柴达木盆地页岩油工程甜点评价技术与应用

Evaluation techniques and applications of sweet spots in shale oilengineering in the Qaidam Basin

2021年首次明确柴达木盆地英雄岭地区干柴沟组上段发育页岩油,属低孔特低渗储层,需要采取压裂措施进行开发。通过体积压裂技术“打碎储层”提高储层渗流能力,是柴达木盆地英雄岭页岩油有效的开发方式。在开展体积压裂过程中,面临着无法准确评价工程甜点的难题,很大程度影响了储层改造的施工效果。通过开展储层矿物成分分析、岩石力学实验、可压性评价等研究,逐步形成了以“岩屑矿物分析技术、可压性分析技术”为核心的柴达木盆地英雄岭页岩油开发工程甜点评价技术。压裂后直井平均产油量17.92 t/d,水平井平均产油量达54.77 t/d,助力页岩油勘探开发取得新突破。

In 2021,shale oil was initially discovered in the upper member of the Xiaganchaigou Formation in the Yingxiongling area of the Qaidam Basin.This reservoir is characterized by low porosity and ultra-low permeability,necessitating the use of fracturing techniques for its development.One effective method for developing shale oil in this area is through the implementation of horizontal well volume fracturing technology,which involves“breaking the reservoir”to enhance its seepage capacity.However,accurately evaluating the engineering sweet spot during the horizontal well volume fracturing process presents a challenge.This issue significantly impacts the effectiveness of reservoir reconstruction.Therefore,techniques such as mineral composition analysis,rock mechanics experiments,and reservoir compressibility evaluation have been studied and applied.As a result,the sweet spot evaluation technology for the Qaidam Yingxiong Ling shale oil development project has gradually emerged,with a focus on“lithic mineral analysis technology and compressibility analysis technology”.The average daily oil production of fractured vertical wells reached 17.92 tons,while that of horizontal wells reached 54.77 tons,contributing to significant advancements in shale oil exploration and development.