CO_2同井驱替工程设计

AUTOMATIC DISPLACEMENT ENGINEERING DESIGN OF HYDROCARBONS BY CO_2 PRODUCED IN THE SAME WELL

针对南海西部某气田上部压力衰竭高烃气藏与下部高压高含CO_2气藏纵向上叠合性较好的特征,经过多年研究,形成了海上CO_2同井自动驱替钻完井技术,利用下部CO_2气体驱替上部高烃气体,提高气田采收率。文章详细阐述了海上CO_2自动驱替钻完井技术,包括井身结构设计、钻井液屏蔽暂堵、水平井射孔及同井自动驱替完井管柱设计。该技术突破了海上平台设备安装空间不足的限制,节省了钻完井费用,为南海西部油田降本增效做出了巨大贡献,为类似井作业提供了借鉴。在国际石油价格持续低靡的情况下,更能显示出其重要意义。

In view of a good superposition between the upper pressure-depleted gas reservoir and the lower high-pressure high-CO_2 gas reservoirs in a western south sea gas field,a set of drilling and completion technology has been developed after years of study to improve the gasfield recovery by displacing the upper hydrocarbon gases using the CO_2 gas from the bottom formation. In this paper,the technology is introduced in details,including casing program planning,drilling fluid shielding and blocking,horizontal well perforation and completion string design for automatic same-well displacement. This technology has broken through the limitation by the insufficient equipment installation space on offshore platforms,lots of drilling and completion costs been saved,great contributions have been made to cost reduction and efficiency improvement at the western south sea gas field,providing reference for similar well operations. At the time of long-term low oil price in the world,this technology will be significant.