Houston-headquartered W&T Offshore is looking to make its US Gulf of Mexico Mahogany field the cornerstone of its 2017 investment program after hitting oil across five zones in a new appraisal well.
The Mahogany field, discovered in 1993, was the industry's first commercial, Gulf of Mexico sub-salt discovery. Sitting 80mi off Louisiana, in 375ft water depth on Ship Shoal Blocks 349 and 359, it has been in production since December 1996 via a fixed facility.
Drilling on the field, which W&T took over operatorship of in 2004, and now owns 100% of, had been halted back in 2015, due to the oil price slump.
The new well will initially be completed as a producer in one zone, with others due to be tapped at a later date.
Tracy Krohn, W&T Offshore chairman and CEO, said: "After pausing our Mahogany field development drilling program since early 2015, when commodity prices slipped, we are very pleased to have resumed drilling activity there to further unlock the significant potential of this huge field. We are benefitting from our recent analysis of our new WAZ seismic data over the field, which allows us to more clearly image the sub-salt formations and assess the additional upside of this field.
"With a number of development and low-risk exploration locations yet to be drilled, the Mahogany field is expected to be the cornerstone of our capital program in 2017 and possibly beyond."
The Ship Shoal 359 A-18 well logged 149ft of net oil pay in the five zones, extending the size and depth of the Mahogany field. The well was drilled on the western side of the Mahogany field to extend the productive limit of the 'T' sand, which was discovered in mid-2013 by the A-14 well.
The A-18 well confirmed that the 'T' sand is present and oil bearing on the west side of the field. It also logged and penetrated four additional "attractive" pay sands in addition to the main 'T' sand target.
After casing the 'T' sand, the company drilled an exploratory tail (about 950ft deeper) beneath the main well target to test seismic reflectors imaged with its newest 3D seismic data and discovered an additional pay interval in a deeper 'U' sand interval. The success of the A-18 well is expected to generate additional drilling locations.
"The A-18 well allowed the company to acquire its first core data from this important reservoir with rock permeability estimated to exceed one darcy, confirming the excellent flow potential of this exceptional reservoir. By comparison, the permeability of shale plays in the Permian Basin is often stated as having permeabilities in nanodarcies. A nanodarcy is one billionth of a darcy, which is obviously significantly less than a darcy," said Krohn.
Tom Murphy, W&T Offshore's COO, said the well also penetrated the field's historic producing intervals - the 'P' and 'Q' sands - in the highest structural position in the field's history.
"This sets up a very attractive attic recovery project in an area of the field with good water drive characteristics and recovery efficiency.
"Our exploratory tail has confirmed the presence of hydrocarbon-bearing sands in a trapped position beneath our currently productive 'T' sand and further extends the vertical column in the field to these previously unpenetrated reservoirs. "The well's success is expected to generate several high-quality additions to our organic drilling inventory, including a future extension of the main 'T' sand based on this most recent penetration, a crestal development well opportunity to exploit the western 'P' and 'Q' attic area, and deeper drilling opportunities to exploit and target the newly discovered deep 'U' sand."
The SS 349 A-18 well was drilled to a total vertical depth of approximately 20,000ft in 372ft water depth. It will initially be completed in the main objective Upper 'T' Sand and is expected to be placed on production early in Q1 2017. The well completion will be set up for a low-cost future recompletion to the untested deeper 'U' sand, and the three additional sands in the 'P' and 'Q' intervals will be exploited as future recompletions or will be considered for further development well locations to accelerate value.
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