How deep is your well?

Elaine Maslin

May 1, 2016

This year, the deepwater drilling record could be broken not just once, but twice, breaking the last record, set back in 2013. Elaine Maslin takes a look.

Total’s Raya-1 well is due to be drilled offshore Uruguay using Maersk Oil’s ultra-deepwater Maersk Venturer drillship and could top the deepest water well on record – ONGC’s 3174m record (OE: March 2016). Anadarko is also expected to drill a potential record breaker offshore Colombia, according to Spectrum’s Neil Hodgson.

Yet, what might be surprising is that the four current deepest water well records were drilled by India’s ONGC (see table). That’s not to mention the mild surprise that such costly drilling is still going on in today’s US$30-40/bbl environment, using rigs still likely to be on rig rates set at least 18 months ago.

However, while deepwater drilling records look set to be broken, the numbers need to be put in context. Many of the deepest water wells are still in the Gulf of Mexico, where drilling is not just about water depth, but total depth, which can mean adding a further 7km of subsurface to the water depth the drill bit has to travel through, highlights Andrew Latham, VP upstream consulting at analysts Wood Mackenzie.

He also points to the fact that there are less than 30 wells in this ultra-deep category, “which, in the global scheme of things is a pretty small subset,” and none of them have been turned into producers. The likelihood that depths continue out to 4000m isn’t that strong either, he suggests, due both to the oil price but also the thinner oceanic crust at those depths.

While breaking records, ONGC’s wells, ranging from 3107-3174m water depth, have had mixed success. The current record holder, drilled in June 2013, well 1-D-1 off the east coast of India, was drilled using Transocean’s ultra-deepwater drillship Dhirubhai Deepwater KG1 and was dry. The DD KG1 is rated to 12,000ft water depth and is currently under contract to Petrobras offshore Brazil, through to December 2017 based on a $394,000 day rate.

The second deepest well, ONGC’s NA7-1, was also dry. The third, ONGC’s KGD051NAA-1, also drilled in 2013, had gas shows and the fourth, CYPR-07-A1, drilled in 2011 by Reliance, was a tight hole. Going to press, OGNC had been tendering for deepwater drillships for future drilling, but it wasn’t clear if this was for exploration or production wells. For the most part, the remaining deepest water wells are offshore US, followed by Mexico and Brazil.

“In this environment, a lot of the planned wells are slipping somewhat to the right in terms of timing,” Latham says. “In particular, the frontier wells in countries where the operator and participants don’t have production so they haven’t got a tax shelter against drilling costs.

“Even though there has been massive deflation in terms of rig costs, most of the wells being drilled now are with rigs signed two years ago on very high day rates.” While rig rates have fallen dramatically, this is mostly theoretical because they are not being used, he points out.

“The general themes we are seeing is de-emphasis of exploration with high costs, high sub-surface risk, frontiers and even play contenders, because they are higher risk, as well as anything that is a longer lead time.”

If there is an ultra-deepwater discovery, the next step is commercializing the wells. “Nearly all of these (ultra-deepwater) locations are frontier with very little infrastructure,” Latham says. While dry gas discoveries could be more attractive to produce, due to lower complexities around subsea facilities and flow assurance, gas markets are “pretty challenging,” and operators still tend to prefer to hunt for more easily monetizeable and transportable oil.

Yet, it’s not all doom and gloom. “The Eastern Mediterranean is a nice reminder that ultra-deepwater large scale gas could be very commercial, such as Eni’s Zohr. The big gas finds in recent years in East Africa, Tanzania and Mozambique, and also Senegal and Mauritania, have positive routes to market.”

Deepwater drilling records 

Well Country Name Operator Well Type Result Water depth (m) Year



ONGC Exploration Dry hole




India ONGC


Dry hole 3165 2013



ONGC Exploration Gas Shows 3150 2013


Uruguay Total Exploration Planned 3150 2016


India Reliance Exploration Tight Hole 3107 2011

LL 511 #1 (G10496)

United States Murphy Oil Exploration Dry Hole 3091 2008

AC 951 #1 (G20885)

United States ChevronTexaco Exploration Oil Shows 3051 2004

LL 370 #1 (G31842)

United States Murphy Oil Exploration Gas 3040 2008


Brazil Petrobras Appraisal Oil 2989 2015

LL 411 #1 (G31847)

United States Eni Exploration Dry Hole 2989 2014

AC 903 #1 (G20876)

United States Unocal Exploration Oil 2970 2001

AC 903 #1ST1 (G20876)

United States Unocal Appraisal Oil 2970 2001

AC 903 #2 (G20876)

United States Unocal Appraisal Oil 2965 2001


India ONGC Appraisal Gas 2965 2010


India ONGC Exploration Dry Hole 2961 2013

AC 947 #1 (G20882)

United States Unocal Appraisal Oil 2948 2002


India Reliance Exploration Gas Shows 2948 2011


Mexico Pemex Exploration   2944  


Mexico Pemex Exploration Dry Hole 2940 2013
AC 859 #1 (G20871) United States Unocal Exploration Oil 2934 2004
AC 859 #1ST1 (G20871) United States Unocal Appraisal Oil 2934 2004
WR 508 #2 (G17001) United States Shell Appraisal   2922 2006
Maximino-1 Mexico Pemex Exploration Oil 2919 2013
Maximini-1 DL Mexico Pemex Appraisal Oil & Gas 2919 2015
3BRSA-1239-SES Brazil Petrobras Appraisal Dry Hole 2917 2014
WR 508 #1 (G17001) United States BP Exploration Oil 2913 2005
WR 507 #1 (G18730) United States Shell Appraisal   2912 2012
Supremus-1 Mexico Pemex Exploration Oil 2900 2012