关键词: 致密砾岩, 甜点分级, 小井距, 密切割, 立体开发

Abstract: With the expansion of global oil and gas exploration towards deep, subtle, and unconventional reservoirs, new breakthroughs have been made in oil and gas exploration in China. The Mahu tight conglomerate reservoirs in the Junggar Basin, Xinjiang, are rich in oil resources and have great potential for the establishment of large-scale productivity. However, the factors that affect oil flow capacity in the reservoir are complex and diverse. Also, there are a number of challenges during development, for example; reservoir heterogeneity is strong, determination and classification evaluation of “sweet spots” are difficult, the difference in horizontal principal stress between the two directions is large, the formation and extension mechanisms of hydraulic fractures is unclear, costs are high, and geological conditions are complex. Guided by geology-engineering integration, combining the geological characteristics of the study area with production practice, a “sweet spot” classification evaluation standard for this type of reservoir has been established. Intensive volume fracturing, stereoscopic development technologies and tests of “long horizontal section, intensive segments, small well spacing, large well clusters and well factory operation” have been explored, forming a set of technical systems for efficient development of tight conglomerate reservoirs and have achieved good results. The improvements of accuracy in “sweet spot” description and 3D geological modeling have significantly increased the efficiency of drilling and completion engineering. The average number of adjustment times of horizontal section trajectory has decreased from 5 times to 2. Penetration rate of the oil layer has reached more than 90%. The average cluster spacing in the Ma-131 well block decreased from 67 m to 35 m. Average cumulative production increased by 37.5% in 300 days.