6iB6i
`
`Society of Petrdewt Engineers
`
`m
`
`SPE 37354
`
`A Case Study for Drilling
`
`and Completing a Horizontal Well
`
`in the Clinton Sandstone
`
`SPE, Belden & Blake Corporation,
`Leo A, Schrider,
`William F. Murray Jr,, SPE, Belden & Blake Corporation,
`Raymond L. Mazza, SPE, Petroleum Consulting
`Services, Albert B. Yost 11,SPE, U.S. DOE
`
`Th!s parer was prepared for Presentation at the 19S6 SPE Eastern Regonal Madmg held
`in Columbus, Ohio, 23-25 Octob8r 19S6
`
`Thw paper was selected for presentat i~ by an SPE Program Comm dtee folbwing rewaw
`of Information c.ontamed in an abstract subm lnad by tha author(s) Contents of the paper,
`as presented have not bean rmwwed by the SOCiety of Petroleum Engtnews and are
`subjected to Cxi’racfion by the author(s) The material, as presented, does not neceaaarlly
`reflect any poslbon of the Scualy of Petroleum Engmears,
`Its offcars, or members
`Papers presented at SPE meetr&s
`are stkpct
`to pubhcabcm rewaw by Eddcmal
`Comm ittaas of the Soc#ety of Petroleum Engineers
`Electronw reproducuon, dwlnbuhon,
`or storage of any paff of thts paper for CQrnmercm puqoaes wdhout the written consent of
`Ihe Soc&tY of Petroleum Ewmeers
`IS prohlbted.
`Pernusslon to reproduce m print IS
`restrtied k! an abstmd of not more than 300 words, dlustrahons may not be cop[ed The
`abstract must conta<n conspicuous acknowledgment of where and by whom the papm
`was presented W’nte Llbrarlan, SPE, P O Box 833838, Richardson, TX 75083-3836
`U S A,
`fax 01-214-952-9435
`
`Abstract
`Horizontal well drilling for the recovery of natural gas and
`oil has been touted as the panacea for optimum recovery
`from hydrocarbon
`reservoirs.
`This technology
`has been
`applied to reservoirs
`throughout
`the world, primarily
`in
`environments
`such as the North Sea off the coast of Great
`Britain and the Austinchalk
`in Southeastern Texas,
`To
`date,
`very
`few wells
`have
`been
`attempted
`in
`the
`Appalachian
`Basin,
`To test
`this
`technology
`in the
`Appalachian Basin, a joint effort between Belden & Blake
`Corporation
`and
`the U.S. DOE resulted
`in the
`first
`horizontal well successfully
`drilled and stimulated
`in the
`Silurian Clinton Sand formation,
`The Central Waste #14
`well (CW #14),
`is located in Smith Township, Mahoning
`County, Ohio, which is one of the better
`remaining areas
`for Clinton Sand developmental
`drilling, The CW #14 was
`spudded in October
`1993 and drilled to a total measured
`depth of 6,505 feet at a maximum inclination of nearly 92
`degrees
`from vertical with approximately
`1,320 feet of
`Clinton interval exposed.
`Total Clinton interval
`footage
`greater
`than 85 degrees was about
`1,142 feet.
`Three
`hydraulic
`fracturing
`stages were
`successfully
`completed
`within the horizontal wellbore.
`Since this was the first
`horizontal well
`drilled
`in the Clinton
`Sand
`interval,
`considerable
`knowledge
`and experience was gained
`in
`
`The actual drilling
`this well.
`and completing
`drilling
`operation required about 45 days of rig time. The well was
`stimulated during the summer/fall
`of 1994 and placed on
`production in early 1995.
`The CW #14 was equipped with a pumping unit and
`downhole pump and has produced approximately
`20,000
`MCF of natural gas and 7,000 barrels of oil in its first full
`year of production. Unlike similar wells drilled in this area,
`the oil production is about twice that expected while the gas
`production
`is less than half of
`the neighboring
`offsets.
`Based on the production
`performance
`to date which has
`displayed a much shallower gas decline rate than a vertical
`well in the area,
`the CW #14 is currently estimated to have
`an ultimate recovery in the range of 330 to 400 MMCFE
`which is approximately
`1.6 to 2.0 times its vertical offset
`wells.
`
`While we are encouraged with the 1,6 to 2.0 increase
`in estimated ultimate recovery, horizontal drilling does not
`appear
`to be a viable economic
`alternative
`for primary
`development
`in this area without
`further
`improvements
`in
`reserve potential along with significant cost reductions. At
`this time, drilling this type well may be limited to special
`applications
`for secondary
`or enhanced
`oil
`recovery
`or
`perhaps
`for natural gas storage.
`The CW #14 horizontal
`drillng project, however, successfully demonstrated that the
`extremely
`hard
`and
`abrasive
`Clinton
`Sand
`can
`be
`horizontally drilled and stimulated which we considered a
`major technical accomplishment
`for drilling a well of this
`type in the Appalachian Basin.
`
`Introduction
`in
`reservoir
`gas
`The Clinton Sand is a low permeable
`Northeastern Ohio with initial well production generally in
`the 75 to 150 MCF per day and 5 to 10 barrels of oil per
`day.
`Ultimate production
`from a vertical well
`in the
`Clinton formation in Smith Township, Mahoning County is
`projected to be
`about 205 million
`cubic
`feet of
`gas
`
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`2
`
`W.M. MURRAY,
`
`LA. SCHRIDER, R.L. MAZZA, A.B. YOST II
`
`SPE 37354
`
`from the surrounding wells.
`equivalent based on production
`Future drilling to the Clinton Sand reservoir maybe
`restricted
`since many of the potential
`locations will require some form
`of directional drilling. Most of the easy, accessible
`surface
`locations
`have
`already
`been developed,
`therefore,
`leaving
`those
`areas
`that are adjacent
`to towns or under
`lakes or
`streams, or
`in the case of the Central Waste area,
`located
`beneath a surface landfill area. The ability to penetrate this
`resource along with improving ultimate gas recovery requires
`the development
`and successful
`application of practices
`such
`as horizontal drilling.
`This report represents a detailed account of events of
`field work
`and
`supporting
`activities
`associated with
`all
`drilling,
`completing,
`testing and stimulating
`the Belden &
`Blake/DOE horizontal Clinton Sand well, CW #14.
`The
`report
`is intended to provide information along with dialog as
`to report on those activities and tasks that worked well and
`those that did not. The intent of the report
`is also to point out
`those areas which will need improvement
`if horizontal drilling
`is to be applied on a more regular basis to low permeable tight
`sandstones
`as
`represented
`by this Appalachian
`reservoir,
`recognizing that
`this is the first horizontal drilling test ever
`completed in the Clinton Sand in Ohio.
`
`Site Selection
`The primary
`this horizontal
`for
`site selection
`for
`criteria
`reserve quality and consistency.
`The
`drilling project was
`Smith Township, Mahoning County area of Ohio was one of
`the best
`remaining areas for Clinton Sand development
`that
`Belden & Blake had in its acreage inventory. As ~
`represents,
`the
`identified
`project
`area
`indicates Clinton
`reserves
`in excess of 200 MMCFE which is considered very
`good for the Clinton formation.
`In addition to quality and
`consistent
`reserves,
`pay thickness
`in the project
`area was
`approximately
`70 feet
`thick as shown in ~.
`This
`Clinton pay interval would provide
`a sizable target versus
`other Clinton areas with pay zone thicknesses
`in the 5 to 10
`foot range making it more difficult
`to drill
`in the horizontal
`direction.
`
`is
`interval, which
`Sand
`anticipated Clinton
`The
`is
`comprised of three members:
`the Stray, Red, and White,
`illustrated in m.
`. Since the Red Member
`is believed to
`have the highest gas saturation,
`the planned lateral was to be
`contained in the Red. The path of the wellbore was planned to
`be drilled on an magnetic azimuth of 156 degrees. A variance
`was obtained by Belden & Blake with an offset producer west
`of the drilling unit to allow a lesser distance from their lease
`boundary normally required by Ohio State law.
`
`Background Information
`from several
`An integrated
`drilling
`plan was developed
`including a
`separate but
`interrelated
`sources of information
`GRI sponsored
`vertical
`test well
`(CW #l 2 - GRI Topical
`Report
`- CER Corporation Contract No. 5091-212-2242).
`
`stress testing, oriented
`openhole
`included:
`This information
`of the target
`formation
`coring, and geophysical monitoring
`and the surrounding
`strata with small
`injection tests
`(mini
`fiats)
`to determine
`the
`elastic
`rock
`properties
`through
`real-time borehole deformation measurements
`of the Clinton
`and surrounding strata. These were used in conjunction with
`an array of
`tilt meters
`to determine
`the orientation
`of the
`principal
`stresses.
`This
`information was incorporated with
`thin-section
`geologic
`interpretations
`to project
`the most
`advantageous
`drill path orientation.
`The objective was to
`determine
`the potentially largest opportunity
`for intersecting
`the target
`interval
`in a location and at an orientation which
`provided the greatest exploitation advantage.
`A nearby high angle well (CW #7) drilled by Belden
`& Blake in 1989 was prematurely terminated because of hole
`problems.
`The limited in-target
`footage was not effectively
`stimulated and had disappointing
`production.
`It was drilled
`with polymer mud and attained
`a terminal
`angle of 70.5
`degrees and penetrated only 200 feet of the Clinton interval
`prior to serious hole deterioration problems.
`Because of this
`experience,
`it was decided to employ an intermediate
`casing
`string in future wells
`to eliminate
`potential
`hole problems
`above
`the Clinton and thereby
`allow maximum focus on
`drilling the target formation.
`and
`In an effort
`to improve on this prior experience
`to incorporate
`additional geophysical
`analytical
`techniques,
`a
`drilling plan was developed which incorporated
`this prior
`experience
`in addition to the information
`derived from the
`geophysical
`testing and analysis.
`
`Drilling Plan Summary
`of a well plan included decisions
`The development
`intermediate
`casing, hole cleaning,
`to build rates,
`relative
`hydraulic pressure and volume requirements
`for both mud and
`air
`in the
`angle
`building
`and horizontal
`hole
`segments,
`measurement while drilling (MWD)
`survey capabilities
`for
`tools both in air and in mud mediums,
`and for downhole
`motor availability and power outputs with both air and mud.
`The plan incorporated
`a number of these decisions
`and also resulted in the selection of the primary and secondary
`service
`companies,
`The
`selection
`criteria
`requirements
`eliminated some service companies because of equipment and
`organizational
`limitations
`and
`unfamiliarity
`with
`the
`application
`of their equipment
`in air drilled environments.
`One major
`service
`company
`related
`an unwillingness
`to
`participate in air drilling projects.
`interval with
`The design included drilling the target
`air as a circulating medium to minimize
`formation damage.
`The drilling
`procedure was
`to include
`a combination
`of
`downhole motors and rotary bottom hole assemblies within
`the target
`interval.
`The design also included an 8-5/8 inch intermediate
`casing string installed in the Stray Clinton. The purpose of the
`intermediate
`casing was to eliminate
`the uphole
`formation
`
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`

`SPE 37354
`
`A CASE STUDY FOR DRILLING AND COMPLETING A HORIZONTAL WELL IN THE CLINTON SANDSTONE
`
`3
`
`encountered while drilling the high-angle CW #7
`problems
`offset well. The design inclination angle at the intermediate
`casing point was 70 degrees. The angle building hole segment
`between the kick off depth and the intermediate
`casing point
`was drilled with mud as a circulating medium. This decision
`was predicated on:
`
`a. Higher degree of survey confidence resulting from
`the increased quantity of information provided by a mud pulse
`MWD,
`resulting in a smoother continuous path to minimize
`drag.
`
`b. The additional cost of the air volume required to
`clean the larger diameter hole.
`to describe and define
`A prognosis was developed
`the drilling parameters and options for drilling horizontally in
`the Clinton Sandstone. The objective being to drill 1,977 feet
`horizontally within
`the Clinton
`geologic
`package, which
`includes
`the Red and subjacent White Clinton formations.
`The local dip is 89.8 degrees and the prognosis was developed
`to obtain tangency in the Red Clinton 34 feet above its base
`and to maintain an azimuth of 156.5 degrees.
`The final selection resulted in the choice of a primary
`service company which offered an integrated
`organization
`which could provide
`the engineering
`design
`and support,
`downhole motors, and MWD hardware for both air and mud
`drilling.
`
`8)
`
`9)
`
`10)
`
`Drill 7-7/8 inch hole with 6-1 /2 inch air motor at a
`build rate of 7.88 degrees per 100 feet maintaining
`156.5 degree magnetic azimuth. Build to a terminal
`angle of 89.8 degrees approximately
`34 vertical
`feet
`into
`the Red Clinton
`formation
`(Red Clinton
`approximately 66 feet thick).
`Attempt
`to hold 89.8 degrees and drill approximately
`1,900 feet staying in the Red Clinton interval.
`Run 4-1/2 inch 11.6 lb/foot M-75 casing to TD with
`spaced to achieve 70 percent
`turbulator
`centralizers
`standoff. Cement with approximately
`560 sacks of
`50/50 Pozmix with 10 percent
`salt and .6 percent
`Halad 344 to provide estimated cement
`top to 4,900
`feet.
`
`Drilling Operations
`
`Drilling Rig and Support Equipment.
`Driiiing Rig. A Wilson Mogul 42 trailer rig with two
`(2) Caterpillar D343 diesel engines with a Wilson 102-300
`mast was selected for the project. There was initial concern
`over maximum hook load requirements
`if hole problems and
`the associated drag were encountered.
`This proved to be a
`worthwhile concern because the full rated load was required to
`remove the drill string as the hole was approaching
`its final
`TD.
`Actually,
`hole degradation was one of
`the primary
`reasons
`that
`the
`drilling was
`discontinued.
`The
`hole
`degradation is probably directly related to the water and soap
`added at the insistence of the service company in the three (3)
`unsuccessful
`attempts
`to start
`their air motors.
`If this liquid
`had not been added,
`it is likely that
`the hole degradation and
`excessive
`drag would
`have
`been
`less
`severe
`enabling
`additional
`footage in the lateral
`to be obtained. Without
`the
`ability to pull 300,000 pounds
`(8 lines),
`the hole may have
`been lost with an expensive
`drill string in it, The crown
`sheave was 102 feet above ground level and the racking board
`was positioned 47 feet above the drill
`floor. The drill floor
`was fitted with a Gardner Denver RT 17-1/2 inch rotary table
`with a 150 ton load capacity, at 100 RPM.
`The substructure
`rating and set back capacity were
`unspecified by the dri Iling contractor
`and were adequate for
`the drilling operations
`as bid. There was a design problem
`that was unanticipated
`and did cause some additional
`cost,
`primarily in additional welding time. The substructure height
`was shorter
`than is generally encountered.
`It was 8,5 feet
`from ground level
`to the kelly bushing
`and the clearance
`between the top of the intermediate casing and the rotary table
`was minimal.
`Fortunately,
`the conductor and surface casings
`were set close to ground level. This situation is mentioned
`because it could have created a significant problem and future
`planning
`for wells with intermediate
`casing strings
`should
`require a minimum ground level to kelly bushing height of 10
`feet.
`
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`3)
`
`4)
`
`5)
`
`The service company support and recommendations
`an integral
`component
`of
`the well
`design
`and
`became
`incorporated,
`at that time, what were believed to be moderate
`but not maximum build rates (8.8 1 & 7.88 degrees/100 feet),
`and MWD hardware
`suitable
`for both mud and air drilling
`scenarios.
`The following is a more specific summary of the
`drilling plan:
`1)
`Drive 60 feet of 16 inch conductor pipe.
`2)
`Drill 14-3/4 inch hole to 730 feet
`(through Berea
`Sandstone)
`and set and cement 710 feet of
`I I-3/4
`inch surface casing.
`Drill 11 inch hole to kickoff depth of 4,373 feet
`taking single shots every 500 feet.
`Run continuous directional
`log to confirm
`bottomhole position.
`Kickoff and drill 11 inch hole on brine with 8 inch
`motor.
`Build angle at 8.8 degrees per 100 feet at
`magnetic
`azimuth
`156.5 degrees
`to top of Stray
`Clinton
`(MD-5 170
`TVD-4985)
`with
`a
`final
`inclination of 70 degrees.
`inch
`8-5/8
`of
`feet
`Set
`approximately
`5,170
`intermediate
`casing (24 lb/foot J-55 from O to 2,000
`feet and 32 lb/foot J-55 from 2,000 to 5,170 feet).
`Cement with 255 sacks Class A with estimated
`cement
`top to 4,100 feet.
`Blow hole dry and drill maximum of 30 feet to dust
`hole.
`
`6)
`
`7)
`
`

`

`4
`
`W.M. MURRAY , L.A. SCHRIDER, R,L. MAZZA, A.B. YOST II
`
`SPE 37354
`
`Drill Pipe, The drill pipe was 4-l/2 inch internally
`plastic coated 16.60 lb/foot Grade G and 60 joints of Hevi
`Wate (trademark) drill pipe were used in the lower portion of
`the build segment
`and in the first portion
`of
`the lateral
`segments while
`approaching
`the final TD. No drill pipe
`failures or limitations were experienced.
`Mud Pumps.
`The rig was furnished with two (2)
`mud pumps, each capable of providing sufficient
`flow rates to
`permit powering the downhole motors and cleaning the hole
`without assistance.
`This requirement
`proved to be important
`because the drilling was continued during periods when the
`primary pump as its prime mover were being repaired.
`The
`primary pump was an EMSCO F1OOO(1O inch stroke) with
`6.5 inch liners (wp = 1558 psi) powered
`by a Caterpillar
`D398T diesel
`rated at 825 continuous
`horsepower
`at 1200
`RPM.
`It was later determined that the engine was capable of
`approximately
`775 horsepower
`because of a limitation in the
`diesel
`injector
`rack. The pump was typically operated at 495
`gallons per minute at a stand pipe pressure of 2200 psi. The
`standby pump was a Gardner Denver FXN (14 inch stroke)
`with 5.5 inch liners (wp = 1800 psi) powered by a 12V71
`Detroit Diesel
`rated at 350 continuous
`horsepower
`at 1800
`RPM.
`It was capable of delivering
`a reduced flow, 370
`gallons per minute at 700 psi.
`air
`The
`Air Compressors
`/ Air Measurement.
`compressors were specifically
`selected to provide excess air
`capacity because of the dependence on having a sufficient air
`volume to power
`the positive displacement downhole motors,
`which are known for their inefficiencies,
`to clean the hole, and
`the derating required
`for air packages
`supplied by drilling
`contractors.
`These units were rented at a premium cost from
`an air rental company.
`Three (3) screw type compressors
`were rented. Each was rated at 1200 CFM of oil free air at
`290 psi. Each of the three (3) screw compressors
`and the
`reciprocating
`booster
`compressor was powered by a 8V7 I
`Detroit Diesel
`rated at 233 continuous
`horsepower
`at 1800
`RPM.
`These were
`installed
`upstream of a reciprocating
`booster compressor,
`Joy WB- 12 (6- l/2 x 5) capable of being
`operated in either a single stage, 3300 CFM at 640 psi or a
`two (2) stage configuration which would deliver 2300 CFM at
`I I00 psi. Both single and two (2) stage operations were used
`during various aspects of the drilling operation, and the excess
`air availability provided the answer to questions
`regarding the
`inability
`to start
`the
`three
`(3)
`faulty
`downhole motors.
`Because of uncertainties
`regarding
`the actual quantities
`of
`drilling
`air being
`delivered
`and the
`importance
`of
`this
`information in operating the air powered mud motors, a 2 inch
`orifice meter
`run and Halliburton
`electronic meter with
`This
`continuous
`recording
`capabilities
`were
`installed.
`in
`information
`proved
`important
`addressing
`questions
`regarding downhole motor problems.
`Light Pianrs. An additional 25 KW electric power
`plant was installed to provide power for the directional service
`companies,
`company trailer, and back-up for the rig, which
`
`proved helpful when the rig power plant was being repaired.
`The efficiency
`of the drilling operations would have been
`reduced without
`the additional electricity generated.
`
`Drilling operations were conducted on
`Drilling Summary.
`site between October 18, 1993 and December 9, 1993 for a
`total of 53 days. The vertical section was drilled on a contract
`footage rate of $8.50 per
`foot by a local contractor.
`Total
`days horn KOP were 45 days compared to 25 days budgeted
`with approximately
`750 feet less hole drilled than planned. A
`plot of actual days versus planned days can be seen in _
`illustrate the actual versus original well
`4. Figures 5 ~
`path in the plan view and vertical view respectively.
`days were
`Approximately
`nine
`(9)
`additional
`experienced
`in the build
`section
`prior
`to cementing
`the
`intermediate casing. All of these days were a direct result of
`mechanical
`problems
`which
`ultimately
`necessitated
`a
`plugback. After examining these mechanical problems,
`it was
`determined
`that
`some were
`inexcusable
`in lieu of
`the
`considerable preplanning and conservative well plan.
`After setting the intermediate
`casing,
`an additional
`seven (7) days were lost when the 6-1 /2 inch air motors would
`not run on bottom. An inline orifice flow meter
`indicated
`sufficient
`air volume was being pumped.
`The directional
`company indicated that the drill pipe scale may have been the
`source of the problem which has not been confirmed to date.
`The lateral was planned to be drilled on dry air,
`soap was employed
`in an effort
`to start
`the air
`however,
`Subsequent
`attempts
`to
`dry
`the
`hole were
`motors.
`and the remainder of the hole was soaped. The
`unsuccessful,
`lateral was prematurely
`TDd
`atler drilling
`approximately
`1,320 feet of target due to drill pipe sticking which may have
`resulted from the soap-mist affect on the shale intervals within
`the Clinton interval,
`
`Detailed Drilling Operations.
`Verticai Section (Surface to KOP-4,367 Feet). The
`section
`of
`the hole was
`spudded
`on
`10/18/93.
`vertical
`Conductor pipe (16 inch) was driven to 87 feet. A 14-3/4 inch
`hole was drilled to 806 feet with 11-3/4 inch surface casing set
`at 760 feet and cemented to surface with 500 sacks of cement.
`An I 1 inch hole was drilled utilizing dry air to the kickoff
`depth of 4,367 feet which was reached on 10/24/93. Eleven
`slick
`line
`retrievable
`single-shot
`surveys which
`provided
`inclination only were run by the drilling contractor.
`These
`single shots ranged from a maximum of 3,5 degrees at 647
`feet and diminished to less than I degree below 1,813 feet.
`An
`openhole
`continuous
`directional
`log
`confirmed
`the
`bottomhole position at kickoff to be north 29.6 feet and west
`I,9 feet from vertical.
`(lCP)
`Point
`Casing
`Intermediate
`Kickoff
`to
`4,367-5,115 Feet, The drilling of this segment was executed
`with an 8 inch mud motor powered by brine water.
`The
`
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`

`SPE 37354
`
`ACASESTUDY
`
`FOR DRILLINGAND Completing
`
`AHORlZONTALWELL
`
`IN THE CLINTON SANDSTONE
`
`5
`
`pulse
`by mud
`provided
`was
`information
`directional
`located
`(MWD)
`survey
`tools
`measurement-while-drilling
`within the drill string.
`The hole diameter was 11 and later
`10-5/8 inches
`to accommodate
`8-5/8
`intermediate
`casing
`string.
`
`to drill
`required nine (9) days longer
`This segment
`than anticipated.
`The additional
`days were the result of
`mechanical
`problems with the MWD directional
`surveying
`and mud motor components.
`reliable
`of
`incapable
`The MWD hardware was
`operation at the specified 600 gallon per minute (gpm)
`flow
`rate required for hole cleaning. The in-hole components
`failed
`twice,
`causing
`breakage
`of a cobalt
`steel
`flow restrictor
`located in the drill string at the top of the MWD tool. Pieces
`of
`the flow restrictor
`passed through
`the motor,
`causing
`internal damage.
`subsequently
`company
`service
`The
`directional
`advised the maximum allowable
`flow rate for their tool was
`now reduced to 400 gpm.
`Drilling was attempted
`at
`this
`reduced flow rate, but hole cleaning problems became evident
`and a polymer mud replaced the brine as a circulating fluid.
`Subsequently,
`the directional orienting sleeve within the drill
`string rotated and the MWD alignment with the downhole
`motor drifted and the hole was drilled off the projected course
`to an unrecoverable
`position. The measure point
`for the tool
`was 56 feet behind the bit and when the incorrect drit? was
`observed,
`it was impossible
`to recover. The hole was then
`plugged back from 4,965 to 4,550 feet with cement.
`style of
`This
`section was
`redrilled with another
`MWD, which permitted the larger flow rate necessary for hole
`cleaning.
`The drilling progressed
`but
`the build rate was
`marginal and, despite several attempts by the service company
`to adjust motor offset angles and stabilizer diameters.
`The
`assembly would not build at their projected build rates. The
`final
`result was that
`the ICP was
`forced to be set at an
`inclination angle of 6 I degrees
`rather
`than the planned 70
`degrees.
`
`Intermediate Casing Point to TD 5,115-6,505 Feet.
`After cementing the 8-5/8 inch intermediate
`casing, a slick
`assembly with a 7-7/8 inch tricone bit was run to blow the
`casing dry with air and drill the float shoe and one (I) foot of
`formation to dust the hole.
`A 6-1/2 inch air motor with an AKO setting of 1,65
`was run with Cartridge Data Transmission
`steering system.
`However,
`the motor would not run, and the next seven (7)
`days were consumed attempting to get a motor
`to run. Over
`this span, only 30 feet of hole was drilled placing the hole at
`5,154 feet and 65.7 degrees.
`contractor was released
`Regrettably,
`the directional
`after a mutually agreed air volume test was performed which
`the contractor
`acknowledged
`should have been a sufficient
`rate to run the motor. Another directional contractor already
`on standby,
`immediately was mobilized
`to perform the
`directional drilling services.
`
`in 9 days from 5,154 to 5,443
`Only 289 feet was cut
`feet MD using 6-1/4 inch motors. A wireline
`steering tool
`with side
`entry sub was utilized
`for directional
`control.
`Motors,
`steering tools, and bits all contributed
`to length of
`time to drill this interval. Two steering tools failed in the first
`38 feet and the first bit
`(Hughes ATJ44AD)
`after 54 feet.
`Subsequent
`trips were made to check motor alignment and to
`increase AKO setting from 1.6 to 2.0, pull a weak Security
`motor,
`trip for bit with 46 feet drilled,
`change motor, and
`replace a 3 axial probe steering tool with a 2 axial probe. This
`section of the hole was extremely rough on the motors, bits,
`and steering tools mainly due to the nature of
`the hard,
`abrasive Clinton Sandstone.
`Five BHA’s were utilized in this
`289 foot
`interval where penetration
`rates averaged only 32
`feet of hole drilled per day.
`Inclinations
`ranged from 66.2
`degrees
`at 5,154 feet
`to 87.7 degrees
`at 5,443 feet which
`provided an
`average build rate of 7.4 degrees per 100 feet, Obviously,
`major improvements must be made if the Clinton Sand is to be
`air drilled with downhole motors and conventional
`steering
`tools.
`
`Due to the lack of success with the motors and
`budget restrictions,
`it was decided to drill the remainder of the
`well with rotary assemblies attempting to slightly build in an
`effort
`to keep the drill path within the Clinton interval, even
`though it may be in the shale between the Red and White
`members.
`It was believed
`that
`a hydraulic
`frac would
`penetrate the Red and/or White even if it initiated in the shale
`between the two.
`Therefore, drilling resumed with rotary BHA’s from
`5,443 to 6,505 feet (TD). The rotary BHA #I which included
`bit, 3 point near bit roller reamer with chert cutters (6.62 feet)
`float sub, survey collar (31. 19 feet), and compressive
`service
`nonmagnetic
`drill pipe (3 1.28 feet).
`This assembly, drilled
`from 5,443 to 5,860 feet (417 feet),
`indicated the angle built
`from 87.8 to 91.7 degrees in the first 100 feet then dropped at
`0.8 degrees per 100 feet.
`Inclination at 5,860 feet was 85.7
`degrees.
`
`to BHA #I
`identical
`Rotary BHA #2 which was
`drilled from 5,860 to 6,105 feet.
`Inclination built from 85.7 to
`86.9 degrees in the first 190 feet then dropped at 0.7 degrees
`per 100 feet to a final inclination of 86.3 degrees at 6,105 feet.
`Rotary BHA #3 drilled from 6,105 to 6,169 feet
`when the decision was made to pull this BHA and to go back
`in the hole with an IBS (Integral Blade Stabilizer).
`The
`inclination
`built
`from 86.3 degrees
`at 6,105 feet
`to 87.4
`degrees at 6,169 feet.
`Rotary BHA #4 including an lBS was used to drill
`from 6,169 to 6,313 feet. At 6,289 feet,
`the angle had built
`from 87.4 to 89.4 degrees. This BHA was pulled due to low
`ROP at 6,313 feet. The bit was 2/ 16 inch out of gage and the
`IBS was l/2 inch out.
`IBS was run and drilled
`Rotary BHA #5 with another
`to 6,505 feet where drilling was stopped to run a survey.
`
`207
`
`5 of 16
`
`Ex. 2100
`IPR2016-01517
`
`

`

`6
`
`WM. MURRAY , L.A, SCHRIDER, R.L, MAZZA, A.B. YOST II
`
`SPE 37354
`
`the bit became stuck at 6,462 feet.
`When pulling off bottom,
`The drill pipe was worked approximately
`six (6) hours before
`the drill string was slowly worked up the hole, The decision
`was made to cease drilling at this point
`to avoid any tlrther
`risk of a stuck drill string. The hole was subsequently loaded
`with
`polymer mud
`and
`conditioned
`to
`run 4-1/2
`inch
`production casing.
`assemblies
`rotary
`the
`Rates
`of penetration with
`ranged from 6 to 30 fph but averaged in the 12 ~h range.
`Total footage, with the rotary BHA’s was 1,062 feet over a 9
`day span averaging 118 feet per day compared to 32 feet per
`day with the motors.
`
`Motor Performance / Rotay BHA Summary
`
`Motor Performance Summary. The downhole motors were
`used to drill hole segments with both liquid and air, The
`initial build section to the intermediate
`casing point was
`drilled with brine water and the final build segment between
`the intermediate
`casing point and the target was drilled with
`air, and a water-soap mist
`as
`the working
`fluid for
`the
`downhole motor.
`The initial build section, 10-5/8 inch, utilized 8 inch
`adjustable bent housing motors.
`The maximum deflection
`angle of 2.5 degrees resulted in a build rate of 8.5 degrees per
`100 feet.
`
`The 7-7/8 inch diameter build segment below the
`intermediate
`casing point was drilled with 6- I/2 and 6-1/4
`inch adjustable bent housing motors which resulted in build
`rates averaging 8.2 degrees per 100 feet from 5,118 to 5,443
`feet (61.2 to 87.8 degrees). The motors drilled a total footage
`of 332 feet averaging approximately
`32 feet per day. The
`motor performance
`in the 7-7/8 inch hole was extremely
`This
`area must
`be
`disappointing
`and
`is unacceptable.
`addressed
`for
`any
`future Clinton
`or
`similar
`formation
`horizontal projects.
`
`Rotary BHA Summary. Rotary
`used to
`assemblies were
`There were two (2) basic
`drill
`the lateral hole segments,
`configurations,
`one utilizing a single three (3) point
`roller
`reamer and the other utilizing integral blade stabilizers
`(IBS)
`in place of the roller reamer.
`reamer,
`a near bit
`utilized
`The
`roller
`assemblies
`service,
`of
`compressive
`one
`(1)
`joint
`collar,
`survey
`non-magnetic drill pipe and 745 feet of 4- 1/2 inch 16.60 lb/ft
`Grade G drill pipe, When fresh,
`they would build angle
`slightly, but afler drilling at 75-150 feet would drop at up to
`0.7 to 0.8 degrees/l 00 feet.
`The IBS assemblies utilized a rigid three (3) bladed
`in place of the roller
`reamer and would build angle
`stabilizer
`for greater distances, was ultimately the BHA of choice, and
`was used to finish the hole.
`The roller assemblies were used to drill 726 feet of
`formation at
`inclinations
`ranging from 87.8 to 85.7 degrees.
`
`inclinations
`The IBS assemblies drilled the final 336 feet at
`ranging from 87.4 to 89.4 degrees.
`The rotary assemblies
`drilled a total of 1,062 feet averaging 118 feet per day.
`
`Directional Control Summaty
`
`The
`to KOP - 4,367 Feet).
`Vertical Section (Surface
`directional control was accomplished
`by slick line retrievable
`single-shot
`surveys which provided only inclination and not
`The bottom hole
`location was
`directional
`information.
`subsequently confirmed with a wireline continuous directional
`Suwey.
`
`The eleven (11 ) single shot surveys were conducted
`and the hole
`inclination
`ranged from a maximum of 3.5
`degrees at 647 feet and diminished to less than 1.0 degrees
`below 1,813 feet.
`the
`survey indicated that
`The continuous directional
`bottom hole position at the kick off depth (4,367 feet) was
`north 29,6 feet and west 1.9 feet from the surface location.
`No problems were encountered
`and there were no
`time losses associated with these routine type operations.
`
`Build Section (4,367-5,1 11 Feet).
`4,3674,605
`Feet. This interval was drilled with a
`wireline retrievable MWD (DMWD) at a designed flow rate
`This tool was
`of 500 gallons per minute of brine water.
`selected
`because
`of
`the benefits
`of wireline
`retrieval
`in
`reducing trip time losses in the event of a tool failure. This
`tool type was used in the offset well with only one tool failure
`taking only 45 minutes to change the tool and resume drilling.
`However, on the CW #14, a bit trip was made at
`4,605 feet and the cobalt
`steel
`flow restrictor
`ring through
`which the upper portion, mud pulse section of the MWD
`protrudes was found to be broken.
`Short metal pieces of it
`were found inside the bit
`indicating that
`they had passed
`through the mud motor.
`The flow restrictor was replaced with one of a larger
`diameter and the DMWD rerun. Drilling continued to a depth
`of 4,762 feet when unexplained
`tool
`face change
`indicated
`problems with the MWD. A trip was made to determine the
`problem and the larger diameter
`flow restrictor
`ring was found
`Internal damage
`to the rubber
`stator was
`to be broken.
`observed in the top of the motor
`indicating that
`the sharp
`metal pieces of the flo