玛湖砾岩油藏体积压裂开发后烃气混相驱提高采收率实验

在新疆玛湖致密砾岩油藏采用烃气驱大幅提高采收率技术，面临水平井体积压裂规模开发后，小井距下水力压裂缝网易形成气窜通道，影响气驱波及体积的问题。为研究压裂后水平井井网对烃气驱开发效果的影响，提出了玛湖致密砾岩油藏人工裂缝+基质注烃气驱油模式，基于该模式设计实验模型，利用拼接比例的不同造缝与未造缝全直径岩心模型进行气驱实验，明确压裂缝与基质关系。结果表明：通过烃气驱岩心采收率可达38.26%;全直径岩心造缝比例越高，采收率越低；小规模的压裂可以使采油速度更加平稳，同时可以获得更高的采收率；烃气驱结束后通过吞吐的方式可进一步提高采出程度7.1%。该项实验可以为烃气驱现场试验水平井压裂规模、合理井距及注气速度提供了具有现实指导意义的研究基础。

Experimental study on enhanced oil recovery by hydrocarbon gas miscible flooding after volume fracturing in Mahu conglomerate reservoir

In Mahu tight conglomerate reservoir in Xinjiang, the technology of hydrocarbon gas flooding was adopted to greatly enhance oil recovery. Faced with the large-scale development of horizontal well volume fracturing, hydraulic pressure fracture NetEase formed gas channelling channel under small well spacing, which affected the sweep volume of gas flooding. In order to study the impact of horizontal well patterns after fracturing on the development effect of hydrocarbon gas drive, a model of artificial fracture+matrix injection hydrocarbon gas drive in Mahu tight conglomerate oil reservoir was proposed for the first time. Based on this model, an experimental model was designed, and gas drive experiments were conducted using full diameter core models with different splicing ratios for fracturing and non fracturing, clarifying the relationship between fracturing and matrix.The results show that the core recovery by hydrocarbon gas flooding can reach 38.26%.The higher the fracture ratio of full-diameter core is, the lower the recovery rate is.Small-scale fracturing allows for smoother oil recovery and higher recovery.After hydrocarbon gas flooding, the recovery degree can be further increased by 7.1% through huff and puff.This experiment can provide a practical guiding basis for field test of fracturing scale, reasonable well spacing and gas injection rate of horizontal Wells in hydrocarbon gas flooding.