准噶尔盆地吉木萨尔凹陷页岩油效益开发探索与实践

Exploration and practice of benefit development of shale oil in Jimsar Sag,Junggar Basin

准噶尔盆地吉木萨尔页岩油藏是典型的陆上页岩油非常规油藏,储层岩性复杂、横向埋深差异大、纵向夹层多、非均质性强,油层薄,原油黏度高,开发难度大。经过勘探发现、先导性试验、动用突破、规模建产4个阶段的探索,取得了重要进展,但产能建设达产率不高,单井投入产出矛盾逐步凸显,开发效益成为制约吉木萨尔页岩油开发的主要问题。2021年以来,中国石油新疆油田公司从管理与技术两方面着手,进行了效益开发探索。针对优质甜点分布、优质储层钻遇率、储层改造强度等单井产量的主控因素,采用储层精细再认识、核磁共振测井可动性评价、提高钻井井眼轨迹调控精度、提高储层改造强度等技术措施,配合市场化自主经营,形成了成熟的管理和技术体系,在实践中得到检验,单井投入下降53.4%,单井最终可采储量(EUR)提升50%左右,实现45美元/bbl下算盈,推动了吉木萨尔页岩油效益开发。

The shale oil reservoir in Jimsar Sag in Junggar Basin is a typical onshore unconventional shale oil reservoir with complex reservoir lithology,large differences in burial depth laterally,many interlayers vertically,thin oil layers,strong heterogeneity,high crude oil viscosity,and great difficulty in development.Major progress has been made during four stages of exploration,i.e.,discovery,pilot test,breakthrough in utilization,and large-scale construction of production capacity.However,the reachability of design capacity is low,and the contradiction between cost and output of single well is prominent,showing that the low benefit is the main issue restricting shale oil development in Jimsar Sag.Since 2021,Xinjiang Oilfield Company has explored benefit shale oil development focusing on two aspects of management and technology.With regard to the main control factors for single-well production such as distribution of sweet spot shale,drilling rate of highquality reservoirs,and reservoir stimulation intensity,technical measures have been adopted,including reservoir fine characterization,shale oil mobility evaluation by NMR logging,improving the precise of borehole trajectory regulation,and increasing reservoir stimulation intensity,so as to form a mature management and technical system by integrating with market-oriented independent operation.The practice shows that the single well cost reduced by 53.4%,single well EUR increased by about 50%,and profits could be achieved at oil price US$45/bbl,which promoted the benefit development of shale oil in Jimsar Sag.