文档介绍：Section 2
Principles of Petroleum Production
System Analysis
• Introduction to well flow capacity calculations
Ø Production from undersaturated oil reservoir
Ø Production from two-phase reservoir
Ø Production from natural gas reservoir
• Single phase flow pressible vs.
pressible flow
• Introduction to two-phase flow systems
Introduction
Due to economy of a production system, the flow capacity of a well is a very important and
therefore crucial to assess. It should be noted however that the flow capacity evolves over time
and it tends to decrease as more fluid is produced.
The flow rate of the well depends on the reservoir driving force, ., the differential pressure
between the reservoir and the back pressure exerted on the downhole (bottomhole pressure),
and other parameters involving formation and fluid properties as it will be discussed in the next
few slides.
1
Undersaturated Reservoirs – Darcy’s law
application
• Darcy’s law in cylindrical coordinate – radial direction
q k dp
= ()
A µ dr
• Transient flow equation: Production-Rate-Decline curve:
¶2 p 1 ¶p φµ c ¶p µ æ k ö
+ = t Þ p = p ­ çlogt +log ­÷ ()
2 wf i ç 2 ÷
¶r r ¶r k ¶t kh è φµ ct rw ø
kh( p ­ p )
q = i wf
æ k ö ()
162 .6Bµ ç log t + log ­ ÷
ç 2 ÷
è φµct rw ø
Single Liquid (Oil) Flow – Udersaturated Reservoirs
Production-rate-decline curves are widely used throughout the producing side of oil industry in
assessing individual well and field performance and in forecasting future behaviour. For an
undersaturated reservoir (where no gas exist – the reservoir pressure is above bubble point),
the analytical technique presented here through the use of radial diffusivity equation, provides
a mathematical model by which the rate of decline of a producing well could be estimated.
The parameters in the transient flow equation were all defined before. The only undefined
parameter is the total pressibility