OH Zonal Isolation in/across Coal layer

Background information:

DNO is planning to drill a gas producer well which penetrates 2 reservoir sections. The reservoirs are separated by a thin Coal layer (ca. 4.5 m TVD / 13 m MD @70 degree inclination). 

There is some initial differential pressure between those formations but not too high (ca. 5 bar). 

The well trajectory will be at 70 deg inclination to limit drilling the coal at high inclination. The lower completion consists of 5 ½” Mesh type screens inside the 8 ½” hole deployed with a Liner Hanger and a Reservoir Barrier Valve (Ball valve type). See the general completion schematic attached.

The problem:

The upper reservoir contains gas only. 

The lower reservoir has a gas/oil contact, and it is believed that after 9 months of production the lower reservoir will have an oil / water breakthrough which will kill the well. We then need to shut in this lower reservoir by either setting a plug or by using a technology that shut off the lower formation remotely. 

The risk, however, is on the isolation on the outside of the screens, which needs to be set across the coal layer to prevent any flow from the lower formation through the annulus into the upper formation.

For now, we have considered OH isolation packers in combination with swell packers to be set across the coal layer to generate the X-flow barrier.

DNO would like proposals for any new technology on OH isolation in the market, and experience setting isolation packers in thin coal layers.