A Deconvolution Method Based on Cumulative Production for Continuously Measured Flowrate and Pressure Data

Abstract This work presents a new methodology for the analysis of permanent downhole gauge and production data based on the deconvolution of cumulative production and bottomhole pressure measurements. In this work we show that the cumulative production is a convolution of pressure drop (as if the well were producing at a series of constant flowing bottomhole pressures) and flowrates (as if the well were producing at a constant pressure throughout the production history). We then employ our modified B-spline based deconvolution algorithm which, in this work, is based on constant stepwise pressures. We use analytical integration of the B-splines, weighted least squares and regu-larization to obtain the constant-pressure rate response function and to estimate the initial pressure. The Laplace transformation is not required in this work. We have validated this approach thoroughly using a synthetic case. We have applied this methodology to various field example cases consisting of both high and low frequency production data. The results indicate that the new method is very efficient in recovering the constant-pressure rate response function in cases where rates are controlled by series of constant flowing bottomhole pressures. We also provide a procedure to check the correlation between pressure and rate measurements by the joint use of two deconvolution methods (SPE 95571 and this work).

A Deconvolution Method Based on Cumulative Production for Continuously Measured Flowrate and Pressure Data Conference Paper