RU2580562C1 - Method of developing oil deposits - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to methods for development of oil fields with maximum accounting for current pressure of drilled portion of oil reservoir. Method comprises drilling vertical and horizontal production and injection wells at one of known design grids with units at point of intersection of grid lines for arrangement of wells. Product is extracted from production wells with injection of working agent to injection wells. Rare grid of wells is selected. Deposits with high heterogeneity define zonal area reduced to 20 % of initial reservoir pressure oil reservoir to saturation pressure. According to results of drilling collector with no areal distribution is identified. As a result of hydrodynamic studies build a map of isobars, which identify areas of high and low reservoir pressures. Multi-hole horizontal wells are drilled in zones with low formation pressure from vertical wells with break-up of faces at 70-180°. In zones with high formation pressure in direction of oil content outline is drilled inclined directed and/or horizontal wells of small diameter, on basis of technical capabilities of drilling. Single-hole or multi-hole horizontal production wells are drilled from selected planned network nodes. In nearby of mouth of multilateral well design mesh nodes rock faces directed multilateral wells.

EFFECT: increasing oil recovery factor with reduction of well stock.

2 cl, 1 ex, 1 dwg

Description

The invention relates to the field of the oil industry, and in particular to methods for developing oil fields with the maximum consideration of the current pressure of the drilled section of the oil reservoir.

The essence of the invention: select a rare grid, and in areas with high zonal heterogeneity, determine zones with a 20% decrease in the initial reservoir pressure of the oil reservoir to saturation pressure, based on the technical capabilities of drilling, drill single-hole or multi-hole horizontal production wells into selected nodes of the design grid, moreover, the faces of a multilateral well are directed to nearby nodes of the design grid.

After flooding the produced products in the producing well below the level of profitability, it is transferred under injection of a working agent (water, chemicals, etc.).

At the same time, the number of wells drilled is significantly reduced, the volume of drained reserves is increased, and the oil recovery coefficient (CIN) is increased.

There is a method of developing oil deposits by injecting water into injection wells and extracting oil from production wells (Craig FF Development of oil fields during flooding. - M .: Nedra, 1974. - S. 65).

The disadvantage of this method is the low oil recovery factor due to an increase in the well stock and drilling with an in-line grid of wells with a low production rate.

Closest to the proposed invention in technical essence is a method of developing an oil reservoir (patent RU No. 2451166, IPC EV 21/20, EV 43/30, published on 05/20/2012 in Bulletin No. 14), including the injection of the working agent through the rows injection wells, production selection through the rows of production wells, compaction of the grid of production wells and transfer of waterlogged production wells to injection wells. Compaction is performed from the second from a series of injection wells of a number of production wells, while compaction from production wells of the second row, lateral vertical and / or horizontal shafts are drilled with the faces of new shafts placed in the reservoir between the first and second rows of production wells equidistant from the bottoms of neighboring wells, with a thickness a productive formation of more than 1.5 m as a lateral well, a horizontal lateral well is drilled with a horizontal part length of at least 30 m in the productive stratum, with a productive thickness of less than 1.5 m long, a sidetrack with a vertical part in the reservoir is drilled as a sidetrack; as a result of flooding, they switch to simultaneous and separate operation of wells with sidetracks, and when flooded, the flooded sidetracks or the wells themselves are turned off for injection depending on the sequence of watering, as the watering of the second row of producing wells, the compaction and operation of wells is carried out from the third row, similarly to operations from the second row, compaction of the central row lev els wells is carried out in the direction of both rows of injection wells.

The disadvantages of this method: when compaction of the grid in-line development system in a highly heterogeneous reservoir, the likelihood of getting into the zone of lack of reservoir in the interwell space and a decrease in oil recovery factor sharply increase.

The technical objectives of the proposed method are to reduce the design fund of wells, increase the oil recovery factor due to the maximum coverage of the oil reservoir by drainage in areas with increased zonal heterogeneity and high layer heterogeneity in areas with low and high reservoir pressure of the oil reservoir.

Technical problems are solved by the method of developing an oil field, including drilling vertical and horizontal production and injection wells along one of the well-known design grids with nodes at the intersection of the grid lines to accommodate wellheads, production from production wells and injection of a working agent into injection wells. A rare grid is selected, and in reservoirs with high zonal heterogeneity, zones are determined that are 20% lower than the initial reservoir pressure of the oil reservoir to saturation pressure, a reservoir that does not have an area distribution is revealed by drilling, and an isobar map is constructed based on the results of hydrodynamic studies, on which areas of high and low formation pressures are identified, multi-hole horizontal wells are drilled in areas with low formation pressure from vertical wells with 70-180 ° boreholes. , in areas with increased reservoir pressure in the direction of the oil content circuit, directional and / or horizontal wells of small diameter are drilled, based on the technical capabilities of drilling, one-hole or multi-hole horizontal production wells are drilled from selected nodes of the design grid, and the faces of the multi-hole well are directed to the neighboring wells its mouth is the nodes of the design grid, in which the wells are not located. After flooding the produced products in the producing well below the level of profitability, it is transferred under injection of the working agent.

The analysis of the proposed method with a prototype shows that the proposed method differs from the known one in that the mesh is selected rare, and in areas with high zonal heterogeneity, zones with a 20% decrease in the initial reservoir pressure of the oil reservoir to saturation pressure are determined based on the technical capabilities of drilling, single-hole or multi-hole horizontal production wells are drilled into the selected nodes of the design grid, and the faces of the multi-well wells are directed to nearby nodes of the design grid, increasing the volume of drains Rui reserves and increasing recovery factor.

After flooding the produced products in the producing well below the level of profitability, it is transferred under injection of the working agent.

The drawing shows a diagram of a method for developing an oil reservoir.

Design wells 1, 2, 3, 4, 5 are drilled along a sparse grid 6 with nodes 7 with a distance between wells of 600-900 m. Based on the drilling results, collector zones 8 adjacent to the non-reservoir of current oil-saturated thicknesses (reservoir lenses) are determined, and hydrodynamic studies in a drilled fund, measure reservoir pressure, identify zones with boundaries 9 with high zonal heterogeneity with a current oil saturated thickness of more than 2 m and a reduced current reservoir pressure of 20% of the initial reservoir pressure and oil to saturation pressure, in which, based on the technical capabilities of drilling, drill single-hole 10 and / or horizontal wells 11 located in nodes 7 of the grid 6, and / or multi-hole horizontal wells 12, 13 with a borehole separation of 70-180 °, allowing to combine one well 12 or 13, the maximum number of design faces 14 so that the faces 14 of a multilateral well 12 or 13 are directed to nearby nodes 7 of the design grid 6 with the minimum technically possible number of wellheads 12 or 13 depending on the tool used and borudovaniya (not shown).

In areas with increased layer-by-layer heterogeneity, the development of a reservoir of small thickness (not more than 2 m), with a high reservoir pressure of the reservoir equal to or greater than the initial reservoir pressure of the reservoir, drilling of vertical, directional and / or horizontal wells of small diameter is possible. Single-hole production well 10 in nodes 7 of the grid 6 as the watering of products is transferred to the injection of the displacing agent.

Thus, the proposed method solves the problem of increasing the maximum drainage of oil deposits while reducing the number of wells drilled, introducing into active development previously undrained zones with low reservoir pressure of the oil reservoir by 20% from the initial pressure of the reservoir to saturation pressure by drilling multilateral wells and reducing risk premature flooding of well products. In areas of small thickness not more than 2 m with high reservoir pressure of the reservoir, in the marginal areas it is possible to drill vertical, directional and / or horizontal wells of small diameter.

The method allows for a decrease in the number of wells being drilled to increase the oil recovery factor by increasing drainage of the oil deposit and to achieve a more uniform displacement of oil by the agent in the areas adjacent to the collector, collector lenses, pillars and zones of small oil-saturated thickness of not more than 2 m

An example of a specific implementation.

We will consider the implementation of this method using an example of a terrigenous carbonaceous sediment deposit site at a depth of 1200 m. A section of an oil deposit is drilled along a triangular grid with a distance of 900 meters between project wells 1, 2, 3, 4, 5, their arrangement and production of oil is performed. During operation, measurements are made of oil, water, and current reservoir pressure. The production rate of production wells is up to 37 tons / day. The initial water cut is up to 10% of the output. According to the results of hydrodynamic studies, the initial reservoir pressure is 120 atm. The current reservoir pressure in wells 2 and 3 was 100 and 95 atm. respectively, i.e. 20% lower than the initial, in the direction of the contour, into the zone of smaller thickness (no more than 2 m), the reservoir pressure increases and in well 1 is 130 atm.

Based on the results of drilling, the geological structure of the deposit is specified, the reservoir properties of oil-bearing rocks are revealed, and the reservoir is not distributed in the area. Well 4 uncovered an analogue of the reservoir, and a sidetrack was made from it in the direction of development of the reservoir.

Based on the results of hydrodynamic studies, a map of isobars is built, on which the areas of high and low reservoir pressure are distinguished. The results are compared with the data of geological and hydrodynamic modeling, taking into account the current development conditions.

Using the information obtained and in order to increase oil production and drainage from design vertical wells 1-5 in the zone with low reservoir pressure, multilateral horizontal wells 12 and 13 with a different number of faces are formed, and in the direction of the oil contour, the boundary of the oil reservoir in the zone of increased formation pressures, drilling of small diameter wells (not shown) is planned.

Equip the wells and put into operation. The flow rate of multilateral wells 13 increased by 2.8 times in relation to the surrounding vertical 1-5. The cost of building small diameter wells is less than the cost of building a new one by 35%. The costs for each sidetrack amounted to 70% of the cost of constructing a new well, i.e. 25.2 million rubles The initial additional flow rate according to the claimed method was 27-15.1 tons / day, the additional annual oil production per multilateral well was 15100 tons, 5569 tons per side well.

Considering that over the study period (10 years) of operation, additional oil production per one multilateral well and one lateral well amounted to 102,000 tons, with an oil selling price of 11,000 r. per ton savings will be:

E = (C-C) × ΔQn = (11000-8500) × 102000 = 255000000 p. = 255 million p.

where ΔQн - additional oil production, t;

C is the price of oil, r / t;

With - the cost of production of one ton of oil, r / t

Small diameter wells in the zone of the development of the reservoir with thicknesses of two or less meters are transferred to the injection rate of the displacing agent as products are flooded.

The application of the proposed method will solve the problem of increasing oil recovery deposits and reducing costs for compaction of the grid of wells.

Claims (2)

1. A method of developing an oil reservoir, including drilling vertical and horizontal production and injection wells along one of the known design grids with nodes at the intersection of the grid lines for placing wells, producing products from production wells and injecting a working agent into injection wells, characterized in that a rare mesh is selected, and in deposits with high zonal heterogeneity, zones with a 20% decrease in the initial reservoir pressure of the oil reservoir to saturation pressure are determined by drilling results a reservoir that does not have an area distribution is identified, and, based on the results of hydrodynamic studies, an isobar map is constructed, on which high and low reservoir pressure areas are identified, multilateral horizontal wells are drilled in areas with low reservoir pressure from vertical wells with 70-180 ° bore holes, in In areas with increased reservoir pressure, directional and / or horizontal wells of small diameter are drilled in the direction of the oil content contour, based on the technical capabilities of drilling, single-hole or multi-hole horizontal production wells from selected nodes of the design grid, and the nodes of the design grid direct the faces of the multi-hole well to the wells located near the mouth of the multi-well well.  2. The method of developing an oil reservoir according to claim 1, characterized in that after the flooding of the produced products in the producing well below the level of profitability, it is transferred under injection of the working agent.

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