石油钻采工艺2025，Vol.47Issue(5)：600-609,10.DOI:10.13639/j.odpt.202506021
不同砾石粒径及含量下裂缝扩展规律大尺度物模实验
Experimental study on large-scale physical modeling of crack extension patterns under different gravel size and content
摘要
Abstract
The dense conglomerate reservoir in the Mahu Depression is characterized by high conglomerate content,uneven particle size distribution and strong non-homogeneity,and the fracturing fracture extension mechanism is extremely complex,so the conventional physical model is limited by scale and boundary effects,which makes it difficult to realistically restore the fracturing construction conditions of deep conglomerate reservoirs.To address this problem,this paper relies on a super-large true triaxial hydraulic fracturing physical simulation system,selects a large conglomerate specimen with a size of 2.0 m×2.0 m×1.0 m,and adopts a real fracturing pumping capacity,and the simulated wellbore and fracturing materials are consistent with the on-site construction,so as to systematically investigate the effects of different conglomerate contents and particle sizes on the fracture extension law,and to realize the physical simulation of fracturing on an industrial scale.The experimental results show that gravel content and grain size have a coupling control effect on fracture morphology:When the content increases from 40%to 60%,the complexity of fracture network shows a trend of"decreasing and then increasing",and the main fracture deflection and branching development are mainly dominated by the spatial non-homogeneity of gravels;and the increase in the grain size makes the tortuosity of fracture show a trend of"decreasing and then decreasing".The increase of grain size makes the fracture tortuosity show the trend of"increasing and then decreasing",in which the medium grain size has the strongest shielding effect,forcing the fracture to expand around the gravel and form a complex branch network.The fracturing pressure curves further reveal that the expansion resistance is high under low content/small grain size conditions,and the curves are of step-shock type;whereas the main fracture paths are relatively regular under high content/large grain size conditions,and the pressure curves tend to be single-peak characteristics.The results reveal the dynamic network formation mechanism under the multi-scale mechanical action of gravel-matrix,and provide data support for the optimization of fracturing parameters in Makuhu tight conglomerate reservoir.关键词
砂砾岩/水力压裂/矿场实验/真三轴/砾石含量/砾石尺寸Key words
sand and gravel/hydraulic fracturing/mine experiments/true triaxial/gravel content/gravel size分类
石油、天然气工程引用本文复制引用
石善志,鲜成钢,郭晓东,张景臣,支东明,程新旺,袭祥瑞,石磊..不同砾石粒径及含量下裂缝扩展规律大尺度物模实验[J].石油钻采工艺,2025,47(5):600-609,10.基金项目
新疆维吾尔自治区两区项目"石油工程中试创新实验平台研发与应用"(编号:2024LQ03023). （编号:2024LQ03023）
