RU2285117C2 - Method for extracting hydrocarbon deposits - Google Patents

Abstract

FIELD: oil and gas industry, in particular, technology for extraction of oil and gas deposits, namely, methods for extracting viscous oil with use of heat in complex with drilling of horizontal and vertical wells.

SUBSTANCE: in accordance to method for extracting hydrocarbons, several horizontal wells are drilled. The latter are positioned in groups of two in the same apsidal plane. Then vertical wells are drilled and a horizontal collector well. Working agent is fed in. Hydrocarbons are extracted. Pit-faces of horizontal and vertical wells are positioned near horizontal part of collector-well or intersect with it. Working agent is fed via horizontal wells and collector well until hydrocarbon enters moving state. Horizontal shafts of horizontal wells are drilled descending to collector-well. After that extraction of hydrocarbons is performed via vertical wells.

EFFECT: increased efficiency of extraction due to increased coverage of bed by process of thermal influence, decreased capital investments and operation costs, increased coefficient of extraction of hydrocarbons from bed and increased well operation coefficient.

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Description

The invention relates to the oil and gas industry, in particular to the development of oil and gas fields, and in particular to methods for producing viscous oil using heat in combination with the drilling of horizontal and vertical wells.

A known method of extracting viscous oil using a continuous horizontal well, the mouth and bottom of which extend to the surface (see RF patent No. 2211318, 7 IPC E 21 B 43/24, publ. 08/27/2005, Bull. No. 24), in which a continuous well is first heated up, and then oil is pumped through the output section of the well, and steam is continued to be pumped through the input. This method is the closest to the claimed invention.

The disadvantages of this method are the difficulty of drilling a continuous well, in particular a deviated outlet section, the difficulty of operating deep-well pumping equipment in deviated wells, the limited coverage of the formation by the process of heat exposure and drainage, which causes a decrease in the oil recovery coefficient, large financial and time costs for drilling a continuous well stock . Also in terrigenous reservoirs there are problems of cleaning the wellbore from sand plugs.

The objective of the present invention is to increase the efficiency of development by increasing the coverage of the formation by the process of heat exposure, reducing investment and operating costs, increasing the coefficient of extraction of hydrocarbons from the formation and increasing the coefficient of well operation.

To achieve this objective, a method of developing hydrocarbon deposits includes drilling several horizontal wells located two in the same apsidal plane, drilling vertical wells and a horizontal reservoir well, injecting a working agent and producing hydrocarbons while downhole horizontal and vertical wells are located near the horizontal part of the well - collectors or cross it, the working agent is pumped through horizontal wells and the reservoir well until the hydrocarbon transfers to a stationary state, horizontal trunks of horizontal wells are drilled downstream to the reservoir well, after which hydrocarbon production is carried out in vertical wells. Apsidal planes in which paired horizontal lateral wells are drilled are perpendicular to the wellbore of the reservoir and parallel to each other, and the lateral wellbores are oriented at the intersection of the maximum filtration planes or at the intersection of cracks. Drilling of wells is carried out in the sequence: first, a reservoir well is drilled, the operation of which is carried out cyclically, the first period of time is the injection of a working agent, the second period is the selection of hydrocarbons; then drill paired lateral horizontal wells, which produce the injection of the working agent; after which vertical production wells are drilled.

The inventive drilled horizontal borehole of a large diameter reservoir, in a vertical plane intersecting the reservoir borehole on both sides, drill horizontal lateral boreholes of smaller diameter, the faces of which are located near the horizontal part of the borehole or open it, from the surface they drill a number vertical wells of large diameter, the faces of which intersect the horizontal part of the reservoir well or are located close to it. Casing strings are installed in drilled wells and cemented to the top of the formation. Some of the wells in the formation are perforated. Inside horizontal wells, columns are installed along which the working agent is pumped. Vertical wells are used to lift hydrocarbon to the surface. The injection of the working agent and the selection of hydrocarbon are carried out simultaneously, if there is no breakthrough of the working agent in vertical wells, and cyclically, if there is a breakthrough of the working agent. The presence of horizontal lateral wells provides a high coverage of the formation by the processes of heat exposure and drainage.

New in the present invention is that instead of continuous wells, horizontal wells of small diameter are drilled, the faces of which are completed at the reservoir well. Two horizontal small-diameter wells drilled in one plane together represent a continuous well, but their construction is significantly cheaper and requires less time. Also new is the fact that the reservoir well is used to transport oil in the reservoir to the bottom of vertical wells. Cleaning of wellbores from sand plugs is carried out according to a system of horizontal and vertical wells.

Figure 1 shows a General view of the development of hydrocarbon deposits in the context, figure 2 is a section along aa, figure 3 is a section along bb.

The method of developing hydrocarbon deposits is carried out by drilling from the surface into the oil reservoir 1 of a horizontal large-diameter reservoir well 2, to which two lateral horizontal small-diameter wells 3 are drilled in perpendicular planes, the faces of which are completed at the horizontal reservoir well, and which together represent one continuous well, and for pumping oil, a number of vertical wells 4 are drilled, the faces of which are completed at the horizontal part of the reservoir well. The coolant is injected into all horizontal wells 2, 3 continuously or periodically. The heated oil enters the horizontal wells 2, 3 and is transported to the reservoir well 2 and through it to the vertical wells 3, which are equipped with downhole pumping equipment for pumping oil.

Specific example 1.

On the Lya-Yolsky area of the Yaregsky field of high-viscosity oil, represented by terrigenous heterogeneous fractured porous formation 1 at a depth of 200-220 m, a thickness of 15 m, with a temperature of 6-8 ° C, a pressure of 0.4-0.6 MPa, a porosity of 26%, and permeability 2-3 microns ² , oil viscosity 12000-16000 MPa · s drill a horizontal well-collector 2 with a diameter of 394 mm and casing string 295 mm. The horizontal part of the collector well 2 is perforated. In the vertical plane crossing the horizontal part of the reservoir-well 2 on both sides, horizontal wells 3 are drilled with a diameter of 216 mm and cased with a 140 mm column; the bottom faces of the well 3 are located near the horizontal part of the well-collector 2 or intersect it. The horizontal sections of the wells 3 are perforated. Vertical wells 4 are drilled from the surface, the faces of which are located near the horizontal part of the reservoir-well 2 or intersect it.

The mouths of horizontal wells 2, 3 are equipped for pumping a working agent (steam). Vertical wells 4 are equipped with deep pumping units for pumping oil.

Horizontal wells 2, 3 provide a high coverage of the formation by the processes of heat exposure and drainage of the formation, while opening up most of the cracks in the formation.

The coolant is fed into horizontal wells 2, 3 and this ensures heating of the formation. The liquefied oil enters horizontal wells 2, 3 and is transported through them to the reservoir well 3 and transported through it to vertical wells 4, where oil is pumped to the surface. In the event of a breakthrough of the coolant in the vertical wells 4, it passes to the cyclic pumping of the coolant and oil recovery. With sufficient heating of the formation and a decrease in viscosity to displace oil, it is possible to switch to the injection of cold or hot water. This system of horizontal wells 3 provides the possibility of alternately pumping coolant into one well 3 and displacing it into other wells 3. This achieves the hydrodynamic displacement of oil from the reservoir.

The wells are cleaned from sand plugs by a system of horizontal and vertical wells.

Specific example 2.

The technological process of mineral development is similar to that described in example 1. The extraction mechanism occurs according to the following principle: at the Kozhimsky coal deposit in coal seams represented by substandard energy coals, coal and host rocks contain gas that is close in composition to natural gas. Coal gas may consist of 95% methane, which is in the coal seams in a bound sorbed state. In this case, carbon dioxide, which displaces methane from micropores, is optimal as a working agent for injection. After transition to a free state, methane moves towards the reservoir well and rises to the surface along vertical wells.

The advantages of the proposed method compared to the prototype:

- a significant reduction in costs and time for drilling wells;

- increasing the coverage of the formation by processes of heat exposure and drainage;

- increase in the rate and coefficient of hydrocarbon recovery

Claims (3)

1. A method of developing hydrocarbon deposits, comprising drilling several horizontal wells located two in the same apsidal plane, drilling vertical wells and a horizontal reservoir well, injecting a working agent and producing hydrocarbons, characterized in that the bottoms of horizontal and vertical wells are located near the horizontal part reservoir wells or cross it, the working agent is pumped through horizontal wells and the reservoir well until the hydrocarbon transitions to the mobile state e, horizontal trunks of horizontal wells are drilled downward to the reservoir well, after which hydrocarbon production is carried out in vertical wells. 2. The method according to claim 1, characterized in that the apsidal planes in which paired horizontal lateral wells are drilled are perpendicular to the collector wellbore and parallel to each other, and the lateral wellbores are oriented at the intersection of maximum filtration planes or at the intersection of cracks. 3. The method according to claim 1, characterized in that the drilling of wells is carried out in the sequence: first, drill a collector well, the operation of which is carried out cyclically, the first period of time is the injection of a working agent, the second period is the selection of hydrocarbons, then paired horizontal lateral wells are drilled, on which the working agent is injected, after which vertical production wells are drilled.

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