In-situ fluid compatibility testing using a wireline formation tester

A method for performing fluid influx tests in a wellbore traversing a permeable formation, comprising:

• a) inserting a well test device comprising a straddle packer assembly into the wellbore such that the straddle packer assembly separates a test section from other sections of the wellbore;
• b) performing a first fluid influx test during which the fluid pressure the test section is reduced, pore fluid is induced to flow from the pores of the permeable formation into the test section and fluid influx into the test section is monitored;
• c) injecting a first completion fluid into the test section, thereby increasing the fluid pressure within the test section and inducing the completion fluid to flow into the pores of the surrounding formation;
• d) performing a second fluid influx test during which the fluid pressure within the test section is reduced, the first completion fluid and pore fluid are induced to flow into the test section, and fluid influx into the test section is monitored;
• e) comparing fluid influx monitoring data acquired during the first and second fluid influx tests according to step b) and d) to determine any effects of the first completion fluid on the influx of formation pore fluid into the test section.