A direct search method called "DFS", Derivative Free Search is proposed for estimation of an initial guess of parameters in non-linear regression technique used in well test interpretations. The procedure consists of locating the neighborhood of a point where the objective function is minimum among qq points which are most uniformly distributed in a kk dimensional space. For certain cases, repetition of the procedure alone may result in a convergence of the solution. In general, however, the coordinates of the neighborhood minimum can be used as a starting point for any gradient type algorithm.

Keywords:
algorithm, neighborhood, spe 15928, objective function, estimation, parameter space, convergence, upstream oil & gas, procedure, numgrd
Subjects:
Formation Evaluation & Management, Information Management and Systems, Drillstem/well testing
Copyright 1986, Society of Petroleum Engineers
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