Well inflow areas isolation technique

FIELD: mining engineering, oil industry.

SUBSTANCE: invention refers to oil industry, specifically to well inflow areas isolation. Technological result is increase of inflow isolation efficiency. Well inflow areas isolation technique including polymer pumping of well, polymer gelatinization curing and further strengthening with cement suspension implies using of polymer composition of viscosity not more 15-20 MPa. Polymer composition is pumped between oil separation layers and further driven to critical area by oil pressure 0.6-0.8 MPa for pore space treatment, curing in specified area is carried out as formation pressure is equal to well pressure.

EFFECT: increase of inflow isolation efficiency.

1 ex

 

The invention relates to the oil industry, in particular to isolate water production zones in the well.

There is a method of isolating zones of water in the well, comprising pumping into the well cement [1, s].

The disadvantage of this method is that due to the direct contact of cement with formation water in the area of water production is a violation of its initial concentration and, as a consequence, the destruction of the insulating screen.

Closest to the proposed invention is a method for the isolation of water in the well, including the injection of viscoelastic composition with time on his gelation in the volume of the wells, the injection and zakreplenie cement mortar [2].

The disadvantage of this method is that in the process of stopping the injection and holding it in the well due to leaks in equipment does not exclude the possibility of mixing and dilution viscoelastic structure post separation fluid and cement, which may disrupt the initial concentration of the viscoelastic composition and, consequently, to deteriorate the stability of the formed insulating screen.

An object of the invention is to increase the efficiency of the isolation zones water production by increasing the resistance of insulating screen in the bottom hole is the region of the formation.

The problem is solved in that in the method of isolation zones water production in a well, comprising pumping into the well of the polymer composition, the extract composition on gelation and subsequent zakreplenie its cement slurry according to the invention using polymer composition with a viscosity of not more than 15-20 MPa·to carry out the injection of dividing it between layers of oil and the subsequent displacement of oil in the bottom zone is produced at a pressure of 0.6-0.8 MPa in the mode of impregnation of the pore space, and the shutter speed in this area - in case of equality of formation and borehole pressures.

To do this, use a low viscosity (not more than 15-20 MPa· (C) easily filterable selective water polymer compositions that react with reservoir water: isocyanate prepolymer polyurethane), organosilicon compounds, acrylates, liquid glass and the like, provided curing them in the pores of the reservoir and is not cured in the wellbore.

The essence of the invention is that the delivery in the bottomhole formation zone of water polymer composition is produced by displacement with a small overpressure (repression), almost spontaneously, in the mode of impregnation of the pores of the layer of the polymer composition, i.e. with a minimum pressure drop across the insulated area of the formation from the borehole. This distinguishes the proposed the first method from the known methods, in which the injection of isolating structures operate at high speed Assembly and at a pressure limited only by the strength of the casing. When using a packer with a short shank equipped with a saddle with the separation tube, gelation occurs when the equality reservoir and downhole pressures, when, as a consequence, the attenuation filter. Occurs mainly spontaneous mixing of the polymer composition due to forces of wetting, capillary imbibition, diffusion and formation water in the pores of the formation adjacent to the wellbore, that is, instead of filtering is implemented mode of impregnation (wetting, capillary phenomena and diffusion), which prevents, as a result, erosion of the polymer composition of formation water in the bottomhole formation zone in the process of gelation. This is the main difference of the proposed method from the known methods of isolation.

An example of a specific implementation.

In the borehole, casing, fluid-filled damping, make the descent and landing is installed on opressovannyh tubing packer with a short shank (Application for utility model №2006103090(003367) "Device for isolating zones acquisitions"). Prepared and injected into podarennuyu the area between the separation layers of the commercial oil poly the policy mix (for example, the prepolymer) and cement slurry. Because, most often, is not known thickness of Obvodnogo reservoir, the need of water the polymer composition of the insulation accept is 0.75-1.5 m3based on the need of produce it, mainly in the bottomhole formation zone. The displacement of water the polymer composition of the produced commodity oil (e.g., Devonian) at a pressure of not more than 0.6-0.8 MPa. Use as a separating fluid tank oil reduces the dilution of the "head" and "tail" of the most critical parts of water compositions and provides continuity (phase relationship) of oil in the wellbore area sepromatiq water saturated productive layers with oil in the wellbore. When the displacement of the cement slurry in podvecerni space of the casing and partly in the isolation zone, the tube sits in the saddle, set in the short shank of the packer. Ring annulus disjoined by the packer, and the volume of the tubing is a tube that aligns reservoir and downhole pressures in isolation (according to the principle of communicating vessels). Thus, exposure of the polymer composition in the wellbore area occurs in the absence of differential pressure and, as a consequence, filtering.

Application of the proposed method for the isolation of p which increases the likelihood of water polymer composition in the flooded area of the reservoir and has a higher profitability, as used small amounts (0.75 to 1.5 m3) polymer composition. In addition, squeezing the oil is completely removed from the wellbore. The method has a high environmental safety both from the point of view of environment protection on the Earth's surface, since it reduces the probability of gusts of communications in the absence or small values of the pressure (repression) duringin, and from the point of view of resource conservation, since it reduces the possibility of contamination of the polymer composition of oil saturated intervals bottom-hole formation zone wells - the main factor limiting the rate of oil production.

Sources of information

1. Molchanov A.G. Underground repair of wells. - M.: Nedra, 1986, s.

2. RF patent №2111337, EV 33/13, 20.05.98, bull. No. 14.

The way to isolate water production zones in a well, comprising pumping into the well of the polymer composition, the extract composition on gelation and subsequent zakreplenie its cement slurry, characterized in that use polymer composition with a viscosity of not more than 15-20 MPa·to carry out the injection of dividing it between layers of oil and the subsequent displacement of oil in the bottom zone at a pressure of 0.6-0.8 MPa in the mode of impregnation of the pore space, and the shutter speed in this area - in case of equality of formation and borehole pressures.



 

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3 ex

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1 ex

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.2
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2 tbl, 4 ex, 2 cl

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