Gas Well Deliquification Workshop Adams Mark Hotel, February 25-27, 2008 Downhole Pressure Boosting: A production enhancement tool for both dry and liquid loaded Gas wells Norman Liley, Project Director Corac Group plc, UK JIP Partners: -
Presentation content Why Compress Downhole? Key Innovative Steps Machine Design Project Progress Liquids handling (video) Application guide Value Proposition 2
Why Compress Downhole? Pressure Gradient Tubing Head Pressure Pressure (Psia) 0 200 400 600 800 1000 1200 1400 1600 0 Reservoir Depth Length (ft) 1000 2000 3000 4000 5000 6000 Pressure profile necessary to produce same flow as a DGC Tubing Flow DGC Boosted Flow Reservoir Pressure Increase in Drawdown 3
Why Compress Downhole? No surface equivalent below FWHP < c.400psi Tubing Head Pressure Pressure (Psia) 0 200 400 600 800 1000 1200 1400 1600 0 Reservoir Depth Length (ft) 1000 2000 3000 4000 5000 6000 Compression No surface compression process equivalent adds to DGC heat at to FWHP the gas < c. 400psi suppressing liquid dropout in upper tubing Tubing Flow DGC Boosted Flow Reservoir Pressure Increase in Drawdown 4
Why Compress Downhole? Gas Velocity Gradient 5
Why Compress Downhole? DGC increases velocity in lower tubing 6
Why Compress Downhole? Well performance with liquids Pwf (psia) 1600 1200 800 No DGC, WGR=0 stb/mmscf No DGC, WGR=1 stb/mmscf No DGC, WGR=10 stb/mmscf No DGC, WGR=38 stb/mmscf 400 Gas velocity <Turner criteria 0 0 5 10 15 20 25 30 Gas Rate (MMscf/d) 7
Why Compress Downhole? DGC increases production to a lower reservoir pressure Pwf (psia) 1600 1200 800 400 No DGC, WGR=38 stb/mmscf With DGC, WGR=0 stb/mmscf With DGC, WGR=1 stb/mmscf With DGC, WGR=10 stb/mmscf With DGC, WGR=38 stb/mmscf > 50% Production Increase 0 0 5 10 15 20 25 30 Gas Rate (MMscf/d) 8
Downhole Gas Compression is a powered artificial lift technique that maintains high production rates at lower tubing head pressures even in wet wells Reasoning: Greater drawdown increases flow from the reservoir; This increased flow, at lower pressure, results in higher gas velocity within the lower tubing deliquification; Compression heat suppresses drop-out in upper tubing; 9
Key Innovative Steps Gas filled brushless permanent magnet motors; Drive and Compressor on one piece shaft; Gas lubricated bearings; Downhole power electronics; Low speed blading. High speed, low loss, no seals and highest power density; No seals / couplings - robustness; Facilitates high speed with negligible losses; Power transmission for high speed; Liquids and solids management. 10
Design: Compressor Module (loop) Internal gas system cooler Motor cooling fan Primary Compressor Discharge Gas flow Rear Bearing Inlet Shaft Motor Front Bearing 11
Progress at new Test Loop The facility: Replicates d/h environment; Various gases; Representative P & T; 2-phase flow. A year of testing: Performance verification; Establish reliability. Field trials late 2008. 12
Full Density Multi-Phase Aero Testing 45% LMF 13
Ideal Wells 7 and above cased wells; Moderate volume (2-50MMScf/d); Average to good deliverability; Those suffering liquid loading are excellent; Low solids production; Available electrical power; Workover rig available; Reservoir temperature < 110 C (short term); Assets with limited low pressure surface facilities; Use as alternative to infill drilling; High value assets (offshore). 14
Illustrative Potential Incremental Economics Figures supplied by a customer from their (real) asset model 15
DGC: The Value Proposition DGC could add value by: - Increasing production (up to 50% and beyond); Lowering abandonment pressure; Unloading wet wells; Delaying decommissioning; Extending field life; 16
Downhole Gas Compression Based on existing technologies Prototype testing underway Field trials planned later this year Further JIP participation sought Commercialisation nearing 17
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