Tuesday, February 1, 2011
The Big Rigs
I decided to post a little bit of information about drilling rigs for those readers who might not be as familiar with operations as others. Drilling takes place both offshore and on land as most know. The four main types of offshore rigs are known as Semi Submersible, Platform, Jack Up Rig, and Drill Ships. These all have certain environments or depths of water at which they are ideal to perform. The main difference in these rigs is the method which they stabilize themselves at the surface. Semi Submersible have floaters if you will that fluctuate up and down with the change in water level and are attached to the sea floor will pillars but can be moved from location to location using tug boats. Jack Up rigs are similar but rather than adjustable floats, they have adjustable jacks which are more of a fixed mechanism to lower or raise the platform to accommodate for changes in water level and are mobile as well with the help of tugboats. Platforms are fixed and used more for generation of greater force to drill deeper wells. Drill ships are just as the name represents. A drill rig is located on a large barge or ship and is completely mobile. Technology today has equipped these large ships with rotors or fans at different corners of the bottom of the ship which electronically center the ship directly above the well being drilled by means of GPS location. On land rigs have evolved from a structure of 2x4's in the first days of drilling to an amazing hydraulic operate rig which is used today. Drilling rig operations have become significantly safer with these well designed machines due to their hydraulic capabilities of making pipe connections and self set up on rig sites. Below is a video of the moving process which the FlexRig by Helmerich and Payne Drilling Company undergoes without the required presence of large cranes as other rigs require. Throw some questions out if you would like and I'll do my best to answer them about these incredible machines.
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The video really shows how complicated it actually is to set up a drilling platform and rig.
ReplyDeleteYou take about the different types of offshore rigs, but do you know what depths of water they are best used for and how deep they drill?
I think it is amazing how a drill ship can stay in place to drill even with all the currents and waves in the ocean. I am sure they have a hell of a time when the waves build up.
So is there any difference in the efficiency at which these 4 types of offshore rigs drill oil? Or do different types yield different amounts of oil, or are they purely for the situation?
ReplyDeleteSemi submersible and drill ships are often used for deep water drilling. These rigs can operate in depth of 9000' of water or greater. Jack up rigs are generally used for shallow operations in waters around 200'. Deep sea operations are generally horizontal wells as a platform can drill many wells from the same pad. I was on a platform off of the shore in Santa Barbara, CA and there were 14 wells drilled but the platform was capable of drilling up to 30 wells. I'm not exactly sure, but I would guess these wells are drilled vertically around 4000' and then directed horizontally to reach reserves. Transocean had a record around 2005 for a deep sea drilling operations where the particular well drilled was 40,320 feet measured depth with a 35,770 foot horizontal section. These rigs are mainly determined by the depth of the water and the desired depth of the planned well to be drilled. Oil production is mostly a function of reservoir properties such as porosity, permeability, pressure, and others. Production however, can also be restricted by capacity of pipelines or on site facility size to hold these fluids or gasses. Keep in mind that on these platforms are also living quarters, a cafeteria, offices, and space for maintenance operations which must be conducted by the personnel. They are truly remarkable structures.
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