A concentric single-hole drilling system and method for in-situ pyrolysis oil extraction from oil-rich coal

By using a concentric single-hole drilling system for in-situ pyrolysis of oil-rich coal, and utilizing concentric well sections and heaters, efficient underground pyrolysis of coal is achieved, solving the problem of unsatisfactory directional fracturing results and improving oil and gas recovery rate and thermal energy utilization rate.

CN117211749BActive Publication Date: 2026-05-26SHAANXI COALFIELD GEOLOGY GRP CO LTD +1
View PDF 1 Cites 0 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
SHAANXI COALFIELD GEOLOGY GRP CO LTD
Filing Date
2023-08-02
Publication Date
2026-05-26

AI Technical Summary

Technical Problem

In existing underground in-situ pyrolysis oil extraction technology using drilling, directional fracturing is not ideal, resulting in large heat loss, high construction difficulty, and low oil and gas recovery rate and thermal energy utilization rate.

Method used

The oil-rich coal in-situ pyrolysis oil extraction concentric single-hole drilling system includes a first, second, and third well section set from top to bottom. It utilizes different types of cement cementing and concentric tube structures, combined with heaters and heat transfer media, to achieve efficient heating and oil-gas separation.

Benefits of technology

It reduces formation damage, lowers construction difficulty, improves oil and gas recovery rate and thermal energy utilization rate, and ensures the efficient operation of the pyrolysis process.

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN117211749B_ABST
    Figure CN117211749B_ABST
Patent Text Reader

Abstract

This invention relates to a concentric single-hole drilling system and method for in-situ pyrolysis oil extraction from oil-rich coal. The system comprises three well sections from top to bottom, with the third section being a bare well located in the coal seam heating zone. A heater is placed on the surface to heat and pyrolyze the coal seam, generating oil and gas. A pressurization device and a heat transfer medium input device installed on the surface introduce the heat transfer medium into the well via an external pipe. A pressure reducing device, heat exchanger, oil-gas separation device, tar storage device, and coal gas storage device are also installed on the surface, enabling the recovery and utilization of heat energy and the separation and storage of oil and gas. This invention reduces the damage to the formation caused by excessive drilling, leading to aquifer water loss and adverse effects on in-situ pyrolysis; it also reduces construction difficulty and improves the oil and gas recovery rate and the utilization rate of residual heat energy.
Need to check novelty before this filing date? Find Prior Art