Well killing method using absorbent resin to protect low pressure oil and gas reservoir

Abstract

The invention discloses a well killing method for protecting a low-pressure oil-gas layer by utilization of water absorbent resin, which is characterized by comprising the following steps: firstly, clear water or salt water with the well killing design flow is prepared; secondly, the water absorbent resin material is added, and the mixture is fully and uniformly stirred to form granular water; thirdly, the granular water is pumped into a pit shaft by a mud pump or a fracturing truck through normal circulation or inverse circulation; fourthly, the granular water is circulated for a circle after well killing, and after observing for 48 hours, the granular water is circulated for more than one circle after the inside of a well is stable, and a well mouth is opened for underground construction; and fifthly, the granular water in the pit shaft is exhausted by means of pumping, air lifting and so on, and the well is put into production. Because the granular water formed by the well killing method has good fluidity and well killing effect, does not use any auxiliary agent, greatly reduces cost, and completely achieves the aims of wide application scope, low harm on a production layer, good well killing effect and low integrated cost.

Description

technical field [0001] The invention relates to an oil-gas well isolation method, in particular to a well-killing method for protecting a low-pressure oil-gas layer by using a water-absorbing resin. Background technique [0002] As we all know, after the drilling and cementing of oil and gas wells are completed, the oil and gas layers must be opened by perforating catapults to connect the production layers with the wellbore so that oil and gas can be produced smoothly through the wellbore. However, after perforating the production layer, it is necessary to take out the perforating gun, lower the production string, install downhole tools and install the wellhead, etc., so the completion fluid must be used as the killing fluid to fill the entire wellbore before perforating (especially gas wells). According to the well control requirements, the liquid column pressure of the killing fluid must be greater than the pore pressure of the production layer, so that the oil and gas wi...

AI Technical Summary

Problems solved by technology

[0006] 3. A large amount of well-killing working fluid enters the production layer, which makes the resumption period after operation too long, and some of them cannot even recover to the original production capacity;

[0007] 4. More seriously, due to the inability to establish circulation, some wells cannot be repaired, which makes oil and gas wells prematurely scrapped (especially gas wells)

Although a well killing method using solid water particles as well killing fluid (application number 0313511.X) discloses a solid water particle killing fluid, it still needs to add a large amount of additives, and the solid water particles are easy to gel When discharging, it is necessary to use a gel breaker to destroy the colloidal structure, which has defects such as increased cost and inconvenient use.