Saturday, January 16, 2010
Drilling equipment class
Staff scientist Adam Klaus took us on a tour of the ship today to introduce us to the drilling operations and equipment. We had to wear hard hats and safety glasses, because of all the moving parts on and around the rig floor. The derrick (right) holds the drill string and once we are on site it will hold the bottom hole assembly composed of the drill bit and core barrel. Pipe will be tripped behind/above the bottom hole assembly enough to reach the sea floor and then to drill into the sea floor. Depending on the types of rocks or sediments cored, different coring equipment will be used. For soft sediments, the advanced piston (APC) corer is used. It is composed of a cutting shoe that is pushed into the sea floor and then takes out 9 m lengths of core. It operates a bit like a syringe. You can see the APC cutting shoe in the image to the left. The APC extends forward through the hole in the center of a drill bit, similar to the one indicated in the photo below. The core will come up through the center of the hole and a core catcher will keep it in place. The core catchers are the small cylinders with the petals in the center in the lower right of the photo. When the sediments are too hard, an extended core barrel (XCB) is used, which will rotate and drill into the sediment. In lithified sedimentary rock, only rotary coring is possible, and most of the work will then be done by the drill bit below with a core barrel behind it (RCB). We will need to learn these terms and abbreviations, because it will affect the preservation of the sediment cores we see.
Posted by Sandra Passchier at 5:34 AM