RIASSUNTO
Abstract
On the well JACINTO 01 (Angola), by 1 632 m of water depth, while pulling out the BOP stack to check a malfunction during the pressure tests of these BOP, before starting the17""1/2 phase, the breaking of the drilling line, while the BOP was at 620 m, caused the fall of the BOP and about 600 m of riser. The top drive felt and passed through the rotary table and, some other parts (bails, balls back-up wrench, elevator, riser running tool and few other metal debris) felt on the seabed with the BOP and the riser.The vessel returned to Cape Town for repair, inspections and preparation of the BOP recovery. In accordance with specialized service companies, we decided to try to recover it and we prepared tools:
For Example:
Lasso tool, Pride design
Modified riser running tools
Use of excavators
Special jet subs with different designs ...
The BOP recovery operation program, that will be developed in the presentation, is:
Installation of a protection cage on well head
Recovery of metal debris around BOP
Recovery of laying riser joints by using jet tools, lasso tools...
Excavation around BOP using excavators, jet tools ...
Cutting first riser
Fishing BOP using two strings in the same time...
The operation ended in success on the 26/01/2000, the entire BOP and the risers has been recovered.
Presentation of the Drill Ship
Pride Africa is a deepwater drill ship. It is to an IHC Gusto 10 000 design and has been constructed at the Hyundai Mipo yard in Korea. It has been commissioned in 1999 with DNV class notation •1A1-Mobile Offshore Drilling Unit DYNPOS-AUTR and full certification for world wide operations.
Main characteristic:
Length overall: 204.5 m
Width overall: 30.0 m
Operating draft: 10.0 m
Max drilling water depth: 10,000 ft
Max drilling depth: 35,000 ft
The drilling equipment comprises a 180 ft×1,600,000 lbs derrick equipped crown mounted compensator travelling block and Top drive. In addition to the standard drill floor equipment, the drill floor is fully mechanized with iron roughnecks and automated pipe handling systems for minimum manned operation.
The vessel is self propelled and dynamically positioned (DP class 2) by means of two azimuth fixed pitched propellers in nozzles at the stern, two fixed pitch tunnel thrusters in the bow and three retractable azimuth fixed pitch propellers in nozzles below the keel level, one at the centerline aft and two port ans starboard forward.
The vessel is equipped with three pedestal cranes, two on the starboard side, one on the port side.
Risers and tubular handling both in and above the holds is by gantry crane.