METHOD FOR NEUTRALIZING HYDROGEN SULPHIDE IN DEPRESSION BAILER Russian patent published in 2023 - IPC E21B37/00 

FIELD: oil industry.

SUBSTANCE: invention is intended for methods for cleaning the bottom of wells with low reservoir pressure containing hydrogen sulphide. At the wellhead, a hydrogen sulphide neutralizer is poured into the depression bailer container installed above the unloading valve, the bailer is lowered into the well on a pipe string to the bottom, the pipe string is unloaded to the bottom by 1/3 of the weight of the pipe string, while the unloading valve opens and the well fluid is sucked in with pollution products containing hydrogen sulphide through the wing, check valve and adjustable fitting and then through the side holes of the unloading valve plunger. The well fluid enters a container with a neutralizer. Wait 5 minutes to fill the internal space of the pipe string, then lift it 1.5 meters up, while the check and unloading valves are closed, wait 15 minutes to react, then sequentially repeat unloading the pipe string hanger to the face by 2/3 of the weight of the string hanger pipes with a holding period of 15 minutes for response, unloading the pipe string suspension to the full weight with a holding period of 15 minutes for response. Then a crowbar is dropped into the pipe string from the wellhead, held for 20 minutes, during which time the crowbar destroys the aeration valve, leaving a hole in the screw of the aeration valve, then a gas analyser is installed at the wellhead and the pipe string with the bailer is raised. As it rises, the well fluid located in the internal space of the pipe string flows into the annulus through the screw holes of the knock-down valve, and contaminants neutralized from hydrogen sulphide settle in the bailer container.

EFFECT: technological capabilities are expanded by neutralizing hydrogen sulphide before lifting the bailer to the wellhead, protecting personnel from hydrogen sulphide at the wellhead, improving the quality of bottom hole cleaning, and reducing labour costs.

1 cl, 4 dwg