RU2359113C1 - Treatment method of layer bottomhole - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention elates to oil products extraction, particularly to methods of impact to pay area for restoration of wells oil recovery. It is provided range of application expansion of method and its effectiveness increase. Essence of invention: method includes delivery into the pay space and burning in it of pyrotechnical charge, creation of depression and following removal from the pay space of downhole liquid with arrived in it from the layer bottomhole - LB mud elements. According to the invention beforehand in well in filter zone of LB it is implemented additional spared perforation with density not more than 3 holes per metre. Then it is pumped into the LB hydrophobic solution in amount, providing the formation of watertight hydrophobic screen, cut off water-saturated beds in the near pay area. Additionally creation of depression and following removal of formation water with arrived in it mud elements is implemented by means of well-swabbing up to installed as constant oil product inflow with simultaneous regulation of mud elements arriving on the surface.

EFFECT: range of application expansion and its effectiveness increase.

Description

The invention relates to the field of oil production, in particular to methods of influencing the zone of a productive formation in order to restore oil recovery wells.

One of the reasons for the decrease in well productivity is the active deposition of asphalt-resin-paraffin substance (AFS) in the casing filter and directly in the pore space of the formation along the surface exposed by the well in the so-called bottom-hole formation zone (BHP).

The deposition of paraffin deposits occurs due to a decrease in the temperature of the produced formation fluid below the crystallization point of the asphaltenes and paraffins dissolved in it. The temperature reduction process is especially intense when the formation fluid moves through the outer surface of the formation filtration and through the openings of the casing filter (Joule-Thomson effect), where the active deposition of paraffin deposits from the colloidal solution occurs, which is mainly an oil emulsion in water.

The specified process significantly increases the hydraulic resistance of the bottom hole and the column filter, leading to a decrease in well productivity.

There are various methods and tools for cleaning the filter and PZP from AFS.

Known methods of chemical exposure to the BFP with the injection into the filter interval of a certain volume of hydrocarbon solvent and keeping it at the bottom for some time (a day or more) until the process of cleaning the BCP from ASPO is completed. (Ibragimov G.Z., Sorokin V.A., Khisamutdinov N.I. Chemical reagents for oil production: Worker's Handbook. - Nedra, 1986, p. 240).

To speed up the cleaning process, in some cases, a solvent is heated up to a certain temperature (V. Raznitsyn, “Methods of Paraffin Control at the Uzen Field.” - Oilfield Business, - M., VNIIOENG, 1979, Issue 10, p. 26-27).

They also use the combined version of ASPA cleaning, in which, to accelerate cleaning, the volume of solvent pumped into the zone of the bottom-hole zone is affected by a source of vibrational vibrations (Musabirov M.Kh. Technologies for processing the bottom-hole zone of an oil reservoir in the PRS process, M., VNIIOENG, 2002 , p. 224).

The disadvantage of chemical methods is the complexity of the equipment used for pumping chemicals into the well, it requires large energy and labor costs, and also does not comply with environmental requirements.

There is a method of cleaning PZP, based on the application of heating PZP using electro-induction converters with simultaneous processing of the heating zone by ultrasonic vibrations from special sources (V. Kudinov. Improving thermal methods of developing high-viscosity oil fields. - M., Oil and gas, 1996, p. 28).

The disadvantage of this method is that it requires laborious tripping operations for the delivery of sources to the PZP and high energy consumption for its heating.

In recent years, more effective technologies have been developed for the cleaning of PPP from ASPO, partially devoid of these shortcomings.

There is a known technology of thermogasobaric impact on the bottomhole formation zone, based on the creation in the bottomhole zone of high temperature and pressure by burning a powder charge in it, lowered into the processing zone on a wireline cable (Pat. RF No. 2072423, "Method for processing bottom-hole zone of a well and device for its implementation ”, priority 04/12/1996, published 01/27/1997, bull. No. 3). The temperature, pressure and duration of exposure are regulated in this case by selecting the appropriate type of PP and the ratio of its dimensions to the dimensions of the processed section of the PPP.

In the process of the combustion of PP in the PZP, a high-temperature vapor-gas bubble is formed, the pulsations of which have an active repressive and depressive effect on the PZP and the filter of the column, leading not only to their active purification from ASPO, but also to an abnormal gas-dynamic effect through the filter openings on the rock surface with the formation in it additional filtration channels (microcracks).

As a prototype of the claimed method, the method according to patent No. 2072423, “Method for processing the bottom-hole zone of a well and a device for its implementation,” was taken.

The known method includes delivering a depression chamber to the interval of a productive formation and burning a pyrotechnic charge therein with gas evolution and creating a depression in which the well is pre-filled with a liquid with increased density and a liquid column pressure corresponding to the formation pressure is created, while the method uses a slowly burning pyrotechnic charge, providing the release of gases with elevated temperature, the burning of a slowly burning pyrotechnic charge is carried out before creating depression, starting from the bottom of the interval of the reservoir for a time corresponding to the time of heating the bottom-hole zone to the melting temperature of the clogging elements, while burning a slowly burning pyrotechnic charge, circulate well fluid to cool the body of the inlet valve assembly of the depression chamber, then produce technological exposure for substitution in the interval of the reservoir of gaseous products of combustion of a slowly burning pyrotechnic number of wells with liquid and after the depression is removed from the reservoir interval portion of the wellbore fluid with the received therein depression bottom zone of the bridging elements.

The advantage of the described method is its high technical and economic efficiency, due to the efficiency of the work on the cleaning of the bottomhole zone, the duration of which is no more than 6-8 hours and a significant field effect, consisting in a significant increase in well productivity (up to 4-5 times) along with a significant ( up to 15-20 months) by maintaining the resulting positive effect.

The main disadvantage of this method is the limitation in the field of its application according to the geological and physical and geological and technical conditions. In particular, this method can be used in the treatment of terrigenous reservoirs with a water cut of not more than 40%, with a bridge power of at least 5 meters to the aquifer.

Another significant drawback of this method is the destruction of cement stone in the zone of active impact (PZP), especially in the wells of the old stock, leading to the subsequent removal of its fragments with the flow of formation fluid during commissioning of the well and, as a result, to the breakdown of pumping equipment with corresponding additional the costs of its lifting and repair.

Such restrictions significantly narrow the scope of the known method, especially in old fields in the late stage of operation, when the water cut in most (90%) of the production well stock exceeds 70-80%, and the average size of jumpers, especially in conditions of widespread complex reservoirs, is no more than 3-4 m.

The objective of the proposed method for processing bottom-hole formation zone is to expand the scope and increase its effectiveness.

This problem is solved by the fact that in the inventive method for processing the bottom-hole formation zone (PZP), which includes delivering a pyrotechnic charge to the interval of the reservoir and burning a pyrotechnic charge therein, creating a depression and subsequent removal of the borehole fluid from the interval of the reservoir, with the colming elements received from it, in the well in the filter zone, additional gentle perforation is carried out with a density of not more than 3 holes per meter, then a hydrophobic solution is pumped into the PZP in an amount that ensures the formation of a waterproof hydrophobic screen that cuts off water-saturated interlayers in the near zone of the reservoir, and the creation of depression and subsequent removal of the reservoir fluid with the fluid elements entering it is carried out by swabbing the well until a steady inflow of oil is obtained with simultaneous control of the arrival of the reservoir elements to the surface.

To disclose the essence of the proposed method provides the following explanation.

From the practice of performing waterproofing works (VIR) in wells conducted to block waterlogged layers, it is known that the greatest effect is achieved when various hydrophobic solutions or emulsions are used that have the properties of selective penetration into the wash zone of the formation, forming a waterproof screen (rim) in them around the PPP (Kleshenko II, Grigoryev AB, Telkov AP Insulation work in the completion and operation of oil wells. M: Nedra, 1998, p.267).

The inventive method is as follows.

When choosing an object of influence, the main attention is paid to the size of the bridge to the aquifer, which should be at least 3-4 m, and the state of adhesion of cement to the casing near the PZP (in the range of ± 10 meters), which should provide a cementation quality coefficient in this interval not below 0.3. The water content of the extracted products can be no more than 80-90%. After selecting a well for processing in the interval of the reservoir (in the filter zone), gentle perforation is performed with a density of not more than 3 holes per meter. Such a perforation density was chosen by calculation and subsequently provides reliable hydrodynamic connection with the formation. Perforation is carried out by the standard cumulative method.

Then, hydrophobic solutions or emulsions are injected into the well to cut off the waterlogged layers and form a waterproof screen around the bottom-hole zone. Implementation of waterproofing works is carried out, for example, according to RD-153-39.0-329-04 “Instructions on the technology for preventing sand removal, fixing the bottomhole zone and reducing the influx of formation water in production wells (Crystal)”, “TatNIPIneft”, Bugulma, 2002 d. According to the instructions “... a highly viscous rim of a structured hydrophobic emulsion is pumped into the selected interval of the well. The rim volume should displace water from the wellbore by 20-25 m. The hydrophobic composition does not dissolve with water, but on the contrary, hardens upon contact with it, i.e. practically does not erode in reservoir conditions under the pressure of water. The screening effect is enhanced by a set of structural and mechanical properties of the emulsion over time (the effect of thixotropic hardening of the structure) ... ”.

Thus, in the case of a further inflow call after the implementation of waterproofing works, only oil-saturated interlayers are actively working, while the washed-out, highly flooded interlayers remain blocked for a long time.

Next, they carry out the technology of thermogasobaric impact on the bottomhole formation zone using a slowly burning pyrotechnic charge, which is carried out according to RD-153-39.0-335-04 “Instructions for the use of the UTI-1 thermoimplosion device with a STGG-80 thermogas generator for impacting the bottom-hole formation zone”, OJSC “ Tatneft ”and LLC NTP“ VUHEC ”, 2004. This technology is protected by patent No. 2072423, selected as a prototype of the claimed method.

After this operation is completed, the swabbing process is carried out, while controlling the dynamics of changes in the oil and water flow rate, as well as the process of removing the clogging elements and fragments of cement stone to the surface until a constant influx of oil product is obtained. The swabbing process is carried out in accordance with RD-39-0147585-140-96 “Technology for invoking swabling inflows during well development”, TatNIPIneft, Bugulma, 1996. Swabling of a tubing string using a bore piston (swab) is used to create depression by lowering the fluid level when lifting it from the well to cause inflow from the reservoir and removing reaction products after treatment of the bottom-hole zone.

After completion of the swabbing process and obtaining confirmation of positive production results from the processing of the bottomhole formation zone, standard pumping equipment is lowered to the bottom and the reservoir is commercially operational.

The implementation of gentle perforation with a density of not more than 3 holes per meter allows without large-scale violation of the cement ring fastening to ensure reliable communication with the reservoir.

The use of hydrophobic compositions to isolate water-saturated intervals will significantly increase (several times) the number of wells in which it is possible to implement highly effective technology of thermogas-bar pressure treatment on the bottom hole even with average water cut of the reservoir from 40% to 80-90% and distance from the aquifer to 3- 4 meters, thereby dramatically expanding the scope of this technology.

Carrying out swabbing before the pump runs down to the bottom prevents the penetration of cement and fragments of cement stone resulting from the inevitable destruction of the cement ring, especially in the old foundation wells under the influence of perforation, high temperatures and pressure during the implementation of thermogas pressure with the help of a pyrotechnic charge, into pumping equipment and subsequent its failure.

Claims (1)

A method of treating a bottom-hole formation zone, including delivering a pyrotechnic charge into the interval of a reservoir and burning a pyrotechnic charge in it, creating a depression and subsequent removal of borehole fluid from the interval of a producing formation from the bottom-hole formation zone (PZP), characterized in that previously an additional gentle perforation with a density of not more than 3 holes per meter is carried out in the well in the zone of the PPP filter, then a hydrophobic solution in the amount providing ducation hydrophobic waterproof screen clipping water saturated interlayers in the near zone of the producing formation and creation of depression and subsequent removal of the bed fluid from it received by the bridging elements is carried via swabbing the well to steady constant inflow of oil while controlling Incoming bridging elements to the surface.