SU1516599A1 - Method of cementing wells - Google Patents

Abstract

The invention relates to the drilling of wells and is intended for their cementing. The goal is to increase the efficiency of cementing wells by filling the contraction pores in the cement stone. To do this, after the casing has been lowered and cement mortar is pumped into it, followed by pushing it into the annulus, the back pressure is maintained during the waiting period for cement to harden by pumping a gassing mixture after the cement slurry. Then, by injecting the squeezing fluid into the casing string, it is forced into the annular space so that the gas-generating mixture is opposite the reservoir. Powdered aluminum is used as a gassing additive in the mixture. The interaction of hydrated lime with aluminum releases hydrogen, which is used to fill the contraction pores formed during the hardening of the cement mortar. In order for the gas evolution over time to be comparable to the process of formation of contraction pores, there is a gas release inhibitor in the gas-producing mixture. The rate of gas evolution is maintained equal to the rate of concentration of the cement slurry. 1 hp ff, 1 ill. 4 tab.

Description

cement slurry concentration rates. A mixture of slaked lime and powdered aluminum and a gas release moderator is pumped as a gas-generating mixture.

Test 1 Cement mortar 3 prepared from sterlitamak Portland cement for cold wells with a density of 1850 kg / m was filled in a glass tube 1 (flask). The beginning of the seizure is 6 h 40 min, the end of the skvvatshan 8 h 50 min. The height of the cement mortar column was 1300 mm, Hydrost. The tical pressure of the cement mortar column was 0.024 MPa. Air outlet at a pressure of 0.021 MPa was applied through outlet 2, which amounted to 0.9 of the hydrostatic cement mortar column.

In run 2, a pressure gauge was connected to tap 2 and, according to its indications, the curve of pressure change on the formation was measured during the hardening of the cement mortar (Table I).

In run 3, a water meter tube was connected to tap 2, and during cement hardening, the rate of contraction was determined (Table 2).

Then, gas evolution from a mixture of powdered aluminum and hydrated lime was determined, and with the help of additives, the rate of gas evolution was slowed down so that it corresponded to the velocity of concentration (Table 3).

In experiment 4, a solution of cement, gas additions and gas release retardants were poured into 1 tube part. Height This area was 5 cm. Cement solution was poured on top of this solution. A man-vacuum meter was connected to outlet 2 and a change in pressure was recorded in outlet 2 during the hardening of the cement slurry (Table 4).

Example, Baseline.

The interval of the reservoir is 4000-4200 m. The technical column is lowered in the interval of 0/4000 m. The internal diameter of the technical colo} 1

those

4 mm. Excluatomyonna

D

the column is lowered in the range of 0-4200 m

The outer diameter of the production string 0 168.3 mm. The diameter of the wellbore in the range of 4000-4200, 9 mm. Cement under1N1mayut to ust. After the descent of the production string, cement solution is pumped into it with a volume equal to

v ri-i °

those 2 pex) and n

H

 3.14 (0.2224--0.1683-). m

Then a gas-blending mixture is pumped in immediately. The following composition:

Portal cement 95% 1 + powdered A1 L3.5% - - KSSB gas release agent 1.5% 1 shut off with water, 5.

Next, the cement slurry and gas-evacuating mixture is forced into the gaps, so that the gas-releasing mixture fills the annular space opposite the reservoir and another 40 m above it and in this

case will receive a Stop.

The volume occupied by the gas evolutionary mixture is 47 m.

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five

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five

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Claims (2)

1. A method of cementing wells, including lowering the casing string, pumping cement mortar into it, followed by pushing it into the annulus and maintaining anti-dazzle in the annulus during hardening of cement (RFQ), characterized in that, in order to increase efficiency cementing the wells by filling the pores in the cement stone, maintaining the backpressure in the annulus during the SFD is carried out by pumping a gassing fluid after the cement mortar mixtures and isodavli1 - together with the cement mortar into the annulus before placing it in the zone of the reservoir, opu -ieM the rate of gas release of the Jepf is equal to the rate of contraction of the cement pac i oopa. 2. The method according to any one of the preceding paragraphs, so that as a gaseous mixture, a mixture of hydrated lime with powdered aluminum and a gas-release moderator is pumped into the mixture. 1516599 Table 1 P, kgf / cm | o, 24o1 0.22o | O, ZOslo, 190 | O, 185 G0.171 1 0, 140 Go, 130 Go, 127 T, HO12461016 20232A table 2 ay, cm G1, tT2.0 Gz, 1 Gz.v D.ZTA.z 5.2 U, Gb, 5 G, T, ch36 1.0 13 15 16 18 20 22 24 T, HO471012 J419222324