DST in Deep Water
Deep Water Definitions Depth of Water (Deepwater >1000ft (300m), Ultra- Deepwater > 5000ft (1500m)) Rig Type - Floaters (Drillships and Semi-Submersibles) Approach and Profile (risk, technology, cost) 2
Deep Water Major Growth Globally 500 Deepwater Fields 400 300 200 100 0 2000 2007 2012 Established Frontier Emerging
SUBSEA OVERVIEW Floating Rigs Semi-Submersible Drill Ship 4
SUBSEA OVERVIEW Subsea Safety Equipment MANDATORY 5
SUBSEA OVERVIEW All Fixed Rigs All Floating Rigs Just Below Rig Floor Ground level Sea level Sea bed BOP stack 6
SUBSEA OVERVIEW System provides a fast acting and reliable means to: Isolate the landing string from the test string Prevent discharge of landing string content (retainer valve) Disconnect the landing string from the test string Provide additional barriers in the flow path Pump through feature Cutting wireline & coil tubing feature 7
SUBSEA OVERVIEW BOP Disconnect 8
System Specifications 9
SUBSEA OVERVIEW 10
SUBSEA DST/TCP job sequence RIH with DST/TCP string, tubing and dummy landing string Land the fluted hanger and close pipe RAM s on the painted pipe Run W/L correlation POOH to the fluted hanger Space out Subsea tree and TCP Run back with Subsea and land FH Set the packer and flow the well End of the test 11
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Packers for DW Operations Retrievable Packers: Posi-test Long stroke packers: used in NGC (no rotation, heaves < 32 ) Use of Slip joints is required: know how to calculate forces on major string? Know the landing string weight (tension required?), the major string weight Assume the worst case: empty pipe ID, Max applied pressure OD 13
Packers for DW Operations Permanent packers: HP: No IF connections, ratings limitations Completion Fluids constraint Be familiar with tubing movement calculation (Hydraulic Calculation handbook) Conduct a high end casing and stress analysis design of the system. E.g. Wellcat, TDAS. 14
Packers for DW Operations Permanent Packers Hydraulics 15
Packers for DW operations Major concern: Deep water Shallow reservoir Wells 16
Downhole Shut-in Valves PCTV, IRDV, DAV, PFSV can be used as the Downhole Shut-in valve Depending on the well parameters Depth, BHP, Applied pressure window, Temperature, Completion fluid, Duration, Test program the choice of shut-in valve and string selection is made PCTH-FF is suitable for most jobs with BHP up to 17.5K psi To minimize operating pressure and stay within the available applied pressure window N2 pre-charge can be increased - This will require RFQ for design review and qualification for the specific job conditions 17
Downhole Shut-in Valves IRDV is ideally suitable for Deepwater operations with integrated circulating valve and its simplicity to operate the valves. - Temperature is limited to 320F - IRDV-DA : Max Tubing 26K, max Annulus 25K (contact SRC if above 21K) - Pressure up and bleed off slowly and keep the rate at 1,000 psi/min to avoid ringing oscillations Slow down the operations. - Do not bleed off pressure quickly, - Do not close the choke back immediately after pressure gauge indicates 0-psi - Do not pressure up quickly and stop. - Stay at a steady bleed and pressure up rate. 18
Downhole Shut-in Valves All pump applied trigger pressure commands should be 200 to 500-psi greater than the tools surface set-up program. High pressure disable commands are preferred over Low pressure disable commands. Wait 10min before sending HP enable commands 19
PFSV-J as Downhole Shut-in Valve Ultra Deep water well conditions Exceeds current IRDV ratings in temperature, pressure, packer or produced fluid environment J-tools are ideal choice - J- tools, PFSV-J and SHRV-J are recommended - These tools bring simplicity to complex well operations - Provides ability to bull head or reverse out before POOH - Seals suitable for Explosive decompression, Extrusion resistant, Temperature resistant, Chemical resistant for high ph fluids and CO2/H2S in produced fluids - Limited by one downhole shut-in TTV-J (or TFTV-J) to pressure test while RIH and SHRV-J to reverse out 20
Deep water well conditions BHP > 25,000 psi Max. pressure > 30,000 psi (BHP + Applied) BHT >400 F Duration > 49 days (up to 90 days) Fluids - ZnBr2, Cesium Formate (proposed) Water depth > 6,000 ft 21
References #3697654 # 3871121 #4092587 Test #3670938 #4181970 #4367922 Test Design Philosophy and Operating Guidelines for Deep Water Testing Deep Water DWCS System and Retrievable Packers Deep Water Well Surge with LS Packer and Subsea Tree Flowrate through by pass of 9 5/8" positrieve IRIS operations in Deep Water applications New Minimum Tension Requirements for all Subsea Trees (SSTT) 22
23 QUESTION?
Space out
Slip Joint Internal Applied Pressure Balanced Slip joint No Internal Applied pressure effect
Slip Joint External Applied Pressure Balanced Slip joint F on Major String F on Minor String
Slip joint External Applied pressure 27 AW 24-Mar-08
Slip joint Internal Hydrostatic pressure 28 AW 24-Mar-08
Space out & correlation 1) Subsea Dummy run Done Prior to RIH with DST string - Dummy landing string will be run and fluted hanger position will be adjusted to well position the ram s in the slick joint - Now, x is fixed. Correlation will be made and space out is done by pulling out of hole up to fluted hanger and adding or removing some tubing lengths from the major string x 29
Space out & correlation 2) Subsea Dummy run Done with DST string -Dummy landing string will be run with the DST string: drill pipe above the adjustable joint is painted to acquire the mark of the pipe ram s - Correlation is done and top shot depth is defined - Space out procedure must compensate for y-x plus any X- over length change below the fluted hanger y x 30