Slim hole well wireline logging
Schlumberger has a set of 2 3/4" diameter tools offering all services for 4 1/8" holes. These tools have ratings of 175°C (350°F) and 137 MPa (20 kpsi) or better. The efforts to reduce micro-scanners and formation testers to less than 3 1/2" have met with some success. For holes down to 4 1/8" a slim hole 3 3/8" formation tester is available with sampling chambers of 2 3/8gallons and 450 cc. Schlumberger also offer their tools in 2 1/2" size to compete in . . .