Abstract
In this paper, we present a new computationally efficient optimization scheme (in the least-squares minimization framework) that allows simultaneous nonlinear parameter and flow rate estimation from multiprobe wireline formation tester packer and probe(s) pressure data. Our optimization scheme is based on a simultaneous iteration of all of the unknown parameters (formation parameters and flow rate steps) and is quite general in that it can also be applied to all transient tests. Parameter optimization is achieved using the public domain Levenberg-Marquardt algorithm with the restricted step, LMDER, from Argonne National Laboratory. Two examples (one synthetic and one actual field data) are considered to demonstrate the applications of the scheme. The first example pertains to a normal buildup test in single layer system where the flow rate data are not available, whereas the second example pertains to real multiprobe wireline formation tester packer and probe data in a three-layer crossflow system.
