大牛地气田致密碳酸盐岩储层酸压裂缝扩展规律研究OA
Study on fracture propagation law of acid fracturing in tight carbonate reservoirs of Daniudi Gas Field
鄂尔多斯盆地大牛地气田下古生界致密碳酸盐岩气藏具有典型的低孔、特低渗特征,发育含泥云岩、含泥含灰云岩、含膏云岩、含灰云岩等多种岩石类型,层内和层间溶蚀孔、缝、洞在构成不同规模的储集空间组合且分布不均,致使储层非均质性极强,裂缝酸蚀特征差异大,酸压改造难度较大.为阐明大牛地气田致密碳酸盐岩储层酸压裂缝扩展规律,提高酸化压裂设计的针对性,利用真三轴酸压模拟实验装置,研究不同压裂液体系、排量及天然裂缝发育特征对酸压裂缝起裂与扩展的影响,并采用三维重构技术,定量表征酸压后裂缝三维分布特征,进而明确酸压裂缝扩展的主控因素.研究结果表明,清水压裂以形成单缝为主,裂缝宽度、数量及复杂程度均显著低于酸化压裂,裂缝宽度约为0.5～1.0 mm;两种酸液交替注入时,酸压裂缝发育明显的蚓孔通道,最大宽度可达2.0～3.0 mm,且形成的裂缝网络更为复杂;排量增大可缩短破裂时间,同时提升破裂压力;天然裂缝数量越多,酸压裂缝越易沟通天然裂缝,进而形成复杂的裂缝网络.该研究可为大牛地气田致密碳酸盐岩储层酸化压裂优化设计提供理论依据,对该区碳酸盐岩气藏的高效开发具有重要指导意义.
The Lower Paleozoic tight carbonate gas reservoirs in the Daniudi Gas Field of the Ordos Basin are characterized by typical low porosity and ultra-low permeability.Various rock types are developed,including argillaceous dolomite,argillaceous calcareous dolomite,gypsiferous dolomite,and calcareous dolomite.Intraformational and interformational dissolved pores,fractures,and vugs form reservoir space combinations of varying scales with heterogeneous distribution,leading to strong reservoir heterogeneity,big differences in fracture acid-etching characteristics,and considerable challenges in acid fracturing stimulation.To clarify the propagation law of acid-fracturing fractures in tight carbonate reservoirs of the Daniudi Gas Field and improve the pertinence of acid fracturing design,a true triaxial acid fracturing simulation test system was used to investigate the effects of different fracturing fluid systems,injection rates,and natural fracture development characteristics on the initiation and propagation of acid-fracturing fractures.Additionally,3D reconstruction technology was employed to quantitatively characterize the 3D distribution characteristics of fractures after acid fracturing,thereby identifying the dominant controlling factors governing the propagation of acid-fracturing fractures.The results indicate that water fracturing mainly generates single fractures,with significantly lower fracture width,quantity,and complexity compared to acid fracturing,and the fracture width ranges from approximately 0.5 to 1.0 mm.When two types of acid fluids are alternately injected,the acid-fracturing fractures develop obvious wormhole channels with a maximum width of 2.0-3.0 mm,forming a more complex fracture network.An increase in injection rate shortens the fracture initiation time and simultaneously increases the breakdown pressure.A greater number of natural fractures facilitates the connection between acid-fracturing fractures and natural fractures,thereby forming a complex fracture network.This study provides a theoretical basis for the optimal design of acid fracturing in tight carbonate reservoirs of the Daniudi Gas Field and holds important guiding significance for the efficient development of carbonate gas reservoirs
张永春;李凌川;毛峥
中国石化华北油气分公司,河南 郑州 450006中国石化华北油气分公司,河南 郑州 450006中国石化华北油气分公司,河南 郑州 450006
能源科技
碳酸盐岩储层酸化压裂三维重构裂缝扩展规律
carbonate reservoiracid fracturing3D reconstructionfracture propagation law
《石油地质与工程》 2026 (1)
24-32,9
中国石油化工股份有限公司科技部项目"致密气藏钻完井及压裂关键技术及应用"(P23156).
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