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四川盆地元坝二叠系长兴组 气藏气水分布特征及水侵早期识别

作    者:吴亚军1,刘莉萍1,2,代 平1,2,任海侠1,2,刘远洋1
单    位:1中国石化西南油气分公司勘探开发研究院;2中国石化西南油气分公司地质中心实验室
基金项目:本文受国家科技重大专项课题“超深层复杂生物礁底水气藏高效开发技术”等联合资助
摘    要:
探讨四川盆地元坝二叠系长兴组气藏气水分布特征及水侵早期识别,可为下一步开发部署指明方向,为气藏 稳产提供实用方法。通过动态跟踪气井流体变化特征,结合静态地质特征,明确气藏气水分布特征及控制因素,在此基 础上根据产水气井出水类型,建立基于生产数据及产出液化学特征的水侵早期识别模式。研究认为:元坝长兴组气藏 气井产出液中凝析水与地层水并存,总矿化度与日产水量、日水气比均呈指数正相关关系。游离气与溶解气并存,随着 水侵程度增加,CH4含量降低、H2S含量增加。③、④号礁带以游离气为主,古油藏应该位于此或范围更小;①、②号礁带 及礁滩叠合区为气水过渡带,局部构造及储层非均质性调整气水分布。裂缝发育程度控制气井产水速度,水产量的上 升与多条裂缝逐渐被突破而沟通周边水体相关;元坝长兴组储层裂缝欠发育,气井出水生产类型以线性型为主,存在水 侵预警期;对裂缝发育、出水生产类型为多次方型的气井,应加强监控,开展合理配产分析,延长无水采气时间。构造高 部位或构造相对低部位裂缝欠发育的礁滩发育区为开发部署首选目标。建立的水侵早期识别模式可推广应用。
关键词:水化学特征;天然气组分;气水分布;出水生产类型;水侵早期识别;长兴组;元坝

Gas-water distribution characteristics and early identification of water invasion of Changxing Formation gas reservoir in Yuanba, Sichuan Basin

Author's Name: WU Yajun, LIU Liping, DAI Ping, REN Haixia, LIU Yuanyang
Institution: 
Abstract:
This paper discusses the gas-water distribution characteristics and the early identification of water invasion of Changxing Formation gas reservoir in Yuanba, Sichuan Basin, and provides a practical method for stabilizing the gas production. By dynamically tracking the fluid variation characteristics of gas wells and combined with static geological characteristics, the characteristics and the controlling factors of gas-water distribution in gas reservoirs are defined. On this basis, according to the water output type of water-producing gas wells, the early water invasion recognition model is established. The results show that: The condensate water coexists with formation water in the produced liquid of gas well, and the total salinity has an exponential positive correlation with daily water production and daily gas-water ratio. Free gas and dissolved gas coexist. With the increase of water invasion degree, the content of CH4 decreases and the content of H2S increases. No. 3 and No. 4 reef belts are dominated by free gas, and the palaeo-oil reservoirs should be located here or in a smaller range. No. 1 and No. 2 reef belts and reef-shoal superimposed belt are gas-water transitional belts, and the local structure and reservoir heterogeneity adjust the gas-water distribution. The development degree of fractures controls the water production rate of gas wells, and the increase of water production is related to the gradual breakthrough of multiple fractures to communicate with surrounding water bodies. The reservoir fractures of Changxing Formation in Yuanba are underdeveloped, and the water production type of gas well is mainly linear, and there is a warning period of water invasion. For gas wells with developed fractures and multi-power type of water production, it is necessary to strengthen monitoring, and carry out rational production allocation analysis, so as to extend the time of water-free gas production. Reef-shoal development areas in high parts of structure or in relative low parts of structure with underdeveloped fractures are the preferred targets for deployment. The established early identification model of water invasion can be popularized and applied.
Keywords: hydrochemical characteristics; natural gas component; gas-water distribution; water production type; early identification of water invasion; Changxing Formation; Yuanba
投稿时间:2021-01-26  
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