A well site is not a place for amateurs. Inexperience is both dangerous and costly, particularly on the difficult downhole project with high temperatures and higher pressures. This is the reason cased-hole well services should be offered only by a team of seasoned veterans.
When it comes to completing a well, there is more to well drilling and casing cementing. After completing the drilling operations, it is important to complete the wellbore to prepare the well for the production phase.
The entire well completion process includes the following steps:
This step of the completion process makes sure that the well will not close in upon itself when drilling fluids are removed after drilling. Also, it protects the wellstream from outside incumbents such as sand or water. Casing is composed of steel pipe joined together to make a continuous hollow tube. The diameter of casing to be installed is defined by the well’s different levels.
This step includes pumping cement slurry into the well to displace the existing drilling fluids and fill in the space between the casing and the drilled well’s sides. The slurry is left to harden to seal the well from non-hydrocarbon that might enter the well stream and position the casing into place permanently.
Open Hole Completions
This type of well completion refers to a well drilled to the top of the hydrocarbon reservoir. The well is cased at this level and left open at the bottom. This step is used for reducing the cost of casing where the reservoir is solid and well-known.
A cased-hole completion requires running the casing into the reservoir. To achieve production, perforation of the casing and cement must be done, so the hydrocarbons enter the wellstream. This can be done by running a perforation gun and a reservoir locating device into the wellbore, often through a wireline or coiled tubing.
With some wells, filtration systems are necessary to keep the wellstream clear of sand. Gravel packing is used for preventing sand from entering the wellstream. It requires pumping a slurry of appropriately sized pieces of coarse sand or gravel into the well between the slotted liner of the casing and wellbore’s sides.
Installing a Production Tree
The last step of the well completion process involves installing a wellhead at the well’s surface. Although both offshore and onshore wells are completed by production trees, offshore wells can be completed by dry and wet trees.