RU2305758C1 - Method for oil field development - Google Patents

Abstract

FIELD: oil field development, particularly obtaining from a multiple-zone well.

SUBSTANCE: method involves choosing upper sheet oil pool arranged in carbonate reservoir having effective oil-saturated thickness of not less than 3 m and lower thick oil pool with total oil-saturated thicknesses more than 15 m; installing profiled shutter between chosen oil pools; lowering casing pipe to lower oil pool roof with filter arranged in productive section of upper oil pool; cementing hole clearance; uncovering upper productive interval; lowering two lifting means in well; drilling vertical and/or directional or branched horizontal injection wells in accordance with design pattern; arranging horizontal bores of injection wells in parallel to horizontal bores of producing wells; drilling horizontally multi-branch well if buffer zones are present and if oil-saturated reservoir thickness of upper sheet oil pool exceeds 5 m; alternately injecting working agent in upper and lower oil pools along with dual oil pool exploitation.

EFFECT: increased oil recovery and coverage of oil fields to be developed coinciding with each other in plan view, located in immediate proximity with each other along section and divided one from another by clay or water-bearing layer, which makes difficult of oil field development.

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Description

The proposed method relates to the oil industry, namely, the development of oil deposits in carbonate reservoirs, which coincide in plan with the simultaneous separate exploitation of these deposits by branched horizontal wells (RGS) or multilateral horizontal wells (MZS), with alternating injection of a working agent into each reservoir, cyclic water injection into injection wells and can be used both at an early stage of development, and at a later stage.

A known method of developing an oil field, including a method and apparatus for oil and gas production from several productive horizons, including drilling a well, casing descent, installing a packer with a valve seat, lowering an installation tool with a firing drill and a removable plug, adjusting the pressure in the well, allowing alternately extract oil from the upper and lower horizons (US patent (US) No. 4637468, publ. 01.20.1987). The disadvantage of this method is the low oil recovery coefficient of productive horizons due to the small coverage of the reservoirs by drainage over the area of the development object.

The closest in technical essence is a method of developing an oil deposit, including drilling a branched horizontal production well and injection wells, placing open horizontal shafts in a vertical plane one above the other, installing a casing string, pumping a working reagent through an injection well, selecting products through a producing well (patent RF №2181430, publ. 06/13/2001). In the known method, the lower open horizontal trunk is drilled in the interlayer with higher permeability, and the upper one with lower permeability, followed by hydrochloric acid treatment of the bottom-hole zones. The method provides an increase in oil recovery of a layered heterogeneous oil field with a carbonate reservoir due to more complete production of interlayers with different permeabilities, however, when several oil deposits coincide in plan, the upper reservoir deposits remain undeveloped. Also, the known method does not simultaneously provide separate operation of two deposits.

The technical task of the proposed method is to increase oil recovery, expand the functionality and scope under various development conditions, ensure the development of oil reserves in deposits that coincide in plan, located in close proximity to the section, separated by a clay or aquifer that causes complications during its passage and increase profitability at the same time separate operation.

This problem is solved by the described method of developing oil deposits, including drilling a branched horizontal production well and / or multilateral well and horizontal injection wells, placing horizontal shafts in a vertical plane one above the other, installing a casing string, pumping a working reagent through the injection well, and selecting products through producing well.

What is new is that before drilling, the upper reservoir in carbonate reservoirs with effective oil-saturated thicknesses of at least 3 m and planes coinciding in plan is distinguished, and the lower massive reservoir with total oil-saturated thicknesses of more than 15 m, a profile overlap is installed between the selected reservoirs, the casing is lowered to the roof the lower reservoir with a filter in the productive part of the upper reservoir, cement the annulus, open the upper production interval, lower two elevators, drill vertical and / or inclined directionally or branched horizontal injection wells in accordance with the design grid, place horizontal wells parallel to the plane of the horizontal wells of production wells, and in the presence of sanitary protection zones and oil-saturated thickness of the reservoir of the upper reservoir over 5 m provide for the drilling of a multi-sided horizontal production well, injection the working agent is carried out cyclically in the upper and lower deposits during their simultaneous separate operation.

The preliminary patent research on the patent fund and technical library of the TatNIPIneft Institute showed the absence of identical or equivalent technical solutions in comparison with the claimed object. At the same time, the distinguishing features of the claimed technical solution are significant, which allows us to conclude that the solution meets the criteria of "novelty" and "inventive step".

Figure 1, 3 shows a schematic geological profiles, and figure 2, 4 - layout of wells on deposits in carbonate reservoirs 1 RGS - 1, 2 trunks; 1a RGS - 1a, 2a trunks; 1 MZS - 3, 4 trunks; 1a M3C - 3a, 4a barrels and injection wells. Nos. 1, 2, 3, 4 and 1a, 2a, 3a, 4a. The inventive method is carried out in the following sequence.

To clarify the geological structure of the deposits, drill a rare grid of vertical and / or directional wells, and arrange them. They select products from production wells and pump water into injection wells.

During operation in vertical and / or directional wells, oil, water and injected fluid are measured. According to seismic data and the results of deep well drilling, the geological structure of the deposits, reservoir properties of reservoirs and the amount of oil reserves are specified. Given the available information, structural maps are built on the roof of reservoirs of the reservoirs under consideration, and oil deposits that coincide in plan are determined.

Then branched horizontal wells are drilled (1РГС, 1аРГС) according to the location: upper trunks 1, 1a - to the reservoir reservoir of the upper reservoir, lower trunks 2, 2a - to the most permeable reservoir reservoir of the lower reservoir (Figs. 1-4), or multilateral horizontal wells (1MZS, 1aMZS): upper trunks 3, 3a with two branches to the reservoir of the upper reservoir, lower trunks 4, 4a to the reservoir of the lower reservoir (Figs. 1-4). In the process of drilling branched horizontal wells or multilateral horizontal wells, the path of horizontal shafts and branches along the reservoirs is corrected.

Wells put into operation. Master branched horizontal wells 1a, 2a, 3a, 4a, FIGS. 3, 4; vertical and / or directional wells 1, 2, 3, 4, 1, 2.

In reservoir strata, a significant length of horizontal boreholes and branches increases the filtration surface necessary for the production to be produced into the well, which is an order of magnitude larger than the filtration surface of the bottom of a conventional vertical and / or directional well, which allows a multiple increase in well production. The degree of connectivity of the wellbore with the formation increases, and the likelihood of a more perfect opening of the formation by the well increases. With minor depressions, oil production rates of producing wells increase. Reducing depression in the reservoir allows evenly displace oil, which helps to reduce associated water production and increase oil production.

Examples of specific performance.

Example 1. The implementation of this method, consider the example of the site, characteristic of the reservoir and massive deposits. The site was drilled with a rare grid of producing and injection vertical and / or directional wells (Figs. 1-4), and they were equiped.

They injected water into injection wells and produced oil from producing wells. They measured the production of oil, water and injected liquid. Structural maps were constructed on the roof of reservoirs of the reservoirs under consideration and maps of effective oil-saturated thicknesses of the upper reservoir and total oil-saturated thicknesses of the massive lower deposits. According to the structural map, a section was identified with the highest hypsometric marks of the drilled wells, 300 meters away from the oil profile, according to thickness maps with effective oil-saturated thicknesses of more than three meters in the upper deposit and total oil-saturated thicknesses of more than 15 meters in the lower deposit, which coincide in plan. Deposits are located in close proximity along the section. Between themselves they are separated by a clay layer. Separate exploitation of deposits is unprofitable.

A branched horizontal production well 1 of the CSG was placed on the design grid, and its horizontal shafts are located in a vertical plane one above the other on the lower and upper deposits.

They drilled a well, mastered and put into operation (Fig.1-4). They mastered the injection of directional wells 1, 2 in order to maintain reservoir pressure in the upper and lower deposits.

Example 2

The implementation of this method, consider the example of the site, characteristic of the reservoir and massive deposits. The site located in the sanitary protection zone was drilled with a rare grid of producing and injection vertical and / or directional wells (Figs. 1, 2), they were equipped.

Structural maps were constructed on the roof of reservoirs of the reservoirs under consideration and maps of effective oil-saturated thicknesses of the upper reservoir and total oil-saturated thicknesses of the massive lower deposits. According to the structural map, the area with the highest hypsometric marks of the drilled wells was identified, according to thickness maps with effective oil-saturated thicknesses of more than 5 meters in the upper reservoir and total oil-saturated thicknesses of more than 25 meters in the lower oil reservoir, which coincide in plan. We placed a multilateral horizontal production well 1a of the MZS on the design grid, and the horizontal well on the upper deposit is drilled with two branches located in the reservoir on the same plane and increasing the coverage area of the mine (Figs. 1, 3).

The well was drilled, mastered and put into operation (Fig.1-4). Wells 3a, 4a were mastered for injection, the horizontal shafts of which are located in a vertical plane one above the other parallel to the horizontal shafts of the producing well 1a of the MZS in order to maintain reservoir pressure in the upper and lower deposits.

As a result of the operation of the branched horizontal production well 1 of the CWG and the multilateral horizontal well 1a of the MZS, the predicted oil production rate of a conventional horizontal well was exceeded, the period of their operation was increased, additional oil production was obtained due to the separate exploitation of two facilities and, accordingly, the economic effect was increased. The efficiency of operation of branched and multilateral horizontal wells is increased as a result of the use of cyclic pumping of a working agent in injection wells.

For the proposed method, with the projected length of the shafts and confirmation of the predicted thicknesses and reservoir properties for the design well 1 of the CWG, the total potential oil production rate will be 16 tons / day, for the design well 1a of the MHS - 20 tons / day. Compared with the prototype, the actual oil flow rate increases on average by 2 times.

The accumulated annual oil withdrawal of a branched horizontal well (1RGS) or a multilateral well branched well (1aMZS), taking into account the development of oil reserves from two deposits at the same time, will exceed the oil production of a conventional well developing one reservoir by more than 1.5 times for 1 reservoir and 2 times for 1a MZS and will amount to 5.84 thousand tons and 7.3 thousand tons, respectively.

The proposed method provides an increase in oil recovery, expansion of functionality and scope under various development conditions, the development of oil reserves in deposits that coincide in plan, located in close proximity to the section, separated by a clay or aquifer that causes complications during its passage. The proposed method eliminates the need for long-term preservation of oil deposits.

Claims (1)

The method of developing oil deposits located in the immediate vicinity of the section, separated by a clay or aquifer, causing difficulties in its passage and unprofitable separate operation, including drilling a branched horizontal production well and / or multi-faceted production well and injection wells, placing horizontal shafts in the vertical plane one above the other, installation of a casing string, injection of a working reagent through an injection well, selection of products through a production well, characterized in that before drilling, the upper formation reservoir in carbonate reservoirs with effective oil-saturated thicknesses of at least 3 m and the lower massive reservoir with total oil-saturated thicknesses of more than 15 m coinciding in plan are identified; to the roof of the lower reservoir with a filter in the productive part of the upper reservoir, cement the annulus, open the upper productive interval, lower two elevators, drill vertical and / or directional or branched horizontal injection wells in accordance with the design grid, place horizontal shafts parallel to the plane of the horizontal shafts of producing wells, and in the presence of sanitary protection zones and oil-saturated thickness of the reservoir of the upper reservoir over 5 m, provide for multi-hole drilling horizontal production wells, the injection of the working agent is carried out cyclically in the upper and lower deposits during their simultaneous and separate exploitation nation.

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