Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06 Particulars Required for Notification under Regulation 6(1) of BSOR
Contents
1.0 Name and Address of the Operator 2
2.0 Particulars of the Type of Well 2
3.0 Particulars of the Rig and Plant 4
4.0 Particulars of Surface Equipment and Fluids to Control Well Pressure 6 4.1 Surface Equipment: Well Control During Drilling Operations 6
4.2 Formation Pressures and Drilling Fluids 10
5.0 Particulars of Well Position and Directional Path 12
6.0 Programme of Works 14
7.0 Activities Involving the Risk of Release of Fluids 15
8.0 Particulars of Geological Strata, Surveying and Well Design 17 8.1 Geological Formations and Fluids 17
8.2 Wellbore Direction Surveying 17
8.3 Relevant Particulars of the Well Design 21
9.0 Existing Well Details 24
10.0 Plug & Abandonment and Suspension 24
11.0 Attachments 25 11.1 Attachment 1: Rig Specifications, Synergy-1 26
11.2 Attachment 2: Well Control Stack-up Drawings 29
11.3 Attachment 3: Wellhead Configurations 31
11.4 Attachment 4: Casing Design Summary 34
Figures
Figure 1: PNR-1 / 1Z Location ...................................................................................... 3
Figure 2: Generic site layout with rig ............................................................................ 5
Figure 3: Well Profile, PNR-1 & 1Z ............................................................................ 12
Figure 4: Design Pore & Frac Pressure Gradients vs Depth ........................................ 16
Figure 5: Geological Prognosis, PNR-1....................................................................... 19
Figure 6: Geological Prognosis, PNR-1Z .................................................................... 20
Tables
Table 1: Diverter and BOP Plan .................................................................................... 6
Table 2: Wellhead Stack-up Planned for PNR-1 / 1Z .................................................... 8
Table 3: Pressure Testing Programme ........................................................................... 9
Table 4: Kick Tolerance Calculation Summary........................................................... 10
Table 5: Planned Drilling Fluids and Expected Formation Pressures ......................... 11
Table 6: Nominal Directional Profile for Preston New Road Pilot Hole (PNR-1) ...... 13
Table 7: Nominal Directional Profile for Preston New Road Sidetrack (PNR-1Z) .... 13
Table 8: Planned Well Operations ............................................................................... 14
Table 9: Geological Prognosis ..................................................................................... 18
Table 10: Surveying Programme, PNR-1 / 1Z ............................................................. 18
Table 11: Casing Plan, PNR-1 / 1Z ............................................................................. 21
Table 12: Minimum & Calculated Casing Design Factors .......................................... 22
Table 13: Cement Barrier Programme, PNR-1 / 1Z .................................................... 23
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 2 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
1.0 Name and Address of the Operator
Cuadrilla Bowland Limited
6 Septre Court,
Bamber Bridge,
Preston PR5 6AW.
Contact: Mike Schneider – Drilling Manager
2.0 Particulars of the Type of Well
The well is referred to as Preston New Road 1 and 1Z (PNR-1 / 1Z) throughout this
notification. The Well Registration Number will be confirmed by the Oil and Gas
Authority but a well number of LJ/06-08 is anticipated. The well’s surface location will
be on EXL269 and the lateral extension will go into and produce from PEDL165. The
well is classed as exploration (unconventional reservoir).
Please note that PNR-1 is one of two wells being drilled at the Preston New Road site.
The particulars for Notification for PNR-2 (LJ/06-07 expected) will be provided under
separate cover. Conductor-setting particulars for Notification for both wells were
provided earlier under separate cover. It is planned to batch-drill top hole sections
below the conductors for the two wells, such that these operations will commence with
PNR-2, then the rig will skid over to PNR-1 and it will be drilled to total depth and
completed with production casing. After that the rig will skid back to PNR-2 and
complete that well to final depth.
PNR-1 is being drilled as an S-shaped pilot hole to the Hodder formation. The
geological information acquired will be used to select the landing depth for a horizontal
lateral, which will be drilled as a J-shaped sidetrack from the pilot hole as PNR-1Z. The
information gained from the pilot hole will also be used for selecting the landing depth
of the second J-shaped well, PNR-2. Within this Notification prognosed kick-off and
landing depths have been indicated for PNR-1Z based on seismic interpretation, and
are subject to change following evaluation of the pilot hole.
This Notification covers planned works up to and including installation of the
frac/production casing string. Following drilling rig release, the well will be stimulated
by hydraulic fracturing and then production-tested, and all works associated with that
will be the subject of a separate Notification to follow.
The site address is Preston New Road Wellsite, adjacent to PR4 3PJ, Lancashire
(nearest property).
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 3 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
Figure 1: PNR-1 / 1Z Location
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 4 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
3.0 Particulars of the Rig and Plant
The drilling rig to be used is DrillTec GUT’s rig “Synergy 1”. The rig uses a
hydraulically powered rack-and-pinion joisting system with a nominal capacity rating
of 3700kN. A summary of the rig’s specification is included as Attachment 1.
The rig is currently operating for NAM in the Berkel Field abandonment in Rotterdam,
and will be brought over to the UK specifically for this project.
Additional plant required during the programme will include:
• Cementing equipment: high-pressure pump unit(s), bulk cement storage, batch-
mix;
• Wireline logging unit;
• Lifting equipment: cranes and forklifts to the capacities required per
application;
• Drilled cuttings auger and skip loading bays.
A general site layout drawing is included in Figure 2 below, showing the drilling rig
and the noise wall (represented by 12m x 2.4m containers which won’t necessarily be
the case). The additional plant is not shown in the layout and will be spotted to suit the
operations.
At the time of this submission, no public announcement or press release has been made
by Cuadrilla Bowland Ltd concerning the engagement of DrillTec GUT for this work.
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 5 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
Figure 2: Preston New Road site layout with drilling rig
(Noise wall represented by 12m x 2.4m rectangles)
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 6 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
4.0 Particulars of Surface Equipment and Fluids to Control Well Pressure
4.1 Surface Equipment: Well Control During Drilling Operations
The diverter and blow-out preventer plan during drilling is shown in Table 1 below.
Since the top hole sections (26" and 16") will be batch-drilled starting with PNR-2,
diverters will be used on that well. Mud logging services (gas and flow detection plus
lithological analysis) will be in place for both wells from start to finish. No shallow gas
or artesian flow is anticipated in the first two hole sections, and if this is confirmed on
PNR-2 then no diverters will be used for top hole sections on PNR-1.
Table 1: Diverter and BOP Plan
PNR Well
in Sequence
26" to ~260m 16" to ~1318m 12-1/4", 8-1/2" & 6"
1st Well:
PNR-2
29-1/2" diverter
(alternatively
pilot hole with
21-1/4"
Diverter
21-1/4" annular
preventer used
as diverter
• 13-5/8" 5000psi annular
preventer
• 13-5/8" 10000psi double
pipe ram (upper VBR,
lower shear/blind)
• drilling cross
• 13-5/8" 10000psi pipe ram
2nd Well:
PNR-1
No diverter as long as mud logging
on 1st well confirms no gas (each
section)
Same as for PNR-2
Stack-up drawings for the 3 systems in Table 1 are shown in Attachment 2.
The wellhead is a “drill-through” style system manufactured to API6A by GE Oil &
Gas Limited, with components as listed in Table 2. Casing hangers are as follows:
• The 13-3/8" casing hanger is a wrap-around slip and seal assembly, with the 13-
3/8" casing is set above the levels at which any hydrocarbons are expected and
which will be confirmed by mud logging.
• The 9-5/8" casing hanger is a mandrel-type, run as part of the casing string with
the primary seal (pack-off) run through the BOP immediately after cementing.
A contingency wrap-around slip and seal assembly is available in case it is not
possible to land the mandrel hanger due to space-out (e.g. casing stuck off
depth).
• For the 5-1/2" casing hanger the primary option is a mandrel-type hanger with
a control line penetration. A contingency slip and seal assembly is also available
for this string but without control line penetration.
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 7 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
No H2S was reported from offset Bowland / Hodder wells in the area, however as a
precaution the upper housing of the 13-5/8" wellhead has been specified to DD-NL for
drilling the 8-1/2" pilot hole and subsequent sidetrack to horizontal, and the tubing
spool has been specified to EE-1.5.
The BOP and wellhead system will be function tested and pressure tested as shown in
Table 3. This also shows the plan for formation integrity and leak-off tests. The pressure
testing levels were selected as follows:
• 20" casing and 21-1/4" annular preventer are tested to 500psi based on the
shallow depth of the top of the Sherwood Sandstone, the continuity of the
porous sand through the 16" interval, the local absence of hydrocarbons in the
section, and the use of the annular preventer as a diverter.
• 13-3/8" casing / SH2 lower housing test to 4000psi based on being above a
theoretical gas-to-surface design from the 12-1/4" total depth and below 75% of
API rated burst strength for 72 lb/ft L80 casing of this size.
• 9-5/8" casing is tested to 5500psi based on being above the equivalent gas
column to surface exceeding a 1.0psi/ft formation break-down strength below
the casing shoe and below 75% of API rated burst strength for 53.5lb/ft L80
casing of this size.
• The 7" liner is tested to 5000psi based on being above a theoretical gas-to-
surface design from the 6" lateral and below 75% of API rated burst strength
for 29 lb/ft L80 casing of this size.
• The 5-1/2" x 4-1/2" frac string / tubing head (wellhead section C) is tested prior
to stimulation to 9500psi, being the maximum treatment pressure planned for
initiating injectivity.
Wellhead schematics are included in the Attachments:
• Wellhead to the end of drilling, shown with 5-1/2" contingency wrap-around
casing hanger without control line penetration though the mandrel hanger with
control line penetration sits in the same spool location, directly replacing it;
• Wellhead with 5-1/8" frac tree installed - please note, frac tree installation and
stimulation operations will be the subject of a separate, later Notification;
• Wellhead with 2-9/16" production tree installed, showing integral tubing bonnet
within mono-block valve tree - similarly to form part of a later Notification.
The latter two stack-ups are included at this stage for general information purposes
only.
Results of kick tolerance calculations for PNR-1 (pilot hole) are included in Table 4.
The sidetrack will be shallower, and as such the pilot hole presents the more extreme
case.
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 8 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
Table 2: Wellhead Stack-up Planned for PNR-1 / 1Z
Wellhead Stack-up Per Section A-B-C API Specification
C Tubing Head:
• 11" 10,000psi x 5-1/8" 10,000psi head
with tie-downs
• Secondary seal assembly for 5-1/2"
casing stub; metal/metal.
• 2 x 2-1/16" 10,000psi studded side outlets
with valves and accessories
• Tubing head adapter, 5-1/8" 10,000psi as
part of production tree.
PU-EE1.5-PSL3-PR2
B Drill-through wellhead assembly (high pressure
wellhead):
• 21-1/4" 2,000psi bottom x 13-5/8"
10,000psi top
• Intermediate flange 13-5/8" 5,000
• 4 x 2-1/16" studded side outlets (2 per
annulus), machined to accept Valve
Replacement Plug, supplied with 1 x
VRP
• each side outlet with 1 x 2-1/16" 5,000 /
10,000psi gate valves (pressure rating as
per flange above)
• Casing hanger for 9-5/8": mandrel-type
with pack-off bushing.
• Contingency slip-type hanger in the event
of stuck 9-5/8"casing / off depth.
• Casing hanger for 5-1/2": mandrel hanger
with control line penetration; back-up of
automatic slip & seal without
penetration.
Temperature: U
Material: AA/DDNL
(lower housing AA, upper
DDNL)
PSL 2
PR2
9-5/8" mandrel hanger:
P/U-DDNL-PSL2-PR2
5-1/2" mandrel hanger:
special design by GE in
8630 steel
5-1/2" slip & seal hanger:
U-DD-2-2
A Casing head assembly (low pressure wellhead):
• 20" OD slip-type x 21-1/4" 2,000 psi
flange
• 2 x 2" 2,000 psi line pipe side outlets or
2-1/16" R-27 flanged
• One side outlet with 2-1/16" gate valve,
other side with bored bull-plug, needle
valve and pressure gauge
• Casing hanger for 13-3/8": automatic slip
& seal.
Temperature: P/U
Material class: AA
Product Spec. Level 1
Performance Req. 2
Casing hanger: L-AA-
PSL3-PR2
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 9 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
Table 3: Pressure Testing Programme
Hole/
Casing
Size
Test
Item Comments Pressure
psi
Time
26"
hole
Diverter
on 28"
Function test of diverter element and
valve
n/a
20"
casing
Casing
head +
diverter
Slip-lock housing O-ring + diverter
element and valve + casing against
cemented shoe track
500 10 min
Top of
16"
Shoe test Hydraulic test at cemented shoe to
15 lb/gal EMW
Approx.
220psi
13-3/8"
casing
13-5/8"
BOP +
SH2
spools
1. 13-5/8" pack-off via test port
2. SH2 spools prior to 9-5/8" casing
3. BOP prior to 9-5/8" casing
500 / 4000
500 / 4000
500 / 4000
10 min
10 min
10 min
Casing +
blind rams
Before drilling out shoe track. 500 / 4000 10 min
Top of
12-1/4"
FIT / LOT Up to 15.5 lb/gal EMW for kick
tolerance
N/A
9-5/8" 13-5/8"
BOP Test
+ upper
SH2 spool
1. Upper SH2 housing after 9-5/8"
pack-off set; + full stack test with
test plug
2. Between pack-off seals / BX160
gasket
500 / 6000
(4000
annular)
500 / 4000
10 min
10 min
Casing
Test
After bumping plug or before
drilling out all cement in shoe track
5500 10 min
Top of
8-1/2"
LOT Conducted below 9-5/8" shoe (kick
tolerance based on 16.5ppg)
(X)LOT
7"
Liner test After bumping plug or before
drilling out all cement in shoe track
500 / 5000
10 min
Every
max. 21
days
13-5/8"
BOP
Full stack test as per test after 9-5/8"
casing
500 / 6000
(4000
annular)
10 min
Top of
6"
LOT LOT for hydraulics management in
6" hole. XLOT may be performed if
required for geotechnical reasons.
(X)LOT N/A
4.5" x
5.5"
Casing /
Tie-back
1. On bumping plug:
2. Prior to stimulation; including
tubing spool/secondary seal
2500
9500
10 min
10 min
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 10 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
All tests will be recorded on charts and annotated with well name, date, item being
pressure tested, and Supervisor’s name. Mud loggers will digitally record well
construction pressure tests as well.
Table 4: Kick Tolerance Calculation Summary
Hole Size 12-1/4" 8-1/2"
Target kick margin 25bbl 25bbl
Kick scenario 0.5ppg above mud weight 0.5ppg above mud weight
Mud weight in use 12ppg (for borehole
stability – higher than
expected pressure)
13.5ppg (Actual may be
higher for borehole
stability)
LOT / FIT at previous
shoe
15.5ppg 16.5ppg
Pressure safety margin 441psi 295psi
Wellbore vertical depth 1845m TVD 3420m TVD
In the event of a lower formation strength being measured at the shoe, the kick tolerance
will be reassessed, which may mean that either the section TD is reduced or, for the pilot
hole, a 7" drilling liner could be required at a calculated point. A risk assessment for this
will be included in the executable programme. It is noteworthy that the prognosed
maximum formation pressure gradient for the Bowland Shale is based on mathematical
derivations from the hydraulic fracture treatments done on Preese Hall-1, though the
calculated formation pressures are higher than the mud weight actually used for drilling
and no well flow was ever in evidence.
4.2 Formation Pressures and Drilling Fluids
A summary of the drilling fluids and expected formation pressure gradients is given in
Table 5 below.
The planned casing programme is given in Section 8.3. All hole section and casing
setting depths are subject to significant adjustment depending on geological and drilling
conditions.
A geomechanical study is currently being completed by Petrolern which is designed
to guide mud weight selection for both borehole stability (avoidance of break-outs)
and avoidance of exceeding fracture gradients (control of dynamic mud losses), and
also provide an additional derivation of predicted pore pressures. The study will be
used to advise the executable drilling programme.
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 11 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
Table 5: Planned Drilling Fluids and Expected Formation Pressures
*See note above regarding derivation of pore pressure estimate from Preese Hall-1
frac data.
Nominal
Hole Size
(inches)
Formations and
Drilling Fluid (Mud)
Expected
Formation
Fluid
Pore Pres.
Gradient
lb/gal
Fluid
Density
lb/gal
26"
Middle Sands / Mercia
MDST: salt-saturated polymer
mud in case of halite beds.
Fresh water,
possibly
brine
8.3 10.2
16"
Sherwood Sandstone: same
salt-saturated polymer mud
with close attention to
possible mud losses.
Water
(brine) 8.75 10.2
12-1/4"
Manchester Marl/Millstone
Grit Group: LTOBM for
borehole stability and quality.
Gas
possible
9.8
(possible)
10.0 – 12.0
for borehole
stability
8-1/2"
Bowland Shale, Hodder MST:
LTOBM carried over from
previous section.
Gas
Expected
9.8 – 13.3*
(possible)
11.0 – 14.0
for borehole
stability
8-1/2"
sidetrack &
6" lateral
Bowland Shale, Hodder MST:
LTOBM carried over from
previous section.
Gas
Expected 9.8 – 13.3*
11.0 – 14.0
for borehole
stability
Production
Casing
Completion fluid: fresh water
+ corrosion inhibitor and
oxygen scavenger
Gas present
only after
perforating
Cased 8.75 – 9.8
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 12 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
5.0 Particulars of Well Position and Directional Path
a) The Ordnance Survey National Grid reference of the location of the top and
bottom of the well is:
Ground level Elevation (GLE): 12.5m
Rotary Table Elevation (RTE): 8.25
Surface location:
Well (OSGB 36 (2)) Northing/m Easting/m
PNR-1 432749.5 337433.6
PNR-2 (for reference) 432752.2 337437.8
Bottomhole location:
Well (OSGB 36 (2)) Northing/m Easting/m TVDRT/m
PNR-1 432749.5 336884.3
PNR-1Z 432749.5 335637.2 2200
b) The well is planned to be drilled directionally in an S-shape as PNR-1, per Table
6. It will then be sidetracked as a J well as PNR-1Z per Table 7. The profile of
the well is shown in Figure 3 below.
Figure 3: Well Profile, PNR-1 & 1Z
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 13 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
Table 6 and Table 7 below indicate the most likely depth cases for PNR-1 & 1Z, based
on placing a horizontal in the lower part of the Upper Bowland. This will be subject to
core analysis in the pilot well to evaluate the most prospective target. The total depths
of each hole and the landing points are all subject to change based on both geological
and operational results.
Table 6: Nominal Directional Profile for Preston New Road Pilot Hole (PNR-1)
Table 7: Nominal Directional Profile for Preston New Road Sidetrack (PNR-1Z)
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 14 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
6.0 Programme of Works
Expected earliest commencement date is early July 2017, subject to site and
conductor installation completion. Depths are measured depths from rotary table (RT)
unless otherwise indicated.
Table 8: Planned Well Operations
Operation Days
Rig mobilization: skid rig over from PNR-2 (from top-hole drilling on
adjacent well). 1.0
Spud well and drill 26" hole to 260 meters. 1.5
Run and cement 20" casing & install and test wellhead. 1.0
Drill 16" hole to circa 1318m and log. 4.2
Run and cement 13-3/8" casing. Install casing head, 13-5/8" BOP and
pressure test. 2.0
Make up BHA and drill out shoe track. Perform FIT. 0.5
Drill 12-1/4" hole to 1908m (adjusted according to actual lithology). 3.4
Run wireline logs. 1.5
Run and cement 9-5/8" casing. Set and test wellhead packoff. 2.5
Drill out shoe track and test formation leak-off strength. 1.0
Drill 8-1/2" hole to approx. 3500m, with coring. 27.9
Run electric wireline logs to evaluate the 8-1/2" section. 3.0
Abandon lower section of PNR-1 and set kick-off plug for sidetracking
at selected depth. 2.5
Sidetrack to PNR-1Z in 8-1/2" hole, building to (near) horizontal at
nominal TD of 2440m. 8.2
Run + cement/test 7" liner. 2.0
Make up BHA and drill shoe track. Conduct LOT. Drill 6" lateral to
nominally 3460m. 8.2
Run electric logs on drill pipe (contingency of wireline / tractor). 4.0
Run 5-1/2" x 4-1/2" frac string and cement (contingency of 4-1/2" liner). 2.0
Clean out frac / production string (incl. contingency of tie-back). 2.0
Total including rig mob/demob: 78.4
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 15 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
7.0 Activities Involving the Risk of Release of Fluids
The design pore and fracture gradients versus formations are summarised in Figure 4.
1. Mercia Mudstone: no abnormal pressures have been found with the exception of
shallow artesian water flow at 19m in Preese Hall-1, which will be mitigated with
the shallow conductor in this well. The water monitoring boreholes drilled during
July-2016 have now provided detailed lithological information, and also
established the limited potential for artesian water flow. The executable conductor
programme has included these details. Below potential artesian conditions, the
Mercia Mudstone can be drilled with 8.9 lb/gal to the target depth of circa 260m.
Based on all available offset well information, the Mercia Mudstone has not been
found to contain shallow gas. The salt-saturated mud system is planned due to the
potential for halite inclusions above the Sherwood Sandstone, and not for
hydrostatic pressure.
2. Sherwood & St. Bees Sandstone: Similar to the Mercia Mudstone, no abnormal
pressures or elevated gas levels have been noted in any offset wells. The Sherwood
Sandstone is prone to mud losses, particularly in the St. Bees formation, and this
will be monitored closely while the salt-saturated mud system is in use.
3. Collyhurst Sandstone and Millstone Grit Group (MGG) below Manchester Marl:
The marl forms a regional seal and first hydrocarbons are generally encountered
only beneath the Manchester Marl, in the Collyhurst Sandstone or Millstone Grit.
From the nearby Elswick Gas Field the original reservoir pressure is taken as
1,726psia at 3395ft TVDRT, giving a gradient of 9.8lb/gal equivalent mud weight
(EMW). This overpressure was not seen in Preese Hall-1 where a mud weight of
9.3lb/gal was adequate, but precautions for an EMW up to and in excess of that
seen in Elswick will be provided for. In any event, borehole stability has been an
issue in the past (Grange Hill, borehole collapse) and elevated mud weights may
be required for borehole support.
4. Bowland Shale Group: no direct formation pressure measurement has been
possible due to the very tight nature of the predominantly shale formation, but the
pore pressure has been deduced from Preese Hall-1 fracturing treatment data at
each of the perforated zones. The average value calculated is 0.69psi/ft (13.3lb/gal
EMW) in the Lower Bowland. The section was drilled with a mud weight of only
10.1lb/gal so evidently the formation is extremely tight as no well flow resulted
even during prolonged coring and logging. Nonetheless there is the potential for
locally isolated lenses of higher permeability which could be charged to such a
high pore pressure, so 0.69psi/ft is taken as the design pore pressure. For the
planned total depth of the pilot hole this in turn requires a 10,000psi BOP.
5. Hodder Mudstone: this was only penetrated in Becconsall-1Z and due to the tight
nature of the formation, again no direct pressure measurement was possible. Being
a mudstone, gas levels were low while drilling with a mud weight designed to
provide borehole stabilisation rather than gas control. There are no indications from
Cuadrilla Bowland Limited
Notification of Intent to Drill Preston New Road 1 & 1Z on LJ/06
Particulars Required for Notification under Regulation 6(1) of BSOR
Page 16 of 37 Document No. PNR-DRI-NOT-001 12-Apr-2017
mud logging and cuttings that pore pressures are higher than in the Bowland Group
and so the same maximum value of 0.69psi/ft is used for the section to total depth.
6. Kick tolerance: See Section 4.1 above.
7. The implementation of the defined drilling practices in association with the
specified well control equipment and drilling fluid systems will minimise any
chance of accidental release of fluids from the well during its construction. Sensors
for gas levels, pit volume and system pressures will be installed, tested and
monitored throughout this operation, with alarms set at suitable levels by the mud
logging service contractor. Flow checks for a minimum 10min will be made prior
to each trip out of the hole from the 16" borehole onwards. Regular well control
drills and site safety meetings will be held and recorded in the rig’s IADC logbook.
Figure 4: Design Pore & Frac Pressure Gradients vs Depth
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8.0 Particulars of Geological Strata, Surveying and Well Design
8.1 Geological Formations and Fluids
The PNR-1 prospect is located 3.7km south of Preese Hall-1 and 9.5km north-west of
Hesketh-1. It lies within the Thistleton Fairway which forms part of the Carboniferous
basin known as the Bowland Basin. The fairway surrounding PNR-1 is bound by
Variscan reverse faulting, comprising of the Haves-Ho Fault to the West and Anna’s
Road / Moor Hey Faults to the East. The well is positioned in a relatively flat lying part
of the fairway, making it an ideal location for future laterals.
The Bowland Basin in which the Thistleton fairway resides is bound to the north by the
Bowland High, and to the south by the Rossendale High (Fraser and Gawthorpe, 1990).
It is an intracratonic extensional basin formed during Late Devonian early
Carboniferous times in relation to the intensified N-S crustal extension. The basin was
subsequently inverted during the Variscan Orogeny, leading to the inversion of many
of the existing faults. The Carboniferous basin fill comprises marine claystones/shales
interbedded with sandstone, siltstones and limestones.
The primary target reservoir is the Bowland Shale Formation, with the Hodder
Mudstone being a secondary target and the shales within the Millstone Grit Group,
namely the Sabden Shales being a tertiary target.
The geological prognosis is listed in Table 9, and shown together with the seismic
sections in Figure 5 (PNR-1) and Figure 6 (PNR-1Z). The seismic interpretation
identifies the potential for a major reverse fault within the MGG, which may result in
drilling directly into a repeat section of Lower Bowland Shale, and then back into either
the MGG or Upper Bowland Shale. The geological prognosis also identifies a minor
reverse fault at 1890m-MD leading to a repeat section.
8.2 Wellbore Direction Surveying
The directional surveying programme is shown in Table 10. The PNR-2 wellbore, being
drilled at 5m surface separation from within the same cellar, is the only wellbore that
will initially present a collision risk. In addition to the surveying shown in Table 10, a
gyroscope (non-magnetic) survey of the final well may be taken to aid any future infill
well planning.
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Table 9: Geological Prognosis
Table 10: Surveying Programme, PNR-1 / 1Z
26" hole Rotary BHA: MWD surveys
16" hole Directional BHA: MWD surveys
12-1/4" hole Directional BHA: MWD surveys
8-1/2" hole and sidetrack Directional BHA: MWD surveys
6" hole Directional BHA: MWD surveys
RT fm GL 8.25
GL fm MSL 12.5
RT fm MSL: 20.75
Formation Top / Event m-TVDSS m-TVDRT m-MDRT
Superficial (Boulder Clay 10 11 10
Mercia Mudstone -20 41 40
Shallow (28") Conductor -40 60 60
Deep (20") Conductor -240 260 260
Sherwood Sandstone -270 290 290
Sherwood St Bees Sst -580 600 610
Manchester Marl -1150 1170 1200
Anhydrite 1 -1180 1200 1240
Anydrite 1 Base -1200 1220 1260
Anhydrite 2 -1230 1250 1290
Anhydrite 2 Base -1240 1260 1300
13-3/8" Surface Casing -1260 1280 1320
Collyhurst Sandstone -1310 1330 1370
Variscan -1350 1371 1420
Upper Bowland Shale -1650 1670 1730
Minor Fault -1800 1820 1890
9-5/8" Intermediate Casing -1820 1840 1910
Core interval 1: Upper Bowland -2050 2068 2150
Lower Bowland -2220 2241 2320
Core interval 2: Lower Bowland -2220 2242 2330
Hodder (Upper) -2680 2701 2780
Core interval 3: Hodder -2680 2703 2790
TD, PNR-1 -3420 3431 3500
Kick-off Point to PNR-1Z -1942 1963 2036
Drilling Liner -2180 2200 2440
Production Casing / TD -2180 2200 3460
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Figure 5: Geological Prognosis, PNR-1
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Figure 6: Geological Prognosis, PNR-1Z
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8.3 Relevant Particulars of the Well Design
The casing programme is summarised in Table 11 below. The cementing programme
and verification scheme is shown in Table 13. The casing specifications are generally
higher than required due to stock availability.
Table 11: Casing Plan, PNR-1 / 1Z
Hole
Size "
Casing
OD "
Casing Setting Criteria and
Purpose
Grade
Lb/ft
Thread
Setting Depth,
MD/m RT
PNR-1&1Z
32 28 Shallow conductor(s): set ahead
of main drilling; see separate
Notification.
X52
WT 0.5-0.6"
Up to 50
26 20 Deep conductor: set in Mercia
Mudstone to nominally 30-50m
above Sherwood Sandstone.
Covers claystones and halites
while drilling next section.
94 lb/ft K55
sufficient but 133
lb/ft in stock;
BTC
260
16 13-3/8 Surface casing: set nominally
100m below top Manchester Marl
(after anhydrite bands) to provide
impermeable seal between the
Sherwood (aquifer) and
hydrocarbon zones.
L80-1
72 lb/ft
Vam Top
1318
(18° Incl.)
12-1/4 9-5/8 Intermediate casing: across
Millstone Grit Group to below the
prognosed fault in the Upper
Bowland Shale: part of barrier
envelope for possibly gas-bearing
sands (note 2).
L80-1
53.5 lb/ft
Vam Top
1908
(18° incl.)
8-1/2 7 Cemented liner across the build
section to up to 90° inclination.
L80-1 29 lb/ft
Vam Top HT
2440
(90°incl.)
6 4-1/2 x
5-1/2
Planned as tapered 5-1/2" x 4-1/2"
string cemented at least 300m into
7" liner (option of cemented 4-
1/2" liner + uncemented tapered
tie-back string is retained).
5-1/2" P110
20lb/ft x 4-1/2"
13.5 lbs/ft
Vam Top HT
3460
(90 - 94° incl.)
Notes:
Casing API grades and lb/ft have been selected based on conventional casing design
calculations using the minimum casing design factors in Table 12, which are in
accordance with Cuadrilla’s Well Integrity and Operational Controls manual. The
casing design calculations were performed using TechDrill’s “DSP-One” casing design
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module with summary graphs (13-3/8" casing onwards) included in Attachment 4. The
graphs display in terms of “normalised safety factors” which show the lowest value of
safety factor calculated, normalised by the minimum design factor in Table 12.
Therefore any value above 1 complies with the design criteria.
�������� �� �� ������ =�� �� �����
������� ������ ����� ������
Table 12: Minimum & Calculated Casing Design Factors
Casing Load Design
Factor
Internal yield (burst) 1.1
Collapse 1.1
Tension (stuck casing,
cementing, pressure
testing)
1.25
Tri-axial stress 1.25
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Table 13: Cement Barrier Programme, PNR-1 / 1Z
Casing (or Liner) Type and Depth (m)
Proposed Low Permeability Strata - Set Into
Cement Details Purpose of Casing/ Liner and Cement Barrier Verification
Shallow conductors
Top of Mercia Mudstone
Pre-installed: separate Notification
Structural support and site protection
Deep Conductor
20" casing
26" hole
250 – 270m
Mercia Mudstone Group
Light-weight lead cement slurry with standard density tail cement (min. 100m tail).
Protect shallow groundwater from well fluids during drilling. Provide a permanent seal across the Mercia Mudstone.
Verified by cement returns + pressures during cementing – top up if required. Hydraulic test (FIT) on drilling out shoe - cement shoe squeeze if required.
Surface Casing
13-3/8" casing 16" hole
1,318m
Manchester Marls Formation
Light-weight lead cement slurry with standard density tail cement (min. tail fill to Sherwood base); specifications tailored to cementing across Sherwood SST.
Protect the Sherwood Sandstone from well fluids during deeper drilling. Prevent fluids migration into Sherwood Sandstone from underlying units (for example the Collyhurst Sandstone).
Verified by cement returns + pressures during cementing. Hydraulic test (FIT) on drilling out shoe - cement shoe squeeze if required. CBL/VDL for monitoring purposes only.
Intermediate Casing
9-5/8"casing / 12.25" hole
1,908m
Upper Bowland Shale
Gas blocking cement from shoe of 9-5/8" casing at least up to base of the Sherwood Sst within 13-3/8" annulus. External casing packer installed close to 13-3/8" shoe.
Casing across Collyhurst Sandstone and Millstone Grit for well control purposes. Provides additional barrier between Sherwood SST and well fluids.
Verified by cement returns + pressures during cementing. Hydraulic test (FIT, LOT or XLOT) on drilling out shoe - cement shoe squeeze if required. CBL/VDL for verification purposes.
Drilling Liner
7" / 8.5" hole
2,440m
Target Formation
Gas blocking cement along liner length.
Part of primary barrier preventing uncontrolled release of well fluids to adjacent formations.
Verified as per 9-5/8" casing.
Production/frac string: 4-1/2" casing / 6" hole
3,460m
Target Formation
High resilience / high flexural strength cement designed to withstand the hydraulic fracturing pressure and perforations cycles.
Provides isolation within the lateral section to be hydraulically fractured.
Verified by cement returns + pressures during cementing. CBL/VDL for verification purposes in first well.
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9.0 Existing Well Details
In the case of an existing well: (a) a diagram of the well, (b) a brief history of the well
including a summary of previous operations, (c) its present status and condition.
The pre-existing well construction will be the cellar and the pre-set 28" conductor set
at least 10m into firm Mercia Mudstone, per separate Notification. The cellar will be
constructed 10m long x 2.9m wide x 4.5m deep to accommodate both PNR-1/1Z and
PNR-2. The cellar depth will provide for the wellhead plus production tree to be housed
below site surface level.
10.0 Plug & Abandonment and Suspension
The lower section of PNR-1 is to be abandoned per guidelines published by Oil & Gas
U.K., with cement plugs being set between all distinct permeable zones within the
openhole, which may involve overlapping of zones that are too close together to plug
separately. It is anticipated that this would only involve a cement plug between the
Bowland Shale and the Millstone Grit Group above. The kick-off plug may be below
this depth and so the abandonment of the lower section would be achieved with the
kick-off plug (subject to confirmation of the sidetracking depth).
Suspension after running the frac (5-1/2" x 4-1/2") string: following cementation, the
string will be displaced to a potentially underbalancing fluid and therefore an inflow
test will be conducted. This will verify the casing string as a deep-set barrier. Following
confirmation of pressure integrity, the 5-1/8" frac tree valves will be installed as a
shallow barrier while the well awaits further operations.
The casing programme for this well has been specifically designed to facilitate eventual
abandonment, providing for separation of separate geological intervals which could
potentially result in flow if not isolated.
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11.0 Attachments
1. Summary of Rig Specifications
2. Well Control Stack-up Drawings:
• 21-1/4" diverter (similar arrangement for 29-1/2")
• 13-5/8" BOP
3. Wellhead Configurations
• Wellhead during drilling
• Wellhead with 5-1/8" 10,000psi frac tree
• Wellhead with 2-7/8" mono-block production tree
4. Casing Design Summary
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11.1 Attachment 1: Rig Specifications, Synergy-1
Ref. Description CONTRACTOR's Supplied Equipment
A LAND RIG SUMMARY
GENERAL DESCRIPTION
- Name MAX STREICHER VDD 370.1 Synergy 1
- Classification Self supporting land rig
- Year Built/Refurbished Construction year 2004
- Nominal drilling depth 5.000 m with 3-1/2" drillpipe
MAST
- Type Gear rack
- API Gross Nominal Capacity 3.700 kN
DRAWWORKS
- Type MAX STREICHER Rack & Pinion Hoisting System
- Drive Hydraulic motor
- Power Rating 900 kW
- Max. designed hoisting capacity 3,700 kN pull, 60kN push
AUXILIARY BRAKE Main 6 hydraulic motion control valves (Rexroth) + auxiliary 6
multi-disc brakes (Zollern)
SUBSTRUCTURE
- Height 8.25m
- Clear height below rotary beams 7.77m
- Setback load N/A (No setback capability)
- Rotary capacity 3,700 kN
- Max. Combined load 3,700 kN static
ROTARY TABLE (auxiliary drive only)
- Drive MAX STREICHER
- Size (inch) 37-1/2 “
- Power Rating (HP) 60 - 180 kW Hydraulic motor; 40 kNm @ 15 rpm
TOP DRIVE SYSTEM
- Make, type MAX STREICHER Hydraulic
- Rated capacity 350 bar, 3.700 kN, 465 kW
- Rated torque M/U, B/U torque 85 kNm
continuous 67 kNm@70 rpm and 19 kNm @ 190 rpm
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- Maximum rotary speed 190 rpm
RIG POWER
- Number of Engines 4
- Number of Generators 4
- Generator power 4 x 1065 kVA / output max. 4 x 800 kW, cont. 4 x 600 kW
- SCR system VFD – Schneider Electric, Siemens
MUD PUMPS
- Make, type Wirth TPK 1600 12”
- Number of pumps 2
- Power Rating 1600 HP each
MUD SYSTEM
- Active tank capacity 118 m³
MUD TREATMENT
- Shale shakers Shaker screens optional at extra cost
- Make, type 3 x Derrick, FLC 2000 4 Panel
-Gumbo (hydrated clays) removal 1 pc
- Make, type Derrick Flo-Line Primer
- Desander Not supplied
- Make, type "
- Desilter yes
- Make, type Derrick 16x4”
DRILL STRING
- Drill Pipe
- Size 5” 3-1/2”
- Length 3500 m 3950
- Weight 19,5 lbs/ft 15,5 lbs/ft
- Grade S-135 S-135
- Heavy-Weight Drill Pipe
- Size 5” 3-1/2”
- Quantity 9 joints 36 joints
- Drill Collars
- Size 4-3/4” 6-3/4” 8-1/4” 9-1/2”
- Quantity 9 12 at request at request
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BLOWOUT PREVENTERS
- Annular preventers
- Make Xinde
- Size 13 5/8”
- Pressure rating 5000 psi
- Ram type preventers
- Make Xinde
- Size 13 5/8”
- Pressure rating 10.000 psi
Single / Double Double & Single (with shear/blind)
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11.2 Attachment 2: Well Control Stack-up Drawings
A. Diverter Arrangement
Bell Nipple
Diverter Spool
21 1/4" flange installed onto 20" casing
20" casing, flange
installed and
cemented in place
Diverter
Annular
6" ID Diverter Line
21-1/4" 2000psi
Annular BOP
21-1/4", 2000psi
21-1/4", 2000psi
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B. BOP
7000mm
6777mm
Annular
1260mm w/ Bell Nipple
1226mm w/o Bell Nipple
Total Height
1790 mm
Double ram
1470 mm
Choke Line Kill Line
Drilling Spool
910 mm
880 mm
Single ram
7490mm
Synergy 1 - BOP - Wellhead & 13 5/8"x 10K BOP Schematic
Rotary Beams
7770mm hoisting cross beam
Center Flowline
Lower Edge Flow Line
Substr
uctu
re
Substr
uctu
re
11” - 10000
2 7/8" - 5" Var. Rams
Shear Rams
13 5/8” - 10.000
Annular 13 5/8" 5k psi
13 5/8"-10.000psi
5" Pipe Rams
13 5/8"-10k
13 5/8"-10k psi
13 5/8" 10k psi
13 5/8" 10k psi
13 5/8"-10k
13 5/8"-5k psi
13 5/8"-5k psi
13 5/8"-5k
21-1/4" 2k psi
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11.3 Attachment 3: Wellhead Configurations
Wellhead: End of Drilling Phase
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Wellhead and Frac Tree
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Wellhead and Production Tree
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11.4 Attachment 4: Casing Design Summary
Normalised Safety Factors:
a) 13-3/8"
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b) 9-5/8"
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c) 7" Liner
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d) 5-1/2" x 4-1/2" Tapered String