2 - Forms of Lift - ESP Methodology

Major forms of Artificial Lift Schlumberger Private

INFLOW AND OUTFLOW PERFORMANCE SURFACE PRESSURE At Wellhead

PRODUCED FLOWRATE

• If Po < Pwf, the well will flow naturally (~6% of wells by number)

• If Po ≥ Pwf, the well will require Artificial Lift –

(~94% of wells worldwide) WELL OUTFLOW RELATIONSHIP

Po Required Po to produce desired rate

Reservoir Pressure- Pr

Pwf

WELL FACE PRESSURE

WELL INFLOW (IPR) Available Pwf as function of the flowrate

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INFLOW PREFORMANCE RELATIONSHIPS • Straight Line (PI): • Vogel Relationship: Qo/Qomax = 1 – 0.2 (Pwf/Pr) – 0.8 (Pwf/Pr)2 Pwf

= flowing bottom hole pressure at sandface (psia)

Pr

= average reservoir pressure (shut in BHP psi)

Q

= oil flow rate (BPD)

Qo

= flow rate (BPD)

Qomax

= maximum flow rate (Vogel or combination),

PI

= Productivity Index BPD/psi.

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Pwf = Pr – Q / PI

Straight line vs. Vogel – Graphically

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OUTFLOW PERFORMANCE RELATIONSHIP • Po = Ph + Pfr + Pwh •

Ph = Hydrostatic pressure

•

Pfr = Pressure drop due to friction losses

•

Pwh = Wellhead Pressure (surface pressures)

• Several correlations have been developed to better model mixed flow considering different factors such as flow-regime, water cut, viscosity, well inclination, roughness, holdup, etc.

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Where,

Pressure to Head Conversion • To convert pressure to head: • Head (in feet )= Pressure (psi) / (SG*0.433)

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• Fresh water gradient = 0.433 psi/ft

The concept of Artificial Lift

• Lift process transfers energy downhole or decreases fluid density in the wellbore to reduce hydrostatic pressure on formations.

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• Artificial Lift is needed when reservoir pressures do not sustain acceptable flow rates or there is no fluid flow at all.

ARTIFICIAL LIFT METHODS OVERVIEW Schlumberger Private

ARTIFICIAL LIFT METHODS Gas Lift (SLB) DuraLift PC Pumps (SLB)

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ESP’s (SLB)

HydroLift Hydraulic Pumps (SLB)

Beam pump (not SLB)

AL Methods Applicability – not ‘one size fits all’ ESP's poor fair good fair fair good good fair good (with VSD) fair

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Applicability of AL Methods Condition Rod Pumps Hydraulic Pumps PCP's GL Scale fair fair/poor fair fair Sand fair very good/poor* good very good Paraffin poor fair good poor Corrossion good fair fair fair High GOR poor fair fair very good Deviation poor very good fair/good very good Rate poor fair fair very good Depth fair very good fair good Flexibility very good very good good very good Temperature very good good poor good

Artificial Lift Market 94% of Wells are on AL

US 541,000

Revenue Spears 2004 Rod Pumps Electric Submersible Pumps PCP's Gas Lift Hydraulic Pumping Russia Others 121,000

Total Expenditures

9,000 Libya Egypt 1,760 1,200 Oman 2,600

Venezuela 15,000 Peru 4,600

China 76,000 India 3,000

Brazil 7,400

Argentina 13,800

Indonesia 9,500

Australia 1,300

World: 845,000 wells

MM$ 717 1725 369 130 30 320 3291

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Wells Spears 2004 % WW Wells WW Rod Pumps 79% 669,716 Electric Submersible Pumps 12% 98,065 PCP's 4% 30,144 Gas Lift 3% 26,892 Canada Hydraulic Pumping