a least squares approach to estimating the average reservoir pressure

least squares method (lsm) is an accurate and rapid method for solving some analytical andnumerical problems. this method can be used to estimate the average reservoir pressure in well testanalysis. in fact, it may be employed to estimate parameters such as permeability (k) and porevolume (vp). regarding this point, buildup, drawdown, late transient test data, modified muskatmethod, interference test, and other methods are equivalent to a separable least squares problem.the main advantage of lsm in the well testing problems is that the results would be confident andno trial and error is required. furthermore, the given method requires a short time. the fast rate ofconvergence and high accuracy of the lsm are demonstrated through two examples. the currentstudy concerns a modified muskat method. the results of lsm combined with the modified muskatmethod are compared with the other iterative and qualitative methods. the preliminary numericalresults with both simulated and field data suggest that the method be capable of producing smoothinterpretable estimates of reservoir parameters from data.