Method for isolating fluid-influx area in a well

FIELD: oil and gas extractive industry.

SUBSTANCE: method includes forming a screen of viscous-elastic mass in well via interaction of working liquid pumped into well in form of alkali waste of kaprolaktam production or its solution, with influx liquid. Necessary speed of transformation of viscous-elastic mass and intensiveness of filling of well adjacent area with it is adjusted by mode of pressing of working liquid into influx zone. For this purpose pressure increase is alternated with pressure decrease. Pressure is decreased for 10-50% from achieved maximum pressure. Relation of exposure time for increased pressure to decreased pressure time is taken in limits 1.1-5.0.

EFFECT: higher efficiency.

7 cl, 1 ex

The present invention relates to the field of oil and gas industry and, in particular, to isolate zones floodproofing in an oil or gas well in the course of its operation, creating a waterproof screen filter in the area of operational wells in the separation of saturated and neftegazonosnyh layers, eliminate cross and annular flows, as well as in the elimination of various leaks of the casing. This area floodproofing can be represented by water seepage and/or signs of gas in the zone of the reservoir or outside it.

The known method of isolation zones floodproofing in the well by the injection into it of insulating material (see, for example, Bulgakov GT, etc. Limit the inflow of formation water in oil wells. M.: Nedra, 1976, p.98-104).

The disadvantage of this method is its low insulating ability in heterogeneous permeability reservoirs, low adhesion to the formation rock. Moreover, the applied insulating material first enters the high permeability channels of the reservoir and at a shallow depth, leaving small pores and cracks with higher filtration resistance uninsulated, which leads to insufficient coverage of the layer of insulating material on its thickness and the depth (in the radial direction of the wellbore), consequently, the lack of a high efficiency isolation zone floodproofing in the well.

The technical result of the invention is to improve the efficiency of the isolation zone floodproofing in the borehole due to the increase of coverage of this area by its thickness and depth from a strictly address the impact.

Required technical result is achieved in that way isolation zone floodproofing in the borehole includes the education of the screen from the plastic mass in the borehole by interacting injected into the well fluid with developing fluid, while the required rate of formation of viscous plastic mass and the intensity of impregnation it well zone adjust mode produce working fluid in the manifesting zone with increasing pressure, alternating pressure drop over 10-50% of the achieved maximum pressure, with respect to the exposure time increased pressure at the time of low pressure taken in the range from 1.1 to 5.

In addition:

as zone floodproofing take an unpressurized area of the casing or annular zone manifestations, or the area of cross-flows, or the area of the perforations against the productive formation;

as the working fluid used alkaline runoff production of caprolactam ((AEA);

as a researcher who is named as the working fluid used solution (AEA technical water in an amount of 0.1 to 1.5% (AEA of the volume of process water;

download (AEA or technical water with admixture (AEA alternate injection of sodium silicate or sodium silicate solution in technical water;

download (AEA or solution (AEA and sodium silicate are intermediate packs of fresh water supply;

after injection (AEA and sodium silicate download penitently solution;

after injection pentimento solution pumped cement mortar;

The essence of the invention.

The essence of the proposed invention is that the method involves the optimization of the isolation zone floodproofing due to the selective interaction of the fluid with fluid manifesting zone, i.e. water and/or gas in this zone than provide a strict targeting effects. This isolation not only provide the most manifest of the channels in this zone - microcannulas, and all connected with them microchannels. This nature provide isolation of the used working fluid and the regime of isolation, when the required rate of formation of viscous plastic mass and the intensity of impregnation it well zone adjust mode produce working fluid in the manifesting zone. This is ensured by the pressure increase, alternating c decompression. This mode of working fluid in the area floodproofing creates unsteady guide is dinamicheski mode multi-directional filtering in the near-wellbore zone, connecting to this filtering all conducting channels, regardless of their size. In the practical research process isolation using (AEA found that at low pressure (10-50% of the achieved maximum pressure with respect to the exposure time increased pressure at the time of low pressure in the range from 1.1 to 5 in the well celebrated piston filtering mode in isolation throughout its thickness and qualitative leap in the quality of insulation manifesting zone. When isolation zone leakage casing is included adjacent to this zone zone rocks with its filter channels. In accordance with the present invention using the entire thickness of the zone of manifestation for its isolation. In the end, insulating material serves in the area of complication in the piston mode, in contrast to known methods, when the main accelerating part of the zone of complications is only part of the zone, i.e. the most conductive of its channels and when the grouting material is injected under pressure above the pressure of the fracturing. In addition, the depth of the isolation zone complications in General, in addition to horizontal cracks fracturing, in the known methods is not great. It does not exceed a few centimeters. The main volume of plugging material goes into highly conductive horizontal channels. Depression in the well and airvana thus the area can not withstand the differential pressure again becomes floridapayday, as revealed precisely the most vulnerable, poor and not deeply plugged the zone complications, defining a generally low efficiency of its isolation.

In accordance with the present invention achieve maximum coverage of the area complications on its thickness and depth due to the exclusion of all its conductive microcannulas and microchannels in this area, combining all raznoprofilnye interlayer zone. The depth of the isolation additionally increase the preliminary and, if necessary, followed by hydrophobization of the zone, for example, using malonate. This uniformity of hydrophobization (waterproofing interlayer zones of different degrees of filtration) and the depth of the plugging achieve and/or enhance non-stationary regime of the injection fluid, characterized by shifts injection regime. Due to periodic changes in exposure conditions in the area complications result the pressure gradients in the direction of the deposition of the interlayer zones, reinforcing the process of capillary (reciprocating) implementation of the injected fluid in the low permeable areas. During periods of low pressure injection, the sign of the gradient of the hydrodynamic pressure changes and introduced into the deposition areas of the fluid receives the possibility of reverse flow in high permeability areas. All this together with hydro is obisanya zone complications in multiples of enhances the effect of the coverage zone complications injected into her liquid, including grouting material for which pre-and inject the liquid repellent, preparing the conditions for the subsequent plugging zone complications. It all works on the qualitative effect of isolation of this area on its thickness and depth.

The positive effect of the method is enhanced with the use of (AEA in combination with sodium silicate. The screen is made of visco-plastic mass is formed by selective reaction (AEA and sodium silicate with formation water or gas. Download (AEA and sodium silicate or their solutions (possible combinations of concentrated (AEA with a solution of sodium silicate or sodium silicate solution (AEA) are intermediate packs of fresh water, making it possible to adjust the start of the reaction reagents. When this reaction occurs at the boundary of contact solutions. Unreacted parts are further additional insulating material by the outburst of gas or produced water. Thus, this system has recovery properties. Side additional effect of reaction (AEA with developing fluid is the release of fresh water from the solution (AEA, which can be used to interact with the cement injected to enhance the effect of isolation manifesting zone. In the oil of the reservoir cement mortar not having hardened the et and can be made from this part of the formation.

Used by the method (AEA (TU 113-03-488-84) is an opaque dark brown liquid without mechanical impurities, low-toxic, with a density of 1.1 to 1.2 g/cm³pH 10-13 and freezing temperature -25°C. Contains 18-30% of adipate sodium, up to 10 pitches and up to 0.8% of cyclohexanol. It is highly soluble in water, has alkaline properties, properties of surface-active substances (surfactants). As a result of application (AEA achieve complex effects on the near-well zone of the reservoir, namely: dissolve asphalt, resin and paraffin deposits (ARPD), reduce the surface tension at the phase boundaries, prevent swelling clays. Universal properties (AEA in conjunction with the described technology supply to the area floodproofing ensure the processing of all matrices of the productive formation the whole of its macro - and micropores. Thereby creating a reliable system of trap zone.

The method is as follows.

For isolation zone floodproofing in the borehole to form the screen of the viscous plastic mass in the borehole. For this interact injected into the well fluid containing (AEA, with developing fluid. With this purpose to floridapayday zone (for example, sole) pouring down the column, for example, of the tubing. is via this column inject the working fluid in the form (AEA or aqueous solution (AEA and push it in fluidframes zone. Necessary to isolate the rate of formation of plastic masses (for example, terms and conditions prevent excessive dilution of the initial working fluid) and the intensity of impregnation it well zone adjust mode produce working fluid in the manifesting zone. This increase in pressure required for injection of the working fluid, alternating with decreasing pressure. Pressure reduced by 10-50% of the achieved maximum pressure. Thus the ratio of the exposure time increased pressure at the time of low pressure taken in the range from 1.1 to 5. To enhance the effect of insulation injection (AEA alternate injection of sodium silicate. The injection solution (AEA and sodium silicate are intermediate packs of fresh water.

After injection (AEA and sodium silicate download penitently solution. After injection pentimento solution pumped cement mortar.

A specific example of implementation of the method.

Select one of the wells oil wells, where the uncovered reservoir with a capacity of 7 m and two interlayer capacity of 2.5 and 4 m with intensive water sources. Geophysical methods determine the acceleration of the productive formation, depending on the pressure of the injection and monitoring of coverage of the injected agent of the productive formation in his power.

Carry out the injection of the zone ingress of water through the column casting pipes aqueous solution (AEA 5 m ³with the addition of the actual (AEA in the amount of 0,05 m³. Start injecting an aqueous solution (AEA at a pressure of 24 MPa. After injection of 2 m³within 10 min, transferred to the injection solution with reduced pressure up to 20 MPa for 7 minutes Then increase the pressure up to 26 MPa. Download 1 m³an aqueous solution (AEA for 5 minutes At this lower pressure injection up to 18 MPa. Then again increase the pressure. Each time taking different values of the pressure, the volume of the injected solution and the injection with the above conditions, the ratio of the pressure and time of exposure to create nestatsionarnogo hydrodynamic regime, precluding the development of habitual ways of filtering and filing of insulating material only in high-conductivity channels.

1. Way isolation zone floodproofing in the well, including the education of the screen from the plastic mass in the borehole by interacting injected into the well fluid in the form of alkaline runoff of caprolactam - (AEA or its solution with developing fluid, while the required rate of formation of viscous plastic mass and the intensity of impregnation it well zone adjust mode produce working fluid in the manifesting zone with increasing pressure, alternating pressure drop over 10-50 % of the reach is th maximum pressure, thus the ratio of the exposure time increased pressure at the time of low pressure taken in the range from 1.1 to 5.

2. The method according to claim 1, characterized in that zone floodproofing take an unpressurized area of the casing or annular zone manifestations, or the area of cross-flows, or the area of the perforations against the reservoir.

3. The method according to claim 1, characterized in that (AEA used in the form of technical solution in water in an amount of 0.1 - 1.5 % of the volume of process water.

4. The method according to claim 1, characterized in that the injection (AEA or its solution alternate injection of sodium silicate or sodium silicate solution in technical water.

5. The method according to claim 4, characterized in that the injection (AEA or solution (AEA and sodium silicate are intermediate packs of fresh water.

6. The method according to claim 4 or 5, characterized in that after injection (AEA and sodium silicate download penitently solution.

7. The method according to claim 6, characterized in that after injection pentimento solution pumped cement mortar.