BP has filed an exploration plan for a block where it recently replaced Talos Energy as operator, just west of its Mad Dog field.

The US independent still holds a 100% stake in the Gulf of Mexico block, according to the database of the US Bureau of Safety & Environmental Enforcement.

The Puma West prospect on Green Canyon 821 is just two blocks east of BP’s 2004 Puma discovery, which was near the top of the UK supermajor’s development queue for years, potentially as a Mad Dog tie-back.

However, that project lost momentum after BP and its partners opted to drop the associated leases in 2009.

BP and Talos plan to start drilling at GC 821 as soon as 1 October, with the probe expected to take 135 days.

A second prospect is planned for as soon as March 2020, to run another 135 days.

The site is about 131 miles (210 kilometres) offshore in 4069 feet of water, about 15 miles west of the Mad Dog spar in GC 782.

Rig plans were not clear as Upstream went to press, but BP currently has the Seadrill drillships West Vela and West Auriga under contract in the US Gulf.

The block’s current lease began when Apache captured the tract at a 2012 lease sale for $3.4 million.

The independent, along with compatriot Stone Energy attempted to revive the discovery in drilling the Parmer well in the months that followed.

Stone Energy took over as operator with a 100% stake in 2015, with the company becoming part of Talos via a 2018 reverse merger.

BP has the longest history at the block, however, which it held from 1996 to 2009.

The Puma discovery in 2004 was drilled in GC 823 just two blocks east, which struck 500 feet of net oil pay in Miocene sands.

BP’s first Puma appraisal well was planned on GC 821 and 822. BP's partners were Chevron, BHP Billiton and StatoilHydro (now Equinor).

Partners said the first two wells drilled there did not yield commercial results, though a third appraisal did come back with positive results.

At the time, the discovery was said to be in a “structurally complex subsurface area”.

Ultimately BP and its partners decided to drop the leases in 2009.

Upstream reported at the time that the decision “left some industry observers mystified as the reasons behind it were never publicly disclosed”.

A new bid by BP in 2010 was rejected by regulators after not being deemed to meet a fair market value.

Apache subsequently picked up the block and tried with more exploration in the area on the nearby GC 867 tract, drilling a 2012 exploration well called Parmer in 2012 in partnership with Stone Energy.

However, that effort fizzled out when Apache exited most US Gulf operations in a deal with Freeport McMoRan. Stone gained a 100% share as of 2015.

A decade later, however, BP has put forth a strategy of keeping its existing Gulf of Mexico hubs full.

It has also emphasised a role for proprietary seismic technology to identify new volumes around existing fields.

That is not to say Mad Dog has not been prolific all on its own. Following an appraisal campaign in 2009, the company has estimated that the greater Mad Dog field contains some 5 billion barrels of oil.

In 2016, BP took a final investment decision on a second floating production facility at the field, which it has since named Argos.

That unit is currently under construction at Samsung Heavy Industries in South Korea.

The new semi-submersible platform is to lie six miles south-west of the original, about 190 miles south of New Orleans, in 4500 feet of water.

This story has been modified to correct the construction yard for the Argos platform.

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BP and Talos set out drill plans for Puma West