Slag for cementing a well, in particular an oil well

Details Slag for cementing a well, in particular an oil well Slag for cementing a well, in particular an oil well

1999-08-09

2001-12-25

Marcantoni, Paul (Department: 1755)

Compositions: coating or plastic

Coating or plastic compositions

Inorganic settable ingredient containing

C106S737000

Reexamination Certificate

active

06332920

ABSTRACT:

TECHNICAL FIELD
The present invention concerns a cementation slag for a well, notably a well for exploration or exploitation of underground deposits, such as hydrocarbon or geothermal deposits.
Well cementations are highly specific operations requiring the injection of a cement slag through pipes (casing or tubing) by pumping from the surface. One of the primary aims of these operations is to cement the annular space between the outside of the casing and the borehole. Other cementation operations, well known to persons skilled in the art, may also be concerned, for example the installation of plugs or “squeeze” operations. The well, the internal space and annular space, is filled with a fluid, generally the drilling fluid from the preceding drilling phase, or with a fluid of closely-related composition. The cement slag must be installed in the annular space by circulation while driving the original annular fluid to the surface. The Principal functions of petroleum cement slags are notably to provide sealing of the annular space against the fluids contained in the rocks, gas, oil or Water, and to mechanically hold the pipes in the borehole. For this, the compression resistance characteristic is of prime importance.
In view of the installation of the slag by circulation, controlling the rheology is also very important, as well as the capability of using additives adapted to particular conditions, for example filtrate reducing agents, retarding or accelerating agents, dispersing agents, antifoaming agents, or agents for making lighter or heavier.
PRIOR ART
The current formulations of a cement slag for oil well cementation include an amount of water of the order of 45% of the weight of the cement, which considerably limits the mechanical properties of the hardened slag, notably its compression resistance.
Moreover, cement formulations are known which lead to greatly superior mechanical properties, as described for example in European patent EP 0 518 777, but which are not suitable as well cementation slag, if only because of their insufficient proportion of water.
DESCRIPTION OF THE INVENTION
The problem consequently arises of defining an optimized slag composition whose rheology is suitable for the cementation of an oil well or similar, which has an amount of water significantly less than that of the slags recommended until now for this application, and which, after hardening, has mechanical characteristics greatly superior to those of the cementation slags of the prior art.
These results are obtained, according to the invention, with a slag which has:
a hydraulic binder of the group constituted by the Class G (API) Portland cements, the Class H (API) Portland cements and the other hydraulic binders with a small a laminate content,
a microsilica of granulometry in the range 0.1 to 0.50 micrometers, in a proportion of 20 to 35% by weight in relation to the hydraulic binder,
an addition of medium particles, mineral and/or organic, of granulometry in the range 0.5-200 micrometers, in a proportion of 20 to 35% by weight in relation to the hydraulic binder, the amount of the said addition of medium particles being less than or equal to the amount of microsilica,
a water-soluble superplasticizing and/or liquefying agent in a proportion of between 1% and 3% by weight in relation to the hydraulic binder, and
an amount of water equal at most to 30% of the weight of the hydraulic binder.
Preferably, for a given composition, the amount of water is slightly greater than that which is just sufficient to fill the gaps between the grains of the composition, so as to provide the essential rheology.
In preferred embodiments, the slag composition of the invention also has one or more of the following characteristics:
the hydraulic binder is a Class G Portland cement.
the hydraulic binder is composed of particles whose sizes are distributed in the range of 0.1-100 micrometers.
the hydraulic binder is composed of particles whose sizes are distributed in the range of 10 to 50 micrometers.
the microsilica is a silica ash coming from the zirconium industry.
no microsilica is present in a proportion of 20-30% by weight in relation to the hydraulic binder.
the microsilica is present in a proportion of 20 to 25%, by weight in relation to the hydraulic binder.
the microsilica is composed of a conglomerate of particles whose mean size is close to 3 micrometers.
the addition of medium particles is an organic addition of balls of plastic material, for example polystyrene.
the addition of medium particles is a mineral addition chosen among silica, clay, glass balls, metallic salts, barite, haematite and ilmenite.
the addition of medium particles is a mineral addition of siliceous particles.
the addition of medium particles is present in a proportion of 20 to 30% by weight in relation to the hydraulic binder.
the addition of medium particles is a mineral addition of silica sand whose particles have sizes distributed in the range of 5-200 micrometers.
the addition of medium particles is a mineral addition or silica sand whose particles have a mean size close to 50 micrometers.
the addition of medium particles is a mineral addition of crushed quartz.
the water-soluble agent is composed of strongly ionized polymer or copolymer derived from sulphonated groups and/or phosphate, phosphonate or carboxylate.
the water-soluble agent is an agent of the group constituted by naphthalene sulphonate, lignosulfate, melanin and analogues.
the water-soluble agent is a liquefier containing sulphonated or phosphatized groups.
the amount of water is preferably in the range of 20-30% of the weight of the hydraulic binder.


REFERENCES:
patent: 4501830 (1985-02-01), Miller et al.
patent: 4935060 (1990-06-01), Dingsoyr et al.
patent: 5073197 (1991-12-01), Majumdar et al.
patent: 5125455 (1992-06-01), Harris et al.
patent: 5522926 (1996-06-01), Richard et al.
patent: 5531823 (1996-07-01), Breton
patent: 5769939 (1998-06-01), Dingsoyr et al.
patent: 5820670 (1998-10-01), Chatterji et al.
patent: 5968257 (1999-10-01), Ahrens
patent: 5976240 (1999-11-01), Vezza
patent: 898398 (1984-03-01), None
patent: 291 075 (1991-06-01), None
patent: 518177 (1992-12-01), None
patent: 0 518 777 (1992-12-01), None
patent: 2673620 (1992-09-01), None
patent: 04104926 (1992-04-01), None
patent: 279524 (1998-12-01), None
patent: WO 90/11977 (1990-10-01), None
“Effect of Microsilica additives on the errosion resistance of reinforcing steel in concrete”, Stepanova et al., Beton Zhelezobeton (Moscow) 1993, (5), p 28-30.*
R. L. Dillenbeck, et al., “The Effect Of Microsilica On The Thermal Stability Fo Lightweight Cement Systems”, Annual Spe/CIM Petrol Soc. Horiz. Wells Conference, No. 116, pp. 1-5 1999. XP-002044825.
E. B. Nelson, “Portland Cements Characterized, Evaluated”, Oil and Gas Journal, vol. 81, No. 5, Feb. 7, 1993, pp. 73-77. XP-000142872.

Affiliated with

Also associated with

Rating

Slag for cementing a well, in particular an oil well does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Slag for cementing a well, in particular an oil well, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Slag for cementing a well, in particular an oil well will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2579390