鄂尔多斯盆地长庆气区复杂致密砂岩气藏开发关键技术进展及攻关方向

Key technological progress and breakthrough direction for the development of complex tight gas reservoirs in Changqing gas field,Ordos Basin

随着天然气勘探开发的逐步深入,开发对象由常规气藏向非常规气藏拓展,致密砂岩气逐渐成为天然气增产的主力。鄂尔多斯盆地致密气分布范围广、资源量占中国致密气资源量的58.2%,与其他国家致密气相比,具有气层更薄、非均质性强、地层压力系数低的特点,效益开发难度更大。经过20余年攻关,长庆油田探索形成了致密气开发配套技术,年产量达到360×10^(8)m^(3),建成中国最大的致密气区之一,并将迈入高质量发展新阶段。通过概述鄂尔多斯盆地致密气藏典型特征,回顾了开发历程及其重大转变,分析了长庆油田致密气开发潜力及前景,指明了攻关方向。研究表明:(1)长庆油田致密气开发历经4个阶段,通过气藏深化认识、工艺攻关、管理提升,解决了大面积低丰度复杂致密砂岩气藏效益开发的难题,实现了长庆气区快速上产。(2)2016—2020年以来,随着储层预测、水平井开发等7个关键瓶颈技术取得突破,开发指标大幅提升,推动致密气高质量发展。(3)通过已开发气田、评价新区致密气资源基础及开发潜力评价,明确了致密气“十四五”(2021—2025年)规划目标。(4)从优化开发技术政策、钻井提速、试气压裂提产等5个方面指明了致密气技术攻关方向,确保长庆油田致密气开发目标的实现。

With the gradually deepening natural gas exploration and development,the target of natural gas development has expanded from conventional gas reservoirs to unconventional reservoirs,and tight sandstone gas reservoirs have been playing an important role in natural gas production in recent years.Tight gas is widely distributed in Ordos Basin,accounting for 58.2%of China's total resources;compared with the tight gas in foreign countries,it is characterized by thinner gas layer,stronger heterogeneity,lower formation pressure coefficient and more difficulty in cost-effective development.After 20 years of technological breakthrough,Changqing oilfield has explored and established a complete set of technologies for tight gas development,with an annual output of 36 billion cubic meters.It has built one of China's largest tight gas fields and will step into a new stage of high-quality development.This paper summarizes the typical characteristics of tight gas reservoirs in Ordos Basin,reviews the development process and its significant changes,analyzes the development potential and prospects of tight gas in Changqing,and points out the research direction.Research results are shown as follows.(1)The development of tight gas reservoirs in Changqing has gone through four stages.Through further understanding of gas reservoirs,technique breakthrough and management improvement,the paper solves the difficulties in the cost-effective development of complex low-abundance tight sandstone gas reservoirs in a large area,thus achieving the rapid production in Changqing gas field.(2)Since the 13th Five-Year Plan(2016-2020),development indicators have been greatly improved through breakthroughs in seven key bottleneck technologies such as reservoir prediction and horizontal well development,thus promoting the high-quality development of tight gas.(3)Based on evaluations on the resource base and development potential of tight gas in developed gas fields,new gas fields under evaluation,the 14th Five-Year Plan(2021-2025)for tight gas is specified.(4)The technical breakthrough direction of tight gas is pointed out in five aspects,such as optimizing development technology policy,increasing drilling speed,gas testing,fracturing,and improving yield.so as to realize the targets for tight gas development in Changqing.