Technological Innovation and Practical Exploration of Yingxiong Ridge Shale Oil in Qaidam Basin
摘要
The shale oil in the Yingxiongling area of the Qaidam Basin is primarily developed in the saline lacustrine hydrocarbon source rocks of the Paleogene-Neogene, with favorable oil-generating conditions and a thickness of 1300m. The favorable exploration area covers 800km2, with resources amounting to 2.1 billion tons. Since the breakthrough in exploration in 2021, it has undergone three phases: “vertical wells controlling the surface to ascertain scale, appraisal horizontal wells evaluating the reservoir, and test well groups tackling technical challenges.” A total of 43 wells have been deployed. Through continuous deepening of sweet spot evaluation, drilling acceleration, and reservoir stimulation techniques such as fracturing, a preliminary technical policy for beneficial development has been established.This paper comprehensively analyzes drilling records, experimental analysis, logging and production data to clarify the four qualities of Heroling shale oil: the best source rock facies are laminated dolomite and clay shale, the best reservoir is layered limestone dolomite, the geological sweet spot section is layered limestone dolomite and laminated dolomite, and the engineering sweet spot section is laminated dolomite combination and layered limestone dolomite and clay shale combination. A “geological model + LWD (Logging While Drilling) + elemental logging” gold target tracking technology is established, achieving over 80% encounter rate of I+II class sweet spots; forming a main process of “dense cutting + extreme flow limitation + large displacement + variable viscous slippery water continuous sand addition”, with 4 wells in the Yingye 2H pilot test platform producing 75 tons of oil daily. Through market-oriented organization mode, the platform production cycle is reduced from 198 days to 140 days, the well construction cost is reduced by 17.4%, and the single section cost is reduced by 23.9%, laying the foundation for the efficient development of Heroling shale oil