全世界海上钻井都一个格式，就是半潜式钻井平台，英文叫drilling rig.在墨西哥湾爆炸的就是这种钻井的drilling rig。钻井船就是drilling rig，半潜式钻井平台也是drilling rig。不过是中国文科记者起个不同名字，两笨蛋还在没来由地咬字嚼文。不知自己蠢得都跟猪一样，不过一头猪白，另一头猪黑。

On Tuesday, hearings in the Senate focused on similar themes: what caused the well to explode, and why the blowout preventer did not work.

Three executives from the three principal companies working on the well all blamed each other.

BP (BP), which owns the well and subcontracted the other companies to work on it, said it was Transocean's job to ensure that the blowout preventer was functioning. Transocean was the owner of the drilling rig that sunk, the Deepwater Horizon, and also owned the blowout preventer.

Transocean (RIG) said the blowout preventer worked just fine in tests, and that it may have gotten jammed with concrete or other well fluids that were injected by a third contractor, causing the well to explode. Either way, argued Transocean's president, it was the faulty well, not the rig or the blowout preventer, that ultimately caused the leak.

Halliburton (HAL, Fortune 500) was the third contractor; it injected cement and other well fluids into the hole before the explosion. But a Halliburton exec said it was only following the orders of BP, which wanted a heavier fluid, known as mud, removed from the well before the well was capped with a concrete plug.

Some senators, citing a Wall Street Journal

report, said this process of removing the heavy fluid before the concrete plug is installed is unusual in deep water drilling, and suggested it may have caused the accident by allowing the highly pressurized oil and gas to escape. But Halliburton's executive said the process was not out of the ordinary.

The Minerals Management Service, the federal agency that regulates offshore drilling, has also come under fire in the wake of the spill.

On Tuesday, senators wanted to know why there weren't other back-up systems in place to stop a leak besides the blowout preventer, and questioned why the blowout preventer may not have been able to cut through thicker sections of pipe to pinch it shut and stop a leak. Lawmakers also questioned the agency's relationship with the oil industry, which some have described as cozy.

The Obama administration announced plans Tuesday to split the agency in two, thus removing an apparent conflict of interest between the drive to maximize oil production and efforts to ensure safety, which could slow drilling down.

Under federal law, BP, as the lead project operator, is responsible for all clean-up costs associated with the spill.

While the subcontractors are thought to have some legal indemnification from BP and the federal government, lawyers say they could still be open to lawsuits from fisherman and others affected by the spill.

Ultimately, experts have said the total cost of the spill could range from $2 billion to $14 billion or higher, depending on when the leaking well is closed and where the oil washes ashore.