| 摘要 |
An earth formation testing system for determining one or more formation parameters comprises a wellbore formation testing tool including straddle packers 107a,107b for isolating a part of the formation, a pump 108 for inducing a fluid flow in the formation and one or more pressure measurement probes 110. A computer 111 is provided which receives and records pressure data and performs a regression analysis using a refined analytical model and the recorded data to determine properties of the earth formation. The refined analytical model is derived using a correction factor determined by assuming the induced flow is hemispherical, preferably by using finite element modelling. The properties of the formation to be determined include horizontal permeability, vertical permeability and porosity. The computer may be located on the drillstem for drillstem formation testing (DST) or it may be located on the surface as part of a wireline formation testing system (WFT) (307, Fig. 3). |
