BP said early Wednesday that its runaway Macondo well appears to have reached a static condition, with pressure now being controlled by the hydrostatic pressure of drilling mud that was pumped into the well Tuesday.

Pumping of heavy drilling mud into the well from vessels on the surface began about 3 p.m. Tuesday and was stopped after about eight hours (see Daily GPI, Aug. 4). The well is being monitored; further pumping of mud may be required depending on results observed during monitoring.

The start of the static kill was based on the results of an injectivity test, which immediately preceded the static kill and lasted about two hours. BP said it is working with federal government responders to determine whether to inject cement into the well.

The aim of these procedures is to assist with the strategy to kill and isolate the well, and will complement the upcoming relief well operation, which will continue, the company said.

A relief well remains the ultimate solution to kill and permanently cement the well. The first relief well, which started May 2, has set its final 9 7/8-inch casing. Operations on the relief wells are suspended during static kill operations. Depending upon weather conditions, mid-August is the current estimate of the most likely date by which the first relief well will intercept the Macondo well annulus, and kill and cement operations commence.

"The vast majority of the oil from the BP oil spill has either evaporated or been burned, skimmed, recovered from the wellhead or dispersed -- much of which is in the process of being degraded," the National Oceanic and Atmospheric Administration (NOAA) said Wednesday.

NOAA said one-third of the oil released by the busted Macondo well was captured or mitigated by federal government recovery operations, including burning, skimming, chemical dispersion and direct recovery from the wellhead. An additional 25% of the total oil naturally evaporated or dissolved, and 16% was dispersed naturally into microscopic droplets, NOAA said.

"The residual amount, just over one quarter (26%), is either on or just below the surface as residue and weathered tarballs, has washed ashore or been collected from the shore, or is buried in sand and sediments. Dispersed and residual oil remain in the system until they degrade through a number of natural processes. Early indications are that the oil is degrading quickly," NOAA said.

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