中国致密砂岩气开发工程技术与实践

致密砂岩气是非常规天然气的主要类型。根据中国近年来发现的大型致密砂岩气藏的开发地质特征,可划分为3种主要类型:透镜体多层叠置致密砂岩气、多层状致密砂岩气及块状致密砂岩气。前2种类型以提高单井产量、降低开发成本为技术目标形成了系列开发技术,推动了致密气的规模化发展。针对透镜体多层叠置致密砂岩气,形成了以优化布井、多级加砂压裂、井下节流与低压地面集输为特点的开发技术。针对多层状致密砂岩气,形成了以富集区预测与评价、水平井整体开发和排水采气为特点的开发技术。中国致密砂岩气具有广阔的发展前景,但仍面临诸多技术挑战,包括提高储量动用程度和采收率、进一步提高单井产量、新类型和难动用储量的开发、气田稳产接替与开发后期气井管理等。

Tight sand gas development technologies and practices in China

Tight gas is the main type of unconventional natural gas. According to the geologic characteristics of large-scale tight sandstone gas reservoirs discovered in China in recent years, tight gas reservoirs can be classified into three main types, multi-layer lens overlaid tight sand gas reservoir, multilayered tight sandstone gas reservoir and massive tight sand gas reservoir. A series of development technologies for the first 2 types of reservoirs have been formed, focusing on improving individual well producing rate and reducing development cost. They drive the scale development of tight gas. As to multi-layer lens overlaid tight sand gas, the specific technologies include well location optimization, multi-stage sand fracturing, down hole choking and low-pressure surface gas gathering system. As to multilayered tight sandstone gas, the specific technologies include sweet-spot prediction and evaluation, integrated horizontal well development technique, and drainage gas recovery technique. There are still great challenges in tight gas development from several aspects, such as the enhancement of reserve deployment ratio and recovery ratio, the improvement of individual well producing rate, the development of new and difficult-to-produce reserves as well as the rate maintenance, replacing and well management in later stage of life cycle of the gas well.