A well test is described as the measurement, under controlled conditions, of all factors relating to the production of oil, gas, and water from a well in a given length of time. Well tests assist in the prediction of production capabilities and trends. Important decisions, such as production methods, secondary-recovery programs, and developmental drilling are made from this information. Regulatory bodies may use the test results to establish withdrawl allocations and tax bases. Well testers have a responsibility to provide complete, accurate data of the reservoir performance.