Regal negotiated an exploration joint venture with the State-owned Chernihivnaftagasgeologia (CNGG) unit in 1999 for a 75% joint venture interest in, and operatorship of, the MEX-GOL and SV fields.

Between 2000 and 2004, the Regal / CNGG joint venture drilled two appraisal / development wells, MEX-102 (taken into production in April 2004) and SV 52 (plugged and abandoned in March 2004), and successfully completed three work-overs on Soviet-era wells.  These results led the Ukrainian Government to declare the fields commercial in December 2003.