China became the world's biggest offshore drilling rig builder after rapid expansion led by the likes of state-backed yards China Merchants Heavy Industry, Dalian Shipbuilding, a unit of China Shipbuilding Industry Corp, and Shanghai Waigaoqiao, a subsidiary of China CSSC Holdings Ltd. All three yards declined to comment for this story.

But their jackup rig market share gains from traditional powerhouses in Singapore came at a financial cost.

China Merchants Heavy Industry has the largest number of orders at 14, followed by Dalian Shipbuilding and Shanghai Waigaoqiao, according to data from shipping consultancy Drewry.

By comparison, less than 5 percent of orders at Singapore yards Keppel and Sembcorp Marine are by speculative buyers, according to Oversea-Chinese Banking Corporation. Sembcorp Marine and Keppel declined to comment.

Except for a single order won by Daewoo Shipbuilding & Marine Engineering in 2013, South Korean shipyards make very few jackup rigs, leaving the business for its Chinese and Singaporean rivals. Companies like Samsung Heavy have concentrated on deepwater drillships instead.

Even without competition from South Korea, prospects look bleak in the jackup rig trade.

"Some yards might have to drop their prices by 5-10 percent in order to attract potential buyers in the current market climate," said Lianghui Xia, a Shanghai-based shipbroker at RS Platou.