RFT vs. DST

Well Test Analysis, Pressure and Production Monitoring........ etc.

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jorge0452
Posts: 11
Joined: Tue Mar 06, 2007 2:06 am

RFT vs. DST

Post by jorge0452 »

Dear friend
I have aquestion about well Testing.

Can RFT (or WFT) method (using a modern tool like MDT) reemplace the information that we can get by DST.(in cased hole) ??
we are talking about an exploration vertical well. Sandstone. low permeabilty. Normal gradient.

thanks very much.
silverline
Posts: 44
Joined: Sun Oct 28, 2007 7:49 pm

Post by silverline »

there is no such a test better than putting the well production.

with dts or other tests you put the well flowing just few hours and days with lots of money paying for service companies.

so what I suggest that just run the injection string after drilling/perforation etc., pump water, measure injectivity at different WHPs (250, 500, 700 psi, ...), if low injectivity try stimulation (if applicable) and measure post-stimulation injectivity. From there you can estimate PI of the well and decide your pump design, accordingly. RIH the pump, put the well production and monitor it.

any other advices will be appreciated.
hichem
Posts: 26
Joined: Sat Dec 15, 2007 1:13 am
Location: TUNISIA
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Post by hichem »

DO YOU HAVE ANY MATERIALS CONSERNING RFT AND DST
THANKS
giri802
Posts: 2
Joined: Sun Feb 10, 2008 10:09 am

Post by giri802 »

In my opinion, MDT (openhole) is extremely useful as preliminary evaluation additional to openhole log data
MDT could measure fluid mobility, formation productivity, and conducting in situ fluid characterization.

This early data will be the justification to run casing and complete the well
miroine
Posts: 6
Joined: Tue Nov 25, 2008 7:43 am

Post by miroine »

You need to be very careful regarding the MDT... some time you get a lot of supercharged and tight points in a low permeability reservoir..... and what I know the MDT test is just for a point a small volume (20 cc) so the radius of investigation can not exceed the invaded zone (damaged zone) which may be very different from the DST results (which will be applied in the whole interval depending of the gauge position). However the Dual packer method can sometime give a good results ..... (for my experience .. nothing can replace the DST data if you want to get the PI and an average KH for the reservoir...... ) however ... a comparison between the different tools ( MDT, CMR, DST) which use different calculation methods can give us a good understanding of the permeability range in the Reservoir....
Also you should know that the MDT will never give us the Permeability ... but the mobility ..... (and the viscosity play an important role in case of invasion..... because it s the viscosity of the fluid withdrawn into the chamber and not the reservoir fluid) .......
Hope that can help you ....
shahid
Posts: 16
Joined: Sat Sep 23, 2006 8:41 am
Location: Kuala Lumpur

Post by shahid »

What I'm understand, MDT is just like mini DST. we can take fluid sample through MDT and plot gradient to determine fluid contact and FWL.

For DST, it is involve in bigger scale, therefore we can more info from DST like kh, skin, PI.

from DST interpretation, we can get information on reservoir characterization within area of investigation such as fault, channel, fracture which MDT cannot determined that.

:D
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