天然气工业2018，Vol.38Issue(2)：90-96,7.DOI:10.3787/j.issn.1000-0976.2018.02.012
天然气井绒囊流体活塞技术不降压压井工艺
A gas well killing process without pressure release based on the fuzzy-ball fluid piston technology
摘要
Abstract
Compared with mechanical well killing technologies,the fluid based well killing technology is more advantageous with a simple process,high safety and controllable costs so it has gradually become a common well killing technology for the workover of gas wells.So far,however,its construction technologies have not been researched systematically.In this paper,a technical idea of well killing and workover operation without pressure release based on the fuzzy-ball fluid piston technology was proposed after the research results of well killing technologies used in domestic workover operation were analyzed and summarized.Then,a series of studies were conducted from the aspects of dosage calculation,pumping mode selection,pumping process design and flowback pattern selection of fuzzy-ball fluid in gas wells.Finally,comparative analysis was carried out based on field application.And the following research results were obtained.First,calculate the height of fuzzy-ball fluid piston and its viscosity at a low shear rate based on the internal structure force required to balance the maximum buoyancy of the bubble in the wellbore,and accordingly determine the properties of the fluid that is prepared on site.Second,calculate the volume of fuzzy-ball fluid to keep the hydrostatic column pressure in the wellbore according to the demand for formation pressure balance,with an additional pressure value of 3-5 MPa for safety.Third,pump the water pad fluid with a liquid column height of 500 m,improve the pumping efficiency by wetting siring and borehole wall,and increase the flowback efficiency through the formation of a slurry mixture section of low-viscosity and low internal structure force with the fuzzy-ball fluid.Fourth,select the pumping mode of positive/reverse circulation according to the connection state and resistance to pressure of strings.Fifth,after the workover,select direct gas lift or gel-breaking gas lift for production recovery according to the depletion degree of formation energy in a gas well.This technological process was practically applied to three gas wells in NW and SW China.Among them,two wells recover to the previous production rate after continuous gas lift for 2-3 days.It is concluded that this technology can well solve the problems in the process of conventional pressure release,such as poor safety and productivity waste,and shorten the operation cycle of gas well killing.关键词
天然气/修井/压井/不降压/绒囊流体活塞技术/储层伤害/井下作业/产量恢复Key words
Natural gas/Workover/Well killing/Process without pressure release/Fuzzy-ball fluid piston technology/Reservoir damage/Downhole operation/Production recovery引用本文复制引用
李治,魏攀峰,吕建,卢冰,牛智民,樊晶晶..天然气井绒囊流体活塞技术不降压压井工艺[J].天然气工业,2018,38(2):90-96,7.基金项目
国家科技重大专项“多气合采钻完井技术与储层保护”(编号:2016ZX05066002-001). （编号:2016ZX05066002-001）
