Bottom water reservoir multi-slug plugging agent and plugging method thereof

Abstract

The invention provides a bottom water reservoir multi-slug plugging agent and a plugging method thereof. The bottom water reservoir multi-slug plugging agent comprises a foam gel plugging agent, a foam gel plugging agent and a reinforced foam plugging agent, and when the plugging well does not have artificial cracks or / and natural crack development, plugging of a foam gel plugging agent is not needed, after the plugging agents of all the slugs are sequentially injected into the plugging well, a well closing reaction is conducted for 5 d to 7 d, and bottom water reservoir multi-slug plugging iscompleted. The reinforced foam plugging agent is mainly used for plugging cracks, the foam gel plugging agent and the reinforced foam plugging agent have high oil-water selectivity, it is guaranteedthat an oil layer is not damaged on the basis of plugging bottom water, the treatment radius can be increased, a water-resisting layer can be effectively sealed, coning is prevented, and the liquid amount of an oil well during later production can be guaranteed.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to a multi-slug plugging agent for bottom water reservoirs and a plugging method thereof. Background technique [0002] The development of bottom water reservoirs is one of the difficult problems in the development of oilfields worldwide. The outstanding problem in the development of bottom water reservoirs is that during the production process, along with the extraction of crude oil, it is easy to cause bottom water coning or ridge ingress, resulting in water flooding of production wells and a sharp drop in water coning, and the speed of water coning is very fast. Entering the bottom of the oil well, the oil well will be flooded quickly, and the water cut will rise to 100%. The Jurassic bottom water reservoirs in the Ordos Basin have thick bottom water layers, large reserves, and low formation permeability, and are basically put into production af...

AI Technical Summary

Problems solved by technology

Among them, the mechanical plugging is easily limited by the well conditions. Once the wellbore has problems such as casing deformation and dislocation, the packer and other large tools cannot be lowered into the wellbore. In addition, the mechanical water plugging method is only carried out in the wellbore. However, if the formation cannot be sealed outside the wellbore, as the oil well continues to produce, the bottom water will continue to cone into the oil well along the formation

The soft diaphragm is mainly achieved by injecting foam, gel or inorganic plugging agent. Due to the weak plugging ability of the injected foam system, it is almost impossible to plug the oil reservoirs with large pressure difference and natural and artificial fractures. Its validity period is also very short, which cannot meet the needs of oilfield production; although gel or inorganic water shutoff agents have high strength, the main problem is that the injection volume and system strength cannot be controlled accurately, and when the injection volume and strength are small, fracture plugging If the injection rate and intensity are large, there is a risk that the production layer will be blocked as a whole (no fluid production after plugging). At the same time, due to the large injection plugging dose of the oil well, it will be difficult to drain liquid in the later stage, and there is a risk of being flooded by the injected liquid. Problems such as death or difficulty in increasing production in the later stage