长宁—威远地区页岩气水平井固井技术研究

发布时间：2018-01-12 12:23

本文关键词：长宁—威远地区页岩气水平井固井技术研究　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：我国四川盆地页岩气资源丰富,能够形成较好的工业产能,是中国页岩气勘探开发最有利和最重要的地区。为此,中国率先在四川盆地开展了页岩气勘探开发先导性试验,设立长宁-威远国家级页岩气示范区。页岩气藏具有自生自储、自然产能低、孔隙度和渗透率极低等储层特征,并具有水敏性强、易膨胀、易垮塌的特点。长宁-威远地区页岩气井采用水平井建井加分段水力压裂的开采模式,以实现页岩气商业化开发和获得比较理想的产量,提高页岩气井的经济效益。在储层钻进时采用高密度油基钻井液来保证井筒安全与稳定。但也给页岩气水平井固井技术带来了一系列难题和挑战：油基钻井液与水基的水泥浆不相容,严重影响水泥浆的凝结和界面胶结质量。水泥石属于硬脆性材料,后期大型体积压裂压力高、时间长,水泥环受高内压与冲击作用极易发生破坏,压裂液随水泥环产生的裂缝流动,降低压裂效果,被破坏后水泥环失去层间封隔和保护套管的作用,严重影响到页岩气井的正常开发与开采寿命。如何保证页岩气水平井的层间封隔质量成为页岩气开发不可忽视的问题之一。论文针对长宁-威远页岩气示范区页岩气水平井固井面临的问题,从评价方法、材料优选、体系研究、工艺技术措施方面开展了研究：(1)开展了油基钻井液与水泥浆相容性评价,油基钻井液会造成水泥浆流变性、凝结时间、抗压强度、胶结强度等性能出现劣化,水泥水化不充分,油滴在水泥石内形成的孔洞,水泥石结构疏松,力学性能大幅降低。(2)根据表面活性剂的作用原理以及前置液的作用效果要求,提出了以表面张力与润湿性、冲洗效率和界面胶结强度评价为核心的表面活性剂评价方法,优选出了冲洗效率和界面润湿效果优良的表面活性剂SD80、悬浮能力和抗温性能良好的多糖聚合物悬浮剂SD85；在此基础上,研发了一套密度1.50-2.40g/cm3的冲洗隔离液体系；(3)开展了聚酯纤维改性水泥石、陶瓷纤维改性水泥石、无机矿物纤维改性水泥石、碳纤维改性水泥石的抗压、抗拉和三轴力学性能测试,优选出无机矿物纤维SD66作为增韧剂；通过线膨胀测试和高温高压体积收缩测试优选出膨胀剂SDP-1,在此基础上形成了一套韧性微膨胀水泥浆体系。(4)从高密度稠浆段塞举砂、扶正器改型与安放、钻井液性能调整、注替排量优化四个方面开展了提高页岩气水平井固井顶替效率的工艺技术研究,并结合全井筒清水顶替预应力固井技术,降低侯凝过程中环空微间隙,降低气窜发生几率。(5)相关研究成果在长宁-威远区块的6口井现场试验,均取得了较好的固井质量,满足了后期水力压裂的要求。
[Abstract]:China's Sichuan Basin is rich in shale gas resources and can form good industrial production capacity, which is the most favorable and important area for shale gas exploration and development in China. China took the lead in the pilot test of shale gas exploration and development in Sichuan Basin and set up Changning-Weiyuan National Shale Gas demonstration Zone. Shale gas reservoir has self-generated self-reservoir and low natural productivity. The reservoir is characterized by very low porosity and permeability, and has the characteristics of strong water sensitivity, easy expansion and easy collapse. The shale gas wells in Changning-Weiyuan area adopt the production mode of horizontal well building and fracturing. In order to realize the commercial development of shale gas and obtain the ideal production. To improve the economic benefit of shale gas wells, the high density oil base drilling fluid is used to ensure the safety and stability of wellbore during reservoir drilling. However, it also brings a series of difficulties and challenges to the cementing technology of shale gas horizontal wells. The oil-base drilling fluid is incompatible with the water-based cement slurry. Cement stone is a kind of hard and brittle material with high pressure and long time of large volume fracturing in late stage. The cement ring is easily destroyed by high internal pressure and impact. The fracturing fluid flows with the fracture produced by the cement ring, which reduces the fracturing effect, and loses the function of interlayer sealing and casing protection after the cement ring is destroyed. How to ensure the interlayer sealing quality of shale gas horizontal well becomes one of the problems that can not be ignored in shale gas development. The paper aims at Changning-Weiyuan shale gas demonstration area. Problems in cementing of horizontal rock gas wells. The evaluation of the compatibility of oil based drilling fluid and cement slurry is carried out from the aspects of evaluation method, material selection, system research, process and technical measures. Oil based drilling fluid will cause rheological change of cement slurry. Setting time, compressive strength, cementing strength and other properties appear deterioration, cement hydration is not sufficient, oil droplets in the cement stone formed holes, cement stone structure is loose. According to the action principle of surfactant and the requirement of the action effect of the presolution, the surface tension and wettability were proposed. The surface active agent SD80 with good washing efficiency and interfacial wetting effect was selected as the core evaluation method of the washing efficiency and interfacial bonding strength. Polysaccharide polymer suspension agent SD85 with good suspension ability and temperature resistance; On this basis, a washing and isolating liquid system with density of 1.50-2.40 g / cm ~ 3 was developed. The compressive, tensile and triaxial mechanical properties of polyester fiber modified cement stone, ceramic fiber modified cement stone, inorganic mineral fiber modified cement stone and carbon fiber modified cement stone were tested. Inorganic mineral fiber SD66 was selected as toughening agent. The expansion agent SDP-1 was selected by linear expansion test and volume shrinkage test at high temperature and high pressure. On this basis, a set of ductile micro-expansive cement slurry system. The modification and placement of centralizer, the adjustment of drilling fluid performance and the optimization of injection displacement were carried out to improve the cementing displacement efficiency of shale gas horizontal wells, and combined with the pre-stressed cementing technology of clean water displacement in the whole wellbore. The related research results were tested in 6 wells in Changning-Weiyuan block, and good cementing quality was obtained. It meets the requirement of hydraulic fracturing in the later stage.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE256

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