horizontal drilling pilot in a shallow heavy oil reservoir

Authors: John Lavelle, Amin Yaghoobi

Horizontal Drilling PilotIn a Shallow Heavy Oil Reservoir in

Northwestern Romania

2 Horizontal Drilling Pilot – Suplac 2010

Discovered 1958Oil Density 960 kg/m3 (16 API)Viscosity 2300 cpArea 1700 hectares – 70 sections Cold production 1960 (0.5t/well/day)Fireflood started 1964Oil to date 20 million tonnesCurrent rate ~1000 t/d from 750 wells

About Suplac Oil Field


Unconsolidated sandDepth 80 to 200mTVD, dipping to northThickness 10 to 25 metresFireflood line-drive and cyclic steamSchist basement below the sandSouthern boundary is a faultNorthern Boundary is the Oil-Water contact

About Suplac Reservoir


Challenges

Using a vertical mast rig, can we turn to horizontal in 200mTVD or less?Will the unconsolidated sand be stable when drilling 300m drains?Will wellbores maintain integrity under steam injection and oil extraction?Will equipment work – liner, slots, pumps?Will the project be economic?


Execution Timeline

Reservoir proposal 2008Pilot go-ahead Q2 2009Well concept Q3 2009Slotted liner testing Q1 2010Peer reviews, tendering, ordering Q2 2010Location construction Q3 2010Spud August 22, 2010


Location Selection

Undeveloped area of reservoirSufficient TVD Available utilities – close to existing electricity, steam and oil linesChosen site:Directional offsets to 60 degrees and 12/30m DLSLow risk of shallow losses


Map


Well Construction

20” at 5m

9 5/8” TB casing

8 1/2” open hole, 7” slotted liner

Liner “hanger”

300 meter

Pannonian

• 9 5/8” close to base reservoir until an inclination of 93+˚ (parallel to basement)

• Horizontal slotted liner is placed in open hole through the zone

• Steam injection through a 3 1/2” tubing, thermal expansion joint and thermal packer

• Production through conventional rod pump / linear rod pumping unit

BOP Waiver

12 ¼” hole

9 5/8” N80 Tenaris Blue casing

Thermal cement to surface


Equipment

Rig► Top drive 75 tonne stroking mast design► Small footprint – typically under 1000 m2 (1800 here)

“Conventional” DD tools – PDM, MWD, GRLogs – DP conveyed memory toolsLiner – flush joint, fine slots, hydraulic rotating running tool, reamer shoe


Rig


Operations

Drilled centre well in 26 days with two plugbacks – total losses at limestone top

Drilled the West well in 12 days with one plugback (trajectory)– horizontal at 197.55mTVD

Drilled the East well in 20 days with two plugbacks (trajectory, losses) and an open hole sidetrack at 201mTVD in 8 ½” hole


Trajectories – Section View

150

160

170

180

190

200

210

-20 80 180 280 380 480 580

H1C PlanH2E PlanH3W PlanH1CH3WH2EBasementLimestone


Trajectories – Plan View

642700.00

642800.00

642900.00

643000.00

643100.00

643200.00

643300.00

316400.00 316450.00 316500.00 316550.00 316600.00 316650.00 316700.00

H3WH1CH2EH1C PlanH2E PlanH3W Plan


How did we do?

Successful shallow KOP of 10m KBSuccessful shallow landing – horizontal at 200mTVD or less in all wellsSuccessful 300m drains in eachSuccessful open hole sidetrackDemonstrated that:

► The time plan of ~ 10 days is achievable► The budget is achievable► Production rates of 50 t/day are realistic► Slotted liner gives acceptable sand control

19

RISK LEARNING

Trajectory Immediate KickOff Up to 14/30m DLS At-bit inclination Low flow rates Sidetrack earlier rather than later Cement and open-hole S/T proven

Hole Cleaning Hydraulics models incorrect – low flow rates cleaned well “High viscosity” and weighted sweeps were ineffective Pumping out – packoffs occurred Casing to bottom

Hole Stability, Differential Sticking No issues

Liner running No issues – rotation, reamer not rqd Liner setting Prototype tool success Geology Unexpected uncertainty – losses in

limestone

Paper Title: Horizontal Drilling Pilot in a Shallow Heavy Oil Field in NorthWestern Romania

Authors: John Lavelle and Amin Yaghoobi, OMV Petrom S.A., Romania

[email protected]

Thank You!

horizontal drilling pilot in a shallow heavy oil reservoir

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