www.dakotaclassifieds.com


Page 27


API GOLF AUGUST 19, 20 & 21 DICKINSON, ND A Deepwater Horizon semi-submersible drilling rig near Rigel gas field in the


Gulf of Mexico Gushers


Gulf of Mexico blew out on April 20, 2010, caught fire, burned for two days, and sank in 4,992 feet of water. This rig was owned by Transocean Ltd. And was on contract to British Petroleum to drill the Macondo prospect in Mississippi Canyon Block 252. Eleven men were killed and another 115 men and women were evacuated, with 17 injured among the group.


Transocean is the world’s largest offshore drilling contractor, and this rig was


contracted through 2013 to BP at a cost of about $500,000/day. However, with helicopters, support vessels, and other services, the cost to BP is probably closer to $1,000,000/day. The cost to build a rig like this was about $350,000,000 in 2001, and it would probably cost double that to replace it today.


This type of rig is called semi-submersible, and it is capable of working water depths up to 10,000 feet. It is a floating rig that does not use anchors, which are too costly, and not strong enough anyway to restrain such a heavy floating structure. Instead a computer system using satellite positioning controls thrusters that keep the rig at all times within a few feet o its intended target.


This prospect was drilled as a delineation well to define the outlines of a


known oil and gas accumulation, and having confirmed the presence of hydrocarbons, BP was in the process of capping the well, probably intending to return at a future date to develop the find. They had just finished cementing steel casing in place when the blowout took place, resulting in an explosion with flames 200 to 300 feet high that were visible as far as 35 miles away.


The well was finally controlled on July 15, 2010 by lowering a 125-ton steel containment dome of the spot where most of the oil was leaking from the sea


S ERVICE, I NC.


B IG S KY W ELL


PO Box 814 • Belfield, ND Office: 701-575-8075 Fax: 701-575-4957


Mandan Refinery & Pipeline, Terminals,


Trucking & Rail 701-667-2400


900 OLD RED TRAIL NE Mandan, ND 58554


PO Box 706 • Belfield, ND 58622


701-575-4666 24 Hour Answering Service


ROUSTABOUT Backhoe Hydrovac


Pipeline Contractors Steam Cleaning


Commercial & Industrial


Oil Industry & Oil Field Equipment & Service


116 East 12th Street, New England, ND 701-579-4191 • 800-559-4191


www.slopeelectric.coop


floor. This succeeded in capturing most, but not all, of the oil. Interestingly, this same technique, but with a box made of wooden timbers, had been attempted as one of the efforts to kill the Lakeview Gusher back in 1910.


A Ågstatic killÅh on August 4, where heavy fluids where injected into the


wellhead, followed by cement, effectively sealed off the well. However, it was not until a relief well that had started on May 2 finally intersected the well bore on September 16 and pumped in cement from below, that the well was officially declared dead on June 19.


All told, the Macondo well spilled an estimated 4.9 million barrels of oil, with


a peak flow rate of about 62,000 barrels/day. By comparison, the Lakerview Gusher spilled 9.4 million barrels, with a peak flow of possibly 125,000 barrels/ day. Thus, the Macondo blowout was big, but the Lakeview twice as big.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48