RU2810357C1 - Method for developing superviscous oil deposits - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: development of high-viscosity oil or bitumen deposits under thermal exposure to horizontal wells. The method for developing a super-viscous oil deposit includes the construction of appraisal vertical wells on a square grid with a distance between wells of 200 m in plan, sampling of cores and geophysical studies of appraisal vertical wells, building a unified geological model of the productive formation based on the obtained data and obtaining data on the distribution of porosity and permeability coefficients and oil-saturated thicknesses. Next, a structural map of the oil-saturated thicknesses of the productive formation is constructed, the contour of the productive formation is identified along an isopach of 10 m, horizontal pairs of production and injection wells located above each other are designed and built with a mutually perpendicular arrangement of a pair of horizontal production and injection wells. The coolant is pumped through injection wells with heating of the productive formation and creating a steam chamber, and the production is taken through steam-gravity drainage through production wells and the condition of the steam chamber is monitored. The development of super-viscous oil deposits is carried out by regulating the current size of the steam chamber by changing the volume of coolant injection into injection wells and withdrawing fluid from production wells while controlling the volume of the steam chamber. When designing, the distance from the bottom of production wells to the bore of a perpendicular production well is selected depending on the average porosity of the productive part of the formation. When the production well bottom is located at a distance of 50-75 m from the perpendicular wellbore, initial heating is carried out by pumping steam in a volume of 50 tons/day for 70 days, followed by thermocapillary impregnation for 30 days, and when the production well bottom is located at a distance of 76-100 m from the perpendicular wellbore, initial heating is carried out by pumping steam in a volume of 80 tons/day for 50 days, followed by thermocapillary impregnation for 15 days. After that, steam injection into injection wells is resumed and products are taken from production wells, monitoring the state of the withdrawn fluid and regulating the rate of liquid withdrawal and coolant injection based on temperature and water cut data.

EFFECT: increased efficiency of development of superviscous oil deposits.

1 cl, 2 dwg

Description

The invention relates to the oil industry, in particular to the development of deposits of high-viscosity oil or bitumen under thermal influence of horizontal wells.

There is a known method for developing a super-viscous oil field (patent RU No. 2471972, IPC E21B 43/24, published on January 10, 2013, Bulletin No. 1), including the construction of horizontal production and injection wells, as well as vertical observation wells, pumping coolant through injection wells with heating productive reservoir and the creation of a steam chamber, the selection of products due to steam-gravity drainage through production wells and monitoring the state of the steam chamber, while the development of a super-viscous oil field is carried out by regulating the current size of the steam chamber by changing the volume of coolant injection into injection wells and withdrawing fluid from production wells , and the current volume of the steam chamber is determined by gas survey on the surface in the area of the proposed steam chamber, and if the area of distribution of the steam chamber in the productive formation is less than the distance between pairs of production and injection wells, then the volume of steam injection is increased, and if it is larger, then it is put into operation as production vertical observation wells to increase the volume of production, and superheated steam mixed with combustion products of combustible fuel is used as a coolant.

The disadvantages of this method are a slight increase in oil recovery and oil recovery factor - oil recovery factor of the field, since an increase in the injection of coolant in the form of steam or steam together with combustion products of combustible fuel leads to premature watering of the field's products; the commissioning of additional production wells does not provide a significant increase in production deposits, but only leads to uncontrolled and costly heating of reservoir zones not covered by production.

There is also a known method for developing deposits of high-viscosity oil or bitumen (patent RU No. 2582256, MPK E21B 43/24, E21B 43/22, published on April 24, 2016, Bulletin No. 11), including the construction of paired horizontal production and injection plants located one above the other wells, as well as additional horizontal wells, injection of coolant through injection wells with heating of the productive formation and creation of a steam chamber, selection of products due to steam-gravity drainage through production wells and monitoring the condition of the steam chamber. Development of an oil or bitumen field is carried out by regulating the current size of the steam chamber by changing the volume of coolant injection into injection wells and withdrawing fluid from production wells while controlling the volume of the steam chamber. Superheated steam or steam with inert gas is used as a coolant. An additional well is built between the production and injection wells in pairs in the range from 1/3 to 2/3 of the distance between them. The solvent is pumped only through an additional well at time intervals into the zones of least heating. The state of the steam chamber is monitored by taking a thermogram in a horizontal production well with additional determination of the zones of least heating.

The disadvantage of this method is the technological complexity of its implementation, in particular the drilling of an additional well vertically between existing horizontal wells with a horizontal section of the well, as well as low production coverage of the lower edge zones of horizontal wells of paired wells in a row, hence low oil recovery factor.

The closest is the method of developing super-viscous oil deposits (patent RU No. 2792478, MPK E21B 43/24, E21B 43/22, publ. 03.22.2023, Bulletin No. 9), including the construction of appraisal vertical wells, as well as pairs located one above the other horizontal production and injection wells, injection of coolant through injection wells with heating of the productive formation and creation of a steam chamber, selection of products due to steam-gravity drainage through horizontal production wells and monitoring the state of the steam chamber, construction of evaluation vertical wells is carried out on a square grid with a distance between wells of 250 m in plan, then they carry out core sampling and geophysical studies of appraisal vertical wells, based on the data obtained, they build a unified geological model of the productive formation and obtain data on the distribution of porosity and permeability coefficients, oil-saturated thicknesses, build a structural map of the oil-saturated thicknesses of the productive formation, and highlight the contour of the productive formation along an isopach of 10 m, with an L-shaped selected contour, two parts of the contour are conventionally identified with a coaxial direction of strike of the productive formation, horizontal production wells are designed with a length of the horizontal part of at least 600 m, with mutually perpendicular arrangement of trunks in two parts of the contour, with adjacent horizontal production wells are designed at a distance of 100 m, and a horizontal production well, located closest to the others to perpendicularly located horizontal production wells, is designed at a distance of no more than 75 m from the bottoms of equidistant perpendicularly located horizontal production wells, then a section limited to 50 m to the axis of the horizontal production well is identified wells located in plan closer than others to perpendicularly located horizontal production wells, the weighted average porosity and permeability coefficients in the selected area are determined, with the weighted average porosity coefficients less than or equal to 0.27 units. or permeability less than or equal to 1.3 µm², horizontal injection wells are designed, located 5 m above and parallel to horizontal production wells, after constructing pairs of horizontal production and injection wells located above each other, geophysical surveys are carried out in horizontal injection wells to determine oil saturation along horizontal wellbore, after which two strings of tubing are placed in horizontal injection wells, with the end of the smaller-diameter column being placed at the beginning of the horizontal wellbore, and the end of the larger-diameter column in the zone with an oil saturation of more than 60%, and for steam injection into In a horizontal production well, one or two tubing strings are placed with the end or ends displaced horizontally relative to the ends of the tubing of the horizontal injection well by at least 10 m, then the coolant is pumped through the horizontal production and injection wells with heating of the productive formation and the creation of a steam chamber, after completion Injection of the estimated volume of coolant in the well is stopped for holding time for thermocapillary impregnation and cooling of the production wellbore, then a fiber-optic cable and an electric centrifugal pump running on the tubing string are placed in the horizontal production wells, and after creating a permeable zone, steam is supplied only to the horizontal injection wells.

The disadvantages of this method are:

- if the construction of an injection well is abandoned, the supply of the displacement agent (in the form of steam) will be provided only from the bottom of the perpendicularly located injection wells, which will entail a decrease in the steam coverage of the area located on the other side of the axis of the production well;

- the filtration and reservoir properties of the reservoir are not taken into account when choosing the distance between the production well and the bottoms of perpendicularly located production wells, which can lead to low production of the considered section of the deposit;

- the risk of overheating of wells due to the close location of injection wells with a perpendicularly located injection well.

Technical objectives are to increase the efficiency of development of super-viscous oil deposits by introducing previously undeveloped areas into development, developing stagnant zones and, as a result, increasing the oil recovery rate, reducing the risk of well overheating, reducing thermal impact, as well as optimizing the operation of downhole pumping equipment .

Technical problems are solved by developing a highly viscous oil deposit, including the construction of appraisal vertical wells, core sampling and geophysical studies of appraisal vertical wells, building a unified geological model of the productive reservoir based on the obtained data and obtaining data on the distribution of porosity and permeability coefficients, oil-saturated thicknesses, building a structural map oil-saturated thicknesses of the productive formation, distinguish the contour of the productive formation along an isopach of 10 m, design and construction of horizontal pairs of production and injection wells located one above the other with a mutually perpendicular arrangement of a pair of horizontal production and injection wells, pumping coolant through injection wells with heating of the productive formation and the creation of steam chambers, product selection due to steam-gravity drainage through production wells and monitoring the condition of the steam chamber. in this case, the development of super-viscous oil deposits is carried out by regulating the current size of the steam chamber by changing the volume of coolant injection into injection wells and withdrawing liquid from production wells while controlling the volume of the steam chamber.

What’s new is that evaluation vertical wells are built on a square grid with a distance between wells of 200 m in plan; additionally, a map of the porosity of the productive formation is constructed; when designing, the distance from the bottoms of production wells to the trunk of a perpendicular production well is chosen depending on the average porosity of the productive part of the formation : with an average porosity of the productive part of the formation from 23.5 to 28%, the bottoms of production wells are designed at a distance of 50-75 m from the trunk of a perpendicular production well; with an average porosity of the productive part of the formation of more than 28%, the bottoms of production wells are designed at a distance of 76-100 m from the trunk of a perpendicular production well, and the bottoms of injection wells are designed at a distance of 100 m from the trunk of a perpendicular injection well, while an additional pair of horizontal production and injection wells located above each other is placed at the level of the bottom of the formation or at the level of the oil-water contact - OWC, when the bottom of the production well is located wells at a distance of 50-75 m from the perpendicular wellbore, initial heating is carried out by pumping steam in a volume of 50 tons/day for 70 days, followed by thermocapillary impregnation for 30 days, when the production well bottom is located at a distance of 76-100 m from the perpendicular wellbore initial heating is carried out by injection of steam in a volume of 80 tons/day for 50 days, followed by thermocapillary impregnation for 15 days, then a fiber-optic cable with temperature and pressure control sensors, as well as tubing and compressor pipes with a deep-well pump, are installed in production wells. equipment, then resume steam injection into injection wells and select products from production wells, monitoring the state of the withdrawn fluid and regulating the rate of liquid withdrawal and coolant injection based on temperature and water cut data.

In fig. Figure 1 shows a top view of the well layout according to the method of developing a super-viscous oil deposit.

In fig. Figure 2 shows the profile of the well layout according to the method of developing a super-viscous oil deposit.

The method for developing super-viscous oil deposits is carried out as follows.

Evaluation vertical wells are built on a square grid with a distance between wells of 200 m in plan (not shown in Fig. 1, 2). Next, core samples and geophysical studies of appraisal vertical wells are carried out, based on the data obtained, a unified geological model of productive formation 1 is built (Fig. 2) and data on the distribution of porosity and permeability coefficients and oil-saturated thicknesses is obtained. A map of the oil-saturated thickness of productive formation 1 and the porosity of productive formation 1 is constructed, and the contour of productive formation 1 is identified along an isopach of 10 m.

Design of horizontal pairs of production 2, 2', 2”, 2”', 2”” located above each other (Fig. 1) and injection 3, 3’, 3”, 3”’, 3”” wells with mutually perpendicular location of a pair of horizontal production and injection wells. When designing, the distance from the bottoms of production wells to the trunk of a perpendicular production well is selected depending on the average porosity of the productive part of the formation: with an average porosity of the productive part of the formation from 23.5 to 28%, the bottoms of production wells are 2, 2', 2”, 2”', 2"" is designed at a distance of 50-75 m from the trunk of a perpendicular production well, with an average porosity of the productive part of the formation of more than 28%, the bottom of production wells 2, 2', 2", 2"', 2"" is designed at a distance of 76-100 m , and the bottoms of injection wells 3, 3', 3”, 3”’, 3”” are designed at a distance of 100 m from the trunk of a perpendicular injection well. In this case, an additional pair of horizontal production wells 2, 2', 2”, 2”', 2”” and injection wells 3, 3’, 3”, 3”’, 3”” located above each other are placed at the level of the formation base or at level of water-oil contact – VNK 4 (Fig. 2).

Construction of pairs of horizontal production units 2, 2', 2”, 2”', 2”” (Fig. 1) located parallel to each other (parallel) and injection units 3, 3’, 3”, 3”’, 3” is carried out. wells, as well as an additional pair of horizontal production 5 and injection 6 wells located above each other, located perpendicular to wells 2, 2', 2”, 2”’, 2”” and 3, 3’, 3”, 3”’, 3 "". The distance from the bottoms of production wells 2, 2', 2”, 2”’, 2”” to the trunk of a perpendicularly located production well 5 (Fig. 2) is determined by the average porosity of the productive part of the formation.

The bottoms of 7 production wells 2, 2', 2”, 2”’, 2”” (Fig. 1) with an average porosity of the productive part of the formation from 23.5 to 28% are located at a distance of 50-75 m from the trunk of a perpendicular production well 5 , the bottoms of 7 production wells 2, 2', 2”, 2”', 2”” with an average porosity of the productive part of the formation of more than 28% are located at a distance of 76-100 m from the trunk of the perpendicular production well 5. The bottoms of injection wells 3, 3' , 3”, 3”’, 3”” are located at a distance of 100 m from the trunk of the perpendicular injection well 6 (Fig. 2). This condition makes it possible to improve the hydrodynamic connection between production wells at a relatively low porosity of the reservoir.

If the bottom 7 of the production well is located at a distance of 50-75 m from the trunk of the perpendicular well 5, initial heating is performed by pumping steam in a volume of 50 tons/day for 70 days, followed by thermocapillary impregnation for 30 days. If the bottom 7 of the production well is located at a distance of 76-100 m from the perpendicular well 5, initial heating is carried out by pumping steam in a volume of 80 tons/day for 50 days, followed by thermocapillary impregnation for 15 days. Then, a fiber-optic cable with sensors for temperature and pressure control, as well as pumping and compressor pipes with deep-well pumping equipment are installed in the production wells 2, 2', 2", 2"', 2"", 5 (Fig. 1) (not shown in Fig. 1, 2). Next, steam injection into injection wells 3, 3', 3”, 3”', 3””, 6 (Fig. 1) is resumed and products are selected from production wells 2, 2’, 2”, 2”’, 2”” , 5 wells with control of the condition of the withdrawn fluid and regulation of the rate of liquid withdrawal and coolant injection based on temperature and water cut data.

Application example:

In the Oikino-Altuninskaya deposit of super-viscous oil, located at a depth of 100 m, represented by a homogeneous reservoir with an average effective oil-saturated thickness of 12.6 m, reservoir temperature 8°C, pressure 0.44 MPa, oil saturation 0.74 units, porosity 32 %, permeability 3.768 µm², oil density in reservoir conditions 980 kg/m³, viscosity 86472 mPa s, we drilled evaluation vertical wells on a square grid with a distance between wells of 200 m in plan. Next, we carried out core sampling and geophysical studies of appraisal vertical wells, based on the data obtained, we built a unified geological model of the productive formation and obtained data on the distribution of porosity and permeability coefficients and oil-saturated thicknesses. We built maps of porosity and oil-saturated thicknesses of the productive formation, identified the contour of productive formation 1 along an isopach of 10 m. The distance from the bottoms of production wells 2, 2', 2”, 2”', 2”” to the trunk of a perpendicularly located production well 5 was determined by the average porosity productive part of the formation.

Production well 2 was placed at a distance of 50 m from well 5 (with an average porosity of 23.5%), well 2" was located at a distance of 55 m (with an average porosity of 25%) from well 5, well 2' was located at a distance of 75 m ( with an average porosity of 28%) and well 2” was located at a distance of 76 m (with an average porosity of 29%), respectively, from well 5, well 2” was located at a distance of 100 m (with an average porosity of 30%) from well 5.

We constructed parallel pairs of horizontal production wells 2, 2', 2”, 2”', 2”” and injection wells 3, 3’, 3”, 3”’, 3””, as well as an additional pair of horizontal production wells 5 and 6 injection wells located perpendicular to wells 2, 2', 2”, 2”’, 2”” and 3, 3’, 3”, 3”’, 3””. In wells 2, 2', 2"" initial heating was carried out by injection of steam in a volume of 50 tons/day for 70 days, followed by thermocapillary impregnation for a period of 30 days. In well 2”, 2”’, initial heating was carried out by injection of steam in a volume of 80 tons/day for 50 days, followed by thermocapillary impregnation for a period of 15 days.

Then, a fiber-optic cable with sensors for temperature and pressure control, as well as pumping and compressor pipes with downhole pumping equipment were installed in the production wells 2, 2', 2”, 2”’, 2””, 5. Next, we resumed steam injection into injection wells 3, 3', 3", 3"', 3"", 6 and produced product selection from production wells 2, 2', 2", 2"', 2"", 5 with control state of the withdrawn fluid and regulation of the rate of liquid withdrawal and coolant injection based on temperature and water cut data.

This solution made it possible to reduce interference from neighboring production wells, improve the operation of downhole pumping equipment (by reducing overheating and failure), increase the development coverage of inter-well zones, and, accordingly, increase the oil recovery factor.

Claims (1)

A method for developing a super-viscous oil deposit, including the construction of appraisal vertical wells, sampling of cores and geophysical studies of appraisal vertical wells, building a unified geological model of the productive reservoir based on the obtained data and obtaining data on the distribution of porosity and permeability coefficients, oil-saturated thicknesses, then constructing a structural map of oil-saturated thicknesses productive formation, identify the contour of the productive formation along an isopach of 10 m, design and build horizontal pairs of production and injection wells located one above the other with a mutually perpendicular arrangement of a pair of horizontal production and injection wells, pump coolant through injection wells with heating of the productive formation and creating a steam chamber , selection of products due to steam-gravity drainage through production wells and monitoring the state of the steam chamber, while the development of super-viscous oil deposits is carried out by regulating the current size of the steam chamber by changing the volume of coolant injection into injection wells and withdrawing liquid from production wells with control of the volume of the steam chamber, characterized by that assessment vertical wells are built on a square grid with a distance between wells of 200 m in plan, additionally, a map of the porosity of the productive formation is constructed; when designing, the distance from the bottoms of production wells to the trunk of a perpendicular production well is chosen depending on the average porosity of the productive part of the formation: with average porosity productive part of the formation from 23.5 to 28%, the bottoms of production wells are designed at a distance of 50-75 m from the trunk of a perpendicular production well, with an average porosity of the productive part of the formation of more than 28%, the bottoms of production wells are designed at a distance of 76-100 m from the trunk of a perpendicular production well , and the bottoms of injection wells are designed at a distance of 100 m from the trunk of a perpendicular injection well, while an additional pair of horizontal production and injection wells located above each other is placed at the level of the bottom of the formation or at the level of the oil-water contact - OWC, with the bottom of the production well located at a distance of 50 -75 m from the perpendicular wellbore, initial heating is carried out by pumping steam in a volume of 50 tons/day for 70 days, followed by thermocapillary impregnation for 30 days, when the bottom of the production well is located at a distance of 76-100 m from the perpendicular wellbore, initial heating is carried out by steam injection in a volume of 80 t/day for 50 days, followed by thermocapillary impregnation for 15 days, then a fiber-optic cable with temperature and pressure control sensors, as well as tubing and compressor pipes with deep-well pumping equipment are installed in the production wells, then steam injection is resumed into injection wells and select products from production wells while monitoring the condition of the withdrawn fluid and regulating the rate of liquid withdrawal and coolant injection based on temperature and water cut data.