HOLE PROBLEMS WHICH RESULT IN EXCESSIVE ROTARY DRILLING COSTS - AND THE CASING DRILLING SOLUTIONS 1. SWELLING FORMATIONS 2. SLOUGHING FORMATIONS 3

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Rolf Fitzgerald
7 years ago
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1 CASING DRILLING A Revolutionary Approach to Reducing Well Costs RODERI Giuseppe Sole Agent for Italy Rotary Drilling vs. Casing Drilling HOLE PROBLEMS WHICH RESULT IN EXCESSIVE ROTARY DRILLING COSTS - AND THE CASING DRILLING SOLUTIONS 1. SWELLING FORMATIONS 2. SLOUGHING FORMATIONS 3. WASHOUT 4. SWAB OIL & GAS 5. HOLE IN CASING OR KEYSEAT 6. RUNNING LOGS & CASING DIFFICULTIES 1

2 Casing Drilling Technical Challenges Changing the Bit & Bottom Hole Assembly Casing Connection Bit Cutting Structure Formation Evaluation Cementing & Drilling Out the Shoe DOWNHOLE TOOLS Wireline BHA Running & Retrieving Tool Axial Dogs (Lock into Lock Collar) Anchor & Seal Assembly (Incorporates by-pass) Stop Dogs (Locate at No Go shoulder) Torque Anchor (Locks into torque collar) Add Mud Motor Bit as required Underreamer Casing Assembly Casing Centralizers as req d Casing Lock Collar Casing Torque Collar Casing Shoe Casing 2

3 Running & Setting BHA Lower BHA (while circulating and reciprocating) until stop dogs locate at No Go shoulders Stop pump and jar down to close by-pass and lock axial dogs into lock collar Continue to jar down to release running tool Retrieve running tool while circulating and reciprocating Drilling Surface Casing Bottom Hole Assembly -Bit (must pass through casing drill string and drill pilot hole) -Underreamer (must pass through casing drill string and underream pilot hole out to desired diameter) 3

4 Retrieving BHA Latch running tool into BHA Jar up to open bypass and release axial dogs Circulate through by-pass to allow underreaming arms to contract Hoist tool out of casing while circulating and reciprocating Cement Surface Casing 4

5 Drilling Out Cement Plug Options -Bit/Underreamer -Bit/ Drilling Casing Shoe -Drilling Casing Shoe / Flat Bottom Mill Drilling Below A Cemented Casing String Bottom Hole Assembly -Bit (must pass through casing drill string and drill pilot hole) -Underreamer (must pass through casing drill string and underream pilot hole out to the inside diameter of the last casing string set) Note: Underreamer arms can be enlarged to underream the last casing string set if required 5

6 Drilling Directionally Bottom Hole Assembly -Bit -Underreamer -Mud Motor with bent housing -MWD -Monel -Anchor & Seal Assembly (Locked into casing) Coring Conventional coring feet per run. Core/underream as a continuous operation. Retrieve coring assembly on wireline. 6

7 Logging Retrieve BHA, pull casing from section of interest, log conventionally in open hole. Log through steel casing (cased hole logs) Log while drilling: Suspend BHA below casing shoe and LWD as currently done and demonstrated here. Casing Drilling Rig Basic changes from conventional drilling rigs -Wireline Winch -Split Crown and Travelling Block with Top Drive -Wireline BOP and pack-off assembly -Casing Handling Tools 7

8 Conclusions Commercially available casing and connections can handle the required torsional and compressive loads while drilling with casing if drilling parameters are controlled and annular clearance is minimal Comparable penetration rates were observed as compared to conventional rotary drilling (through alternating siltstone, shales, coal, sandstone) Significant time can be saved for tripping with wireline compared to conventional tripping with pipe Conclusions Rig Efficiencies -reduced capital and logistics costs due to lighter substructures and single derricks -reduced personnel and increased safety by eliminating extensive pipe handling -separate strings of drill collars and dill pipe need not be acquired, transported and maintained -lower horse power from reduced circulating pressure and elimination of drawworks tripping 8

9 Conclusions Operational Efficiencies -elimination of back reaming and reaming back to bottom after trips -lower fuel consumption and increased bit hydraulics -lower mud and cementing costs due to reduced wellbore diameters -elimination of casing running and drill string handling time Conclusions Unscheduled events eliminated -taking a kick while tripping the drill string -unintentional sidetracks while reaming back into the hole -hole problems caused by swab and surge pressures -key seats and wearing holes in previously set casing 9

10 Summary The conclusions drawn from the initial casing drilling test well suggests cost savings in the 10-15% range for trouble free wells. Elimination of unscheduled events encountered in troublesome wells is expected to increase potential savings up to 30% or higher. CASING DRILLING A Revolutionary Approach to Reducing Well Costs 10

11 Rig Move / Load 1 - Mud Tank 7 Load Rig Capacity 100 Ton Depth Rating 10,000 ft. 5-1/2-17ppf L-80 casing (with 50,000lbs over pull) Rig Move / Load 2 - Mud Pump - Shale Shaker 11

12 Rig Move / Load 3 - Rig Rig Move / Load 4 - Power Unit, Drilling Control Centre 12

13 Rig Move / Load 5 - Generator, Accumulator Rig Move / Load 6 - Water Tank, BHA s, Choke 13

14 Rig Move / Load 7 - Casing Handler Rig Move / Load 8 - Rig Managers Trailer 14

15 Rig Move / Control Room & Mast Up Rig Move / Pick Up Casing and Drill 15

16 CASING DRILLING A Revolutionary Approach to Reducing Well Costs RODERI Giuseppe Sole Agent for Italy 16

Drilling Problems. pull

Drilling Problems. pull Drilling Problems Pipe Sticking Lost Circulation Hole Deviation Pipe Failures Borehole Instability Mud Contamination Formation Damage Hole Cleaning H S General Equipment & Personnel Pipe Sticking Can not