week 4 notes for lab on well deliverability

7/24/2019 Week 4 Notes for Lab on Well Deliverability

1/15

PETE 325Petroleum Production Systems

Week 4Nodal Analysis, or

Well Deliverability, orNODAL Analysis


2/15

Divide system at a point (node) into upstream

and downstream components

Production System Analysis

Upstream components are inflow

Downstream components are outf low

Endpoint pressures are fixed: Pres; Psep


3/15


4/15

Each component has a corresponding q and P relationship

for inflow and outflow

(for a given flow rate, the pressure at a component is fixed)

Flow through the system is determined from

the facts thatonly one pressure is present at a node

inflow must equal outflow at a nodemass

balance requirement

q

Pnode

Inflow performance governed by Pres- Pwf

VLP governed by Pwf- P*wh

*PPS usesPtf


5/15

We can compute IPR Curves and VLP Curves for given sets

of condit ions. Their combination determines well deliverabili ty.

q

Pnode

Inflow performance impacted by Pres- PwfPlus - ?

VLP impacted by Pwf- Pwhplus - ?


6/15

We can compute IPR Curves and VLP Curves for given sets

of condit ions. Their combination determines well deliverabili ty.

q

Pnode

Inflow performance influenced by Pres- PwfPlus - fluid properties

- k, h- ln(re/rw)

- skin

VLP influenced by Pwf- Pwhplus - Ppotential energy

- Pkinetic energy

- Pfriction

For a given IPR and well configuration,We can determine flow rate as afunction of required wellhead pressure, for example.


7/15

Example

What can we say about P for the VLPin this well and for this oil?

-PKE

? PPE

? PF?

= 1.7

Reservoir Data:B = 1.1 bbl/bbl; = 1.7 cp; kh= 8.3 md; h = 53 ft

re= 2980 ft; rw= 0.328 ft (7 7/8 in)


8/15

+

=

sr

rB

pphkq

w

eoo

wfeH

ln2.141

Radial inflow relationship for steady-state black oil:

qkh

sr

r

Bpp

w

e

oo

ewf

+

=ln2.141 Rearrange:

qpwf 54.55651=For our example:


9/15

IPR Curve for this Well


10/15

Now for the VLP


11/15

Single-Phase Liquid Flow: Incompressible

or

Fanning friction factor or Moody friction factor


12/15

Example, Contd

unitsoilfieldin481orD

q.

D

qDvN

RE

==

PKE= 0 (incompressible fluid, no diameter change)

PFis a function of flow rate (friction factor)

(Independent of flow rate.)

But:

ff=16/vd = 16/NRE


13/15

Example, Continued

Must assume turbulent flow.

Instead of implicit eqn. shown last week, we can useChens explicit method (shudder) from PPS, Ch 7:


14/15

Continued

Likewise:300 BPD PF= 8 psi

500 BPDPF = 20 psi700 BPDPF = 35 psi

Therefore total pressuredrop, if surface pressureis zero?


15/15

Thus Well Deliverability:

The VLP Curve crossesthe IPR Curve atabout 3060 psi (+/-)

So the flow rate atzero wellhead pressureis ~470 bpd or so.

week 4 notes for lab on well deliverability

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