A thermal recovery method of carbonate heavy oil reservoir and its application

Abstract

The invention relates to a thermal recovery method of a carbonate rock heavy oil reservoir. This method adopts the technology of combining horizontal wells and vertical wells, and changes the steam injection into the ground in the steam injection technology to bring heat into the ground; at the same time, the lifting of the horizontal section and the deflection section is changed to the lifting of the vertical well section; the production at one end of the horizontal section is changed to Both ends are used to increase the degree of production in the horizontal section; in addition, the single-well steam injection is changed to double U-shaped connected wells or multi-U-shaped connected wells to circulate steam injection, so that the seepage area of ​​fracturing stimulation can be compared with the same length Compared with ordinary open-hole horizontal wells, the horizontal section is significantly larger, and the fin effect heat dissipation capacity of the wellbore is increased, thereby improving the utilization rate of steam. Through the implementation of the technical scheme of the invention, the recovery rate can be increased by 15% while reducing the production cost. Applying the method of the invention to the horizontal well development technology of deep wells in carbonate heavy oil reservoirs in the field of petroleum development engineering has wide application prospects.

Description

technical field [0001] The invention belongs to the technical field of heavy oil reservoir exploitation, and relates to a thermal recovery method of carbonate rock heavy oil reservoir and its application in the thermal recovery of heavy oil reservoir. Background technique [0002] Heavy oil is also called heavy crude oil or high-viscosity crude oil. In the oil extraction of oil fields, heavy oil has special characteristics of high viscosity and high freezing point, especially for the exploitation of carbonate rock heavy oil reservoirs. All aspects encountered some technical difficulties. [0003] For example, the problem of heat transfer. In the process of oilfield thermal recovery development, the main thing to accomplish is to bring heat into the oil layer, improve the fluidity of crude oil and reduce the viscosity of crude oil according to the temperature sensitivity of heavy oil, the reason why the development effect of carbonate rock heavy oil reservoir Poor, mainly b...

AI Technical Summary

Problems solved by technology

The current lifting equipment is mainly for the development of vertical wells. Below the kickoff point, there are technical problems such as sucker rod breakage, valve balls not tightly closed, plunger and valve eccentric wear, etc. Process technology has undergone many improvements, but major technical challenges remain

[0005] In addition, there is the problem of uneven use of long horizontal sections

Generally speaking, the liquid production contribution of horizontal wells is mainly in the first half of the horizontal section or the high-permeability section. For a long time, it is not conducive to the overall production of the reservoir, and the ultimate recovery rate is reduced.

[0006] Moreover, the current development of low-permeability heavy oil mainly relies on horizontal well technology, but due to low permeability, the quality of steam injection is poor, and the heat is difficult to reach the formation. Generally, technological measures such as fracturing and acidification are adopted. In the case of the same steam absorption area, the steam absorption capacity is weak, and the method of multi-well injection at the same time, or the method of subcritical or supercritical boilers is often used for on-site construction, which not only fails to solve the above problems, but also increases the cost of use and safety. coefficient drop

[0007] Therefore, the current problem is that it is necessary to research and develop a thermal recovery method for carbonate heavy oil reservoirs, which can solve the technical difficulties encountered in the production process of the above-mentioned carbonate heavy oil reservoirs, such as thermal Problems such as transmission, lifting, and uneven development of long horizontal sections can reduce production costs and increase recovery

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