Treatment method for abandoned uncased wells in coal mining area

Abstract

The invention provides a treatment method for abandoned uncased wells in a coal mining area. The treatment method comprises the four steps of well-mouth recovery, well unblocking and sweeping, well logging and three-section plugging. By means of the treatment of the abandoned oil and gas uncased wells in the coal mining area, as for each abandoned uncased well, about 100 thousands of tons of accumulated coal can be released, and direct economic loss of more than 50-million yuan can be reduced. In addition, by effectively treating the abandoned oil and gas uncased wells in the method, oil and gas leakage and various potential safety hazards are also avoided during mining, and various types of loss caused by movement are reduced.

Description

technical field [0001] The invention relates to the management field of oil and gas wells, in particular to a treatment method for abandoned oil and gas open hole wells before coal mining in abandoned oil and gas well areas. Background technique [0002] The exploration and development of coal and oil and natural gas in my country are undertaken independently by two mutually independent energy industry systems: the coal system and the oil and natural gas system. Due to the differences in the objective occurrence conditions and regional characteristics of coal and oil and natural gas buried underground, coal seams are generally shallow underground, while oil and gas layers are deep below 1,000 meters underground, and in local areas where coal seams and oil and gas fields overlap , each have a great influence on each other's mining. Usually, in their respective mining planning and design, both parties take isolation measures. The coal mines set up isolated coal pillars within...

AI Technical Summary

Problems solved by technology

The characteristics of open hole wells are: 1. Under normal circumstances, the oil and gas layer pressure in this type of wellbore is not high, but affected by the water injection pressure of the surrounding production oil and gas wells, the formation pressure may gradually increase; 2. Since the production casing is not run, the well The middle and lower part of the wellbore has been blocked and compacted due to wall collapse and drilling mud deposition, making it difficult to pass through the wellbore; 3. There is no production casing in the openhole wellbore. If there is a confined aquifer in the formation, the wellbore can be directly connected as a water-conducting channel Coal mine underground roadway poses a great threat to coal mine safety production

Oil and gas leakage from such abandoned oil and gas open-hole wells near coal mines, water in the water layer entering the coal mine along the oil well, etc., are one of the direct causes of hidden dangers such as major fires, explosions, toxic and harmful gases, and water damage in coal mines in overlapping areas. The normal design and production of coal mines have brought great inconvenience and potential safety hazards. At the same time, the mining of coal mines will also pose a certain security threat to the oil and gas wells in production.

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