RU2480581C1 - Method to isolate inflow of reservoir water in low-angle and horizontal wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method provides for isolation of an inflow of reservoir water in low-angle and horizontal wells, equipped in productive formations with a tail filter separated into sections with solid and filter sections with packers installed on each segment of solid sections and connected with a lift string, the diameter of which is more or equal to the diameter of the tail filter. According to the invention, as water level increases in the productive formation, serially, without well plugging, a perforation charge is lowered on a flexible pipe via a stuffing box into the tail filter. Perforation holes are created under the packer in the zone of inflow of reservoir water. The flexible pipe is extracted. Then a packer plug is lowered on it with circulation holes. The pipe space is sealed over the zone of reservoir water inflow in the segment of the solid section, and a process fluid is injected for absorption into a waterlogged section of the bed under the packer plug for displacement of the reservoir water. This zone is filled with a tamping fluid. Afterwards the flexible pipe is disconnected from the packet plug, lifted above the packer plug to close circulation holes and extracted from the well. After dismantling of the stuffing box the well is put in service with operation of the bed above the packer plug.

EFFECT: improved accuracy of injection of a water-isolating composition into an interval of reservoir water arrival in low-angle and horizontal wells without their plugging.

3 dwg

Description

The invention relates to the oil and gas industry, in particular to the construction, operation and repair of shallow and horizontal wells equipped with a filter liner, with isolation of formation water inflow.

There is a method of isolating produced water in horizontal open-hole wells, which consists in pumping a water-isolating composition into the flooded interval with the subsequent installation of a metal shutoff (RF patent No. 2114990, class 6 E21B 43/32, 33/13, 1996).

The disadvantage of this method is the necessity of killing the well and the high complexity of the installation of a metal shutter.

The closest technical solution is a method of isolating the influx of formation water in horizontal wells equipped with a filter liner with injection of a water-insulating composition using a sleeveless long pipe (RF patent No. 2235873, CL 6 E21B 43/32, 33/13, 2004).

The disadvantage of this method is the lack of accuracy in the injection of the water-insulating composition into the interval of formation water intake, since when selling into the reservoir, the absorption interval will be in the most permeable part of the wellbore, as well as the necessity of killing the well, which worsens the subsequent operational characteristics of the waterless part of the reservoir.

The task of the invention is to increase the efficiency of isolation of the influx of formation water in shallow and horizontal wells with a liner-filter without compromising the operational characteristics of the non-irrigated part of the formation.

The technical result of the invention is to increase the accuracy of injection of a water-insulating composition in the interval of formation water in shallow and horizontal wells without killing them.

The task and technical result are achieved by the fact that the method of isolating the influx of formation water in shallow and horizontal wells equipped with a filter shank in productive formations, divided into sections by continuous and filter sections with packers installed in each section of the solid sections and connected to the lift column, diameter which is greater than or equal to the diameter of the filter liner, consists in the fact that, as the water level rises in the reservoir, successively, without killing the well, to a flexible pipe through the wellhead sealant into the perforation charge filter shank, create perforations under the packer in the zone of formation water inflow, remove the flexible pipe, then lower the packer plug with circulation holes on it, seal the pipe space above the zone of formation water inflow in the area a continuous section, and a process fluid, for example a polymer solution or a hydrocarbon fluid, or a hydrophobic emulsion, is pumped into the flooded section of the formation under a packer plug for absorption water, fill this zone with a plugging mixture, for example cement mortar or a quick setting mixture, after which the flexible pipe is disconnected and lifted above the packer plug to close the circulation holes in the packer plug, and removed from the well, which then, after dismantling the wellhead sealant, put into operation with the operation of the reservoir above the packer plug.

Figure 1 shows the proposed design of a shallow well. Figure 2 shows the descent into the interval of formation water inflow perforation charge and the creation of holes. Figure 3 shows the installation of a packer plug above the zone of formation water inflow.

Well 1 is equipped with a filter liner 2 installed in a reservoir having clay or low permeability interlayers. The filter shank 2 is connected to the elevator column 3, the diameter of which for lowering the packer plug must be greater than or equal to the diameter of the shank. The shank 2 is divided into sections containing solid sections 4 and filter sections 5, equipped with a slotted or mesh filter element. Packers 6 are installed on each section of the continuous sections 4. Packers 6 are installed in clay layers of the formation or in the layers of the formation with low permeability.

The method is implemented as follows.

With the operation of well 1, the level of underlying formation water rises and, when it reaches the lower filter section, water enters the liner 2, and the well begins to work with water. To carry out waterproofing works, the well is stopped by closing the valves of production equipment 7. A sealant (preventer) 8 is installed in the upper part of the production equipment, through which perforation charge 10 is lowered through the riser column 3, holes 11 with a diameter of enough for pumping process fluid and plugging mixture. After that, the flexible pipe is lifted to the surface, equipped with a packer plug 12, for example, a casting packer plug with circulation holes and a technological tool in the form of an installation arrangement configured to close the circulation holes after completion of the operation (for example, according to the type of solution described in RU 94628 U1, 05.27.2010).

The packer plug is lowered into the well and placed above the perforation holes 11 in the area of the continuous section 4. A technological fluid, for example a polyacrylamide-based polymer solution, is pumped into the flexible pipe, by unpacking the packer plug 12 by creating pressure in the flexible pipe using the actuator of the hydraulic installation arrangement, then the pressure in the flexible pipe is increased, the channel in the installation arrangement is opened into the sub-packer zone and the polymer solution is pumped for absorption under the packer plug 12 through circulation nnye opening 11 in reservoir water inflow zone to displace the water and then pumped backfill mixture, for example cement mortar based particulate well cement. After pumping and selling cement mortar under the packer plug 12, the flexible pipe is disconnected from the packer plug to close the circulation holes in the packer plug 12 and removed from the well.

After dismantling the wellhead sealant (preventer) 8, the well is put into operation with the operation of the formation located above the packer plug 12. During further operation of the well and raising the water level to the next filter section, operations to isolate the influx of formation water are repeated. This creates a reliable screen for moving the bottom water from the water inflow zone both behind the liner and inside it, to a precisely defined place without killing the well.

Claims (1)

A method of isolating formation water inflow in shallow and horizontal wells equipped with a filter shank in productive formations, divided into sections by continuous and filter sections with packers installed in each section of continuous sections, and connected to an elevator column whose diameter is greater than or equal to the diameter of the filter liner, which consists in the fact that as the water level rises in the reservoir, successively without killing the wells, they run on a flexible pipe through the wellhead sealant into the filter liner perforation charge, create perforations under the packer in the zone of formation water inflow, remove the flexible pipe, then lower the packer plug with circulation holes on it, seal the tube space above the zone of formation water inflow in the continuous section and pump it into the flooded section of the reservoir under absorption packer plug technological fluid to displace produced water, fill this zone with a plugging mixture, after which the flexible pipe is disconnected from the packer plug, lift it above the packer plug to close the circulation openings and removed from the well, which is then, after removal dock wellhead, launch into operation with the operation of the reservoir above packer plug.

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