Method and well pattern structure for exploiting heavy oil reservoir through gravity assisted nano magnetofluid flooding

Abstract

The invention relates to a method and a well pattern structure for exploiting a heavy oil reservoir through gravity assisted nano magnetofluid flooding. The method comprises the steps that a plurality of top horizontal wells and bottom horizontal wells are uniformly arranged at the top and the bottom of an oil layer to form a horizontal well space orthogonal well group, a slotted screen and blind pipe sectorial connecting manner is adopted at horizontal sections of the top horizontal wells and the bottom horizontal wells for well completion, high-energy electromagnets are placed in positions, corresponding to slotted screens, in shafts at the horizontal sections of the bottom horizontal wells respectively, surfactant wrapped hydrocarbon-based nano magnetofluid dispersion solutions are injected into the top horizontal wells at a certain speed, the electromagnets in the bottom horizontal wells are started, nano magnetofluid injected into the oil layer is magnetized, is diffused and moves from the top of the oil layer to positions nearby shafts at screen segments of the bottom horizontal wells of the oil layer by the action of attraction and self gravity, and displaces crude oil in the oil layer, and the crude oil is exploited to the ground by intermittent magnetism stop production of the bottom horizontal wells. The method can increase and improve the oil recovery rate and recovery efficiency of the heavy oil reservoir.

Description

Technical field [0001] The invention relates to a method for exploitation of heavy oil reservoirs in the field of petroleum exploitation, in particular to a method for gravity-assisted nano magnetic fluid flooding and exploitation of heavy oil reservoirs and a well pattern structure. Background technique [0002] At present, the main technologies for the development of heavy oil reservoirs at home and abroad are thermal development technologies such as steam huff and puff, steam flooding, oil burning, and steam assisted gravity drainage (SAGD). [0003] Steam huff and puff technology has the advantages of low cycle injection and fast investment payback period. However, it is affected by the viscosity resistance of heavy oil. The radius of the oil layer used by steam is small and the recovery rate is only about 8% to 15%. It is necessary to change the mining method after the huff and puff. . [0004] Steam flooding is mainly used as a main replacement technology after steam huff and ...

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Problems solved by technology

However, it is only suitable for the exploitation of heavy oil reservoirs with a single-layer thickness greater than 15m. Since the fluidity of steam is much higher than that of crude oil, steam is easy to escape into the lower production well in the high-permeability area, resulting in low production degree of the horizontal section. Effective technology flexibly controls the drawing section of the horizontal section so that it can be evenly drawn

[0006] Incineration reservoir technology has been successfully applied in the Suplacude Barcau Oilfield in Romania and the Mehsana Oilfield in India. However, due to the lack of an effective fire line front control technology for fire flooding, the fire line is likely to break through the bottom of the production well during the fire flooding process, causing serious damage. potential safety hazards, therefore, the field success rate is not high, and the scope of application is small

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