关键词:

稠油油藏, VHSD, 接替开发, 物理模拟, 扩容改造

Abstract:

In the late development stage of heavy oil reservoirs by steam injection huff and puff，the vertical well + horizontal well pattern steam drive （VHSD） is considered an effective way to sustain the recovery of mature heavy oil blocks. However，due to the interlayer distribution，low formation pressure coefficient，and the presence of steam channels in mature heavy oil blocks，the resultant oil gain of this method is unsatisfactory. The SAGD dilatation stimulation technology for heavy oil recovery can effectively break through the interlayers between injection well and production well and improve the overall production degree of the reservoir. Therefore，it is necessary to perform in-depth investigation of the dilatation technology for heavy oil reservoirs in the context of the VHSD. A one-dimensional core dilatation experiment was carried out，and the results showed no considerable post-dilatation variation of the core porosity and yet，an increase in the effective permeability by about 200 times. Based on large scale three-dimensional physical modeling，a dilatation experiment under the VHSD well pattern mode was carried out. The experiment shows that：（1） When the horizontal well trajectory is parallel to the direction of the maximum principal stress，the dilatation area is larger；（2） The distance of less than 35m between the vertical well and horizontal well is conducive to the formation of the combined dilatation zone；（3） After the high-permeability channels are plugged，an effective dilatation zone can still be formed. The experimental results are applied to the field practice，which shows that the recovered degree of the horizontal section of the production horizontal well is increased by more than 15% and the well production is effectively improved. This research provides effective references for the optimization of key parameters of the dilatation stimulation of heavy oil reservoirs，and is of great significance for the continuous efficient development of mature heavy oil blocks.

Key words:

heavy oil reservoir, VHSD, follow-up development, physical modeling simulation, dilatation stimulation