Method to prevent gas channeling after liner cementing of high pressure gas well

Abstract

The invention discloses a method for preventing gas channeling after liner cementing of a high-pressure gas well. Casing pressure: After the slurry replacement operation is completed, with the help of the casing pressure established by the heavy drilling fluid sent into the drilling tool, the surface back pressure pump and the throttle valve group work together to maintain the liquid level of the drilling tool water eye and achieve a constant casing pressure. Drilling; tripping out to the design well depth, implement different annulus slurry column time at different stages of heavy drilling fluid in the drill tool, heavy drilling fluid exiting the pipe shoe, all the heavy drilling fluid reaching the annulus, and the heavy drilling fluid circulating out of the wellhead. Ground back pressure compensation, so that the high-pressure air layer is stable without pressure leakage. The invention aims at the fine pressure control of the annulus after the completion of the cementing injection of the cement slurry, realizes the full pressure control of the liner cementing without short boards, and eliminates the loss of weight caused by the drilling suction and gelation during the stationary period of the annulus cement slurry column after the cementing gas channeling phenomenon.

Description

technical field [0001] The invention relates to a method for preventing gas channeling after cementing of a liner pipe of a high-pressure gas well, which is used for the cementing liner operation of oil and gas exploration and development, and belongs to the technical field of oil and gas field cementing engineering. Background technique [0002] The Sichuan-Chongqing area is a basin area with complex geological structures, large horizontal differences in strata, many vertical oil and gas water leakage shows, and many pressure layers, especially in the Lower Permian and below deep reservoirs in the western Sichuan exploration area, where the vertically complex pressure layers It makes it difficult for the casing of each layer to effectively isolate different formation pressures in sections, resulting in the coexistence of multiple complex engineering conditions such as blowout, leakage, sticking, collapse, and high-pressure brine in the same well section. Drilling encounters...

AI Technical Summary

Problems solved by technology

However, after the cement slurry injection is in place and the pump is stopped, the feeding drilling tool needs to be lifted away from the cement plug surface. The outer diameter of the sand control cap at the front end of the feeding tool is relatively large. It has not been possible to find a practical solution to complete the tripping cycle operation without inducing gas channeling.

The sending pipe string of the cementing liner is different from the drilling string. In order to ensure the diameter of the rubber plug, a check valve cannot be connected to the sending pipe string, so the pressure controlled tripping method of the drilling process is not suitable for the liner cementing Drilling operation after bumping

Images