The method of saving the reservoir properties of the near-well zone of the reservoir

 

(57) Abstract:

The invention relates to the field of the oil industry and can find application in various impacts on the reservoir during operation of the well and, in particular, with its perforations, killing for the possibility of repair of wells, emergency shutdown, the intensification of oil production, the alignment of the injectivity profile while maintaining reservoir pressure, for example, flooding, etc. of the Invention can be applied in various geological conditions and, mainly, in terms of complex Geology, characterized by the heterogeneity of the productive layer with a high coefficient of its ruggedness. Provides a more effective method due to the possibility of maintaining the reservoir properties of productive layer throughout its thickness and at a distance from a borehole into a formation, not a smaller zone of sedimentation. The inventive method involves placing against the productive formation fluid with the addition of malonate. The volume of the working fluid take in the volume of pores and/or cracks of the productive formation in a radius of 0.3 m and 2.0 m from the wellbore. Then push the working fluid in the reservoir in dir is unique cracks productive formation. Impregnation of the layer is carried out at a pressure less the pressure of the disclosure natural vertical fractures 5-15% of the set pressure and cyclic modes increase of pressure relief. Then carry out the planned impact on the reservoir. 5 C.p. f-crystals.

The invention relates to the field of the oil industry and can find application in various impacts on the reservoir during operation of the well and, in particular, with its perforations, killing for the possibility of repair of wells, emergency shutdown, the intensification of oil production, the alignment of the injectivity profile while maintaining reservoir pressure, for example, flooding, etc. of the Invention can be applied in various geological conditions and, mainly, in terms of complex Geology, characterized by the heterogeneity of the productive layer with a high coefficient of its ruggedness.

Under the term "preservation of reservoir properties" should be understood also, and restore the modified reservoir properties to their initial state. These changes can be caused by imperfection of drilling in PR is about this invention.

There is a method of preservation of reservoir properties of the near-well zone of the reservoir using a fluid-based aqueous solutions of mineral salts used individually or as mixtures thereof (Orlov, A. and others applying the inverse emulsions in oil production. M.: Nedra, 1991, S. 118).

The method allows to securely plug the well. However, after putting the well into operation there has been a sharp decline in well productivity. This recovery of the reservoir properties of the near-well zone of the reservoir well to initial (original) properties is not possible.

The technical result of the invention is to increase the efficiency of the method due to the possibility of maintaining the reservoir properties of productive layer throughout its thickness and at a distance from a borehole into a formation, not a smaller zone of sedimentation.

Required technical result is achieved by the fact that the way to preserve the reservoir properties of the near-well zone of the reservoir wells involves placing against the productive formation of the working fluid with the addition of malonate, the volume of pores and/or cracks of the productive formation in a radius of 0.3 m and 2.0 m from steel its thickness, what set opening pressure natural vertical fractures of the reservoir, and the impregnation layer is carried out at a pressure less the pressure of the disclosure natural vertical fractures 5-15% of the set pressure and cyclic modes increase-pressure relief, followed by a planned impact on the reservoir.

In addition:

with gentle throttled well for repair works as the working fluid use technical water with the addition of malonate in the amount of 0.15 to 1.2% of the volume of process water, while above the working fluid in the well is placed weighted process liquid in the form of a salt solution of one or more species;

accidental killing the well above the working fluid in the wellbore is placed a portion of the blocking fluid with additives of calcium chloride and malonate in the amount of 0.3-1.4 m31 m thickness of the formation, with over blocking fluid in the well is placed weighted process liquid in the form of a salt solution of one or more species;

at the opening of the productive formation as the working fluid used is their oil after produce working fluid with mylanta in the reservoir are aging well within 12-36 h, then reduce the pressure in the reservoir and carry out the removal of the reaction products from the formation;

to maintain reservoir pressure in the reservoir, the displacement of the working fluid in this layer perform with mylanta and rims of calcium chloride solution, then stand well before the injectivity profile alignment of the productive formation and carry out the injection of the displacing agent.

The essence of the invention.

In many known types of action on a productive stratum, i.e., when the primary opening of the reservoir, its time killing for some period of time, when the secondary opening, etc. in the near-wellbore area of the reservoir is formed (accumulated) as a rule, water-saturated zone. This is because the collector layer is hydrophilic. Due to the capillary pressure in the pores of the small diameter of the liquid will rise in the capillary tube up until the capillary pressure balanced hydrostatic pressure of a column of rising fluid. As a result of this water is retained in the reservoir by capillary forces and blocks the flow of oil from the reservoir.

When killing the well water solutions of salts with the addition of surface-active what eftu several times. However, it is necessary to reckon with vasilevousa ability of highly concentrated aqueous solutions of salts of this surfactant. With increasing temperature of the reservoir, this property is enhanced and killing the well by such technology becomes ineffective. In addition, the surfactants have a narrow range of physico-chemical actions on the near-well zone of the reservoir. Applied technology does not provide an effective impact on the reservoir throughout its thickness, particularly given the strong heterogeneity of the reservoir, and to the desired depth of the near-wellbore zone. The effects are, as a rule, the zone of increased filtering, which is the main ablation of expensive reagents that do not provide the desired result. Whilst the rest of the matrix of the reservoir, characterised by decreased filtering, remains indifferent as under stimulation, and at the stage subsequent input wells in operation. This response of the productive formation with each impact, the situation is only getting worse. From here it becomes clear why the rate of oil recovery from wells barely exceeds 35% (with an average value under ivacy the whole system of existing and potential filtering of the reservoir, including its micro - and macropores, in all its height and radius in the range of 0.3-2 m from the wellbore (in the area of the most severe clogging). For example, if necessary, temporary plugging of wells near well zone activates a large enough pressure to supply in this zone of the reservoir fluid damping. In the General case, the ideal pressure is the pressure of the disclosure natural vertical fractures the reservoir. Disclosure of natural vertical fractures unite all the diverse on the permeability of the substratum and provide improved throttle response of a productive formation in the whole of its thickness. However, this pressure precedes the development of water-based fracturing with the formation of horizontal cracks, which in this case is not valid, because fraught with repeated “usual” hydraulic fracturing is already at lower pressures. Therefore, the displacement of the working fluid in the reservoir is carried out in the mode of impregnation, i.e., at a pressure of 5-15% less pressure erection natural vertical fractures and in cyclic mode boost-pressure relief.

It is noticed that cyclical changes in pressure creates conditions permeability gradients occur hydrodynamic pressure contributing to the intensification of flows of liquids from one layer to the other with the compulsory introduction of fluid into permeable areas with less pressure than is required when stationary version of produce working fluid. Marked minimum inertia response of the deposition sites on the cyclic changes of pressure close to the pressure of the disclosure natural vertical fractures of the reservoir, with the addition of the working fluid malonate. Mylonaft is a sodium salt of naphthenic acid is a product of alkaline neutralization of naphthenic acid (saponification). It dissolves well in water, is active surfactant that reduces surface tension at the boundary of the oil-metal-water and dispersing the asphalt-resin-paraffin education (ASPO), provides a clay formation removal of critical area. Universal properties malonate in conjunction with the described technology to its submission to the reservoir to ensure processing of all matrices of the productive formation the whole of its macro - and micropores. Thereby creating a reliable system of water seal of the reservoir, necessary, for example, when jamming of the productive formation. The impact on all sorts of pores is then for the subsequent drainage of the oil throughout the thickness of the reservoir. At this time of bringing the well into operation after jamming can be reduced to a few hours (compared to a few days by a known method). Thus ensure the preservation of the filtration properties productive in their extended interpretation (restoring these properties to the original) due to the dispersion of the asphalt-resin-paraffin formations and clay formation removal of critical area. This provides significant time and cost savings in comparison with the known method, in which the input wells in operation takes a few days in case of permanently partial loss of filtration properties of the reservoir.

The feature of the secondary drilling with the use of the present invention is that the autopsy carried out using explosives) with a large outgassing and low-speed detonation to increase the duration of the explosive impulse, for example, ammonium Selitrennoe village CENTURIES (type hanita). When this is chosen the power of the explosion, when opening the natural vertical fractures. Gaseous products of the explosion form the so-called gas bubble, which in hydrogenous the displacement of the working fluid with mylanta in the reservoir in the mode of impregnation of the layer throughout its thickness, i.e., at a pressure less the pressure of the disclosure natural vertical fractures and non-stationary (cyclical) mode boost-pressure relief.

Unsteady pressure impregnation productive layer provides connectivity to areas of active drainage of the deposition zones of difficult drainage from saturation of all zones mylanta that increase from cycle to cycle, the hydrophobicity of these zones, the clay formation removal and dispersion of sediment. As a result, when a subsequent call flow of oil from the reservoir the latter ensures the removal of all the products of the reaction and recovery of the entire system of macro - and micropores.

The peculiarity of the method for the case of its use to maintain reservoir pressure in the reservoir (during development) is the application of the rims of calcium chloride solution. These rims can be separated from the rims of the solution malonate rims, for example, fresh water. This creates the necessary conditions for the mixing of solutions of malonate and calcium chloride. Well maintain necessary time. The result is a thickened mixture, keeping all the required properties according to the method and provides additional alignment property of pri fluid, for example, water.

The method is as follows.

In the well against the productive formation put the working fluid, with the addition of malonate. The amount of additives malonate choose depending on the impact on the reservoir. For example, while sparing the throttled well mylonaft take in the amount of 0.15 to 1.2% of the volume of the working fluid, accidental killing the well in the amount of 0.3-1.4 m31 m thickness of the formation, at the opening of the productive formation - in the amount of 0.15 to 10% by volume of the working fluid. The volume of the working fluid take in the volume of pores and/or cracks of the productive formation in a radius of 0.3 m and 2.0 m from the wellbore. Then push the working fluid in the reservoir in the mode of impregnation of the layer throughout its thickness. For this pre adjacent wells or samples of the breed set opening pressure natural vertical fractures the reservoir. The actual impregnation of the productive formation is carried out at a pressure less the pressure of the disclosure natural vertical fractures 5-15% and in cyclic mode boost-pressure relief. Then carry out the planned impact on the reservoir, the e, or the intensification of oil production, or the alignment of the injectivity profile while maintaining reservoir pressure, for example, flooding, etc.

1. The method of saving the reservoir properties of the near-well zone of the reservoir, including room against the productive formation of the working fluid with the addition of malonate, the volume of pores and/or cracks of the productive formation in a radius of 0.3 m and 2.0 m from the wellbore, the subsequent displacement of the working fluid in the reservoir in the mode of impregnation of the layer throughout its thickness, for which the set opening pressure of the natural vertical fractures of the reservoir, and the impregnation layer is carried out at a pressure less the pressure of the disclosure natural vertical fractures 5-15% of the set pressure and cyclic modes increase-pressure-relief then carry out the planned impact on the reservoir.

2. The method according to p. 1, characterized in that at moderate throttled well for repair works in this well as a working fluid using water with the addition of malonate in the amount of 0.15 to 1.2% of the volume of process water, while above the working fluid in the well is placed is on p. 1, characterized in that in case of emergency killing the well above the working fluid in the wellbore is placed a portion of the blocking fluid with additives of calcium chloride and malonate in the amount of 0.3-1.4 m31 m thickness of the formation, with over blocking fluid in the well is placed weighted process liquid in the form of a salt solution of one or several species.

4. The method according to p. 1, characterized in that at the opening of the productive formation as a working fluid using water with the addition of malonate in the amount of 0.15 to 10% by volume of process water.

5. The method according to p. 1, characterized in that when the intensification of oil production after produce working fluid with mylanta in the reservoir are aging well within 12-36 hours, then reduce the pressure in the reservoir and carry out the removal of the reaction products of this layer.

6. The method according to p. 1, characterized in that in order to maintain reservoir pressure in the reservoir, the displacement of the working fluid in this layer perform with mylanta and rims of calcium chloride solution, then stand well before the injectivity profile alignment of the productive formation and the

 

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