Mixed mining method capable of improving recovery ratio of thick oil in shallow oil reservoir

Abstract

The invention discloses a mixed mining method capable of improving the recovery ratio of thick oil in a shallow oil reservoir. The method comprises the following steps of: arranging three horizontal wells which are directly extended to the lower side of an oil bearing reservoir and are positioned on the same horizontal surface in a shallow oil reservoir area; injecting high-temperature high-pressure steam into the three horizontal wells by a steam stimulation method, and closing for several days; opening the oil wells to make the thick oil with reduced viscosity start to flow out, and recovering; discontinuously emitting hot steam diffused into the oil bearing reservoir upwards in the oil producing process of the three horizontal wells so as to form a steam cavity above the three horizontal wells; starting to inject the high-temperature high-pressure steam into a steam injection pipe of a middle horizontal well only at the moment so as to continuously heat the steam cavity, wherein the three horizontal wells continuously produces oil at the same time; and stopping injecting the high-temperature high-pressure steam into the steam injection pipe of the middle horizontal well when the oil yield of the oil bearing reservoir is continuously reduced and cannot reach anticipated oil yield so as to stop oil extraction. By the method, the extension range of the side surface of the steam cavity above the oil wells can be enlarged, and the using efficiency of heat can be improved, so that the oil yield, the ratio of oil to gas and the oil production ratio are improved.

Description

technical field [0001] The invention belongs to the technical field of oilfield oil recovery, and in particular relates to a mixed recovery method for enhancing heavy oil recovery in shallow oil reservoirs, mainly utilizing CSS (steam stimulation) and SAGD (steam assisted gravity displacement) methods to optimize the location of wells And operating parameters, so as to improve the recovery of heavy oil in shallow oil reservoirs. Background technique [0002] Heavy oil has a high viscosity and is not easy to flow. It cannot be exploited by ordinary mining methods, and it must be carried out by physical or chemical viscosity reduction. Nowadays, in physical viscosity reduction production methods, SAGD (Steam-Assisted Gravity Drainage) and CSS (Steam Stimulation) methods are two important methods for heavy oil production in my country, Canada and Venezuela. Up to now, these two methods still play a huge role in the production of heavy oil. Among them, the CSS (steam stimulatio...

AI Technical Summary

Problems solved by technology

Shallow reservoir development, the use of SAGD (Steam-Assisted Gravity Drainage) method Single horizontal well can save cost and make its development possible, but using CSS (Steam Surge) and SAGD (Steam-Assisted Gravity Drainage) mixed production The methods for shallow reservoirs have never been published, so there is a need for improvement