Steam and nitrogen composite swallowing-spitting oil extraction method

Abstract

The invention provides a steam-and-nitrogen composite swallowing-spitting oil production method, comprising the following steps: a, steam injection string laying: a pipe column structure successively comprises an even steam distribution pipe column provided with an even steam distribution valve and a compensator, an injection and extraction integrated pump connected to the even steam distribution pipe column, an oil pipe arranged on the pump, and a subcritical steam injection well from bottom to top; b, N2 and steam injection: steam is injected through an oil jacket annulus, meanwhile, nitrogen is injected into an oil well through the oil pipe, nitrogen injection speed is regulated to evenly allocated and injected during the whole steam injection process; c, soaking: soaking is carried out for 2-7 days after steam injection and nitrogen injected are over; d, blowout: when the well pressure drops to 0.5Mpa / day, blowout is controlled by an oil nozzle; and e, pumping start: when open-flow liquid amount reaches 3t / d, the injection and extraction integrated pump is used to start pumping.

Description

Technical field: [0001] The invention relates to the technical field of oil recovery in oilfields, in particular to a combined steam and nitrogen huff and puff oil recovery method for shallow ultra-heavy oil reservoir exploitation, medium-depth ultra-heavy oil reservoir exploitation and shallow extra-heavy oil reservoir exploitation. Background technique: [0002] For shallow ultra-heavy oil reservoirs, in addition to reducing the viscosity of crude oil and increasing the fluidity of heavy oil, since the oil layer is buried shallowly, the formation pressure is low, and the driving force for crude oil to flow in the oil layer is small, it is also necessary to supplement formation energy. To achieve economical and effective development. At the same time, during the steam injection process of shallow ultra-heavy oil reservoirs, there are still high steam injection pressures, which are easy to fracture the formation. After the formation is fractured, the steam will flow along t...

AI Technical Summary

Problems solved by technology

Although these technologies can achieve certain effects, the above-mentioned technologies can only meet one of the requirements for the development of shallow super-heavy oil reservoirs, and cannot solve the production problems of shallow super-heavy oil reservoirs well and comprehensively. Therefore, there is still a need in this field for a new type of shallow ultra-heavy oil reservoir recovery technology, which can simultaneously reduce the viscosity of crude oil, replenish formation energy, reduce steam injection pressure, prevent steam overburden, and increase the drainage area.

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