RU2841844C1 - Method of oil deposit development - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention relates to oil industry and can be used in development of oil deposit with different type of reservoir. Horizontal and vertical production wells are drilled on the oil deposit. Horizontal production wells are drilled with length of 300-350 m in a formation with thickness of not less than 12 m above the deposit bottom with not less than 3 m. Vertical production wells are arranged at distance of 1/2 of the approved interwell space of the production stock on the deposit from the bottomhole of horizontal production wells. In production horizontal well there performed is deep perforation along spiral along the whole shaft of horizontal section of well, with distance between holes of 10 m and perforation depth of 1.5 m, having in this case at least 30 perforation holes. Oil is extracted. When the oil flow rate in the vertical production wells reaches 0.5 tons/day or less, two side horizontal shafts are cut in opposite directions to each other, from the main shaft at distance of 60-80 m, with a horizontal section length of 150-200 m, wherein at angle of 80-85° in relation to production horizontal well, well is transferred into injection stock, opening the lower aquifer, developing the vertical production well with two side horizontal shafts for injection, pumping is performed by downhole pumping in vertical production well with two side horizontal shafts from lower water-bearing formation with pressure by 10-15 % higher than initial formation pressure and with pumping cycle of 4 days of injection and 2 days of downtime.

EFFECT: proposed method provides uniform oil displacement from the oil-saturated formation, high oil recovery rate and increase in well productivity due to the proposed wells grid application, which allows to take into account the maximum drainage coverage of the deposit by area by using horizontal technology and section by increasing the volume of drained rock around the horizontal wellbore using deep perforation, connecting to drainage maximum possible thickness in inhomogeneous oil-bearing reservoir of deposit.

1 cl, 1 dwg

Description

The invention relates to the oil industry and can be used in the development of oil deposits with various types of reservoirs.

A method for developing oil deposits at a late stage of development is known (patent RU No. 2506418, IPC E21B 43/16, published 10.02.2014, Bulletin No. 4), including drilling vertical injection and production horizontal wells, pumping a displacing agent through injection wells, and withdrawing products through production horizontal wells. A horizontal well is drilled above the level of the water-oil contact (WOC), and a vertical well is drilled at a distance of at least 50 m from the bottom of the horizontal well, secondary opening of the deposit is performed in the vertical well above and below the horizontal well, wherein secondary opening in the vertical well above the horizontal wellbore is performed with a higher density of opening holes than opening below the horizontal wellbore to create a more uniform flooding front.

The disadvantages of this method are insufficient development of residual oil reserves and oil extraction, and the possibility of premature flooding.

The closest in technical essence is the method of developing an oil deposit (patent RU No. 2823943, IPC E21B 43/16, published on 30.07.2014, Bulletin No. 22), which includes drilling one or more horizontal production wells in a formation with a thickness of at least 10 m above the base of the deposit by at least 3 m, and a vertical injection well - at a distance of 1/3 of the approved interwell space of the producing vertical well stock on the deposit from the bottom of the horizontal production well, secondary opening of the deposit in the vertical injection well is carried out above the hypsometric mark of the base of the deposit, but not above the position of the horizontal shaft of the production well, the lower aquifer is opened, injection is carried out by downhole pumping in the vertical injection well from the lower aquifer with a pressure of 10% above the initial reservoir pressure and an injection cycle of 7 days of injection and 5 days of downtime.

The disadvantage of this method is the low efficiency of the reservoir pressure maintenance system, incomplete development of oil reserves, uneven displacement of oil from the deposit, and the presence of uninvolved residual oil reserves in the deposit.

The technical result of the invention is to ensure uniform displacement of oil from an oil-saturated formation, a high rate of oil recovery and an increase in well productivity due to the use of the proposed well grid, which allows for maximum coverage of the reservoir drainage area by using horizontal technology and section by increasing the volume of drained rock around the horizontal wellbore using deep perforation, connecting the maximum possible thickness in a heterogeneous oil-bearing reservoir of the reservoir to drainage, avoiding an increase in costs for drilling and equipping additional injection wells

The technical result is achieved by the method of developing an oil deposit by drilling horizontal and vertical production wells, and extracting products through production wells.

What is new is that horizontal production wells 300-350 m long are drilled in a formation with a thickness of at least 12 m above the base of the deposit by at least 3 m, and vertical production wells are placed at a distance of 1/2 of the approved interwell space of the production fund on the deposit from the bottom of the horizontal production wells, while in the horizontal production well deep perforation is carried out in a spiral along the entire wellbore of the horizontal section of the well with a distance between holes of 10 m and a perforation depth of 1.5 m, having in this case at least 30 perforation holes, when the oil flow rate in vertical production wells reaches 0.5 t/day or less, two side horizontal trunks are cut in the opposite direction to each other, from the main trunk at a distance of 60-80 m, with a horizontal section length of 150-200 m, while at an angle of 80-85 ° in relation to to a horizontal production well, then a vertical well with two lateral horizontal wellbores is transferred to the injection fund, after which the lower aquifer is opened, a vertical production well with two lateral horizontal wellbores is developed for injection, injection is carried out by downhole pumping in a vertical well with two lateral horizontal wellbores from the lower aquifer with a pressure 10-15% higher than the initial reservoir pressure and an injection cycle of 4 days of injection and 2 days of downtime.

The drawing shows a diagram of a well grid used to develop an oil deposit, where 1 is a horizontal production well with deep perforation, 2 is an injection well with two lateral horizontal wellbores.

The essence of the method is as follows.

Horizontal and vertical production wells are drilled in oil deposits. Horizontal production wells are drilled 300-350 m long in a formation with a thickness of at least 12 m above the base of the deposit by at least 3 m. Vertical production wells are placed at a distance of 1/2 of the approved interwell space of the production fund on the deposit from the bottom of the horizontal production wells. In a horizontal production well, deep perforation is carried out in a spiral along the entire trunk of the horizontal section of the well, with a distance between holes of 10 m and a perforation depth of 1.5 m, having in this case at least 30 perforation holes. Oil is produced. When the oil flow rate in vertical production wells reaches 0.5 t/day or less, two lateral horizontal wellbores are cut in the opposite direction to each other, from the main wellbore at a distance of 60-80 m, with a horizontal section length of 150-200 m, while at an angle of 80°-85° relative to the production horizontal well, the well is transferred to the injection fund, the lower aquifer is opened, a vertical production well with two lateral horizontal wellbores is developed for injection, injection is carried out by downhole pumping in a vertical production well with two lateral horizontal wellbores from the lower aquifer with a pressure 10-15% higher than the initial reservoir pressure and an injection cycle of 4 days of injection and 2 days of downtime.

An example of specific implementation.

They are developing an oil deposit with a highly productive zone 12 m thick with a temperature of 25°C, a pressure of 11.4 MPa, an oil saturation of 0.92 units, a porosity of 31%, a permeability of 1.122 μm2, an oil density of 889 kg/ ^m3 and a viscosity of 23.4 mPa⋅s. The depth of the roof is 1140 m

On the oil deposit in the productive formation above the deposit base at the 1149 m mark, one horizontal production well 300 m long was drilled, according to the approved grid of the vertical fund, which extinguished the drilling of two vertical well points of the production fund, the well is being equipped. In the production horizontal well, deep perforation is carried out in a spiral along the entire trunk of the horizontal section of the well, with a distance between holes of 10 m and a perforation depth of 1.5 m, having in this case at least 30 perforation holes. At a distance of 150 m from the bottom of the horizontal well, a vertical production well was drilled, the well was equipped. Production horizontal and vertical wells are being put into operation.

After 6 years of operation, the flow rate of the vertical production well was 0.5 tons/day. Two side horizontal wells are cut in the opposite direction to each other, from the main well at a distance of 60 m, with a horizontal section length of 150 m, at an angle of 80° relative to the production horizontal well, the well with two side horizontal wells is transferred to the injection fund, the lower aquifer is opened, and the vertical production well with two side horizontal wells is developed for injection.

Injection is carried out by downhole pumping in a vertical production well with two lateral horizontal wellbores from the lower aquifer with a pressure of 12.5 MPa with an injection cycle of 4 days of injection and 2 days of downtime.

Thus, the proposed method ensures uniform displacement of oil from an oil-saturated formation, a high rate of oil recovery and an increase in well productivity due to the use of the proposed well grid, which allows for maximum coverage of the reservoir drainage by area by using horizontal technology and section by increasing the volume of drained rock around the horizontal wellbore using deep perforation, connecting the maximum possible thickness in the heterogeneous oil-bearing reservoir of the reservoir to drainage.

Claims (1)

A method for developing an oil deposit, including drilling horizontal and vertical production wells, extracting products through production wells, characterized in that horizontal production wells 300-350 m long are drilled in a formation with a thickness of at least 12 m above the base of the deposit by at least 3 m, and vertical production wells are placed at a distance of 1/2 of the approved interwell space of the production stock on the deposit from the bottom of the horizontal production wells, while in the horizontal production well deep perforation is carried out in a spiral along the entire trunk of the horizontal section of the well with a distance between holes of 10 m and a perforation depth of 1.5 m, having in this case at least 30 perforation holes, when the oil flow rate in the vertical production wells reaches 0.5 t/day or less, two side horizontal wells are cut in the opposite direction to each other, from the main well at a distance of 60-80 m, with a horizontal section length of 150-200 m, at an angle of 80-85° relative to the horizontal production well, then a vertical well with two lateral horizontal wellbores is transferred to the injection fund, after which the lower aquifer is opened, a vertical production well with two lateral horizontal wellbores is developed for injection, injection is carried out by downhole pumping in a vertical well with two lateral horizontal wellbores from the lower aquifer with a pressure 10-15% higher than the initial reservoir pressure and an injection cycle of 4 days of injection and 2 days of downtime.