RU2526047C1 - Development of extra-heavy crude oil - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: proposed method comprises drilling with the boundaries of one formation of parallel horizontal or inclined horizontal injection wells and production well, injection of heat carrier in injection wells and oil withdrawal from production well. Production well is located at equal distance from injection well bottoms which rules out heat carrier outburst bur allows hydrodynamic communication with injection wells. Injection wells are provided with two parallel channels with filters alternating over production reservoir length. Channels are used for injection of heat carrier while, after reservoir heating, one of said reservoirs is used for in-well product flow towards production well.

EFFECT: higher efficiency.

3 dwg

Description

The invention relates to the development of oil fields, in particular to methods of thermal exposure of a reservoir containing highly viscous and heavy oil.

A known method of developing deposits of highly viscous and heavy oil with thermal exposure (patent RU No. 2442884, IPC 8 EV 43/24, published in Bulletin No. 5 of 02/20/2012), including the construction of a well cased with casing pipes, descent into it two columns of pipes at different depths in the interval of the reservoir with a packer, pumping coolant along one pipe string and selecting products from the second pipe string. A horizontal injection well is drilled towards a horizontal production well in the same interval, followed by the construction of horizontal sections of multidirectional sidetracks parallel to the horizontal production well with a pitch of 50-400 m from it and the secondary opening of these shafts.

The disadvantage of this method is that the drilling and further operation of multilateral wells involve certain risks. In addition, the entire reservoir is not covered by heating and it is difficult to warm up certain necessary sections of the reservoir.

There is also a method of developing deposits of high viscosity and heavy oil with thermal effects (patent RU No. 2435948, IPC 8 ЕВВ 43/24, published in Bulletin No. 34 dated 12/10/2011), including drilling horizontal injection wells located within the same formation and production wells, injection of coolant into injection wells and selection of products from production wells. At the same time, horizontal production wells are drilled in one interval from one main horizontal wellbore, and horizontal injection wells are drilled from another main horizontal wellbore towards production wells, alternating with them in the same interval, while watering during development of products extracted from the main wellbore production wells, production production and coolant injection are stopped and product research is carried out from each production well with the definition of the production well from the most more water-flooded products, after which injection wells located next to this well are isolated from their main wellbore and product production and coolant injection are carried out as usual, etc.

The disadvantage of this method is that the drilling and further operation of multilateral wells involve certain risks. In addition, the entire reservoir is not covered by warming and it is difficult to warm up certain necessary sections of the reservoir.

The technical task of the proposed method is to increase the efficiency of development of deposits of high viscosity and heavy oil with thermal effects.

The stated technical problem is solved by the proposed method, including drilling within the same layer of parallel horizontal or inclined horizontal injection wells and production wells, pumping coolant into injection wells and selecting products from the production well.

What is new is that the production well is located at an equal distance from the bottom of the injection wells, eliminating the breakthrough of the coolant, but allowing to create a hydrodynamic connection with the injection wells, while the injection wells are provided with two parallel channels with alternating filters in the reservoir, the channels being used for coolant injection, and after the formation is heated up, one of the channels is for downhole flow of products towards the producing well.

Figure 1 schematically depicts the proposed method for the development of deposits of high viscosity and heavy oil with thermal effects.

Figure 2 - section aa in figure 1, where the horizontal injection well is conventionally shown rotated 90 °.

Figure 3 is a section bB in figure 1.

The method is carried out in the following sequence. On the developed reservoir of high-viscosity and heavy oil 1 (reservoir) (Fig. 1), parallel horizontal injection wells 2 are drilled with channels 3 and 4 equipped with alternating filters 5. These wells 2 cover the entire reservoir 1 and are located at a calculated distance from each other . Depending on the physicochemical properties of the formation, this distance may be 50 m or more. Filters 5 are also placed at a calculated distance from each other, which may be 5 m or more. Next, a production well 6 is drilled so that it is located at an equal calculated distance from the bottom faces 7 of the injection wells 2. Well 6 is equipped with filters 8, which are located in the bottom zones of the 7 wells 2. Well 6 is also equipped with pumping equipment for pumping high-viscosity and heavy oil ( products) (not shown in FIG.).

At the first stage, coolant (for example, steam) is pumped through channels 3 and 4 into all wells 2. The coolant penetrates through the filters 5 into the formation, heats it and forms steam chambers 9 (FIGS. 2 and 3). As the coolant is pumped in, the product warms up, which liquefies, that is, its viscosity decreases, and in this state drains into the zones of the wells 2. Then, the coolant flows into the channels 3 of the wells 2, and the flow into the channels 4 is continued. The products heated in the zones of the wells 2 through the filters 5 begin to flow into the channel 3, under the influence of the coolant pressure and gravitational forces it moves to the producing well 6 and through the filters 8 penetrates inside and is pumped to the surface by the pump. At this time, the coolant pumped through the channels 4 of the wells 2 continues to warm the formation. Then the coolant begins to be pumped into the channels 3 of the wells 2, and the flow into the channels 4 is stopped. In this case, the production of the formation through the filters 5 penetrates into the channels 4 of the wells 2 and also moves to the production well 6. The coolant pumped into the channels 3 of the wells 2 continues to heat the production of the formation through the filters 5 and at the same time pushes the products remaining inside the channel 3 to the production well 6. Next, the process repeated.

The technical and economic advantage of the proposed method for the development of deposits of high viscosity and heavy oil is as follows. The method is simple and cheap to implement. There is an opportunity to effectively warm up the entire deposit, as well as its necessary sections. In case of a parocyclic effect on the reservoir through two-channel injection pipes, oil production is carried out continuously through the production well. The controlled technology of vapor-cyclic impact on the reservoir will speed up the process of formation of a large number of small-volume steam chambers due to the periodic renewal of the injection of a new portion of steam with the necessary parameters and the maintenance of a rational temperature and pressure drop simultaneously in many impact zones along the length of the horizontal well. The estimated coefficient of oil recovery from the reservoir may be 0.7-0.8.

Claims (1)

The method of developing deposits of high viscosity and heavy oil with thermal impact, including drilling within the same layer of parallel horizontal or inclined horizontal injection wells and production wells, pumping coolant into injection wells and selecting products from the production well, characterized in that the production well is positioned at equal the estimated distance from the bottom of the injection wells, eliminating the breakthrough of the coolant, but allowing you to create a hydrodynamic connection with the injection wells, while the injection wells are provided with two parallel channels with alternating filters in the reservoir, the channels being used to pump the coolant, and after heating the reservoir, one of the channels is used for downhole flow of the product towards the producing well.

Images