川北地区下侏罗统东岳庙段页岩气富集规律研究

发布时间：2018-11-26 09:54

【摘要】：由众多的研究资料显示,中国页岩气资源丰富,在富集条件上与美国有相似之处,但地质条件的差异较大,因此不能照搬美国的开发模式,应注重页岩气地质特性的研究。通过对川北地区下侏罗统东岳庙段的页岩气资料考察,认为其主要为湖相沉积,资源潜力良好,且含有一定量的脆性矿物,利于后期压裂改造,但埋深普遍较大,总体勘探程度较低,故可以对其页岩气的富集规律进行细致研究,寻找和确定“甜点”,对后期的生产起指导作用,能够决定高产和采收率。本文通过川北地区的前人资料综合分析,以及中石化勘探区块的钻井、地物地化资料的收集,结合岩芯观察、野外实地考察、典型剖面的测制、岩石薄片镜下鉴定、地物地化送样分析等,对川北地区下侏罗统东岳庙段的页岩气富集规律进行多学科、多方法的综合研究,主要得出以下认识:(1)发育湖泊和湖泊三角洲两种沉积相类型,主要以湖泊为主,滨湖、浅湖及半深湖沉积广泛分布。(2)建立了适合研究区的一套泥页岩划分标准:在砂岩和灰岩层段中,连续厚度大于2m且泥地比小于40%作为常规油气系统;在泥页岩层段中,连续厚度大于9m,泥地比大于60%作为泥页岩油气系统。(3)富有机质泥页岩有机地化分析显示,其干酪根类型以III型为主,但是II1和II2型所占比例也较大,有机质丰度为较好的烃源岩,有机质成熟度高,属凝析油-湿气阶段,但页岩气含气性不如美国好。(4)富有机质泥页岩以粘土矿物、石英为主,可见少量长石和方解石,其中脆性矿物含量总体中等偏多,杨氏模量和泊松比显示泥页岩具有较好的脆性,且抗压强度整体上并不高。(5)富有机质泥页岩物性分析显示,泥页岩主要发育有机孔、无机孔(粒内孔、粒间孔、晶间孔)及裂缝系统(宏观裂缝和微裂缝),平均孔隙度和渗透率均较高,孔隙度和渗透率总体呈正相关关系。(6)研究页岩气的成藏机理,认为温度、压力、有机碳含量、热演化程度、矿物成分、孔隙和裂缝等因素影响页岩气的含气量,而沉积相、岩相、裂缝和隔离层决定页岩气的富集高产,并优选元坝西部地区、元坝东南-仪陇地区以及达州西北地区为有利区。
[Abstract]:According to many research data, China is rich in shale gas resources and has similarities with the United States in the enrichment conditions, but the geological conditions are quite different, so it is not possible to copy the American development model, so we should pay attention to the study of the geological characteristics of shale gas. Based on the investigation of shale gas data in Dongyemiao formation of Lower Jurassic in northern Sichuan, it is considered that the shale gas is mainly lacustrine sedimentary, with good resource potential and a certain amount of brittle minerals, which is conducive to later fracturing reconstruction, but the depth of burial is generally larger. The overall exploration degree is relatively low, so it is possible to study carefully the law of shale gas enrichment, to find and determine the "dessert", to guide the later production, and to determine the high yield and oil recovery. Based on the comprehensive analysis of previous data in northern Sichuan, drilling and geochemistry data collection in exploration blocks of Sinopec, core observation, field investigation, typical profile measurement and microscopic identification, Based on the analysis of geo-chemical samples and so on, this paper makes a multidisciplinary and multi-method study on the law of shale gas enrichment in the Dongyemiao section of the Lower Jurassic in northern Sichuan. The main conclusions are as follows: (1) two types of sedimentary facies, lake and lake delta, are developed. The sediments of littoral lake shallow lake and semi-deep lake are widely distributed. (2) A set of shale classification criteria suitable for the study area is established: in sandstone and limestone formation. The continuous thickness is more than 2m and the ratio of mud to soil is less than 40% as the conventional oil and gas system. In the shale formation, the continuous thickness is more than 9 m and the ratio of mud to soil is more than 60% as the shale oil and gas system. (3) the organic geochemistry analysis of organic matter rich shale shows that the kerogen type is mainly III type. However, the proportion of II1 and II2 type is also large, organic matter abundance is good source rock, organic matter maturity is high, it belongs to condensate oil-wet gas stage, but gas content of shale gas is not as good as that of the United States. (4) the organic matter rich shale is clay mineral. Quartz is dominant, a small amount of feldspar and calcite can be seen, among them, the content of brittle minerals is generally moderate, and the Young's modulus and Poisson's ratio show that shale has better brittleness. The compressive strength is not high on the whole. (5) the organic pore, inorganic pore (intragranular pore, intergranular pore) and fracture system (macroscopic fracture and micro-fracture) are mainly developed in the shale, which is rich in organic matter. The average porosity and permeability are all high, and the porosity and permeability are positively correlated. (6) the mechanism of shale gas accumulation is studied. It is considered that temperature, pressure, organic carbon content, thermal evolution degree, mineral composition, temperature, pressure, organic carbon content, thermal evolution degree, mineral composition, temperature, pressure, organic carbon content, thermal evolution degree, mineral composition, The porosity and fracture influence the gas content of shale gas, while sedimentary facies, lithofacies, fracture and isolation layer determine the enrichment and high yield of shale gas, and the favorable areas are the west area of Yuanba, the southeast of Yuanba and Yilong area and the northwest of Dazhou.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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