摘要
在非常规储层水力压裂施工过程中,水力裂缝容易与天然裂缝交汇形成复杂裂缝,支撑剂的运移和铺置形态直接决定了储层的增产效果。为了研究支撑剂在复杂裂缝中的铺置规律,基于欧拉-欧拉方法建立了支撑剂-压裂液两相流数学模型,并利用复杂裂缝室内实验装置与数值模拟的砂堤铺置形态对比的方式进行了模型验证,结果表明,选取的模型可用于研究滑溜水在复杂裂缝内的携带支撑剂的运移铺置规律。以相似准则为基础,建立了简化的复杂裂缝平板模型,并将砂堤形态参数、砂堤面积进行归一化处理,获得了压裂液排量、黏度、支撑剂粒径、裂缝宽度以及裂缝形态对支撑剂在复杂裂缝中铺置的影响规律。结果表明:增大排量、黏度和减小粒径均有利于支撑剂向裂缝深处运移,并且排量对支缝中的砂堤形态影响最明显,但增大排量不利于支撑剂填充近井地带。缝宽的影响体现在壁面效应,在注入时间相同的情况下,当压裂液黏度从1 mPa·s增加到5 mPa·s时,主缝砂堤的归一化长度平均增加了37.9%,归一化高度平均降低了61.4%。裂缝结构越复杂,所有支缝中的支撑剂铺置面积占比越高,分流作用越大。随着复杂裂缝的支缝数量、级数以及支缝延伸长度的增大,支缝中的砂堤高度与长度均有所降低;相对于T1型裂缝,T3和T5型裂缝中的砂堤长度、高度减小最多。
During the hydraulic fracturing construction of unconventional reservoirs,hydraulic fractures easily intersect with natural fractures to form complex fractures.The migration and the laying form of the proppant directly determine the stimulation effect of the reservoirs.In order to study the laying rules of proppants in complex fractures,a proppant-fracturing fluid two-phase flow mathematical model was established based on the Euler-Euler method,and the dune laying shapes in complex fractures of the indoor test device and the numerical simulation were compared to verify the model.The results show that the selected Euler two-fluid numerical model can be used to study the migration and laying rules of proppants carried by slick water in complex fractures.Based on the similarity criterion,a simplified complex fracture plate model was established,and the morphological parameters and area of the dune were normalized to obtain the influence of the fracturing fluid displacement,viscosity,proppant particle size,fracture width,and fracture morphology on proppant laying in complex fractures.The results show that increasing the displacement and viscosity and reducing the particle size is beneficial to proppant migration to the depth of the fractures,and the displacement has the most obvious impact on the shape of the dune in the branch fractures,but increasing the displacement is not conducive to proppant to fill the near-well zone.The influence of the fracture width is reflected in the wall effect.Under the same injection time,when the viscosity of the fracturing fluid increases from 1 mPa·s to 5 mPa·s,the normalized length of the main fracture dune increases by 37.9%on average,and the normalized height reduces by 61.4%.A more complex fracture structure indicates a higher proportion of proppant laying area in all branch fractures and a more significant diversion effect.As the number,series,and extension length of the branch fractures of complex fractures increase,the height and length of the dune in the branch fractures decrease;compared with the T1 type fracture,the dune in the T3 and T5 type fractures decreases the most in terms of length and height.
作者
张涛
蹇胤霖
何乐
梁天成
王菲
ZHANG Tao;JIAN Yinlin;HE Le;LIANG Tiancheng;WANG Fei(Petroleum Engineering School,Southwest Petroleum University,Chengdu City,Sichuan Province,610500,China;Downhole Operation Company,China National Petroleum Corporation Chuanqing Drilling&Exploration Engineering Company Limited,Guanghan City,Sichuan Province,618300,China;PetroChina Research Institute of Petroleum Exploration&Development-Langfang Branch,Langfang City,Hebei Province,065000,China)
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2024年第3期123-136,共14页
Petroleum Geology and Recovery Efficiency
基金
国家能源致密油气研发中心开放课题“压裂支撑剂复杂裂缝导流能力及输送铺置机理研究”(2022-KFKT-12)。
关键词
水力裂缝
滑溜水压裂
两流体数值模型
支撑剂
归一化
hydraulic fractures
slick water fracturing
two-fluid numerical model
proppant
normalization
