A Technique To Acquire Wireline Pressure Data In Cased Hole: A Case History Available to Purchase

Acquisition of pressure data is a critical point for pressure maintenance projects. Recently, a workover on a production well had been planned in an on/off-shore field nearRavenna coast (Italy), to transform a production well into an injector, to repressurize the depleted layers of a multilayer reservoir (Porto Corsini Formation - Lower Pliocene). An exact definition of dynamic model was necessary to determine the most depleted layers. Usually, the acquisition in cased wells of the required pressure data is achieved by performing DST's. A different approach, based on the use of Dual Packer Module of Modular Dynamics Tester (MDT*) in Cased Hole, was planned to acquire the necessary data, taking into consideration the several measures requested for the characterisation of dynamic framework. After verifying the cement condition of 7" casing with USIT*(Ultrasonic Imaging Tool), the casing was perforated in the selected intervals with wireline guns at 12 spf, followed by a scraper run for casing cleanup purposes. Then, the MDT* Dual Packer was run, conveyed by wireline, setting the tool packers across the perforated intervals and acquiring pressure data. Up to three buildups and drawdowns were acquired at every point with the possibility to interpret data similarly to Drill Stem Tests (DST's). An accurate planning of operations was necessary to prevent losses problems and MDT packers seal failure due to the potential high differential pressure expected. The Geological Dept. team of ENI Div. E&P, using a dedicated software (GRAD), compared acquired data with historical data, defining in real time depleted layers and value of depletion, with contribute of Reservoir Dpt. In this operation the MDT* Dual Packer Tool demonstrated to be an effective solution, in alternative to conventional DST's, to determine reservoir pressures in cased wells.