Method for breaking interlayer in oil layer during double horizontal well SAGD exploitation

Abstract

The invention provides a method for breaking an interlayer in oil layer during double horizontal well SAGD exploitation. A pit path is dug in oil exploitation areas for a steam injection well and a production well; the pit path extends along a direction transversely facing a horizontal section of the steam injection well; the pit path longitudinally passes through the interlayer, so oil layers on two sides of the interlayer can be communicated with each other; diversion medium fills the pit path, so a flow channel is formed in the pit path for steam and crude oil flow; steam is injected into the steam injection well; steam is conveyed to the oil layer over the interlayer via the flow channel, so thickened oil over the interlayer is heated and viscosity is reduced; the crude oil after viscosity reduction enters the production well via the flow channel, so oil can be explored in the production well. Oil layers on the upper and lower sides of the interlayer can be communicated with each other; the steam and the crude oil can be effectively conveyed to the other side of the interlayer to ensure a steam cavity to develop in a balance way in a horizontal direction and a vertical direction; and advantages of the horizontal well can be well developed and low cost is realized.

Description

technical field [0001] The invention relates to a method for SAGD exploitation of a double horizontal well, in particular to a method for breaking through an interlayer of an oil layer in the SAGD exploitation of a double horizontal well. Background technique [0002] The resources of ultra-heavy oil in the world are huge. As a cutting-edge technology for the development of heavy oil in the world, SAGD (Steam-Assisted Gravity Drainage, that is, steam-assisted gravity drainage) occupies a dominant position in Canadian oil sands mining. my country's Liaohe, Xinjiang Oilfields have also been applied on a large scale. The method utilizes horizontal wells and steam to effectively exploit heavy oil, super heavy oil and other resources. By continuously injecting high-quality water steam into the horizontal steam injection well, the latent heat of vaporization is released from the upper layer of the steam to heat the reservoir. Hirai output. As the reservoir fluid is continuously ...

AI Technical Summary

Problems solved by technology

The physical model study of interlayers between injection and production wells has confirmed that short interlayers between wells have little effect, and long interlayers will reduce the oil production rate. The interlayer will cause the upper crude oil to be unable to be recovered

Numerical simulation studies on the development of interlayers above steam injection wells show that the greater the distribution of interlayers, the closer to the steam injection wells, and the lower the permeability are, the more unfavorable it is for SAGD development.

Generally speaking, interlayers lead to slow production increase, cumulative oil production and low oil-steam ratio, and it is necessary to carry out targeted research work on breaking through interlayers

[0004] The common technology of breaking through interlayers can be divided into two categories. One is to rely on rock mechanics methods to break rocks in situ due to shear or tensile failure. In this case, narrow cracks will be formed. Weaker, it takes a long time for hydration, creep and fluid erosion to form an effective seepage channel. In fact, this kind of method requires high pressure and high temperature. High pressure operation will increase the pressure of the steam front and reduce the effective permeability of interlayer rocks. stress, thereby reducing its strength and providing the possibility for shear failure

However, high-temperature operation may cause the internal pore pressure of the interlayer rock to rise, resulting in the shrinkage of the mudstone interlayer, so there is a tensile failure (similar to hydraulic fracturing); the other type is to directly partially physically remove the interlayer rock and establish a high-permeability diversion channel , this type of method does not require high temperature and high pressure, but only requires a certain technical process, but the disadvantages of the existing such technology are: it is difficult to locate the underground interlayer, so the cost is high and the risk is high

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