![]() ![]() This is a test that involves more than one well in the same reservoir. One limitation is that the properties of injected fluid are different from reservoir fluid, hence a non-uniform displacement may cause erroneous interpretation of reservoir properties. Then fluid is injected into the reservoir, the bottom-hole pressure increases, now injection rate & bottom-hole pressure are measured as a function of time. Initially the well is shut in such that the bottom-hole pressure stabilize at a static reservoir pressure. Injection test is conducted on an injection well. Figure 1: Buildup test & Drawdown test 3. It is not able to evaluate reservoir pressure. Its limitation is the inaccuracy due to fluctuations in flow rate. Ideally, the well should be producing at constant rate but in practice, drawdown data is not regular and the analysis is frequently inaccurate. Now, P wf is measured with respect to flow rate for several hours or day depending on the anticipated reservoir properties & objective of test. In this type of test, flowing bottom-hole pressure (P wf) is stabilized to a static reservoir pressure. In case of tight gases, the transient needs several days to travel to boundary. It also cause loss of cash flow as the well is at no production for a couple of days. Shut-in of well may cause loss of reserves as gases can move to someplace adjacent to original reservoir. During shut-in periods, the flow rate is accurately controlled. Before the build-up test, the well must have been flowing long enough to reach stabilized rate. The increase of bottom-hole pressure after shut-in is used for analysis. The Shut-in bottom-hole (P ws) pressure is recorded for several hours & days. This type of test is conducted on a well that has been producing for some time at a constant rate. The types of Pressure Transient test are: Reservoir properties (permeability, skin).Well Testing topic is discussed on this link. This type of test is usually performed at early stages of development of reservoir when we want to accurately know reservoir properties. The quality of the communication between the well and the reservoir can also be indicated, which can help us to improve the well productivity. These results are also used to build a reservoir model for prediction of the field behavior and fluid recovery to for different operating scenarios. This pressure response provides us different information which may be about reservoir, associated to geological and geophysical characteristics. This pressure transient is noted only for a short period of time as compared to total life of reservoir. During a well test, a temporary change in production rate helps us to note a pressure transient. ![]() Well testing flow regimes are main difference in Pressure transient test and deliverability test. Change in pressure with respect to time is regarded as pressure transient. The well tests in which pressure is recorded as a function of time. ![]()
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