SU1661356A1 - Method of drilling hazardous conditions - Google Patents

Abstract

The invention relates to the technique of drilling wells. used in the construction of oil and gas wells in conditions of powerful productive sediments with abnormally high reservoir pressures. The goal is to increase the reliability of preventing gas transmission and absorption of drilling fluid when opening powerful productive formations with abnormally high formation pressures. For this, drilling is carried out to the first absorption zone or to open the first compatibility interval by hydraulic parameters. Then the movable casing is lowered into the well. The annular space is filled with a reservoir pressure balancing solution to the top of the producing formation and from the top of the producing formation to the bottom formation fluid. Inside the movable casing, the washing fluid is replaced with a lightweight drilling fluid as applied to the downhole conditions. Then, drilling is carried out with expansion from under the movable casing. After the next interval of the reservoir has been opened, the moving column is moved to the bottom and the density of the drilling fluid in it is changed according to the new reservoir conditions. Before opening the reservoir, the wellhead is equipped with a serially started column, head and preventers. 4 il.

Description

pressure 10 after opening the absorption zones, hydrostatic pressure 11 of formation fluid.

The method is carried out as follows.

Before opening the productive stratum, casing columns 1–4 are incompatible by geological and technological conditions of the upper horizons. The productive strata are drilled to the first intake zone or the first compatibility interval is opened according to the drilling conditions. Then, the movable casing 5 is lowered into the well. The annular space is filled with a balancing drilling fluid to the top of the producing formation 6 and from the top of the producing formation 6 to the formation fluid. Inside the movable string 5, a replacement is made for a lighter drilling fluid as applied to the bottom hole condition. Next, drilling is carried out with expansion from under the shoe of the movable casing 5. After opening a certain interval, the moving casing 5 is moved to the bottom and replaced with the drilling fluid for subsequent recess.

Before opening the reservoir, the wellhead is equipped with a serially driven column, head, and preventers. FIG. 3 shows the mouth of the funnel 12. The preventive assembly includes a universal hydraulic preventer 13, a twin-mounted preventer 14, a preventer 18 with cutting dies 15, a crosspiece 16, a hydraulic shutter 17. In addition to the above-mentioned anti-surge equipment, the column head (19 and 20) a single spot preventer 18 for sealing the annulus of the moving column 5.

The suspension of the movable column is carried out on the internal support shoulder of the coil of the column head 19 using a sub. Seal the annulus of the movable column is carried out by the lower preventor and the seal of the gap between the sub and the coil. The top of the sub is protected by a safety cone.

The extension of the next section of the moving casing string is carried out on the rotor with the column lifting to the required height to be mounted on the slider. The movable column mounted on the support is sealed by a sealing preventer 18. A rotating preventer can be included in the layout of the preventer assembly, allowing drilling operations to be carried out.

study in conditions of minor depressions on the reservoir,

Example. The productive stratum is drilled to the first absorption zone or the first compatibility interval is opened by hydraulic parameters in the range of 4000–4300 m. Then, the suspended casing 5 is lowered into the well, for example, IBR-2 balancing pressure with density 2 , 04 g / cm3, viscosity on a small funnel 25 s, CHCi / io 30/60 dPa to the roof and in the range of 4000-4300 m with formation fluid 22, IBR-2 solution with the specified rheological parameters prevents depletion fluid at the wellhead, t. e. boundary fluid-solution is stable. Inside the moving string 5, the IBR-2 drilling fluid, of lower density, is replaced with a bottom-hole condition. Next, drilling is carried out with expansion from under the slide of the moving casing string 5.

After opening the next interval of 4300-4600 m of the productive formation, the movable casing string 5 is advanced to the slaughterhouse at 4600 m by filling

fluid (interval 4000-4600 m). Then, in the moving casing 5, the IBR-2 density is reduced relative to the reservoir condition at a depth of 4600 m. Further, the recess is carried out similarly.

Claims (1)

Invention Formula Well boring method in complicated conditions, including regulation counter pressure on the reservoir by changing the density of the drilling fluid, characterized in that, in order to increase the reliability of preventing the gas flow and absorption of the drilling fluid during opening powerful reservoirs with abnormally high reservoir pressures, drilling is carried out to the first absorption zone or opening the first compatibility interval by hydraulic parameters, then the movable casing is lowered into the well, the annular space is filled with a solution balancing pressure from the reservoir and from the roof the reservoir before the in-formation fluid, inside the moving casing, the flushing fluid is replaced with a lightweight drilling fluid as applied to the bottomhole conditions, then the drilling is extended from under the moving casing, after opening the next interval of the producing formation, the moving string is moved to the bottom change the density of the drilling fluid in it in accordance with the new reservoir conditions. one 2 T 45m 3460m 3040m  . 7000M W2. It P.Mth Phil.2 chey Fig.Z Chome - Uzoom Chome 4