Keyseating is one of the primary reasons for fishing during drilling. A key seat is a small hole cut into the well bore wall due to the movement of the downhole drilling assembly. This cut usually happens when the hole changes direction, the hump of doglegs, in undetected ledges near washouts. A part of the …
The decision to fish or not must be weighed against a need to preserve the wellbore, recover costly equipment, or comply with regulations. Each choice is fraught with its costs, risks, and repercussions. This is why learning how to calculate the economic and optimum fishing time is important. Before committing to a specific course of …
Oilfield Magnetic fishing tools consist of permanent or electric magnets running on a conductor line. The outer edge of permanent magnets has circulating ports, which wash away fill and cuttings and make contact with the fish. A brass sleeve is fitted between the magnetic core and the outer body to avoid any drag on the …
Safety joint can be used in drilling, fishing, drill stem testing, washover or any pipe string. It is a threaded connection with coarse threads or other special features that will cause it to unscrew before other connections in the string. It is one of the great tools that have been used in oil and gas …
A fish can be defined as a part of the drill string or completion string that already parted, cut, or lift in the hole. This may be due to a mechanical problem in the string or due to being cut after a sticking problem and unsuccessful trials to free. These are non-drillable items that must …
The junk basket is very useful if you want to collect small pieces of loose junk in the basket. They are doing that easily due to the reduced annular velocity at the junk basket opening. Baskets are also good for picking up relatively small junk such as steel cuttings. Also, are good in carbide inserts …
The main application of a junk mill as a milling tool (milling in drilling) is clearing the junk for shortening tubular, bit cones, and general junks. Mills and boot baskets go hand-in-hand while oil and gas fishing operations. It is common to use Boot baskets with these mills because they collect the pieces of the …
Casing repair is not exactly a drilling fishing job, but if the casing collapses, splits, or parts you’re fishing skills can help you repair the casing. Casing repair involves using a variety of tools downhole. Each casing failure must be evaluated based on the specific conditions of the failure before a method of repair can …
There are several methods for patching damaged casing while maintaining pressure ratings and without restricting internal bore diameters. The casing repair is made by removing the damaged section of the casing and then preparing the casing stub with a Dress-Off Mill. The external patch is run in the hole on the bottom of the new …
At times, you will need to mill out collapsed casing and repair the casing using a casing alignment tool. You can also use a string mill and casing alignment tool to repair split casing. Bottom Hole Assembly The bottom hole assembly should contain, from bottom to top (connecting to drill collars): See the diagram below. …