Application of material balance in pumping well analysis

A new technique has been developed to estimate the flowing bottomhole pressure for a pumping oil well. The P/sub wf/ data for an undersaturated oil well, published elsewhere, demonstrates the validity of the proposed method. However, direct verification for a saturated oil well case is yet to be made. This study also highlights some of the misapplications of the material balance equation for estimating the P/sub wf/, q/sub 1/, and the annular influx rate. The techniques employed to obtain such parameters are of questionable merit. The direction of error (underappraisal of P/sub wf/) has been consistently predicted by our model. This provides indirect support of the proposed technique. The suggested method of P/sub wf/ estimation is superior to the AWS method, specially in a foaming annulus. While testing a saturated oil well, the proposed method should prove to be more accurate compared to the AWS technique, since no empirical correlation needs to be employed for estimating the liquid gradient like the AWS method. 11 refs.