RU2630320C1 - Method for adjustable liquid injection in production formation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method includes exploring formation properties, constructing an injection well that opens up different horizons with different properties, equipping well tubing with a packer separating the open horizons, and adjusting the pumping equipment when injecting liquid into the required horizon. Investigation of the formation is carried out to determine watered sections of the formation or cuts of aquifers and the level of water-oil contact if they are present in the oil-bearing part of the formation. Additionally, the studies are carried out to determine presence of oil-bearing areas or oil-bearing cuts, as well as to define the difference of permeability of the formations. A branched well with horizontal sections is used as an injection well, among which an aquifier area or formation cut is opened first, and then above the bottom of the formation oil-bearing area or directly above the water-oil contact if present. The distance between the watered area or the watered cut to the oil-bearing area or the oil-bearing cut is allowed 700 m at most. The packer with the well tubing cuts off the first horizontal section above the aquifer or the formation cut, from where the water is pumped to the well above the hydrodynamic level of the formation oil-bearing area for natural overflow and to maintain the formation pressure in this area. The amount of pumped liquid is adjusted by the pumping equipment capacity.

EFFECT: increasing method efficiency by using watered areas or formation cuts for pumping large volumes of liquid, creating a uniform front of displacement by small-capacity pumps.

1 ex, 1 tbl, 1 dwg

Description

The invention relates to the oil and gas industry, and in particular to technologies for the selection of products from the reservoir and injection of fluid to maintain reservoir pressure.

A known installation for pumping fluid into the upper layer of the well from the lower (patent RU No. 2436939, E21B 43/00, publ. Bull. No. 35 from 12/20/2011), which carry out a method of pumping fluid from one horizon to another to maintain reservoir pressure, including opening of the upper and aquifer lower horizons of the well, separation of horizons by a packer, adjustable pumping of liquid by pumping equipment from the lower to the upper horizons.

There is also known an installation for pumping fluid into one formation and oil production from another reservoir of a well (patent PM RU No. 62161, E21B 43/14, publ. Bulletin No. 09 of 03/27/2007), which carry out a method of pumping fluid from one horizon to another to maintain reservoir pressure, including the opening of the upper and aquifer lower horizons of the well, separation of horizons by a packer, adjustable pumping of liquid by pumping equipment from the lower to the upper horizons.

There is also known an installation for pumping fluid into one formation and oil production from another formation of the well (patent PM RU No. 92693, E21B 47/10, publ. Bulletin No. 09 of 03/27/2010), which carry out a method of pumping liquid from one horizon to another to maintain reservoir pressure, including the opening of the upper and aquifer lower horizons of the well, separation of horizons by a packer, adjustable pumping of liquid by pumping equipment from the lower to the upper horizons.

The disadvantages of all methods are the narrow scope due to the inability to use within the same reservoir with different development, as well as the use only in vertical wells, opening several layers, the inability to pump large volumes of fluid due to the small filtration area.

The closest in technical essence and the achieved result is a method of controlled injection of fluid into the reservoirs (patent RU No. 2495235, E21B 43/14, publ. Bull. No. 28 from 10.10.2013), including the descent into the well on a pipe string of packers of mechanical action without or with a column disconnector, packing packers and their crimping, pumping fluid from the mouth into the cavity of the pipe string, determining the total fluid flow pumped into the upper and lower reservoirs, measuring fluid flow from one of the reservoirs, determining the fluid flow from the other reservoir Niemi previously measured flow rate of the total flow, lifting extracted regulating unit on the surface, changing its characteristics extracted reinstall the regulating unit and injection therethrough of liquid in the respective layers. An arrangement of underground equipment, including a lower packer, a disconnector, an injection distribution device — URZ, an upper packer, a disconnector, lower and upper packers is installed in the well, the lower and upper packers are crimped, the depth meter and plug are inserted above the last seat , carry out the supply of fluid into the tubing cavity, measure the total flow rate of fluid pumped into the lower and upper layers, then lower the plug into the seat, supply fluid to the H cavity T, the flow rate of the fluid pumped into the lower reservoir is determined, the flow rate of the fluid pumped into the lower reservoir is subtracted from the total flow rate and the flow rate of the fluid pumped into the upper reservoir is found, the actual flow rate of the fluid for the reservoirs is compared with the given values, and if they differ, the extracted part is raised URZ to the surface using a fishing tool on a geophysical cable, wire or coiled tubing installation, then the upper and lower fittings are installed in the seats of the extracted part of the URZ, the extraction is lowered PSR second part in the tubing before its planting in the body portion, and performed PSR regulated injection of liquid at the end of works produce lift installation.

The disadvantages of the method are the narrow scope due to the inability to use within the same reservoir with different development, as well as the use only in vertical wells, opening several layers, the inability to pump large volumes of fluid due to the small filtration area, while the high costs associated with water delivery to the surface and injection from the surface into the reservoir.

The technical task of the invention is the creation of an economical way of controlled injection of fluid into the reservoir due to the lack of injection from the surface and the use of flooded sections or cuts in the reservoir with the possibility of pumping large volumes of fluid and creating a uniform displacement front due to the large filtration area in a horizontal injection well.

The technical problem is solved by a method of controlled injection of fluid into a reservoir, including the study of the properties of the formation, construction of an injection well opening different horizons with different properties, equipping a string of pipe wells with a packer separating the opened horizons, and adjustable pumping of fluid into the required horizon.

New is that the study of the reservoir is carried out to determine the encircled portions of the reservoir or aquifers and the level of water-oil contact - oil and gas contact in the oil-bearing part of the reservoir, opening the horizons by constructing a branched well with horizontal sections, the first of which reveals the aquifer or cut of the reservoir, and the second is carried out above the bottom of the oil-bearing section of the reservoir or directly above the level of the oil-and-gas complex, if any, the first horizontal chastok above aquifer or incision site formation, from where the water pumping equipment is pumped into the well above the level of the hydrodynamic oil reservoir portion for natural flow and maintain reservoir pressure in this region, the volume of fluid pumped is controlled pumping equipment performance.

The figure shows a method of controlled injection of fluid into a reservoir.

The method of controlled injection of fluid into the reservoir is carried out in the following way.

According to the proposed method, productive formation 1 is examined for determining waterlogged areas (not shown in the drawing) or aquifers 2, as well as the level of VNK if it is present in productive formation 1. Productive formation 1 is also examined for oil-bearing areas 3 (for example, incisions, lenses etc.). Further, according to the method, a branched injection well 4 is constructed with two horizontal sections 5 and 6, one of which 5 reveals a waterlogged area or aquifer 2, and the second 6 - the interval above the bottom of the oil-bearing section 3 of the productive formation 1 or directly above the level of the oil-and-gas industry (in the drawing, shown) if available. The construction of the second horizontal section 6 of the borehole 4 into the oil cut 3 is possible subject to the maximum distance between the waterlogged section or the aquifer cut 2 to the oil cut 4 in 700 m, due to the long distance the use of the method is not cost-effective.

The packer 7 with the pipe string cuts off the first horizontal section of the well 4, which works on the irrigated section or the aquifer 2, from where water is pumped by pumping equipment 8 to the well 4 above the hydrodynamic level (not shown) of the productive formation 1 for the natural flow of formation water from the irrigated section or aquifer incision 2 in the interval above the bottom of the oil-bearing section of the reservoir 1 or directly above the level of the oil-bearing complex, if any, or oil incision 3 to maintain the reservoir pressure and improve the technological parameters of development. The volume of the pumped liquid to maintain pressure in the reservoir 1 or oil cut 3 regulate the performance of the pumping equipment 8.

Concrete example

A reservoir of 1 Tournaisian oil is being developed. The geological and physical characteristics of the Tournaisian and Bobrikov deposits are shown in the table.

The geological profile or 3D geological model determines the presence of aquifer 2 and oil 3 cuttings, as well as the distance between them, if there are cuts. At a specific object 1, there are 5 Bobrikov incisions, three of which are aquifers 2, and two oil incisions. When determining the distance between the cuts, it was found that the distance between the aquifer 2 and the oil 3 cuts is 570 m, which allows the proposed method to be applied. From the geological and physical characteristics, we determine the difference in permeability of objects, which is 5.85-34.2 times. Due to the large difference in permeability in the oil cut, the formation pressure from it will decrease the reservoir pressure due to the low permeability in the Tournaisian layer and its supply with reservoir energy. A branched injection well 4 is built with two horizontal sections 5 and 6, one of which 5 opens an aquifer 2, and the second 6 an oil pipeline 3. Next, the method pumps water to maintain reservoir energy of the oil pipeline 3.

A vertical well 9 or a well with a horizontal end (not shown) is drilled into a Bobrikovsky oil-bearing insert 3 for production.

The proposed method of controlled injection of fluid into the reservoir allows economically to produce controlled injection of aquifer into the reservoir (or insert) of the reservoir due to the lack of injection from the surface and the use of flooded sections or cuts of the reservoir with the ability to pump large volumes of fluid and create a uniform displacement front due to the large area filtration in a horizontal injection well. The method also allows the use of low-performance pumps, which saves energy during their operation, and also benefits at their relatively low cost.

Claims (1)

A method of controlled injection of fluid into a reservoir, including the study of the properties of the formation, construction of an injection well opening different horizons with different properties, equipping the well with a pipe string with a packer separating the opened horizons and adjustable pumping of liquid by pumping equipment into the required horizon, characterized in that the study of the formation produce to determine the waterlogged areas of the reservoir or aquifers and the level of water-oil contact - VNK in the presence of oil the reservoir, additionally conduct studies for the presence of oil areas or oil cuts, as well as to establish the difference in the permeability of the layers, as an injection well, use a branched well with horizontal sections, the first of which open the aquifer or cut of the reservoir, and the second is carried out above the bottom of the oil section formation or directly above the level of the oil-gas complex, if any, while the distance between the watered area or the watered cut-in to the oil-bearing area or a maximum of 700 m is allowed for a fenestrated insertion, the first horizontal section is cut off from the pipe string by the packer above the aquifer or the formation insertion, from where water is pumped to the well above the hydrodynamic level of the oil-bearing section of the formation for pumping and maintaining reservoir pressure in this section, and the volume of pumped liquid regulate the performance of pumping equipment.

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