Question

What is the difference between the two major types of well testing: 1. Pressure Transient Testing 2. Deliverability Test

Please answer in detail

(Well Testing- Petroleum Engineering)

Answer 1

The well tests in which pressure is recorded with respect to time.

The major difference between pressure transient test and Deliverability test is flow regims.

Change in pressure with respect to time is known as pressure transient rest.During well test,a temporary change in production rate helps to note a pressure transient.This pressure transient is noted onlt for short period of time compared to total life of well.

The results of this tests utilized to develop reservoir model for the estimation of field behavior and fluid recovery.

This type of test is usually carried out for early stages of development of reservoir when its properties has been identified.

There are five types of pressure transient tests exists.

1. Build up test

2. Drawdown test

3. Injection test

4. Intereferece test

5. DST.

Applications : Reservoir behavior, Permeability and skin, fractional length calculation, well pressure,Boundaries estimation.

whereas Deliverability tests refers to the testing of a gas well to measure production capabilities under specific conditions of reservoir and bottom hole flowing pressures.

A most common productivity indicator of this test is "Absolute open flow" AOF

AOF is the maximum rate at which a well could flow against the theoretical atmospheric back pressure at the sand face.

Application: To generate reservoir inflow performance relationship or gas back pressure curve.

1.Flow after flow test

2. Single point test

3. isochronal test

4. Modified isochronal test are the different types of tests falling under deliverability test method.