Constant-pressure gas collecting device and method for recycling casing pipe associated gas inside oil field wellbore

Abstract

The invention provides a constant-pressure gas collecting device and method for recycling casing pipe associated gas inside an oil field wellbore. The constant-pressure gas collecting device comprisesa body and an outer barrel connected to the outside of the body in a sleeving mode. The upper end of the outer barrel is fixedly connected with the body. An exhaust valve with the exhaust pressure being adjustable is further connected between the outer barrel and the body. An annular part among the outer barrel, the body and the exhaust valve forms an exhaust passage, and the exhaust passage communicates with an inner cavity of the body. The constant-pressure gas collecting device and method for recycling the casing pipe associated gas inside the oil field wellbore are designed in order to achieve the technical aims that the pressure of the casing pipe associated gas is higher than return pressure inside an oil pipe, when the differential pressure reaches a set value, the exhaust valve can be opened without other extra dynamic effects, and the associated gas enters the oil pipe to form oil and gas mixed fluid with oil flow; and when the differential pressure value approaches the opening pressure of the exhaust valve, the exhaust valve can be closed automatically, the gas collecting process is ended and oil leakage inside the oil pipe can be prevented in oil well production. Due tothe fact that the associated gas can absorb a large amount of heat when being released to be in a low-pressure state from a high-pressure state quickly, low-temperature freezing can happen easily.

Description

technical field [0001] The invention relates to a gas collection and recovery device and method for associated gas in casings in oilfield wellbores, and belongs to the technical field of small downhole tools in oilfields. Background technique [0002] At present, the recovery of associated gas at the wellhead of domestic oil wells mainly applies the process of laying pipeline network for gas collection and wellhead oil and gas mixed transportation. Wellhead oil and gas mixed transportation usually adopts the process mode of installing a gas release valve on the wellhead oil collection manifold. The valve body is installed on the oil collecting manifold or the purge head, and the air is introduced from the wellhead casing head to the air inlet of the purge valve through a high-pressure hose quick connector. When the pressure of the associated gas in the casing is greater than the back pressure of the oil pipeline, the vent valve is opened, and the associated gas enters the o...

AI Technical Summary

Problems solved by technology

[0003] In order to overcome the leakage risk of conventional ground air release valves and gas-gathering pipeline connections, the hidden dangers of pipelines and air-release valves freezing in winter, and the difficulty of repeated disassembly and assembly of gas-gathering pipelines during workover operations, the purpose of the present invention is to provide a Casing associated gas recovery device and method in oilfield wellbore

Images