Radial horizontal drilling system using supercritical carbon dioxide and drilling method thereof

Abstract

The invention discloses a radial horizontal drilling system using supercritical carbon dioxide and a drilling method thereof. The drilling system comprises a liquid carbon dioxide supplying device, a drilling device, an in-well pressure control device, a solid, liquid and gas three-phase separating device and a carbon dioxide recycling device, wherein the drilling device is arranged in a shaft, and includes an oil pipe, a steering gear mounted at the bottom of the oil pipe, and a flexible drill stem sleeved in the oil pipe; the flexible drill stem passes through the steering gear and then realizes steering; the flexible drill stem has a hollow drill stem channel; a supercritical carbon dioxide jet drill is mounted at the end of the part, in a horizontal direction, of the flexible drill stem; a nozzle, which is communicated with the drill stem channel, is formed on the jet drill; the in-well pressure control device is disposed at the opening of a well; the solid, liquid and gas three-phase separating device and the carbon dioxide recycling device are disposed on the ground. The radial horizontal drilling system disclosed by the invention uses supercritical carbon dioxide fluid as rock breaking fluid, thus avoiding pollution to oil reservoir layers, effectively protecting the oil reservoir layers, greatly increasing rock breaking efficiency, and realizing cyclic utilization of the carbon dioxide; and the radial horizontal drilling system using supercritical carbon dioxide and the drilling method thereof have important application value to increase of production of old wells and to development of unconventional oil-gas reservoir.

Description

technical field [0001] The invention relates to the technical field of radial horizontal drilling, in particular to a supercritical carbon dioxide radial horizontal well drilling system and a drilling method using the drilling system. Background technique [0002] Under the current situation of energy shortage, improving oil and gas recovery in old oil areas and strengthening the development of unconventional oil and gas resources are of great value to ensure my country's energy security. Compared with conventional horizontal drilling technology, radial horizontal well technology has the advantages of accuracy, speed, high drilling speed and low cost. Especially in improving the production capacity and recovery rate of old oilfields, it has more significant advantages. In the middle and late stages of oilfield development, this technology can be used to drill radial horizontal wells in old wells, renew old wells, revive dead wells, and effectively exploit dead oil areas...

AI Technical Summary

Problems solved by technology

[0003] However, at present, water and water mixed with abrasives are mainly used as rock-breaking fluids in the drilling process of radial horizontal wells. This type of fluid is easy to pollute the reservoir, especially for old oil wells and water-sensitive formations, where water can easily enter the formation and cause water damage. Lock or produce hydration, resulting in production reduction of oil and gas wells; at the same time, the rock-breaking threshold pressure of water jet is relatively high, and ordinary sandstone needs to be above 40MPa, and the requirements for ground booster pumps are relatively high

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