Well completions and workovers. Part 10. Systems approach to well testing (feedback)

If well operators are interested in maximizing profits and minimizing unnecessary completion or workover expenditures, they must use well tests to determine what factors make up the well's environment and resources and what constraints act on the well's inflow and outflow systems. For planning completions or workover, the most important data provided by well tests are the reservoir pressure, wellbore damage, production, and fluid characteristics. The three types of well tests are 1) transient tests (buildup, drawdown, injection, fall-off, pulse, and interference), which determine wellbore damage and formation parameters, 2) production tests, which measure a well's oil, gas, and water outputs, and 3) productivity tests, which determine a well's stabilized inflow capabilities. The importance of proper well-test feedback to adequately describe a reservoir cannot be overemphasized; the data acquired affect every phase of a completion or workover, and follow-up feedback helps to evaluate the success of the operation.