Ball Seat Milling on Wireline Saves the Reservoir

With an effective milling campaign in Canada, Welltec has turned a risky, high cost operation into an economical, non-intrusive solution for optimization of a sensitive reservoir.

An operator working in the Bakken formation in Saskatchewan needed to remove a series of ball seat restrictions in order to set a bridge plug near the toe of the well. They had been using jointed pipe and coiled tubing, which resulted in some formation damage as a consequence of pumping large amounts of fluid to power the mud-motors. The costs were high and the results were not ideal.

The client was therefore looking for a cost-effective solution that would not require introducing more fluids into the reservoir. They decided that Welltec’s milling capabilities on e-line was an attractive alternative based on the technical advantage of an electrically powered milling tool.

Once on location, the Well Tractor was used to convey the toolstring down the horizontal well path to the exact location of every ball seat. Once there, the Well Miller, equipped with a 2.845” ball seat milling bit, was activated and milled out the ports for further accessibility below.

To date, Welltec has removed 11 ball seats for this operator with milling times typically less than one hour per ball seat. This has been achieved without adding significant fluid to the formation or requiring large amounts of surface equipment. Improved production is anticipated from these low pressure, fluid sensitive formations.