Mod 1 Flashcards
Name some of the general reasons to test your well
Initial pressure determination
Current average reservoir pressure
Absolute Open flow potential
Deliverability potential under various conditions
Determine formation KH (productive capacity)
Presence of formation damageand potential to stimulate well
Size of drainage area
Determination of reservoir boundaries
What is the purpose of a gas well deliverability test? And what is is also known as?
To predict the production rate as a function of reservoir pressure and flowing pressure.
AKA - Back pressure test, relating to the pipeline or wellhead pressure
What is an AOF?
a prediction of what the well could potentially produce against zero sandface pressure
What are the four types of gas well deliverability tests?
Conventional test
Isochronal Test
Modified isochronal test
Single point test
Describe a conventional test
4 or more stabilized flows at increasing rates followed by a single shut - in period ( pressure build-up)
Stabilization is achieved when the flow rate and back pressure appear to be steady
What are the common problems with the conventional test?
Long flow durations may be needed for the well to stabilize. These long flows may result in environmentalor wastage problems
Describe a Isochronal Test
Based on the assumption that the effective drainage radius of a given well is a function of time NOT flow rate
4 or more unstabilized flow periods at increasing rates but equal times. Each flow is followed with a shut- in period to a stabilized pressure. finally, a single extended flow to stabilization.
Describe how the stable shut-in pressure relates to time
Stable shut-in pressures take progressively longer to fully build- up because of the larger flow / pressure disturbances
What is the common problem with the isochronal test
Long shut in durations may be needed for the pressure to build - up
Describe the modified isochronal test
4 or more unstabilized flow periods at increasing rates but equal times. Each flow is followed with a shut in period, same duration as the flow period. Finally, a single extended flow to stabilization
Equal flow and build-up times
Briefly describe a Single point test
Only a single flow period at one rate is conducted
When can a single point test be warrented
for reservoirs where a large number of multi-point tests are already available or in very tight reservoirs where the time to stabilization is very long
What does a deliverability test record?
Gas production rates and cum. volumes Oil rates and cum. volumes Condenstate rates and cum. volumes Water rates and cum. volumes Sandface pressure Tubing head pressure Annulus pressure wellhead temp time
