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The full name for this most common type of downhole safety valve is a Tubing Retrievable Surface Controlled Sub-Surface Valve, shortened in completion diagrams to TRSCSSV. If a tubing retrievable valve fails, rather than go to the expense of a workover, a "wireline retrievable" valve may be used instead.
A roof must be designed with a suitable fall to allow the rainwater to discharge. The water drains into a gutter that is fed into a downpipe. A flat roof should have a watertight surface with a minimum finished fall of 1 in 80. They can drain internally or to an eaves gutter, which has a minimum 1 in 360 fall towards the downpipe.
In some cases, a cricket can be used to transition from one roof area to another. On low-slope and flat roofs with parapet walls, crickets are commonly used to divert water to the drainage, against or perpendicular to the main roof slope. The pitch of a cricket is sometimes the same as the rest of the roof, but not always. For Steep-slope roofs ...
Water seeps into a cavity in the open bottom, or comes up from a pipe sunk down from the center of the well into the water-bearing sand. [14] The top part of the well should prevent foreign matter or surface water from entering the well, so should be impervious. The top of the well should be protected and the area around the well drained. [13]
In a completed well, there may be many annuli. The 'A' annulus is the void between the production tubing and the smallest casing string. The 'A' annulus can serve a number of crucial tasks, including gas lift and well kills. A normal well will also have a 'B' and frequently a 'C' annulus, between the different casing strings.
This stored water is recovered during late summer and early autumn for irrigation needs. [citation needed] Both of these well types use a down-hole control valve. ASR can also be used to re-inject water used by HVAC systems to maintain the ground water levels and store the thermal differences from summertime cooling for winter time heating ...
Gas lift well: gas is fed into valves installed in mandrels in the tubing strip. The hydrostatic head is lowered and the fluid is gas lifted to the surface. Single-well alternate completions: in this instance there is a well with two zones. In order to produce from both the zones are isolated with packers.
Artificial lift is the use of artificial means to increase the flow of liquids, such as crude oil or water, from a production well. Generally this is achieved by the use of a mechanical device inside the well (known as pump or velocity string) or by decreasing the weight of the hydrostatic column by injecting gas into the liquid some distance down the well.