摘要
储层可压裂性评价是储层改造方案设计的重要依据,影响致密砂岩可压裂性的主要因素有天然裂缝、砂岩脆性、水平应力差异、断裂韧性等。研究以准噶尔盆地中部1区块Z109井侏罗系致密砂岩为例,综合考虑天然裂缝、砂岩脆性、水平应力差异、断裂韧性四种影响因素,采用改进的层次分析和熵值法相结合的方法进行了致密砂岩储层可压裂性评价。研究结果表明:可压裂性指数越大,致密砂岩储层越易于压裂,压裂时越能获得较复杂的裂缝网络;可压裂性指数大于0.44,砂岩脆性高,断裂韧性小,裂缝发育程度高,水平差异系数小的储层段为Ⅰ级优质压裂层;可压裂性指数大于0.44,砂岩脆性高,断裂韧性小,裂缝发育程度低,水平差异系数大的储层段为Ⅱ级可压裂层;研究区Z109井4036~4039 m、4062~4067 m、4214~4218 m和4260~4272 m为Ⅰ级优质压裂层,4093~4108 m和4284~4313 m为Ⅱ级可压裂层。研究成果可为致密砂岩压裂改造提供科学依据。
Evaluation of reservoir fractability is an important basis for reservoir reconstruction, and the main factors affecting the fracability of tight sandstone are natural fracture, sandstone brittleness, horizontal stress difference, fracture toughness and so on. Taking Jurassic tight sandstones in Well Z109, Block 1, Central Junggar Basin as an example, four influencing factors, namely natural crack, sandstone brittleness, horizontal stress difference and fracture toughness, were considered comprehensively, and then improved analytic hierarchy process and entropy method were adopted to evaluate the fractability of tight sandstone reservoirs. The results show that the higher the fracturing index is, the easier it is to fracture tight sandstone reservoirs and the more complex fracture networks can be obtained during fracturing. The reservoirs with fracture index higher than 0.44, high brittleness, small fracture toughness, high degree of fracture development and low level difference coefficient are level I high quality fracturing layers, and the reservoirs with fracture index higher than 0.44, high brittleness, small fracture toughness, low degree of fracture development and high level difference coefficient are level II fracturing layers. In the study area, 4036~4039 m, 4062~4067 m, 4214~4218 m and 4260~4272 m of Well Z109 are level I high quality fracturing layers, 4093~4108 m and 4284~4313 m are level II fracturing layers. The research results provide scientific basis for fracturing reconstruction of tight sandstone.
作者
宋明水
刘振
张学才
汪勇
李静
杨飞跃
SONG Mingshui;LIU Zhen;ZHANG Xuecai;WANG Yong;LI Jing;YANG Feiyue(Shengli Oilfield Company, Sinopec, Dongying 257000, Shandong, China;China University of Petroleum,Qingdao 266580, Shandong, China;Manage center of Oil and Gas Exploration, Shengli Oilfield Company, SINOPEC, Dongying 257200, Shandong, China)
出处
《地质力学学报》
CSCD
2019年第4期509-517,共9页
Journal of Geomechanics
基金
国家科技重大专项(2016ZX05002-002)
国家自然科学基金(41272141)
关键词
准噶尔盆地中部1区块
侏罗系
致密砂岩储层
可压裂性指数
层次分析法
熵值法
Block 1 in the Central Junggar Basin
Jurassic
tight sandstone reservoirs
fracability index
analytic hierarchy process
entropy method
