Method for recovering extra-heavy oil and super-heavy oil in horizontal well fire flooding assisted gravity drainage mode

Abstract

The invention discloses a method for exploiting extra-heavy oil or super-heavy oil in a fireflood-assisted gravity oil drainage mode of horizontal wells. The method includes the steps that an injection-production well pattern is deployed for a selected extra-heavy oil and / or super-heavy oil reservoir; each vertical gas injection / ignition well in the well pattern corresponds to one or more horizontal production wells; gas injection and ignition are conducted on the vertical gas injection / ignition wells; after combustion is stable, the gas injection speed is raised gradually, the gas discharging speed is also raised as the gas injection speed is raised, the ratio of the total daily gas discharging amount of all the horizontal wells to the daily gas injection amount of the vertical wells is controlled to be 0.9-1.0; therefore, stable oil drainage production of all the horizontal wells is achieved. By means of the method, the engineering risks of firewire propelling and displacement, horizontal wellbore fire surging and the like existing in the fireflood-assisted gravity oil drainage process of horizontal wells in the prior art can be avoided, and safe and steady production is achieved.

Description

technical field [0001] The invention belongs to the technical field of petroleum development, and in particular relates to a technical method suitable for a horizontal well fire flooding assisted gravity drainage mode mining of extra-heavy oil and super-heavy oil reservoirs. Background technique [0002] According to my country's crude oil classification standard, extra heavy oil refers to the crude oil whose viscosity of degassed crude oil exceeds 10000mPa.s and is less than 50000mPa.s under the condition of formation temperature; 50000mPa.s crude oil. [0003] At present, the main methods of developing extra-heavy oil and super-heavy oil in my country include steam huff and puff (accounting for about 70%) and steam-assisted gravity drainage (SAGD) (accounting for about 30%). High viscosity, for steam huff and puff, there are problems such as high steam injection pressure, small thermal front sweep radius, short effective production time, and low cumulative oil production pe...

AI Technical Summary

Problems solved by technology

[0005] Some Chinese scholars (Guan Wenlong, Wu Shuhong, Liang Jinzhong, et al. Looking at the risks of fire flooding assisted gravity drainage technology from laboratory experiments [J]. Journal of Southwest Petroleum University: Natural Science Edition, 2009, 31(4): 67-72) once This article discusses in detail the reservoir and engineering risks faced by THAI technology. The reservoir risk is that once a fire occurs in a horizontal well, the range of its thermal front will no longer expand. The engineering risk is that the horizontal wellbore may be burned due to fire and cause Increased danger on the ground

There are also Chinese scholars (Liang Jinzhong, Guan Wenlong, Jiang Youwei, etc., Horizontal well fire flooding assisted gravity drainage combustion front distribution and regulation, Petroleum Exploration and Development, 2012 No. 6: 720-726) pointed out that the current horizontal well fire In the flooding-assisted gravity drainage production mode, it is easy for the combustion front to creep along the horizontal wellbore, which leads to the premature failure of the project

[0006] The inventors of this case conducted systematic analysis and research on the existing horizontal well fire-flooding assisted gravity drainage mode production technology, and found that it still has the following defects: (1) flue gas is easy to pull the fire line to the direction of the horizontal well ( like figure 2 shown); (2) The temperature of the high-temperature produced fluid passing through the horizontal wellbore may reach 200-350°C. Once oxygen enters the horizontal wellbore, it will burn in the horizontal wellbore, thus posing a threat. Dangerous situations are difficult to deal with - shutting down the well means that the fire will be extinguished without supplementary oxygen, and if the well is not shut down, the danger will continue and the risk level will be increased; (3) once the horizontal well needs to be operated due to sand burial, the project may It means that it is forced to stop and cannot be restarted, because whether it is a problem with the gas injection end or a problem with the exhaust end, it means that the combustion cannot continue, and after the fire is extinguished, it can no longer be ignited at the original position-because the nearby fuel has run out

[0007] CN103089230A discloses a method for recovering oil reservoirs by solvent-assisted fire-flooding gravity drainage. Although the well net has been improved, its purpose is only to expand the lateral sweep, and it cannot solve the problems that the injection well must be shut down due to engineering problems.

[0008] In summary, the existing horizontal well fire flooding assisted gravity drainage mode production technology needs to be further improved

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