RU2436943C1 - Procedure for extraction of high viscous oil from deviating hole by method of steam cyclic pumping into reservoir - Google Patents

Abstract

FIELD: gas and oil production. ^ SUBSTANCE: procedure for extraction of high viscous oil from deviating hole by method of steam cyclic pumping into reservoir consists in drilling ascending section in producing borehole, and in arrangement of tubing string with centrators for cyclic pumping heat carrier through them and of flow string with pump for withdrawal of oil in this section. The lowered tubing string is heat insulated. An ascending section of the hole is equipped with a filter with two opened zones at the beginning and end of this section, while tube space between the filter and the tubing string and between opened zones is insulated with a packer. Also, the pump is set in the flow string of the hole above the filter within the ranges of a sub-face of the reservoir, but below the bottomhole of the ascending section. The bottomhole in its turn is arranged below a top of the reservoir along vertical at distance not less, than 2 m. Upon heat carrier has been pumped, it is conditioned for distribution of heat in the reservoir. Oil is withdrawn with the pump till allowed reduction in yield, where upon the cycle of steam pumping is repeated. ^ EFFECT: increased yield of hole with simultaneous reduced material and power expenditures. ^ 1 ex, 1 dwg

Description

The invention relates to the oil industry, to thermal methods of oil or bitumen production from a single horizontal well.

A known method for the development and production of highly viscous oil (RF application No. 2007122922/03 ЕВВ 43/24, published on December 27, 2008), which includes drilling a horizontal floor well with two horizontal shafts in one vertical plane, while the horizontal shank windows are located in oil-saturated formation at a distance of 8-10 m from each other, and the displacement of viscous oil or bitumen is carried out by pumping the coolant. Horizontal trunks are drilled along an ascending path and are placed towards the domed part of the reservoir, the bottom of each trunk is located above the cutoff window. The coolant is pumped through tubing of the upper horizontal wellbore, and the fluid is taken through the lower horizontal tubing.

The disadvantages of this method are the high cost of drilling a floor horizontal well with the placement of two horizontal shafts in one vertical plane, the complexity of the installation of lowered equipment. The obligatory direction of well drilling towards the domed part of the reservoir limits the choice of the developed area.

The closest in technical essence to the proposed method is a method of thermal displacement of oil from a horizontal well (US Pat. RF No. 2067168, ЕВВ 43/24, publ. 09/27/1996), including the production of highly viscous oil by cyclic injection of coolant into the final part of the horizontal well bore and selection of liquid from the steam injection zone of the nearest section separated by the packer. The method is implemented as follows: perforation is carried out along the annular generators at the beginning and at the end of the horizontal part of the well production casing section, tubing equipped with a packer device separating the horizontal wellbore between these two perforation groups descends to the closest perforation interval. The coolant is pumped through the tubing into the formation through a remote perforation zone, and the fluid is taken from the perforation zone closest to the mouth. Liquid is transported to the surface along the annular annular space of the well.

The method has the following disadvantages:

- the coolant is injected and the liquid is lifted to the surface via a non-insulated tubing, as a result of which an intensive heat exchange of the injected coolant with the produced fluid and the fluid located in the annulus occurs in the annulus, which leads to large heat losses and a decrease in the temperature of the injected agent;

- in the proposed method provides only a fountain method of lifting liquid to the surface along the annulus.

The technical objectives of the invention are to reduce material and energy costs due to the drilling of a single directional well, as well as to increase the flow rate of the well realized by mechanized fluid withdrawal.

The problem is solved by a method of producing highly viscous oil from a directional well by cyclic injection of steam into the formation, including drilling an upstream section of the well in the production well, placement of tubing strings in this section with centralizers for cyclic coolant injection through them and a production string with a pump for oil selection.

The new fact is that the bottom of the ascending section is located at least 2 m below the roof, and before the descent of the pipe string that is thermally insulated, the ascending section of the well is equipped with a filter with two exposed zones at the beginning and end of this section, and the annulus between the filter and the pipe string and between the exposed areas isolate the packer, while the pump is located in the production casing of the well above the filter within the plantar of the reservoir, but below the bottom of the ascending section.

The drawing shows a diagram of a directional well in the context of an oil reservoir.

The method is implemented as follows.

Oblique drilling of the wellbore 1 is carried out under the production string 2 to a depth below the roof 3 of the formation 4 at least 2 m. The production string 2 is lowered and the annulus 5 is cemented. The smaller diameter of the bit is used to drill the ascending section 6 of the wellbore along an inclined directional ascending path, this maximum angle of curvature is located in the bottom part 7 of the reservoir 4, then the wiring of the ascending section 6 of the wellbore 1 is carried out with an angle of elevation of at least 5-8 ° from the bottom 7 to the roof 3 with the installation of the bottom 8 of the well at a distance of at least 2 m vertically below the roof of the reservoir 4.

The filter 9 is lowered with two open perforation zones 10, 10 'at the end and beginning of the ascending section of the well 6.

Heat-insulated tubing 11 is lowered, equipped with a heat-resistant packer 12, separating the upstream section of the well with two exposed zones, which are located at the beginning and end of this section 6. Above the opened perforation zone 10, but below the bottom 8 (to obtain the maximum influx of heated oil due to gravitational forces ) the electric centrifugal pump 13 is lowered to the tubing 14 with a thermocouple cable (not shown in the drawing) to control the temperature at the pump inlet.

The slope of the ascending section 6 of the wellbore 1 from the roof 3 to the sole 6 of the formation 4 allows heated oil to flow to the lower exposed zone 10 of the wellbore 1 under the influence of gravitational forces.

The use of heat-insulated tubing 11 reduces the heat loss of the injected steam, and the absence of heating of the outer surface of the tubing 11 makes it possible to use a series-type electric centrifugal pump 13, which is in acceptable temperature conditions during the period of steam injection into the formation 4.

The calculated amount of coolant is pumped into a remote exposed zone 10 'along the column of heat-insulated tubing 11. A certain period of time is maintained for heat distribution in the reservoir 4 and the liquid is pumped by pump 13 along the tubing 14 until the flow rate can be reduced, after which the steam injection cycle through the string of heat-insulated pipes 11 repeated.

An example of a specific implementation.

A well with an ascending section 6 was drilled in a section of a highly viscous oil reservoir in formation 4. It was arranged. The reservoir and thermal properties of the discovered reservoir were refined 4. Based on the studied and refined reservoir properties, a stationary geological model of the reservoir was built 4. The reservoir development area on which the claimed technology was simulated has a geometric dimension of 200 × 100 × 15 m. The average thickness of the reservoir is 15 m

In the directional well 1, steam was supplied. After warming up and the beginning of creating a steam chamber, the steam supply to the well 1 was stopped and the selection of liquid by pump 13 via tubing 14 began.

For the comparison base, the option was calculated using a single horizontal well with a horizontal bore length of 200 m. The calculation results showed that the efficiency of the proposed method is higher: the maximum oil recovery coefficient is 5% higher; the maximum oil production rate obtained according to the model was 8 tons / day versus 3 t / day using horizontal horizontal wells.

Thus, in contrast to the application of technology for injecting steam into horizontal wells, the proposed method due to the use of heat-insulated tubing, a special profile of the well and a mechanized production method allows to reduce material and energy costs and to obtain a higher rate of fluid withdrawal from the well.

Claims (1)

A method for producing highly viscous oil from a directional well by cyclic injection of steam into the formation, including drilling an upstream section of a well in a production well, placing tubing strings in this section with centralizers for cyclic coolant injection through them and a production string with a pump for oil selection, characterized in that the bottom of the ascending section is located below the roof for at least 2 m and before the descent of the pipe string, which are thermally insulated, the ascending section of the well We equip the filter with two open zones at the beginning and end of this section, and the annular space between the filter and the pipe string and between the open zones is isolated by a packer, while the pump is located in the production casing of the well above the filter within the bottom part of the reservoir, but below the bottom of the bottom plot.

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