Remedy for an Underground Blowout in a gas well causing incidents like contamination of ground water

We have been experiencing shallow gas flows (gas broaching) following an abnormal sound in one of the gas wells, since July 2011. This was later identified as a case of underground blowout. One of the contributing factors was erosion of tubing due to sand ingress and annular pressure buildup. Several attempts were made to address the problem by killing the well, drilling of relief well and vent holes, etc. Although the extent of gas flow was contained to a great extent, the same is continuing. The contamination of ground water, fire incidents, etc. are some of the issues that need to be addressed. Complaints of shallow gas flows are reported by people residing in the area neighboring to the well and need to be resolved.

Can anyone suggest a remedy to this persistent problem?