Drilling And Completions
Drilling and Completions are Equally Important
When a company has determined that oil and gas are present at a location, the immediate thought is to drill a well. However, the initial drilling only provides access to the deposit. Keeping at access open relies on the proper completion solutions. Without good completion, the initial borehole will soon collapse, leaving the deposit unattainable.
Even dry wells must be completed. This is mainly for safety reasons. Although they, too, will eventually collapse, there will be an open hole until that time. This hole will typically be filled with drilling fluids at first, but may dry up over time. Open holes are dangerous to both people and wildlife, and for companies, they are big liabilities. It's better for all involved to undertake a completion process to cap them.
For wells that are going to be productive, a number of steps are taken to not only keep the holes open for the long term, but to make it possible to install pumping equipment. As with water wells, the first step is to install a casing. This is a metal sheath that fits inside of the initial hole and resists the forces put on it by the surrounding soil and fluid. Then, liquid cement is pumped in between the casing and the sides of the bore hole. This both displaces drilling fluids, and once cured, provides a stable surrounding material.
Further details of completion are determined by the intended well type. With some, the casing ends at the top of the resource reservoir, but with others, it continues all the way down. Experts in completions solutions determine these details on a per-well basis. Other aspects, such as whether or not gravel-pack filtration will be needed, are also determined at planning time.