A Logical Approach To Killing An Offshore Blowout West Cameron 165 Well No. 3 - Offshore Louisiana
Authors: Barnett Richard D. 
Published: December 2007

This paper describes the planning and engineering that was used in killing a blowout that occurred offshore in West Cameron Block 165. By utilizing the basic concepts presented in this paper, an operator could determine the equipment and planning necessary to kill all offshore gas blowout with a relief well.

Introduction

West Cameron Block 165 is located 32 miles southwest of Cameron, Louisiana, in a water depth of 48 feet. The field was developed by six single well platform installations. On March 23, 1976, all six platform installations. On March 23, 1976, all six single well platform installations in the field were manually shut-in to install new production equipment on the No. 1 platform (FIGURE 1); the central gathering platform for this field. At 7:00 a.m., on March 24, 1976, gas was discovered escaping from around the bradenhead flange of West Cameron 165 Well No. 3. Well No. 3 was out of control - blowing gas, mud, and sand (FIGURE 2). Tenneco Oil Company immediately assembled its Contingency Task Force and began planning strategy to bring Well No. 3 under control. planning strategy to bring Well No. 3 under control. FIGURE 3 and FIGURE 4 depict the wellbore schematic of Well No. 3 prior to the blowout. The 7 5/8" production string had been landed in tension in the production string had been landed in tension in the 10 3/4" casinghead. Due to the abrasive nature of the blowout's flow stream (gas, mud, and sand), the 10 3/4" casing head was eroded in a short period of time and the 7 5/8" casing resultingly moved downhole (FIGURE 5) which severely limited the chance of a surface kill. Consequently, the decision was made to drill a relief well; West Cameron 165 Well No. 12.

The objectives of the relief well would be fourfold:To encounter the blowout reservoir (K-2 Sand) within 50 feet of the No. 3 wellbore.To establish communication with the blowout wellbore from the relief well by injecting sea water into the K-2 reservoir and kill the blowout via this water injection operation.To inject mud from the relief well into the No. 3 wellbore and then follow the mud with cement to plug the No. 3 wellbore.Maintain continuous injection once pumping operations began.

When the kill plan was formulated it was intended to use visual observations of the flow from the 16" casing on Well No. 3 to determine when the injection operation had established communication with the blowout. However, before the relief well reached total depth, the casing strings and platform of Well No. 3 subsided beneath the Gulf of Mexico, thus severely limiting qualitative observations of the blowout.

From this point in time (April 11, 1976), the relief well would be the only means of killing Well No. 3. This paper will discuss only the relief well drilling operations, required kill equipment, and the planning of the kill. A second paper will describe planning of the kill. A second paper will describe the use of the computer and some other special tools that were used to monitor the blowout and help to successfully kill Well No. 3.

The exact BOTTOM HOLE LOCATION OF WELL NO. 3 was not known. When this well was drilled during 1969, the only surveys required were TOTCO-type surveys, which measure angle without azimuth. When these surveys were projected in the same direction, it was found that the bottom hole location of the No. 3 Well was within a circle with a radius of 112 feet. However, since a three dimensional plot of a straight hole will usually approximate an elliptical helix, it was felt that the actual bottom hole location of the No. 3 Well would be within approximately 50 feet of the surface location of the No. 3 Well when projected onto the K-2 reservoir. Therefore, the bottom hole target of the relief well was chosen to be directly below the surface location of the blowout well, at the top of the K-2 reservoir. This would reasonably insure that the relief well would be within 50 feet of the blowout wellbore.