Water Drive

[Jriad]

What sort of things do you look for from logs, production data, and pressure data to determine whether or not a gas reservoir is a water drive mechanism?

 

[DrillerNic]

Classical reservoir engineering is the easiet way: material balance.

For gas reservoirs, this means plotting P/Z (y-axis) against production (x-axis) which should be a straight line (with GIIP at the x axis intercept) for a pressure depletion drive. If the points don't fall on a straight line it means you've got pressure support from somewhere.

This pressure support couild be coming from a number of places: water drive, across a leaky fault from an undrained fault block...

So look at all the resevoir pressure estimates you've got (NOT FBHP...you want to be doing welltests to find out the reservoir pressure), and plot P/Z against the total production to the date of the particular test.

 

[accademics]

what are the major functions of wellhead equipment and their major manufacturers?

 

[accademics]

what are the main differences between valves and chokes?

 

[Ashereng]

accademics,

You may want to start new threads for your two posts above. You are highjacking Jrida's posting.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[DrillerNic]

Accademics- wellhead equipment consists of the wellhead, the christmas tree and the choke.

The wellhead provides the foundation for the well, supports the different casing strings and the tubing, and provides pressure integity. The wellhed also allows access to the different annuli (for monitoring, gas lift and occasionally nowadays for cuttings re-injection).

The christmas tree provides pressure integrity for the top of the well and a way of shutting off flow from the well and a way of gaining (limited) access to the well. The Christams tree connects the well to the surface flowline.

The choke provides flow control from the well- if it's correctly sized, it's a constant flow device, so the flowing wellhead pressure is decoupled from any pressure fluctuations that may happen down stream.

Manufacturers are:
Vetco (good equipment, especially subsea, but I've always had QA/QC problems whenever I've used their surface wellhead gear)
FMC (I have no experience of their wellheads)
Cooper Cameron
Konigsberg (I think they specialise in subsea equipment)
Claxton (cheap & cheerful surface trees, but excellent customer service)