RU2070284C1 - Method for development of oil deposits - Google Patents

Abstract

FIELD: oil producing industry, particular, methods for development of oil deposits with high-viscosity oils. SUBSTANCE: method for development of oil deposits includes drilling of wells of complicated profile. Vertical part of well is introduced into the upper part of producing formation. Then, well is drilled parallel to producing formation. The next stage of well is drilled below the previous one but also parallel to producing formation. Upper and lower stages of each well are located in same vertical plane. In this case, each stage of any well is used alternately as injection and producing. Injection of heat carrier and oil withdrawal from each well is performed simultaneously. The lower stage of well when heat carrier is injected heats the formation and oil is withdrawn from the upper stage of this or other well. In case of injection of heat carrier into the upper stages of the well, formation is heated in the given vertical plane and oil is withdrawn from the lower stages of the well, both, of this and other one. EFFECT: higher efficiency. 2 cl, 2 dwg

Description

 The invention relates to the oil industry, and more particularly to methods for developing oil fields with high viscosity oils.

There is a method of developing an oil field, which consists in displacing oil from the reservoir by transferring thermal water into it through wells and transporting them to the surface along the annular space between the tubing and production tubing strings and extracting oil to the surface through the wells [1]
The disadvantage of this method is the fact that it is necessary to drill certain rows of injection wells, which leads to additional costs, spoils the environment.

There is also known a method of developing oil fields, including pumping coolant into the formation and extracting oil from it through deviated and steep-hole wells drilled from a mine located beneath the oil reservoir, additionally drill vertical wells, break all the wells into groups, inject them into one well, and oil is taken from other wells [2]
The disadvantage of this method is the need to build mines, which increases the cost of oil production, in addition, this method is not applicable in combination with other methods of heating the oil reservoir, for example by combustion.

 The aim of the invention is to increase the oil recovery of an oil reservoir containing heavy and highly viscous oil, while conserving resources and preserving the environment, since fewer wells are drilled, and therefore less casing, cement, etc. are required.

 This goal is achieved by the fact that in the method of developing oil fields, including heating the oil reservoir containing heavy oil, and displacing the oil by pumping coolant into the reservoir, complex wells are drilled so that when they enter the oil reservoir, the wells are drilled stepwise parallel to the oil reservoir, covering oil layer, with the upper and lower stages of each well located in the same vertical plane, each stage of the well is used alternately as injection, then as production, at th injection coolant and selection of oil from each well are performed simultaneously, and the intermediate stage of each subsequent well located above (below) the previous steps of the well.

 In FIG. 1 depicted in the space of the location of the wells; in FIG. 2 shows a section of an oil reservoir with an arrangement of wells of complex profile.

 The method is as follows.

 Well trunks in the productive horizon can be located in space either in rows or radially.

 A vertical section of the well is introduced into the upper part of the reservoir, and then the well is drilled parallel to the last.

 Then the next stage of the well is drilled below the previous, but also parallel to the reservoir (see Fig. 1 and 2).

 The upper stages of all wells are located on the same level. The lower stages of all wells are located at a different level. Moreover, each step of any well is used alternately, either as injection, then as producing. In addition, the injection of coolant and the selection of oil from each well is carried out simultaneously. In this case, the recoverable oil, moving through the annular or pipe space, is additionally heated by the heat carrier pumped through the corresponding pipe or annular space. This reduces the need for additional heating of the extracted oil on the surface for its transportation through oil pipelines to the collection point.

 Here, methods of pumping the coolant and extracting oil are not described in detail, since the essence of the invention lies in the location and shape of the well, and the selection of oil and pumping of the coolant can be carried out by known methods.

 Example. The claimed method can be implemented on any field, for example, on the Yaregsky field of the Komi Republic. The productive layer of this field is of average thickness of 20 m and contains oil with a viscosity of 15 thousand MPa. To implement this method, it is necessary to drill several wells from each other at a distance of 100-150 m. In this case, each well should have two stages, the top of which is located at a distance of 2-3 m from the upper level of the reservoir, and the bottom at a distance of 3-5 m from the bottom of the reservoir.

 All wells are cased with 114 mm diameter pipes, which are cemented with heat-resistant cement to the middle of the second inclined section. The further part of the 2nd inclined section and the second stage are not cemented; a shank is placed in them. Both steps are perforated. To pump the coolant, the wells are equipped with a tubing string with a diameter of 50-60 mm. Then, steam injection begins with a pressure of 0.2-0.3 MPa for 25-30 days. Then they start oil production.

 The underlying step of the well, when the coolant is injected into it, heats the formation, and oil is pumped out of the overlying section of the well.

 Using this method can significantly increase the rate of oil extraction from the reservoir.

 In addition, the claimed method has the possibility of wider application, since it can be applied with any method of heating the oil reservoir with steam, hot water, combustion, etc.

 The claimed method can be carried out when drilling wells as a cluster method, and linear and can use existing wells.

Claims (2)

 1. A method of developing oil fields, including heating the oil reservoir containing heavy oil, and displacing the oil by pumping coolant into the reservoir, characterized in that the wells of complex profile are drilled so that when they enter the oil reservoir, the wells are drilled stepwise, parallel to the oil reservoir, covering the oil layer, while the upper and lower stages of each well are located in the same vertical plane, each stage of the well is used alternately as pumping, then producing, while the heat carrier and oil selection from each well are performed simultaneously.  2. The method according to p. 1, characterized in that the intermediate stages of each subsequent well are located above (under) the steps of the previous one.

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