岩溶储层地层水地球化学特征及气水分布规律——苏里格气田南区马家沟组马五5亚段
- 1. 中石油长庆油田第六产气厂
- 2. 西南石油大学地球与科学学院
- 3. 中国石油勘探开发研究院
- 4. 西南石油大学
- 收稿日期:
2024-08-14
- 网络出版日期:
2024-12-03
摘要: 苏里格气田南区奥陶系马家沟组马五5亚段主要为岩溶储层,探明储量超千亿方,在开发生产过程中地层出水严重,气水关系复杂,气水分布规律及主控因素不明确,在很大程度上制约了该区的天然气产能释放。在地层水离子浓度分析的基础上,利用氯钠系数、脱硫系数、钠钙系数、镁钙系数和变质系数等化学参数对地层水的形成环境进行分析,进而通过单井出水层位识别、连井剖面对比以及平面展布特征刻画研究了气水分布规律;最后结合烃源岩、储层非均质性和构造等方面探讨了气水分布的主控因素。结果表明,苏里格气田南部马五5亚段地层水矿化度分布较为集中,平均83598.7mg/L,pH显示弱酸性,水型均表现为CaCl2型,地层水整体表现为低氯钠系数、低脱硫系数、低镁钙系数、低钠钙系数和高变质系数的特征,表明地层封闭性较好,有利于气藏保存,并且各参数平面特征相似,受岩溶储层控制。根据成因差异、空间分布和储层特征将地层水分为I型构造低部位水、Ⅱ型孤立透镜状水和Ⅲ型低渗带滞留水,I型主要在岩溶区发育,受岩溶残丘单元控制,具有统一气水界面,是高效井主要分布区,Ⅱ型在平面零星分布,受岩溶洼地和沟槽平面分布影响,储层物性一般,是潜在有利区,Ⅲ型储层物性较差。地层水分布受烃源岩、岩溶储层非均质性和同一岩溶单元局部构造等三个因素同时控制。烃源岩供烃能力不足是地层水水体发育的根本,岩溶储层非均质性决定了气水分布模式,局部构造造成气水分异,同一岩溶单元具有统一气水界面。
Geochemical characteristics of formation water and gas-water distribution in karst reservoir-- Section Ma 5 of Majiagou Formation, southern area of Sulige Gas Field
- Received Date:
2024-08-14
- Available Online:
2024-12-03
Abstract: The Ordovician Majiagou Formation in the southern Sulige gas field is mainly a karst reservoir with proved reserves of over 100 billion square meters of gas. In the process of development and production, the formation water is serious, the gas-water relationship is complicated, the gas-water distribution law and the main control factors are unclear, which restricts the natural gas production capacity release in this area to a large extent. Based on the analysis of formation water chemical characteristics, the formation environment of formation water is analyzed by using chemical parameters such as sodium chloride coefficient, desulfurization coefficient, sodium calcium coefficient, magnesium calcium coefficient and metamorphism coefficient, and then the gas-water distribution law is studied through the identification of single well water level, the correlation of well profile and the characterization of plane distribution characteristics. Finally, the main controlling factors of gas and water distribution are discussed in terms of source rock, reservoir heterogeneity and structure. The results show that the formation water in the southern part of the Sulige gas field has a relatively concentrated salinity distribution with an mean of 83598.7mg/L, a light acidic pH, and a CaCl2 water type. The formation water as a whole is characterized by low sodium chloride coefficient, low desulphurization coefficient, low magnesium calcium coefficient, low sodium calcium coefficient and high metamorphism coefficient, indicating that the formation is well sealed. It is beneficial to gas reservoir preservation, and the plane characteristics of each parameter are similar and controlled by karst reservoir. According to the genetic difference, spatial distribution and reservoir characteristics, the formation water is divided into water in the lower part of type I structure, isolated lensing water in type II structure and water retention in type III low permeability zone. The water in the lower part of type I structure mainly develops in the karst area and is controlled by the karst residual hill unit, and the water in type II lensing water is scattered in the plane, and the water in type III low permeability is difficult to identify due to the plane distribution of karst depressions and trenches. The distribution of formation water is controlled by three factors: source rock, karst reservoir heterogeneity and local structure of the same karst unit. The lack of hydrocarbon supply capacity of source rock is fundamental to the development of formation water bodies. The distribution pattern of gas and water is determined by the heterogeneity of karst reservoir, and the differentiation of gas and water is caused by local structure. The same karst unit has a unified gas-water contact.
孙振, 张正红, 郭智, 田国庆, 张云峰, 彭军, 万慈眩, 赵明睿. 岩溶储层地层水地球化学特征及气水分布规律——苏里格气田南区马家沟组马五5亚段[J]. 沉积学报. doi: 10.14027/j.issn.1000-0550.2024.114
Geochemical characteristics of formation water and gas-water distribution in karst reservoir-- Section Ma 5 of Majiagou Formation, southern area of Sulige Gas Field[J]. Acta Sedimentologica Sinica. doi: 10.14027/j.issn.1000-0550.2024.114
Citation: |
Geochemical characteristics of formation water and gas-water distribution in karst reservoir-- Section Ma 5 of Majiagou Formation, southern area of Sulige Gas Field[J]. Acta Sedimentologica Sinica. doi: 10.14027/j.issn.1000-0550.2024.114
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