四川盆地川西坳陷新场须家河组二段致密砂岩储层裂缝发育特征及主控因素  

Characteristics of and main factors controlling the tight sandstone reservoir fractures in the 2^(nd) member of Xujiahe Formation in Xinchang area,Western Sichuan Depression,Sichuan Basin

作　　者：李王鹏 刘忠群 胡宗全[1] 金武军[1] 李朋威[1] 刘君龙 徐士林[1] 马安来[1] Li Wangpeng;Liu Zhongqun;Hu Zongquan;Jin Wujun;Li Pengwei;Liu Junlong;Xu Shilin;Ma Anlai(Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083,China)

机构地区：[1]中国石化石油勘探开发研究院,北京100083

出　　处：《石油与天然气地质》2021年第4期884-897,1010,共15页Oil & Gas Geology

基　　金：国家自然科学基金项目(41902149,41702238);中国石化科技部项目(P18089-1)

摘　　要：四川盆地川西坳陷新场须家河组二段(须二段)砂岩储层具有埋藏深、致密的特点,天然裂缝的发育对储层至关重要。通过地表露头调查、岩心观察、常规测井和成像测井解释等手段分析新场须二段气藏天然裂缝的发育特征,认为须二段储层裂缝可划分为网状缝、立缝、高角度缝、斜缝、低角度缝和平缝,以低角度缝和斜缝为主;裂缝主要发育在新场构造带中东部地区的须二段中、上亚段,走向主要为NE-SW向、NW-SE向和EW向,以EW向晚期构造裂缝最发育,并与区内现今最大主应力方向一致。基于裂缝参数与产能参数交会分析,明确不同类型裂缝对产能的贡献度,认为新场须二段气藏有效裂缝为倾角大于30°的构造裂缝(立缝、高角度缝和斜缝)。区内有效裂缝的发育受控于断裂、构造变形、岩石粒度、岩石成分和岩层厚度等多方面因素,但距离晚期SN向逆断层的距离是须二段天然构造裂缝发育的关键控制因素,其次是构造变形及构造组合样式。距离晚期SN向逆断层上盘200 m范围内的褶皱发育区可作为新场地区今后裂缝预测、评价及天然气开发的重点区域。The sandstone reservoirs in the 2 nd member of Xujiahe Formation(hereafter referred to as Xu 2 Member)in Xinchang area,Western Sichuan Depression,are characterized by deep burial depth and tightness,to which the natural fractures are critical.An integration of outcrop survey,core description,conventional and imaging logging interpretation is applied to analyze the development characteristics of natural fractures in the gas reservoirs therein.It is believed that these fractures can be categorized as network fractures,vertical fractures,high dip angle fractures,horizontal fractures,oblique fractures,and low dip angle fractures,with the last two in the dominant position.Mainly developed in the middle and upper submembers of Xu 2 Member in central and eastern Xinchang tectonic belt,these fractures generally trend NE-SW,NW-SE and EW,basically consistent with that of the present maximum principal stress within,with the EW-striking structural fractures in the late period the most developed.On the other hand,the cross-plotting analysis of fracture and productivity parameters,serves to clarify the contribution of different types of fractures to productivity,and the results show that the effective fractures in the Xu 2 Member gas pool are structural ones with a dip angle of over 30°(namely,vertical,high dip angle and oblique fractures).The development of effective fractures in the study area is controlled by many factors,including faulting,tectonic deformation,grain size,rock composition,and stratum thickness,etc.,and the distance from the late SN-striking reverse fault is the most critical factor controlling the development of natural structural fractures,followed by structural deformation and structural pattern in combination.In conclusion,the area with well-developed folds and within 200 m away from the hanging wall of the late SN-striking reverse fault can be regarded as a key zone for future fracture prediction,evaluation and natural gas development in Xinchang area.

关 键 词：逆冲断层 构造裂缝 致密砂岩储层 须家河组 新场气田 川西坳陷 四川盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]