RU2431743C1 - Procedure for development of deposits of high viscous oil and bitumen by means of wells with horizontal inclined sections - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: procedure consists in drilling wells along specified network with inclined-horizontal sections developed in reservoir, in withdrawal of reservoir fluids through producers positioned closer to lower boundary of reservoir, inclined-horizontal sections of which are parallel, in pumping replacing agent through pressure wells with inclined-horizontal sections located closer to upper boundary of reservoir between producers and parallel to them. Additional wells with developed sections in interval by thickness of the reservoir between the inclined-horizontal sections of producers and pressure wells are arranged at equal distance between the horizontal-inclined sections of the producers and pressure wells with the shortest distance between them so, as to eliminate outbreak of replacing agent between the wells. Also, the additional wells are used as pressure wells. Upon establishing hydro-dynamic communication between the inclined-horizontal sections of the producers and pressure wells the additional wells are converted to producers. Opened sections of the additional wells are vertical and/or horizontal. Horizontal sections of the additional wells are opened at not over 2/3 of distance between the horizontal-inclined sections of the producers and pressure wells and at equal distance from them.

EFFECT: raised efficiency of procedure due to reduced time of heating; increased oil yield of payout reservoir owing to increased sweep of development zone of deposit of high viscous oil and bitumen.

2 cl, 2 dwg

Description

The invention relates to the oil industry, in particular to the development of oil fields, namely, deposits of high viscosity oils and bitumen using heat in combination with inclined horizontal wells.

A known method of developing deposits of high viscosity oils and bitumen inclined horizontal wells (patent RU 2237804, IPC 7 ЕВВ 43/24, published in bull. 28 from 10.10.2004), including drilling wells on a specific grid, injection of a displacing agent through injection wells and the selection of formation fluids through production wells, while the wells are drilled along a radial grid, so that injection wells are located along the productive formation closer to the upper boundary of the formation along the most permeable layers, and production wells are closer the lower boundary of the formation, wherein the initial stage of development in all wells is carried thermocyclic treating the formation with steam stimulation, followed by transfer to selection of formation fluids through the production wells with areal influence on the formation through injection wells.

The disadvantages of this method are:

- firstly, it does not provide full coverage of the production zone and, as a result, a smaller volume of recoverable high-viscosity oils and bitumen;

- secondly, the heterogeneity of the formation by permeability is not taken into account when developing deposits of high viscosity oils and bitumen by wells with inclined horizontal sections and, as a result, the low efficiency of the method.

The closest in technical essence is the method of developing deposits of high viscosity oil and bitumen wells with inclined horizontal sections (patent RU 2368766, IPC 7 ЕВВ 43/24, published in bul. 27 from 09/27/2009), including drilling wells for a certain the grid, injection of the displacing agent through injection wells located closer to the upper boundary of the formation, and the selection of formation fluids through production wells located closer to the lower boundary of the formation, characterized in that before drilling the inclined horizontal sections Geophysical surveys determine the formation zones with the same permeability, after which inclined horizontal sections are drilled from the vertical production wells with a horizontal offset relative to the grid within the zones with the same reservoir permeability, in which the production wells are located parallel to each other, and from vertical injection wells drill horizontal-inclined sections in the parallel direction of the nearest horizontal-horizontal sections of production wells in within the corresponding zone with the same permeability of the reservoir.

The disadvantages of this method are:

- firstly, low heating efficiency, since it takes a large amount of time to warm up deposits of highly viscous oils and bitumen, which requires financial and material resources;

- secondly, it does not provide full coverage of the zone of development of deposits of high viscosity oils and bitumen and, as a result, a smaller volume of recoverable high viscosity oils and bitumen.

The objective of the invention is to increase the efficiency of heating deposits of high viscosity oils and bitumen by reducing the heating time, as well as increasing oil recovery of the reservoir by increasing the coverage of the development zone of deposits of high viscosity oils and bitumen by wells with inclined horizontal sections.

The problem is solved by the method of developing high-viscosity oil and bitumen deposits with wells with inclined horizontal sections, including drilling wells on a specific grid with inclined horizontal sections uncovered in the reservoir, and selecting reservoir fluids through production wells located closer to the lower boundary of the reservoir, inclined horizontal sections of which are parallel, and injection of the displacing agent through injection wells with inclined horizontal sections located closer to the upper face tse formation between production wells and parallel to them.

What is new is that at an equal distance between the horizontally-inclined sections of production and injection wells, the shortest distance between them is used to place additional wells with exposed sections in the interval along the thickness of the reservoir between the inclined-horizontal sections of production and injection wells so as to prevent the displacement of the displacing agent between wells, while additional wells are used as injection wells, and after the hydrodynamic connection between the inclined horizontal sections With the production and injection wells, additional wells are transferred to production wells.

It is also new that the exposed sections of the additional wells are made vertical and / or horizontal, and the horizontal sections of the additional wells are opened at a distance of no more than 2/3 of the distance between the horizontally-inclined sections of the producing and injection wells at an equal distance from them.

The figure 1 shows a diagram of the development of deposits of high viscosity oil and bitumen wells with oblique-horizontal sections during the period of intensive heating of the reservoir.

The figure 2 shows a diagram of the development of deposits of high viscosity oil and bitumen wells with oblique-horizontal sections during the period of intensive selection of the reservoir.

The essence of the method is as follows.

At a field of high viscosity oils and bitumen, represented by reservoir 1 (see Fig. 1), drilling is carried out on a specific grid (for example, several pairs) of producing 2; 2 ′; ... 2 ⁿ and injection 3; 3 ′ ... 3 ⁿ wells with inclined horizontal sections 4; 4 ′ ... 4 ⁿ and 5, 5 ′ ... 5 ⁿ , respectively, uncovered in the reservoir 1.

Inclined horizontal sections 4; 4 ′ ... 4 ⁿ and 5, 5 ′ ... 5 ⁿ , respectively, mining 2; 2 ′; ... 2 ⁿ and injection 3; 3 ′; ... 3 ⁿ wells are made parallel to each other at a distance L = 50 ÷ 400 meters, depending on the size of the field.

Moreover, the inclined horizontal sections 4; 4 ′ ... 4 ^{n of the} corresponding production wells 2; 2 ′; ... 2 ⁿ are located closer to the lower boundary of the reservoir 1, and the inclined horizontal sections 5; 5 ′ ... 5 ^{n of the} corresponding injection wells 3; 3 ′; ... 3 ⁿ are located closer to the upper boundary of the reservoir 1.

The figure 1 shows one of the pairs of wells, i.e. these are producing 2 and injection 3 wells with inclined horizontal sections 4 and 5, respectively, opened in reservoir 1.

The remaining pairs of mining 2; 2 ′; ... 2 ⁿ and injection 3; 3 ′ ... 3 ⁿ wells with inclined horizontal sections 4; 4 ′ ... 4 ⁿ and 5, 5 ′ ... 5 ⁿ , respectively uncovered in reservoir 1, are made similarly to this pair.

At an equal distance between the inclined horizontal sections 4 and 5 of the producing 2 and injection 3 wells according to the shortest distance between them, i.e. additional wells are placed perpendicularly: vertical 6; 6 ′ ... 6 ⁿ and horizontal 7; 7 ′ ... 7 ⁿ with exposed sections in the interval along the thickness of the formation 1 between the inclined horizontal sections 4 and 5, respectively, of the producing 1 and injection 2 wells so as to prevent the displacement of a displacing agent (for example, water vapor) between additional wells (vertical 6 ; 6 ′ ... 6 ⁿ and horizontal 7; 7 ′ ... 7 ⁿ ) in practice, this distance should be at least 5 meters.

Horizontal sections of additional horizontal wells 7; 7 ′ ... 7 ^{n are} opened at a distance of no more than 2/3 of the distance between the inclined horizontal sections 4 and 5, respectively, of the producing 2 and injection 3 wells at an equal distance from them, i.e. horizontal sections of additional horizontal wells 7; 7 ′ ... 7 ⁿ opened at a distance of 2/3 × L = 2/3 × 100-400 = 33-267 meters.

After that, the field is developed, that is, tubing columns and pumping equipment are lowered into the wells.

The displacing agent is injected (see Fig. 1) into the zones of the formation 1 through an inclined horizontal section 5 of the injection well 3, as well as through all additional wells: vertical 6; 6 ′ ... 6 ⁿ and horizontal 7; 7 ′ ... 7 ⁿ with exposed sections in the interval along the thickness of the reservoir 1 between the inclined horizontal sections 4 and 5 of the producing 2 and injection 3 wells.

The selection of formation fluids (high viscosity oils and bitumen) is carried out (for example, using a screw pump) from an inclined horizontal section 4 of the producing well 2.

At the initial stage of development, due to the fact that during heating of highly viscous oil and bitumen in reservoir 1, in addition to injection well 2 with horizontal section 4, all additional wells are included: vertical 6; 6 ′ ... 6 ⁿ and horizontal 7; 7 ′ ... 7 ⁿ with exposed areas in the interval over the thickness of the formation 1, heating of the productive formation is faster in time, and therefore the heating efficiency is increased.

As high-viscosity oils and bitumen are heated in reservoir 1, for example, after 180 days (depending on the value of the highly viscous oil or bitumen field heated up), steam is injected into additional wells: vertical 6; 5 ′ ... 6 ⁿ and horizontal 7; 7 ′ ... 7 ⁿ with exposed sections in the interval over the thickness of the reservoir 1 is stopped.

Next, a hydrodynamic connection is established between the inclined horizontal sections 4 and 5, respectively, of producing 2 and injection 3 wells.

To do this, a displacing agent (water vapor) is pumped through an inclined horizontal section 5 of the injection well 3, and the pressure change is determined by a pressure gauge located at the mouth of the producing well 2 or in its inclined horizontal section 4.

If the pressure of the formation fluid at the mouth of the producing well 2 or in its inclined horizontal section 4 does not change according to the pressure gauge, then the development of the field continues, that is, the formation 1 continues to be heated with highly viscous oil and bitumen, as described above, until the hydrodynamic connection is established in a similar way through a certain a period of time, for example after 90 days.

If the pressure of the reservoir fluid at the mouth of the producing well 2 or in its inclined horizontal section 4 increases, for example, by 10-20 atm according to the pressure gauge, then the hydrodynamic connection between the parallel inclined horizontal sections 4 and 5, respectively of the producing 1 and injection 2 wells, is established . Then additional wells, initially operated as injection wells: vertical 6; 6 ′ ... 6 ⁿ and horizontal 7; 7 ′ ... 7 ⁿ with exposed sections in the interval of thickness 1, equip pumping equipment and transfer them to production wells.

The advantage of the proposed method compared to the prototype is to reduce the time (by 20-30%) for heating up a highly viscous oil and bitumen deposit due to the involvement of additional vertical and horizontal wells located along the shortest distance between parallel-located horizontally inclined sections of the producing and injection ones wells, which improves the efficiency of the method. Also, in comparison with the prototype, the proposed method allows to increase oil recovery of the productive formation by increasing the coverage (by 10-20%) of the zone of development of deposits of high-viscosity oils and bitumen by additional vertical and horizontal wells.

Claims (2)

1. A method of developing deposits of high viscosity oils and bitumen, including drilling wells on a specific grid with inclined horizontal sections uncovered in the reservoir, selecting reservoir fluids through production wells located closer to the lower boundary of the reservoir, horizontal inclined sections of which are parallel, and pumping out agent through injection wells with inclined horizontal sections located closer to the upper boundary of the reservoir, between production wells and parallel to them, characterized in that at an equal distance between horizontally-inclined sections of production and injection wells, the shortest distance between them is used to place additional wells with exposed sections in the interval along the thickness of the reservoir between the inclined horizontal sections of production and injection wells so as to exclude the displacement of the displacing agent between the wells, while additional wells are used as injection wells, and after the appearance of a hydrodynamic connection between the inclined horizontal sections of the producing and production wells, additional wells are transferred to production wells. 2. The method according to claim 1, characterized in that the exposed sections of the additional wells are made vertical and / or horizontal, and the horizontal sections of the additional wells are opened at a distance of not more than 2/3 of the distance between the horizontally-inclined sections of the producing and injection wells at an equal distance from them.

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