API RP 59:2006(2012) pdf download
API RP 59:2006(2012) pdf download.Recommended Practice for Well Control Operations.
2. When the heavy drilling Iluid reaches the bit, read the
drill pipe pressure gauge and hold the drill pipe pressure
constant at the kill-rate by manipulating the choke until
the heavy drilling fluid reaches the surface.
3. Shutdown the pump and check for flow.
4.10.2.5 Example: Driller’s Method of Circulaung Out a Kick—Figure 4.12 illustrates an example of casing pressure and pit volume increase bused on the well conditions shown in Figure 4.11. Initial closed-in drill pipe and easing pressures are 520 psi and 875 psi respectively. When circulation is started, a 50-barrel gas influx is alongside the drill collars and the lower part of the drill pipe. The initial closed-in easing pressure is 875 psi and kick volume is 50 bands as shown at point A. When 25 barrels of drilling fluid is pumped, the gas bubble is alongside the drill pipe and its total length is shortened in the larger annulus. This produces a longer column of drilling fluid and less easing pressure is required at point H to balance bottom-hole pressure. Gas expansion is slow at first, increasing as it rises in the hole. Maximum easing pressure. gas volume in the hole, and pit gain occur when the gas reaches the surface at potnt C. Hetween points C and D. the easing pressure decreases rapidly as gas is being replaced in the well by drilling fluid. Pit volLtme decreases accordingly. At point DalI gas is removed and casing pressure is the same as the original closed-in drill pipe pressure. Casing pressure and drill pipe pressure are the same because 10.0 lb.gal drilling fluid fills both the drill pipe and annulus. During a kick while drilling, gas flows into the circulating drilling fluid and a mixture occurs. When the well is shut-in, gas migrates up the hole. While circulating the kick, the gas generally rises faster than the drilling fluid. Hecause the drilling fluid flow rate outside the drill string is not the same at all points across the hole, some gas will be pushed ahead during the circulation and some will lag. As a result, casing pressures are not exactly as discussed for a single bubble nor are they precisely calculable. Fortunately, the peak casing pressure can be expected to be somewhat less and will occur sooner than displacement volume would indicate as shown at point C in Fig- we 4.13. t)ue to lag of gas, some additional volume of drilling fluid will be pumped before the well is free of gas as shown in Figure 4.13.
4i0.3 Wait and Weight Method
When the Wait and Weight Method is used, the well is closed-in on the kick, drilling fluid density is increased as required. and the kick is circulated out using the weighted fluid. (‘ireulation is established at the kill-rate as described in 4.10,1. Drill pipe pressure is used to control bottom-hole pressure because of gas expansion in the annulus, but the required drill pipe pressure changes as the pipe tills with the heavy drilling fluid. Dnll pipe pressure is maintained by manipulation of the choke.
4.10.3.1 A schedule of dull pipe pressure change should be prepared and followed. Figure 4.14 shows such a schedule based on the conditions of the 50-barrel kick illustrated in Figures 4.11 and 412. Initial circulating pressure is plotted above zero pumpstrokcs. and final circulating pressure is plotted above punipstrokes to the bit. A line is drawn between the two points. If a pumpatroke counter is no available, the drill pipe pressure reduction schedule can be constructed acing either minutes or barrels instead of pumpstro&es in Figure 4.14. These salues are the drill pipe pressures to hold at the strokes. minutes or barrels shown.
