体积改造油藏注水吞吐有效补充地层能量开发的新方式

New effective energy-supplement development method of waterflood huff and puff for the oil reservoir with stimulated reservoir volume fracturing

体积改造技术能够提高超低渗透和致密油油藏的初期产油量,但衰竭开采期的产油量递减快、累积产油量低、经济效益差,且注水开发会导致油井快速水淹,需探索有效补充地层能量的开发方式。体积改造油藏注水吞吐开发是有效补充地层能量的一种新方式,首先建立体积改造油藏注水吞吐的3个阶段模型,研究渗吸产油和不稳定驱替双重开发机理,并推导相应的产能公式,理论研究注水吞吐的开发效果,进一步通过油藏工程方法和室内实验研究注水吞吐的主控因素,并结合现场开发实践论证了注水吞吐的可行性。研究结果表明,体积改造油藏产生的裂缝网络系统使得裂缝与基质之间的流体交换速度和数量均发生质变,注水吞吐已经从注水开发中的辅助作用上升为一种新的有效开发方式,从而为超低渗透和致密油油藏的有效开发提供新的开发思路,由于其附加开发成本低、投资效益高,有望成为超低渗透和致密油油藏有潜力的补充能量开发方式。

Technology of stimulated reservoir volume fracturing brings higher initial oil production in the ultra-low permeability and tight oil reservoir,but rapid decline of oil production,low cumulative oil production and poor economic effect in the depletion development and waterflooding will result in watered-out oil wells rapidly. Therefore,it is necessary to explore new effective development method of supplying energy to the reservoir. Waterflood huff and puff in the oil reservoir with stimulated reservoir volume fracturing is a new method. Three-stage model of waterflood huff and puff were built to explore the development mechanism of imbibition and unsteady driving and to deduce the corresponding oil productivity formulas. Obvious development effect of the waterflood huff and puff was studied theoretically. The major influential factors of the waterflood huff and puff were researched by oil reservoir engineering method and laboratory experiment,and the feasibility of the waterflood huff and puff was certified combined with field practice. Research results show that exchange rate and quantity of fluid between fracture and matrix has changed qualitatively in network fracturing system formed by the stimulated reservoir volume fracturing,so waterflood huff and puff has been changed from a supplementary method to a new economical and effective development method. Therefore,a new thought for effective development of ultra-low permeability and tight oil reservoir has been formed. It can be a potential development method of energy supply in the ultra-low permea-bility and tight oil reservoir considering its low additional cost for development and high investment benefit.