Cutting drilling time

With the cost of rigs and personnel running at tens of thousands of US dollars per day, cutting down on time makes good commercial sense. A time of 75 days to complete a production well in the North Field was considered a good performance in the industry. Shell is completing wells for Pearl GTL in as little as 45 days. In all Pearl is on track to deliver 22 wells with a total saving of more than 600 days relative to what was considered good performance. On average 10 days on each well are saved through faster drilling and another 20 days by carrying out activities in parallel.

Drilling a well and then getting it ready for production usually happens in two stages – firstly drilling and completing the well, and secondly getting it ready to produce. For Pearl GTL, Shell is combining both in a programme we call simultaneous operations, or SIMOPS.

The jackets or ”legs” of the permanent Pearl 1 and Pearl 2 platforms have been in place offshore.  At the centre of the SIMOPS approach is a temporary deck installed on each jacket. These temporary decks have been used to carry out the entire second stage of the operations at the same time that the first stage is conducted by the much larger mobile drilling rigs positioned over the temporary decks. Drilling on Pearl 1 was completed in July 2009.

What seems straightforward in fact needed two years of planning. Engineers had to consider the safety and design aspects of having more staff on the main rig, including supplies of power, lighting, air and water. Almost every feature of a conventional rig had to be re-thought. The rig was modified to install a nine-storey staircase and elevator between jacket and rig and a gantry crane below the rig to handle perforating guns.

The rig is cranked up twelve storeys high above the water to allow for the perforation activity below.