On the protection against coning provided by horizontal barriers of limited lateral extent

The paper determines critical rates to coning for horizontal and vertical wells shielded by favourably positioned impermeable horizontal barriers of limited lateral extent. Mathernatical techniques mimic those used by previous authors for unshielded coning. The Muskat approximation is employed. It turns out that vertical wells can benefit strongly from the presence of a barrier, as measured by the critical rate, depending on barrier position and radius. With horizontal weIls, however, the the critical rate to coning is decreased, except for very wide barriers.