Time-division and segmental thermal injection production string and method for offshore heavy oil horizontal well

Abstract

The invention relates to an offshore viscous oil time-divided and segmented heat injection oil extraction pipe string of horizontal wells and a method thereof. The pipe string comprises a sand control completion pipe string body composed of a central pipe string, a sand control screen pipe and a sand control packer. The bottom of the central pipe string is sequentially connected with a porous pip, N ball seats and pressure rupture disks through the free end of an oil pipe. The ball seats are provided with through holes, the diameters of the through holes of the ball seats are sequentially increased, and the outer diameters of steel balls are sequentially increased correspondingly. After being injected into the central pipe, heat media are injected into oil reservoirs through the porous pipe and the steel ball with the smallest outer diameter is cast when a target is reached; the steel ball with the smallest outer diameter penetrates through the ball seats to reach the first ball seat to close the through hole of the first ball seat; after pressure is increased to a design pressure value, the first pressure rupture disk is opened and injects heat to the ambient oil reservoir; when the design target is achieved, the second steel ball is put and reaches the second ball seat to close the through hole of the second ball seat; through successive operation, all the rupture disks in the upper part can be sequentially opened and time-divided and segmented heat injection can be achieved.

Description

technical field [0001] The invention relates to a time-division and segmental thermal injection production string and a method thereof for an offshore heavy oil horizontal well. Background technique [0002] Horizontal wells are widely used in offshore thermal recovery. When injecting heat in offshore horizontal wells, the variable density hole layout technology of the heat injection string is used, and it is expected to obtain the effect of the whole well section. However, due to the long horizontal section of the offshore thermal recovery well and the relatively limited displacement of the offshore heat generation device, the heat injection string with scattered holes not only makes it difficult to heat the entire well section, but also reduces centralized heating, Opportunity to reduce viscous oil. [0003] Therefore, in the effective displacement conditions of offshore thermal generators and long horizontal wells, it is an effective means to improve the thermal recover...

AI Technical Summary

Problems solved by technology

However, due to the long horizontal section of offshore thermal recovery wells and the relatively limited displacement of offshore heat generation devices, the heat injection string with scattered holes not only makes it difficult to heat the entire well section, but also reduces centralized heating, Opportunity to reduce viscous oil

Images