vg;:'d1'L 2
`2b
`
`In the second case:
`
`b
`---—‘C
`Viv};
`
`l.33a
`
`VIC};
`
`h
`:F‘'*.——‘*
`Ykz
`
`187
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`Exhibit 2014
`IPR2016-01517
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`5 of 25
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`
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`.'_III I NEW DEVELOPMENTS: ENERGY. TRANS?0flT, SUSTAINABILITY
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`NEW UPSTREAM TECHNOLOGIES
`
`This gives:
`
`SR = F.ijr.,'+ + Pry
`
`-5235’ LE
`P*-‘"
`as
`it
`iis b+b2 +
`
`1'
`
`».a=<::
`
`'l(°'i3“li‘Ell;+:"+:§l
`
`Pm will have the same form as given earlier.
`above.
`
`Another set of equations are those derived by Joshi
`(1988). For the case of an isotropic formation
`(kx=k,,=k;=)'c} (Fig. 2), the equation for flow is given
`by:
`'
`
`2:rtkhAp
`I
`
`2_
`
`.2 l
`
`at -2i l:0.5 + 0.25 +(
`
`2,.m_)4]o.s
`
`L
`
`wiell
`
`L 2 0.25
`
`where Ap is the pressure drop and 20: is the large axis
`of the horizontal drainage ellipse around a horizontal
`well (see again Fig. 2), and rm is the equivalent radius
`of a presumed circular drainage area.
`For the case of anisotropic fonnations, where
`horizontal permeability is not equal to vertical
`permeability, (kh-séky}. the solution developed by Joshi
`and modified by Econotnides er at’. (1991) gives:
`
`q:
`
`Zrrkflhifltp
`
`or + gal -(L/2)’
`
`fifi
`
`;.¢B[In{-——-in + L in rw“ +
`
`pa
`
`i
`
`These equations indicate the main applicationstuf
`horizontal holes and the conditions under which
`'
`provide the best production results. Consider a
`horizontal hole with an ellipsoidal drainage radius of---
`5.000 ft (around 1,500 m). Suppose the intent is to
`drill a horizontal hole with a radius of 0.4 it (12.2 cm '
`We will assume four different formation thicknesses '.
`150, I00. 50 and 25 ii. or46, 30. I5 and 7.5 rn) and
`three different hole lengths (2,000. 1,000. and 500 it, I
`or. 610. 305 and I52 m). We further assume ten
`different values of Ir,/ks (0.5 through 10). For each
`case we will compute the ratio of well production to
`that ofa similar well in a uniform permeability
`formation. The results are shown in Fig. 3. The data
`show the following important points:
`- Thinner fon-nations yield better production resul .-
`R
`relativc to a vertical well.
`0 The impact of formation penneability anisotJ'opjr_"‘
`more prominent in thick formations. This effect is
`often masked by the higher productivity of thickerf
`formations.
`
`-
`
`-
`
`Effect ofpermeability anisotropy increases as "i;
`length increases.
`in thick formations, behaviour of short horizontal
`well lengths is about the same as a vertical weli.
`- Horizontal holes can create spectacular results in‘.
`wells with high effective vertical permeability,
`such as some of the naturally fractured reservoizis
`of the Middle East.
`The above analysis shows that horizontal holes
`not offer a panacea for every production scenario.
`Their effectiveness diminishes in thick. highly
`laminated and heterogeneous formations.
`From the above reported .loshi‘s equations. if
`Libel and L/Zaé 1, then:
`
`_
`
`Znkhrisp
`ti = Tr’fl
`pBh:1
`L/4
`
`k
`is = e“
`to
`
`This is the same as the expected flow from an
`infinitely conductive vertical fracture. This simple
`observation was one of the reasons for slow initial
`
`26 is the minor axis of the ellipse represented
`in Fig. 2.
`
`acceptance of horizontal holes. The argument used
`that since one can get the same effective productiott
`
`Fig. 2. Flow geometry
`in a horizontal hole.
`
`'1 --90¢-
`
`A
`
`
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`188
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`ENCYCLOPAEDIA or moat"
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`6 of 25
`
`Exhibit 2014
`IPR2016-01517
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`

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`
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`UPSTREAM TECHNOLOGIES. NOVEL WELL AND PRODUCTION ARCHITECTURE
`
`
`
`' 3. Elfect oft,/k,v
`on horizontal
`
`production.
`
`L4
`
`L0-
`
`I
`
`F7‘ X
`
`953asml.I
`
`Pto
`
`C1 34.:
`
`
`
`productionratio
`
`
`
`kit-fkv
`
`
`
`.'i' "m a less expensive vertical well with a long
`draulic fracture, there was no compelling reason to
`a horizontal hole with all of its associated
`
`-L a plications. higher costs. and tower operational
`.~ 'bilities. With time and experience the industry has
`) ed the short-comings of the above argument.
`it ulic fractures seldom deliver the theoretical
`
`'
`
`uction levels {simply because of the difference
`een theoretical and actual Fracture behaviours;
`
`eshy, 2003).
`
`r and gas coning in horizontal holes
`The produced fluid from many oil and gas
`oirs is a mixture of water together with oil and
`The volume of produced water increases with
`oir age. In addition to the eonnate water present
`"'.‘th oil and gas. water can come from three other
`"
`es: bottom-water (through coningjl, edge-water,
`injected water {through high conductivity channels).
`'ng, processing, and disposing of the produced
`It t require large operational and capital expenses.
`= -addition. many reservoirs use water flooding as a
`‘in for maintaining reservoir pressure as well for
`-
`ing the oil out of the formation. Thus, it is
`'ous that delaying and reducing the production of
`ter will add to reservoir value. One of the observed
`
`efits of the initial horizontal holes was the delayed
`'.. - I uction of coning water (Giger er al'., 1984).
`Many oil reservoirs include large volumes of gas
`are usually trapped above the oil zone. With
`uction, because of its lower density and viscosity,
`in s gas can cone through the oil zone and flow out of
`51: e reservoir. The negative effect of gas production is
`
`that it decreases the reservoir energy available for oil
`production. Thus, delayed gas production is also
`beneficial for reservoir economics.
`
`Joshi { 1988) offers the following equation for
`computation of the maximum gas-fi'ee oil production:
`
`qmsu _
`
`l-535(9a \9g)k[h2 ‘VF ‘ 1.31]
`ln(r,_./rw}
`
`where qm, is the ntaxirnurn gas fi'ee oil production rate:
`99 is the oil density, g/cm3,' 9g is the gas density. g/cm3;
`2,. is the distance between the gasfoil interface and
`perforation top; r‘, is the reservoir drainage radius, ii.
`To use this equation for horizontal holes, one needs
`to substitute rm. (effective wellbore radius) for r,,.:
`
`I‘
`we_ re
`
`L
`” up + .-'a2— (L/2}=][i/2r,,.]M
`
`where the expressions for 0: and r,” are as given
`earlier.
`
`The expression for maximum water-free oil
`production rate, qr, is given by Giger etat’. (1984) in
`the form:
`
`IrAp at
`=1.53-10-3——
`#5
`L
`
`qt‘
`
`A more rigourous solution to determination of
`critical cresting rate (see below) for horizontal holes is
`provided by Guo and Lee (1992).
`
`Horizontal hale operational challenges
`Together with all of its benefits. the drilling and
`completion of a horizontal hole poses operational
`challenges that must be overcome for its successful
`
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`Ill! NEW DEVELOPMENTS: ENERGY. TRANSPORT. SUSTAINABILITY
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`7 of 25
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`NEW UPSTREAM TECHNOLOGIES
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`implementation. Among these complications is the
`hole navigation. The production outcome of a
`horizontal hole depends greatly on the location of
`the hole relative to the forrnation. For example.
`delaying water production requires placing the
`horizontal bole close to the top of the reservoir.
`Without water or gas, best production results come
`from a hole which is at the centre of the reservoir.
`
`Given the complex geology and structure of most
`reservoir forrnations. placing the well at the desired
`part of the formation can become a daunting task.
`Consider the structure shown in Fig. at A. A straight
`horizontal hole in this formation will intersect the
`
`water zone and lose most of its advantages. The
`success of the horizontal hole depends on the ability
`to steer the well properly within the reservoir. For
`example. the case shown in Fig. 4 B satisfies the
`requirement for distance from the oilfwater contact.
`but it could face operational problems due to hole
`curvature and the possibility of debris collection at
`the bottom of the well, thus impeding flow of
`reservoir fluid. A shorter and better placed hole can
`offer better production results, as shown in Fig. 4 C.
`Obviously the challenge here goes beyond planning
`and drilling operations. It mandates superior
`reservoir mapping and characterization.
`At the present time, most horizontal holes are
`completed operihole. The main reasons for this
`choice are:
`- The main benefit of horizontal holes comes from
`
`their long contact with the permeable reservoir.
`Casing and perforating these holes reduces this
`contact. However, whenever completion operations
`require hydraulic fracturing, the horizontal holes
`are in fact cased, cemented, and perforated to
`facilitate effective fracturing.
`- Contrary to initial fears, in many formations hole
`stability has not been a big problem- This is
`specially true in those areas where the rnaxirnum in
`sin: principal stress is horizontal. Concerns about
`hole stability have sometimes been addressed by
`placing slotted or perforated liners inside the
`horizontal section.
`
`Side-tracking off of an existing well and drilling a
`branch well has long been an established practice of‘
`the oil and gas industry. In the past. the use of this
`technique was limited to problem wells where
`continuation of the existing well path was either
`impossible or very costly. The process consisted of
`placing a high strength cement or mechanical plug
`inside the well to divert the bit into a new path. But
`doing this left the original hole plugged and
`inaccessible for future production or operations.
`With the feasibility and benefits of horizontal
`wells verified by actual applications, industry
`innovators quickly considered extension of the
`process for more robust production schemes. Sev '
`groups. mostly in the North Sea. began planning for
`completion architectures involving production From"
`multiple horizontal holes connected to a mother
`bore. Among these were groups such as Maerslc,
`BEB, Norsk Hydro, BP, and service companies
`as Halliburton and Baker. Although the side-tt'acldrt'
`technology was mature and well-established, new
`technologies were needed to allow the selective
`re-entry of various laterals, as well as commingled
`production from them.
`The technology for side-tracking and drilling
`of existing wells had been in existence for many
`years. Almost all of these side-tracked wells were
`mandated by drilling problems that made
`continuation of the existing bore either impossible on :
`very costly. But in all these applications, the original
`
`I
`
`_
`
`'
`
`'
`
`-
`
`.
`
`.
`
`-
`
`Since drilling a horizontal hole costs more and
`takes longer, part of the added cost is offset by
`openhole completions.
`- Cemented completion of horizontal holes is still
`uncharted territory for many operators and
`therefore preference is given to alternative
`completions.
`More discussion of horizontal hole completions .-
`presented later in this chapter.
`V"
`
`3.1.3 Multilateral wells
`
`‘
`
`.
`
`
`
`
`
`l‘i.»ri.-._mt:t|
`
`ln:|-._-
`
`Fig. 4. Different hole layouts in a horizontal hole: A, undesirable orientation with respect to oilfwater contact:
`B. hole tracking oil/water contact; C. the same as B, but with a shorter and better placed hole.
`
`I90
`
`ENCYCLOPAEDIA or Hroflli
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`Exhibit 2014
`
`IPR2016-01517
`8 of 25
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`

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`
`
`'
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`-«
`
`;and hydraulic isolation was necessary to
`-
`.
`t: d internal resewoir pressure during
`___..._uct1'on from the laterals.
`Access. Full utilization of the system required
`"rive access to each of the laterals at any given
`This feature was necessary to perform the
`us well services during the wells life.
`These three requirements, connectivity,
`,
`‘on, and access {abbreviated by their
`
`' ynls CIA) became the standard reference for
`‘lateral definitions until it was replaced later
`number system.
`The first comprehensive plan for installation of a
`l ateral well was prepared by a joint team
`.
`'sed of Mobil Germany and I-lalliburton
`-
`. t Research Centre. The target was the deep
`e
`fields in Soelingen. Germany. The main intent was
`ce the overall drilling costs of the deep High
`I , High Temperature ("I-{Pl-KT] wells in this field,
`_'e increasing well productivity by selective
`fulic Fracturing of the laterals when required for
`I h productivity. This plan was approved for
`_ g by the European Commun.ity under the
`' ‘e project. However, the complex nature of the
`' deep HPHT operations) caused this plan to be
`an by plans to drill the multilateral off ofa well
`Forties field offshore UK. operated by BP. In this
`I
`I target the intent was access and production of
`-passed by water flooding operations. This
`Tlateral was later successfully executed in [996
`(la er al.. 1996}.
`- The first actual installation of a multilateral well
`
`"
`
`successfully completed through collaborative
`'ng, development and operations by Norsk Hydro
`' Halliburton in well Oscberg 12C in the central
`- Sea in April 1996 (Jones er a1., 1997). More
`u ation about the details and features of this
`
`is presented later in this Chapter.
`
`'-“I'll! NEW DRIELOFMENTS: messy, TRANSPORT. SUSTAINABILITY
`
`UPSTREAM TECHNOLOGIES. NOVEL WELL AND PRODUCTION ARCHITECTURE
`
`was abandoned and replaced by the side-tracked
`ch. In the new drilling model, the desire was to
`'onally drill a second well. re-establish contact
`. the mother bore. and continue production from
`. (or multiple) branches. It was quickly
`ized that the success of such completions
`cled on satisfying the following criteria:
`-(','artrtectr'vl’r_t-'. This meant the lateral is connected
`main well such that standard oilfield tools
`
`be deployed within the entire wellbore system
`perforrning conventional well services.
`_,.'§galari'o:i. The junction needed to be
`' ulically and mechanically isolated from the
`‘on. This feature was required to satisfy two
`mm system needs: mechanical integrity of the
`on was needed to satisfy North Sea
`tions to withstand external formation
`
`Classification of multilateral wells
`Classification ofrnultilateral wells is based on
`
`the properties and capabilities of the junction. The
`various levels of multilaterals are described below:
`
`Level I. This is the simplest type of multilateral.
`The two bores are open above the junction which
`otters no mechanical or hydraulic strength or
`isolation (Fig. 5 A). This type ofjunction may be
`suitable for applications where the junction is within
`the pay zone. However. the system does not offer
`any options for flow control. nor is the well suitable
`for re-entry for remedial work.
`Level 2. In this type of multilateral. the main
`bore is cased and cemented, but the lateral is
`openhole (Fig. 5 B}. The lateral may include an
`uncemented, slotted or perforated liner for
`mechanical protection. The advantage of this type of
`junction is that it allows re-entry into the main bore.
`as well as installation of flow control devices. This
`
`system is common in applications where all the
`junctions and laterals are within the pay zone. Its
`main disadvantage is poor access to laterals in case
`there is need for re-entry and service work.
`Level 3. In this system. the main bore and lateral
`are both cased. but only the main bore is cemented
`(Fig. 5 C). The lateral casing may be attached to the
`main casing through a liner hanger. This type of
`junction provides access to the lateral in case there is
`need for it.
`
`The main advantage of the next three levels of
`multilaterals is that they allow placement of the
`junction outside the pay zone.
`Level 4. In this system, both main bore and
`laterals are cased and cemented, and this provides
`flow isolation within the well system (Fig. 5 D).
`However, the junction may not have sufficient
`mechanical strength. This type of multilateral may
`be suitable for cases where the-junction is placed
`within a strong and competent formation.
`Level 5. in this system. also known as a
`downhole splitter, the junction is mechanically
`isolated from the flow conduit (Fig. 5 E}. Both main
`bore and laterals are cased and cemented. This
`
`system is suitable for high pressure andfor high
`temperature applications. It also allows selective
`reentry into the main bore and laterals for remedial
`service work. However, installation of dual flow
`lines requires larger size main hole. which adds to
`the drilling cost.
`Level’ 6. In this system, the two strings of easing
`are mechanically connected together at the junction
`such that the connection itself provides pressure
`isolation as well as mechanical strength (Fig. 5 F).
`One option for the construction of‘ such systems may
`be the use of expandable pre-fabricated junctions.
`
`9 of 25
`
`191
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`Exhibit 2014
`IPR2016-01517
`
`

`
`
`
`junctions.
`
`NEW UPSTREAM TECHNOLOGIES
`
`Levels 2 and 3 may not be suitable when there is
`possibility of sand or solid production. Having a
`borehole support device provides a means for re-entry
`if this becomes necessary.
`When there is possibility of solids production, a
`level 4 cemented junction offers a barrier to solid
`production and may be a better choice. The full ID
`(Inside Diameter) access through the intersection
`provides additional operational flexibility. such as
`deploying tools below thejunction. It is suitable for
`high rate injection or production wells. It can also
`allow use of large IDJOD (Outside Diameter) isolation
`andfor completion equipment for high rate stimulation.
`Level 4 laterals can also be upgraded to a level 5
`junction by placing a seal—bore packer or PBR
`{Polished Bore Receptacle) in the lateral.
`A level 6 junction can also be installed in a level 4
`lateral by using a PBR or seal-bore packer in the
`lateral below the window.
`
`Junction construction
`
`Construction of the junction is one of the most
`critical parts of multilateral well construction. As the
`requirements of the junction increase, so do the
`difficulties and costs associated with its construction.
`Several critical considerations are involved in selection
`
`of the location and properties of the junction in
`multilateral wells. including the following.
`Junction location. The location of the junction is
`often dictated by the drilling and production
`requirements. Ideally it should be placed in a
`competent rock and located so as to minimize the
`drilling costs and difficulties while enabling maximum
`access and penetration into the reservoir. In the initial
`
`Fig. 5. Level I to 6
`{A to F) multilateral
`
`applications of multilateral wells, the junction was
`located in the slanted part of the well above the pay
`zone. Whenever the reservoir formation is a compete
`rock, drilling advancements have made it possible
`,
`easily place the junction in the horizontal section oft.
`the well and within the pay zone itself. This ability ' _,
`locate the junction substantially simplifies the jun -
`requirements for hydraulic isolation. But when the ’i'''
`zone is not mechanically competent to maintain
`junction stability during the well life. the junction
`must be placed somewhere else. In such applicationgl
`one needs to consider building a more complex
`_
`junction, preferably a level 5 or 6 type ofjunction.
`'_
`JIJHCHOH orientation. Afier selecting the location
`the junction. the next question is orientation of the
`junction with respect to the main bore: above. below
`to the sides. Advancements in directional drilling
`I
`provide flexibility to reorient the lateral from any
`direction into any other direction to fit the junction -'
`production requirements. However, the mechanical
`stability of the junction depends on its orientation » ' ny-
`respect to the magnitudes and orientations of the '
`‘ '
`principal stresses. In an experimental and numerical
`
`study of this problem, Papanastasiou er at‘. (2002)
`that the most stable direction for the lateral is V :
`
`'
`
`with the maximum in sin: stress. They also found
`as expected failure occurs initially in the inte -
`' -
`‘
`area between the two wells and spreads outward.
`in Sim stresses were not equal ( which is usually the
`case), junction failure preceded wellbore failure.
`
`_
`
`.'
`
`Case history: first high level multilateral well
`As mentioned earlier, the first advanced
`multilateral well was drilled in 1993 and was the
`
`‘
`
`,
`
`1
`
`ENCYCLOPJAEDIA OF H -H
`
`10 of 25
`
`Exhibit 2014
`IPR2016-01517
`
`

`
`
`
`of collaboration between Norslt Hydro and
`"burton. Development of the hollow whipstock
`. 1; was critical to the implementation of this
`)was led by Weatherford. The target well was
`berg 12C in Oseberg C platform. which was
`cted for production of Oseberg Field in the
`I North Sea, with recoverable reserves of l .6
`
`m s of barrels. Oseberg C is a fully integrated
`-. that produces through horizontal holes.
`-, formation is a medium to coarse grained
`gone in the Middle Jurassic Brent group (Jones
`1997). in addition to the main pr