RU2350744C1 - Method of operating double-head well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to development of hydrocarbon deposits with double-head horizontal wells and can be used at extraction of high viscous oil and bitumen. The method consists in exposing payout bed with a horizontal borehole and in casing the borehole with production string preliminary equipped with a filter in the interval of the exposed payout bed, then in equipping the heads, in installation of a blind packer through the first head in the interval of the payout bed of the well and in operating the well through the second head. According to the invention the blind packer is installed in filter interval when the part of the filter apertures through which water flooding occurs is closed. The blind packer is reinstalled and additional part of apertures through which water flooding occurs is closed when the circuit of water flooding has changed in the process of operation and watering of extracted production has increased. This reduces level of water flooding of extracted production. In case of repair works from the side of the second head the exposed section of the payout bed is cut off by the blind packer from the second head.

EFFECT: increased efficiency of method due to simplification of packer assembly in well and possibility to re-install packer, also possibility to carry out repair works eliminating well killing.

1 dwg

Description

The invention relates to the field of development of hydrocarbon deposits by double-well horizontal wells and can be used for the extraction of high viscosity oils and bitumen.

A known method of developing deposits of viscous oils and bitumen (RF patent for the invention No. 2246001, IPC 8 ЕВВ 43/24; published in Bulletin No. 5 of 02/10/2005), including drilling a two-well horizontal well, fixing it with a production string, dragged from one wellhead along its wellbore to another wellhead together with packers for installing the latter in the roof of a productive formation, raising and supplying oil to a flow line at one of the wellheads, and the wellhead sections of the production string are interconnected by a ground section in the form of arcs a similar pipeline with an identical inner diameter to form a closed channel, the above-ground portion of which is fixed on the support frame of the drive unit, after which an additional string is installed in the production string, which acts as a tubing in the underground part and has perforation channels for communication with the productive layer, in the cavity of the additional column at equidistant distances from each other establish a system of cylindrical elements interconnected by means of power rods with the formation of a closed traction system, while sections of the underground part of the tubing from the wellhead to the boundaries of the perforation section of the production string together with the aforementioned cylindrical elements form piston pump pairs, and during operation, the system of cylindrical elements is forcedly moved using a drive unit with continuous successive displacement of oil from the tubing by means of the piston pump pairs mentioned above.

The disadvantage of this method is the metal consumption of the structure on the surface, associated with the presence of a land section in the form of an arcuate pipeline, which is fixed on the supporting frame of the drive unit, and this leads to an increase in the cost of the structure as a whole.

The closest in technical essence and the achieved result to the proposed one is a method of constructing a horizontal well (RF patent for the invention No. 2159317, 11/20/2000), which includes opening a productive formation with a horizontal shaft and securing it with a casing production string, wellhead equipment, perforation and well development, after installation of the equipment for the selection of hydrocarbons at the second wellhead, the well is developed and production starts from the mouths and when the waterflood circuit approaches the installation site of the packer tube space of the production tubing in the packer setting overlap interval, e.g., polymeric pad and the mouth located on the side opposite the direction of movement of waterflooding circuit is used to discharge a liquid or gaseous agent in order to maintain the reservoir pressure, while the opposite mouth - for the production of hydrocarbons.

The disadvantages of this method are:

firstly, the complexity of installing an annular packer in the well, since it is installed as part of the production casing during the construction of a horizontal well;

secondly, the annular packer is stationary, since it is fixed in the production casing, and this does not allow it to be moved during operation, depending on the changing contour of the waterflooding of the well;

thirdly, the design of the well does not allow repair work from the side of the second wellhead without killing the well during production with steam injection to maintain the temperature in the formation.

An object of the invention is to simplify the installation of the packer in the well and the installation of the packer in the production casing with the possibility of completely cutting off the exposed section of the reservoir and then reinstalling the packer in the interval of opening the reservoir, depending on the waterflood circuit, as well as the possibility of repair work without killing the well.

The technical problem is solved by the proposed method of operating a two-well well, including opening a reservoir with a horizontal wellbore and securing it with a casing string pre-equipped with a filter in the interval of the opened reservoir, installing wellheads and operating the well, installing a blind packer through one well in the interval of the producing well waterflood circuit, operation through a second mouth.

What is new is that the wells are operated through the second wellhead, and the deaf packer is installed with the possibility of removal and reinstallation with complete cut-off of the exposed section of the reservoir from the second wellhead, as well as in the interval of the opened section of the reservoir in accordance with the change in the waterflood contour.

The proposed method is as follows.

First, the productive formation 1 is opened by a horizontal wellbore 2, which is then fixed by the casing production string 3. Next, the mouths 4 and 5, respectively, of the two-well well are equipped. In addition, before the descent of the production casing 3 into the horizontal barrel 2, it is equipped with a filter 6 in the interval of the opened reservoir 1.

Next, through the second mouth 5, the tubing string 7 is lowered with the pump 8 at the end. The pump 8 may be of any known design, for example, electric centrifugal (ESP), designed for pumping highly viscous oil or bitumen.

Then seal the mouth 5 with wellhead fittings 9 and begin operation of the double-well well. In the process of operating a two-well well from the second wellhead 5, it may be necessary to carry out any work on the part of the second wellhead 5, for example, replacing the pump 8.

To solve this problem, a blind packer 11 (for example, an inflatable packer) is lowered into the two-well well from the first wellhead 4 at the end of the tubing string (flexible pipe) 10.

The descent of the tubing string (flexible pipe) 10 is continued until the deaf packer 11 is behind the openings of the filter 6 of the production casing 3, that is, between the filter 6 and the pump 8 (see drawing). Then turn off the pump 8 and produce a deaf packer 11.

After that, the tubing string 7 is lifted, the pump 8 is replaced, and the tubing string 7 is re-run with pump 8 at the end.

Next, the deaf packer 11 is unpacked and the pump 8 is launched into operation and the operation of the double-well well from the second wellhead 5 continues.

The tubing string (flexible pipe) 10 is lifted and, accordingly, the blind packer 11 is moved towards the first wellhead 4 depending on the position of the waterflooding circuit (not shown in the drawing) until the flow of water into the production string 3 through the filter openings 6 is eliminated or limited side of the second mouth 5.

Next, a blank packer 11 is planted in this interval of the filter 6 of the production casing 3, and the tubing string (flexible pipe) 10 is removed to the surface. As a result, the deaf packer 11 cuts off part of the production casing 3 from the side of the first wellhead 4, cutting off part of the openings of the filter 6, through which the produced products are flooded from the double-well well.

During the further operation of the double-well well, due to the operation of the pump 8, the waterflood circuit is pulled towards the pump 8 and the water through the openings of the filter 6 of the production casing 3 before the deaf packer 11 begins to flow into the production casing 3. As a result, the water content of the products produced from the well again increases.

In order to reduce the water content of the extracted products from the mouth 4, the tubing string (flexible pipe) 10 is again lowered.

After that, the deaf packer 11 is gripped by the fishing head (not shown in the drawing) and the deaf packer 11 is unpacked in the production casing 3. Next, the tubing string (flexible pipe) 10 is dropped into the two-well bore from the side of the first wellhead 4, i.e., the deaf packer 11 is reinstalled. so that it is in front of the waterflood circuit. Next, the deaf packer 11 is planted in the production casing 3, while the deaf packer 11 further disconnects part of the openings of the filter 6 of the production casing 3, through which the produced products were flooded from the two-well borehole. Subsequently, if necessary, as described above, it is possible to remove and reinstall the deaf packer 11 in the production casing 3 in the required interval depending on the change in the waterflooding circuit.

Thus, the operation of the well (production of highly viscous oil or bitumen to the surface) is carried out through the second wellhead 5 of the two-wellhead, shutting off the pump 8 for the duration of the repair work (replacing the pump 8), and the deaf packer 11 is lowered through the first wellhead 4 and installed with the possibility of clipping the exposed area from the second mouth, as well as removal and reinstallation in the interval of the exposed area of the reservoir in accordance with the change in the waterflood contour.

The proposed method simplifies the installation of the packer in the well, since the packer is installed directly in the production string, and the ability to cut off the exposed section of the reservoir allows repair work from the second mouth of the two-well borehole without killing the well. In addition, according to the proposed method, there is the possibility of subsequent reinstallation of the packer in the production casing in the filter interval in accordance with a change in the waterflooding circuit, which allows to reduce the water content of the produced products and makes the operation of a double-well well more efficient.

Claims (1)

A method of operating a two-well borehole, including opening a reservoir with a horizontal wellbore and securing it with a casing production string, previously equipped with a filter in the interval of the borehole, opening the wellhead, installing a blind packer through the first wellhead in the interval of the producing wellbore, and operating the well through a second wellhead that the deaf packer is installed in the interval of the filter with the shutdown of part of its holes through which the flood of water occurs products, and when the waterflood circuit changes during the operation of the well with an increase in water cut in the produced product, the deaf packer is reinstalled and an additional part of the filter holes through which the water is flooded is turned off, thereby reducing the amount of water flooding, while for repair work from the second wellhead it is deaf the packer cut off the exposed section of the reservoir from the second mouth.