BP has commenced the drilling of a relief well to intercept and isolate the oil well that is spilling oil in the US Gulf of Mexico. The new well, in 5000ft of water, is planned to intercept the existing well around 13000ft below the sea-bed and permanently seal it.

The new drill site is about half a mile on the seabed from the leaking well in Mississippi Canyon block 252, and drilling is estimated to take some three months.

BP has also carried out a second approved trial injection of dispersants directly into the oil flow at a point close to the main leak on the seabed. The technique is intended to efficiently mix the oil and dispersant, breaking up and dispersing accumulations of oil and allowing it to degrade naturally and reduce surface impact.

BP said rapid progress is also being made in constructing a coffer dam, or containment canopy. A 14 x 24 x 40 foot steel canopy has already been fabricated and other-sized canopies are under construction and being sourced. Once lowered over the leak site and connected by pipe, the canopy is designed to channel the flow of oil from the subsea to the surface where it could be processed and stored safely on board a specialist vessel.

Weather permitting, first installation of a canopy on site is expected to start in a little over a week, allowing the process of testing and commissioning to begin.

Tony Hayward, chief executive of BP Group, said: “This is another key step in our work to permanently stop the loss of oil from the well. At the same time we are continuing with our efforts to stop the leak and control the oil at the seabed, to tackle the oil offshore, and to protect the shoreline through a massive effort together with government agencies and local communities.”