Wireline & Downhole Tools
On the larger diameter, thick-walled guns, there is much much less distortion than on the small, thin-walled via-tubing guns. In wells during which clearances between the gun and tubulars are important, the quantity of distortion of the gun ought to be determined from the service firm earlier than the gun is used.
Gun physique swell ranges from roughly 10% diameter development in small, 1 eleven∕16 -in. weapons shot in low stress wells to less than 1% diameter growth in bigger guns and those shot at high pressure. diameter or much less, whereas bigger weapons, because of the increased resistance to bending with rising diameter, show no proof of bowing. This entails the injection of chemicals to eat away at any pores and skin damage, 'cleansing up' the formation, thereby improving the move of reservoir fluids. A robust acid (usually hydrochloric acid) is used to dissolve rock formations, however this acid doesn't react with the Hydrocarbons.
There is a significant distinction in cost between the conveyance methods. Wireline usually is the decrease price system in wells by which only a few gun runs are needed to complete the perforating design. Two elements that have an effect on the cost performance in hollow-carrier perforators are standoff and gun clearance. Standoff is the gap between the base of the charge and the inside of the port plug or scallop and is a fixed part of the gun/cost system design. Gun clearance is the distance from the skin of the port plug or scallop to the wall of the casing.
Filtration requirements could vary with the task, however usually a 2- to 5-μm filter with a beta score of 1,000 is sufficient for many applications. No matter how good the perforating system, it is ineffective if the perforations are not made in the most effective pay zone.
Acid can be used to clean the wellbore of some scales that form from mineral laden produced water. If used, it'll normally be positioned below the packer and can provide an alternative entry path for reservoir fluids into the tubing in case the shoe becomes blocked, for example, by a caught perforation gun. This is the element, which sits on prime of the wellhead and serves as the main help for the manufacturing tubing.
Typical strategies of depth management include gamma ray tie-in and correlation to the unique openhole gamma ray system. Until the development of sturdy gamma ray logs that could stand the shock of firing, the primary depth management technique was to match openhole gamma ray to cased-hole gamma ray strip log and then tie into the collar locator log. When this technique was executed properly, the depth control was correct to within half the length of the collar. Unfortunately, a miscount would end in taking pictures the gun one joint off depth, which is a complete miss for many zones.
With gamma ray logs that run with the gun, the process is simplified and extra dependable. Well management requirements are additionally a consideration as a result of live-well perforating requires a lubricator or advanced snubbing strategies.
Unless centralizers are used on the gun, one fringe of the gun will contact the casing wall, and maximum clearance will occur at a hundred and eighty° to the wall contact. For this purpose, small guns are decentralized purposely by magnets, and the costs are all aligned to fireside in the path of the magnetic positioning (0° phasing). Larger weapons with smaller clearance distances use costs phased across the gun. Typically, the utmost gun diameter chosen ought to allow washing over the gun with washpipe within the given casing measurement.