Top 5 Deadliest Oilrigs Disaster

5. GLOMAR JAVA SEA DRILLSHIP

Rig: Glomar Java Sea Drillship

Date: October 1983

Operator: Arco

Location: South China Sea

Fatalities: 81

The U.S. drillship GLOMAR JAVA SEA, with 81 persons onboard, capsized and sank in the South China Sea at a position approximately 63 nautical miles southwest of Hainan Island, People's Republic of China and 80 nautical miles east of the Socialist Republic of Vietnam. Prior to the sinking, the GLOMAR JAVA SEA had secured drilling operations due to the severe effects of tropical storm 'LEX' approaching from the east of the drilling site.

At 2348 local time, the Assistant Rig Manager, onboard the drillship, called Global Marine's office in Houston, Texas and reported that the drillship had a 15 deg starboard list of unknown origin and was experiencing 75 knot winds over the bow. Communications were cut off during the conversation, and all attempts to re-establish contact failed. At about 2351 the GLOMAR JAVA SEA capsized and within minutes sank in 317 feet of water. An extensive search was conducted but no survivors were found. A diving expedition found the wreck in an inverted position approximately 1600 feet southwest of the well site. The wreck was searched and 31 of the 36 bodies found were recovered. The remaining 45 persons are missing and presumed dead.

4. OCEAN RANGER

Rig: Ocean Ranger

Date: February 1982

Operator: Mobil Oil Canada Ltd.

Location: Hibernia Field, North Atlantic

Fatalities: 84

Ocean Ranger was designed by Ocean Drilling and Exploration Company, Inc. (ODECO) and constructed in 1976 by Mitsubishi Heavy Industries's Yard in Hiroshima, Japan. The vessel was a self-propelled large semi-submersible design with a drilling facility and living quarters. She was one of the largest semi-submersibles working offshore in the early 1980s.

Part II: Types of Offshore Platforms

Ladies, here we meet again for Part II. Ok last time I already explained about the introduction of the offshore structures and now we move to the main contents, types of offshore structures. Either fixed or float, as simple as that. Ah, layman terms. Fixed platforms is a platforms that its substructure attached / piled to the seabed while floats platforms does not. However, floating systems normally moored i.e chained or anchored.

Fixed Platforms

Steel Jacket Platform

Semangkok-A Platform

In Malaysia, especially in Peninsular Malaysia (PM) blocks, water depth is range to 50-70 metres (shallow waters). Hence, it is economically feasible to built a steel jacketed platforms. But the application of the jacket platform usually up to 300 metres. Topside of jacket platform are normally built either integrated (alltogether) or modular type (section per section e.g Living Quarters + Power Generation + Booster Compression + bla bla bla). For middle school level of understanding, JACKET PLATFORM = TOPSIDE + JACKET.

Compliant Tower

Compliant Tower Design

Petronius - Compliant Tower Platform

Obviously, the compliant tower platform are designed for water depth more than jacket platform which are normally up to 600 metres. The difference with jacket is that it has more narrowed frame support structure by a piled foundation. Compliant towers are designed to sustain significant lateral deflections and forces. Kids, read this out loud. COMPLIANT TOWER = TOPSIDE + FLEXIBLE TOWER.

Concrete Gravity Structure

Hibernia Platform

Practically, this type of structures are being used in the harsh environments such as North Sea and Scandinavian. Also known as Gravity Base Structure (GBS) platform, it is design to withstand the loads (environment + iceberg) and also for the storage of its base support. Normally GBS is applicable for water depths up to 300 metres. When completed, a GBS is towed to its intended location and sunk. Again kiddos, GBS = TOPSIDE + CONCRETE BASE.