Improvements in heavy oil well testing

An interesting case study using a multi-disciplinary approach to formation testing in heavy oil wells.

Formation testing in heavy oil reservoirs via Drill Stem Testing (DST) can be challenging due to flow control problems associated with higher fluid densities and viscosities. The problem is further complicated in the case of exploratory wells where little is known (or can be inferred) about the reservoir properties, reservoir fluids, and pressures. SPE 110743 looks at a new approach in formation testing heavy-oil exploratory wells of Northeastern Peru.

The paper explores different configurations consisting of Tubing Conveyed Perforating (TCP), DST, and Electric Submersible Pumps (ESP) run in two different discovery wells. Based on lessons learned, a TCP-DST-ESP string was run in the third well with the purpose of perforating under dynamic under-balance conditions, producing at stable rates, sampling, and shutting the well in down-hole for pressure transient testing - all in the same run. The paper cites good results including getting an accurate reservoir evaluation without reservoir formation damage while saving rig time and reducing operational costs.

This multi-disciplinary approach, combining reservoir engineering, well testing, and artificial lift disciplines is worth further study as a good example in getting good formation test results in challenging heavy oil wells.

Kambiz.