In the petroleum industry, a well test is the execution of a set of planned data acquisition activities to broaden the knowledge and understanding of hydrocarbons properties and characteristics of the underground reservoir where hydrocarbons are trapped. The test will also provide information about the state of the particular well used to collect data. It is very important to the oil and gas field development because precise reservoir model is the foundation for all oil and gas field development work. Well Testing is recognised by many operating oil and gas companies to be the most hazardous operation they routinely undertake. Therefore, it is of great importance that such operations are extremely well planned and executed. This valuable book covers all the major "Operational Aspects of Oil and Gas Well Testing" and uses a structured approach to guide the reader through the steps required to safely and effectively plan a well test operation.