An operation on a well designed to demonstrate the existence of moveable petroleum in a reservoir by establishing flow to the surface and/or to provide an indication of the potential productivity of that reservoir. Some flow tests, such as drill stem tests (DST) are performed in the open hole. A DST is used to obtain reservoir fluid samples, static bottomhole pressure measurements, indications of productivity and short-term flow and pressure buildup tests to estimate permeability and damage extent. DSTs are performed in the open hole. Other flow tests, such as single-point tests and multi-point tests, are performed after the well has been cased. Single-point tests typically involve a measurement or estimate of initial or average reservoir pressure and a flow rate and flowing bottomhole pressure measurement. Multi-point tests are used to establish gas well deliverability and absolute open flow potential. When you test a small amount of gas or oil over a period of days the pressure it is at will often decline indicating limited amounts of oil or gas present. If a performance modeling indicates that a well can be ultimately completed to achieve a high production rate (e.g. production rate of over 150 Mmcf/d. as reported by Noble Energy regarding Tamar), it is an indication that the pressure in the well was fine, although eventually it is long term testing over several months rather than days that proves an accurate state of affairs