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INPUT   DATA

♥ EXAMPLE Of Input/Output

Title

Reservoir pressure		psi
Flowing bottomhole press.		psi
Oil flow rate		BOPD
Bubblepoint pressure		psi
Skin factor

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OUTPUT   VARIABLES   &   GRAPHS

Open flow oil rate	bbl/day
♦  (qo)max, Vogel
♦  (qo)maxs=0, Klins
♦  (qo)max, Klins

IPR For Vertical Solution Gas-Drive Wells

The relationship between well flow rate and the pressure drawdown (or flowing bottomhole pressure FBHP) is defined as the Inflow performance relationship (IPR). If the FBHP is below the bubblepoint pressure or if inertial effects become significant at high rates, IPR becomes curvilinear rather than linear.

A number of empirical methods have been proposed to generate IPRs, beginning with the seminal work of Vogel on the subject. These methods usually require a least one stabilized flow test (so-called single-point test) in which flow rate, FBHP and average reservoir pressure are measured. These 3 attributes uniquely define the IPRs coresponding to that reservoir pressure.

In Vogel's method, the IPR curve for a well producing saturated oil from a solution gas drive reservoirs can be approximated by the dimensionless quadratic equation:

The standard Vogel's method was modified by Klins et al to explicitly account for the effects of bubblepoint presure and skin, as follows:

where
     q_o = oil flow rate, bbl/day
     (q_o)_max = oil flow rate at FBHP = 0, bbl/day
     (q_o)_maxs=0 = oil flow rate at FBHP = 0 & skin = 0, bbl/day
     p_wf = FBHP = flowing bottom hole pressure, psia
     p_r = reservoir pressure, psia
     p_b = bubblepoint pressure, psia
     s = skin factor, dimensionless, psia
     M = skin-dependent multiplier
     n = bubblepoint-dependent exponent

Tips

    ◊ Use link EXAMPLE Of Input/Output  to demo data entry expectations and results; you may edit & use it as starting point

BIBLIOGRAPHY

• Klins, M.A. & Majcher M.W.; Inflow performance relationships for damaged or improved wells producing under solution-gas drive; JPT, Dec. 1992, 1357-1363.
• Klins, M.A. & Clark J.W.; An improved method to predict future IPR Curves; SPERE, Nov., 1993, 243-248.
• Vogel, J.V.; Inflow performance relationships for solution-gas drive wells; JPT, Jan. 1968, 83-92.
• Ahmed, T.; Reservoir Engineering Handbook; Pennwell Publ Co, Tulsa, Oklahoma, 2000, chap. 7.