RU2322575C2 - Method for productive reservoir well bore zone treatment - Google Patents

Abstract

FIELD: oil production, particularly stimulation oil production by well bore zone treatment.

SUBSTANCE: method involves selecting injection and producing well pattern in oil reservoir to be developed; creating single engineering process of oil reservoir treatment by simultaneous well bore zone treatment in injection and producing wells. At the first stage productive reservoir well bore zone is heated simultaneously in all producing wells of selected pattern up to mudding component melting temperature, for instance with the use of heat-gas generators and time delay necessary for heat effect increase and gaseous combustion product substituting from liquid inside well bore is executed. At the second stage thermogas hydraulic fracturing of productive reservoir well bore zone is carried out in injection wells, for instance, with the use of quick-burning pyrotechnic charge. Impact pressure drawdown is created simultaneously in all producing wells of productive reservoir well bore zone, for instance by implosion method. To attain this, quick-burning pyrotechnic charge is triggered inside injection wells simultaneously with beginning of impact pressure drawdown in all producing wells, for instance by means of mobile communication system. At the third stage part of well fluid mixed with mudding components is simultaneously removed from productive reservoir well bore zone of all producing wells. Injection and producing well pattern is created to provide producing well selection from ones, which are the nearest to injection wells in productive reservoir.

EFFECT: increased efficiency due to provision of reliable hydrodynamic link in productive reservoir between injection and producing wells.

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Description

The present invention relates to the field of oil production, in particular to methods for influencing the borehole zone of a reservoir, and is used to increase well productivity.

One of the rational and effective methods of influencing the borehole zone of a productive formation in order to establish a reliable hydrodynamic connection between a well and a formation is to break the formation with products of combustion of a powder charge. Under the influence of gas pressure equal to or greater than the rock, rocks are irreversibly deformed. The method of formation fracturing by powder gases is based on the mechanical, thermal and chemical effects of gases on rocks and fluids saturating them (Thermogasochemical effect on low-production and complex wells / Chazov G.A. et al. - M .: Nedra, 1986. - P. 107 )

This method can be implemented, for example, by known devices for thermohydrohydraulic fracturing, protected by RF patent No. 2178072 (M.cl .: E21B 43/263, Bull. No. 1, 2002) and a positive decision of FIPS according to the RF application for invention No. 2004119183 / 03 (020696) (M.cl .: Е21В 43/263, Bull. No. 1, 2006).

The essence of thermal gas-hydraulic fracturing is to burn a quick-burning charge in the treatment zone, at which the formation ruptures with the formation of cracks in the near-wellbore zone. In this case, the products of charge combustion, drilling mud and particles of the protective coating of the charge rush into the cracks, due to which they are fixed.

The known method and device is used in an injection well, where there is an intense penetration of the injection fluid into the resulting fractures and its further penetration into the depth of the formation.

A disadvantage of the known method is that the impact on the formation only in the injection well does not provide reliable hydrodynamic communication between the injection well and the producing well, since the flow may stop when the injection fluid flows to the producing well if no operations are performed in the producing well to call the inflow from productive formation.

Another method is known that increases the efficiency of processing the bottom-hole zone of a producing well, including the simultaneous exposure of the formation to high temperatures and shock depression, resulting in the destruction of the mud zone, the creation of wave processes in the well and bottom-hole zone, the removal and removal of substances that impede the flow of formation fluids , while the bottom-hole zone and the well are cleaned (RF patent No. 2072423, Mcl .: Е21В 43/25, Bull. No. 3, 1997 and Russian patent No. 2087693, M.cl .: Е21В 43/25, Bull No. 3, 1998).

The well-known (thermoimplosion) method comprises the steps of creating a pressure depression and burning a slowly burning pyrotechnic (or any other combustible composition) charge emitting gases with an elevated temperature in the interval of the reservoir during the time corresponding to the time of heating the bottom-hole zone to the melting temperature of the clogging elements, and after Depression - removal from the zone of the interval of the reservoir of a part of the wellbore fluid with incoming clogging elements.

The known method is used in production wells, in which, when exposed to high temperatures and shock depression, an intense influx of formation fluids from the reservoir occurs.

The disadvantage of this method is the inconsistency in the time of operations of the impact on the reservoir in production and injection wells, which negatively affects the establishment of reliable hydrodynamic communication between the wells.

Thus, a separate method for processing the near-wellbore zone of a productive formation in injection wells (thermogas-hydraulic fracturing) is known, and a separate method for processing a producing well is known - thermoimplosion.

Closest to the claimed is a method of extracting viscous oil from a reservoir according to the USSR copyright certificate No. 1744998 (M.cl .: E21B 43/24, publication ban).

The essence of the known method is as follows. The oil reservoir is opened with a grid of injection (PS) and production wells (PS) with the formation of heat exposure elements (sections), and then a single technological process of thermal exposure of the oil reservoir is created, for which: at the first stage, the coolant is pumped in a certain amount simultaneously to the central PS and DS located through one, and from other DS carry out the selection of products, at the second stage DS, through which the coolant was pumped, are transferred to the selection of products, and DS from which the selection of products is transferred to coolant injection in the same amount as in the first stage; in the third stage, the wells are changed, as in the first stage, and the coolant is again pumped. In this case, the cycle of heat exposure is repeated 3 ÷ 5 times.

Thus, there is a known method for simultaneously influencing injection and producing wells by pumping coolants, and a single technological process of thermal action on the oil reservoir is created, which allows to achieve increased oil recovery by increasing the coverage of the formation by thermal action.

The disadvantage of this method is as follows. The known method provides for a very long exposure to the coolant on the oil reservoir - up to 1.7 years (p. 18 of the description of the USSR copyright certificate No. 1744998) using a large amount of coolant, requires a high level of energy consumption and labor. The technology provides for a long preparation of operations, the preparation of a special project involving the use of bulky stationary installations for heating the coolant and pumping it into wells, up to the construction of boiler houses in the field. The duration of application of such technology can last up to 6 years (ed. Certificate of the USSR No. 1744998).

The objective of the invention is to reduce labor costs of energy, time spent on creating a reliable hydrodynamic connection in the reservoir between the producing and injection wells.

The present invention allows to solve this problem by more modern and effective means.

The problem is solved in that in the method of processing the borehole zone of the reservoir, including the selection of the grid of injection and production wells in the oil field being developed, the creation of a single technological process of influencing the oil reservoir by simultaneously processing the borehole zone of the reservoir in injection and production wells, at the first stage at the same time in all producing wells of the selected grid warm up the borehole zone of the reservoir to temperatures Melting bridging elements, e.g., via termogazogeneratorov process and produce an extract necessary to enhance the thermal effect, and replacement of the combustion gases in the barrel fluid wells. At the second stage, thermogas-hydraulic fracturing of the near-wellbore zone of the reservoir in injection wells is performed, for example, using a quick-burning pyrotechnic charge and simultaneously in all producing wells in the near-well zone of the reservoir, an impact pressure depression is created, for example, by implosion, for which the initiation of the initiation of the response of the quick-burning is combined in time pyrotechnic charge in injection wells with the onset of shock depression in all producing wells, for example, with using mobile communications. At the third stage, in all production wells, at the same time, part of the borehole fluid with colming elements is removed from the borehole of the producing formation, while the grid of injection and production wells is formed from the condition that the selection of production wells is carried out from the wells located closest to the injection wells in the production formation.

The method is as follows.

The decrease in the natural permeability of the bottom-hole zone during the operation of the wells is one of the reasons for the decrease in their production rate. At the final stage of oil field development, about 50-70% of the initial oil reserves remain undeveloped (Oil Industry. - 1995. - No. 5. - P.29-32).

To date, to increase the production rate in the oil industry, advanced methods of processing the near-wellbore zone of the formation are used, such as thermogasochemical treatment (THC), thermogas-hydraulic fracturing (TGRP), based on the burning of high-energy thermogasochemical charges in the interval of the formation and shock-depressive effect.

The presented method is based on the simultaneous use of these methods. In fields with a late stage of development, the grid of drilled wells is formed taking into account the artificial impact on the reservoir, for example, by pumping water into injection wells and by taking liquids from production wells. In this mode, there is a pattern of pressure distribution in the reservoir from the injection zone to the extraction zone, shown in the drawing.

As can be seen in the diagram, energy is expended at the oil-water interface to overcome capillary forces. On curves 1 and 2, this is reflected by an increase in pressure Δp, which at this boundary increases with increasing fluid flow; therefore, the rise is higher for the upper curve.

At small pressure drops at the oil-water interface, only large pores will mainly participate in the filtration in the section of the reservoir. With an increase in the pressure gradient Δp (curve 2), the number of pores participating in the fluid filtration increases. This leads to a more complete flushing of the rock from oil, that is, an increase in the oil recovery coefficient (Ovnatanov S.T., Karapetov K.A. Oil recovery in the development of oil fields. - L .: Nedra, 1970. - C.116-118).

Thus, in order to increase the oil recovery coefficient, it is necessary to increase the pressure of the injected fluid, which occurs during gas-hydraulic fracturing, and the injectivity of injection wells increases several times. If, at the same time, pressure is reduced in production wells in the area of the treated interval of the formation, for example, by an implosion chamber, then the pressure gradient ΔР on curve 2 will increase even more, as with a decrease in pressure in the production well, fluid withdrawal will increase and filtration in the formation will increase, together with it, the number of pores with oil involved in the filtration increases, which further increases the oil recovery coefficient.

To implement the method, logging hoists are used that are installed on all wells of the selected grid (the grid of wells is formed from the condition that the selection of producing wells is carried out from the wells closest to the injection wells located along the reservoir) and high-energy and thermogasochemical sources delivered to the reservoir interval. For example, for producing wells, downhole tools are used that contain a thermogas generator and an implosion chamber (NTV Karotazhnik. - Tver: Publishing House AIS, 1998. - Issue 40. - P.81-83). For injection wells, borehole devices containing high-energy fast-burning charges are used.

At the preparatory stage, with the help of logging hoists, borehole devices intended for thermoimplosion treatment of a productive formation in all producing wells are set to the desired interval, and borehole devices containing quick-burning charges for thermohydrohydraulic fracturing are installed in injection wells. Then at the same time in all producing wells, according to a command received by mobile communication, thermogas generators are started (ignited), after which for several minutes the temperature in the treatment interval reaches 160-180 ° C, decreasing to the background within 4-5 hours. As a result, softening of asphalt-resinous and paraffinous clogging elements occurs, and their viscosity decreases.

After the end of combustion, a technological pause is maintained, which is necessary to enhance the thermal effect and replace the gaseous products of combustion in the wellbore with liquid.

At the second stage, after maintaining a technological pause in production wells, thermogas-hydraulic fracturing is performed in the near-wellbore zone of the productive formation in injection wells, simultaneously with the creation of shock depression on the formation in all production wells, for which, by a command from a mobile phone, a quick-burning pyrotechnic charge is triggered in injection wells and at the same time open the implosion chamber in downhole tools installed in all production wells. In doing so, the following occurs. The essence of implosion is the short-term exposure of the formation to a sharp depression that occurs when the implosion chamber is opened and a certain volume of water is drawn into it. The depression phase, during which, along with the borehole fluid, softened elements from the pore space of the formation are fed into the chamber, is replaced by the repression phase, due to the fall of the liquid column and its compression in the processing interval. Compression and rarefaction waves with a damping amplitude can be observed for 10-100 s after opening the chamber. Thus, alternating decaying pressure fluctuations, which propagate deep into the reservoir, act on the bottom-hole zone of the formation, and if thermal and gas-hydraulic fracturing of the productive formation is performed simultaneously in injection wells, then the cracks formed as a result of this rupture and the cracks formed as a result of alternating pressures in production wells , allow you to create a zone in which the pore fluid from the high pressure zone (injection wells) rushes through the cracks into the zone of low pressure I (depression) in the production wells, thereby forming a reliable hydrodynamic connection between the wells, since the gap at the time of operation DS and NS no, then a single cycle of the stimulation, resulting in a reliable hydrodynamic communication between the wells.

Subsequently, during the implementation of the third stage - the selection of a part of the liquid with colming elements from the producing wells, the treated zone of the producing formation is cleaned and the pore oil is subsequently supplied to the wellbore, this mode can last up to two years. At the same time, a super-cumulative effect is observed from the results of exposure to the reservoir from the application of two methods simultaneously.

The undoubted advantage of the proposed method is the safety of the application, the effectiveness of the impact, low cost, high efficiency. The well production rate after treatment increases several times with a decrease in water cut by 6-8%. The gentle nature of the treatment allows you to apply the method in the wells of the old stock, where the use of other technologies for processing the bottom-hole formation zone is impossible.

The undoubted advantage of the proposed method is the safety of the application, the effectiveness of the impact, low cost, high efficiency. The well production rate after treatment increases several times with a decrease in water cut by 6-8%. The gentle nature of the treatment allows you to apply the method in the wells of the old stock, where the use of other technologies for processing the bottom-hole formation zone is impossible.

Claims (1)

A method of processing a borehole zone of a productive formation, including selecting a grid of injection and producing wells in a developed oil field, creating a single technological process of influencing an oil formation by simultaneously treating a borehole zone of a producing formation in injection and producing wells, characterized in that at the first stage simultaneously in all producing wells of a selected grid of wells warm up the borehole zone of the reservoir to the melting temperature the clogging elements, for example, using thermogas generators, and they produce the technological exposure necessary to enhance the thermal effect and replace the gaseous products of combustion in the wellbore with liquid; at the second stage, thermogas-hydrofracturing of the borehole zone of the producing formation in injection wells, for example, using a quick-burning pyrotechnic charge, and at the same time, in all production wells in the near-wellbore zone of the reservoir, shock pressure depression is created, for example, the method Ohm implosion, for which they combine in time the initiation of the initiation of the operation of a quick-burning pyrotechnic charge in injection wells with the beginning of the creation of shock depression in all production wells, for example, using mobile communications, at the third stage, in all production wells, at the same time, part of the borehole zone is removed well fluid with mudding elements, while the grid of injection and producing wells is formed from the condition that the choice of producing wells is carried out yayut of the most closely spaced on the producing formation to the injection wells.