摘要
铝土岩与常规储层不同,在岩石力学参数、压裂地质特征等方面具有较大差异,前期先导试验井压裂施工难度大。为解决储层改造难题,针对复杂铝土岩系储层开展了岩石力学、地应力、储层伤害等基础实验,明确了泥质铝土岩、铝土质泥岩具有高杨氏模量(35.5~44.5 GPa)、高脆性(55%~60%)和高地应力(最小水平主应力53~71 MPa)等压裂地质特征。同时不同取心方向的铝土岩岩石力学也具有显著差异,表明各向异性程度较强。储层伤害主控因素主要包括水锁伤害、水敏伤害及固相伤害,应力敏感性较弱。综合实验认识与现场实践分析,针对黏土含量高、杨氏模量高、裂缝起裂延伸难度大、加砂难度大等工程难题,通过集成“体积压裂增大裂缝体积、高黏液提净压造缝携砂、加密射孔确保起裂、前置酸液降低工压”四项技术措施为一体,通过单项技术的持续优化,初步固化形成多岩性铝土岩压裂改造技术模式,在矿场实践中获得显著成效。储层改造加砂成功率由前期的44%提升至100%。
The Bauxite series is different from conventional sandstone and carbonate reservoirs in rock mechanics parameters and fracturing geological characteristics.Those previous wells were difficult to conduct hydraulic fracturing.To solve the reservoir stimulation problem,basic experiments on rock mechanics,in-suit stress,and reservoir damage were conducted for the bauxite rocks.The Young's modulus of bauxite is 6-10 GPa.Bauxitic mudstone and muddy bauxite have mechanical characteristics of high Young's modulus(35.5-44.5 GPa),high brittleness(55%-60%)and high in-situ stress(minimum principal stress 53-71 MPa).And there are significant differences in rock mechanics of bauxite with different core directions,indicating a strong degree of anisotropy.The main controlling factors for reservoir damage include water lock damage,water sensitivity damage and solid damage,with weak stress sensitivity.Based on experimental conclusions and on-site practical analysis,by integrating the four technical measures of“volume fracturing,high viscosity fluid,dense perforation,and pad-acid”,a multi lithology bauxite rock fracturing technology model has been preliminarily solidified and achieved significant results in field practice.The success rate of sanding increased from 40% to 100%.
作者
徐晓晨
陆红军
王文雄
叶亮
王龙
吴勇
赵倩云
XU Xiaochen;LU Hongjun;WANG Wenxiong;YE Liang;WANG Long;WU Yong;ZHAO Qianyun(Oil and Gas Technology Research Institute of Changqing Oilfield Company,PetroChina,Xi'an 710018,China;Exploration and Development of Low-Permeability Oil&Gas Fields,Xi’an 710018,China;PetroChina Changqing Oilfield Company,Xi'an 710018,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2024年第8期1488-1501,共14页
Natural Gas Geoscience
基金
中国石油天然气股份有限公司生产技术攻关与现场试验项目(编号:2022KT0504)资助.
关键词
鄂尔多斯盆地
铝土岩
体积压裂
环空气举阀
多效耦合活性酸
Ordos Basin
Bauxite rock series
Volume fracturing
Annular gas lift valve
Multi-functional acid system
