CURIOSITY | 3Dent Technology

2019 JACK-UP CONFERENCE

by J. Vazquez

October 30, 2019

Let me start by clarifying that what I call the Jack-up conference has a slightly different official name: International Conference: The Jack-Up Platform. This conference has been held at City University of London every 2 years, since 1985. My first time attending the conference was 2003. At the time, the hot topic was “RPD” or Rack Phase Differential – the observable tilting of a jackup leg (w.r.t. the jack case) that can develop when jacking the hull if the leg has a non-negligible bending moment and the leg-to-hull moment gradually switches from being transferred mostly as a vertical couple (i.e., differential axial load on the pinions/chords) to mostly a horizontal couple (i.e., upper/lower guide loads increasing leg shear and thereby adding load to the leg braces). For that conference, I co-authored 3 papers on the subject (as listed below):

Spudcan Footprint Interaction and Rack Phase Difference (RPD) by KS Foo, MCK Auah, P Wildberger and J Vazquez.
Rack Phase Difference (RPD) by KS Foo, MCK Quah, P Wildberger and J Vazquez.
A SIMPLIFIED MODEL FOR UNDERSTANDING RPD AND ASSOCIATED BRACE LOADING by JH Alford and J Vazquez.

Two years ago, the hot topic at the conference was jackups going on location, and I presented the two papers listed below.

SEABED MODELING EFFECTS ON JACK-UP RESPONSE WHILE GOING ON LOCATION by JH Vazquez, BD Grasso, M Gamino and JS Templeton.
EARTHQUAKE EFFECTS ON THE CANTILEVER BEAM OF A DRILLING JACKUP by BD Grasso, JH Vazquez and J Santos.

This year’s conference was dominated by topics that are more specific to Wind Turbine Installation Vessels (WTIVs) than drilling jackups. In addition, soils and soil-structure interaction topics were also very dominant. Below is a list of the papers that were presented, with a very short description partly based on the ABSTRACT but heavily influenced by my interpretation of the intent of the paper.

Below, I offer a couple of pictures from various presenters (included herein with their permission).

From left to right: Qing Yu, Michael Perry and Rupert Hunt, presenting at the Jackup Conference (photos by J. Vazquez)

I discuss one of the papers in more detail in a separate article of this newsletter. Also note that one of the papers actually references two of papers I’ve coauthored on the coming off location of jackups. The two papers that are references are as listed below.

3-STAGE APPROACH FOR OPTIMIZING COMING OFF LOCATION OPERATIONS by MJ Dowdy, JH Vazquez and C Nelson. 2018 SAME Offshore Symposium. Houston, TX.
GSF GALAXY I JACKUP CASE STUDY FOR OPTIMIZING RIG MOVE PERFORMANCE IN NORTH SEA USING AN ADVANCED SIMULATION MODEL by D Carre, L McArthur, A Simpson, P Zhang and JH Vazquez. 2018 SNAME Offshore Symposium. Houston, TX.

It was interesting to see that there is still no clear distinction between jackups and liftboats. Those of you who have been reading this newsletter from its inception may recall that on the first issue, I had an article on self elevating units with this short paragraph:

There are many kinds of self-elevating units, many of which have been in continuous operation for over three decades. Depending on their purpose and capacity, self-elevating units are referred to as jackups, liftboats or lift barges or jackup barges. There is no definitive distinction among these categories, but each of these units have unique features that are generally accepted as the differentiating factors in what the units are referred to as in the offshore industry.

To me, the key distinctions are as follows:

Liftboats have at least some form to the bow (to improve transit speed) and are most definitely self-propelled.
Lift barges and jackup barges have almost rectangular shape (and they are not self-propelled).
Jackups encompass liftboats, lift barges, jackup barges, plus all other types of units which have legs and a hull that can be jacked up from an afloat mode to an elevated mode.

So, I think at the very least we can say that all liftboats are jackups, but not all jackups are liftboats.

The table below presents a list of the papers from this year’s conference. I note that the brief description is mostly taken directly from the abstracts (so, please note that credit is certainly given to the authors), but note that in the interest of brevity, I abbreviated some and paraphrased/simplified some parts instead of posting the full abstract. One more thing to note is that there were a couple of presentations that did not provide a paper, and as such I am not listing them.