俄罗斯页岩油地质特征及勘探开发进展

俄罗斯主要页岩油资源赋存于西西伯利亚地台的巴热诺夫组和东欧地台的多玛尼克地层,页岩油区可采资源总量大,具备大规模开发利用的基础设施和外部环境,是未来开发利用的重要潜力区。巴热诺夫组主要岩性为硅质泥页岩,分布于上侏罗统-下白垩统,平均厚度为30 m,TOC平均为7%,有机质含量一般大于4%,以Ⅰ-Ⅱ型有机质为主,成熟度介于0. 5%～1. 1%;多玛尼克页岩油层系为一套泥盆系中弗拉阶-石炭系下杜内阶硅质/含硅的泥质石灰岩,整体厚度在100～600 m,有机碳含量在0. 5%～24%,以Ⅰ-Ⅱ型有机质为主,在伏尔加-乌拉尔盆地中北部成熟度介于0. 5%～1. 5%,南部靠近滨里海地区以生气为主。目前虽然受国际油价影响,俄罗斯页岩油资源的勘探开发探索却未停滞:2016年对巴热诺夫组146口垂直井进行测试,在活跃天数范围内日产油流量10. 8 t,对36口水平井进行测试,在活跃天数范围内平均日产流量7. 5 t;俄罗斯天然气工业股份有限公司2018年成立的巴热诺夫技术中心,目前已将水力压裂的时间减少50%,单位生产成本减少40%。在俄罗斯开发页岩油资源享受矿产开采零税率,不少油田地质资料充分、相互之间距离不远且基础设施完善,未来俄罗斯页岩油有望实现商业开采。

Geological characteristics and latest progress in exploration and development of Russian shale oil

Russia is rich in unconventional shale oil resources,covering almost all sedimentary basins ranging from Cambrian to Neogene in age.The major areas of prospecting potential in Russia are the Bazhenov Formation of the Western Siberian platform and the Domanik formations in the Eastern European platform.Bazhenov Formation is the Upper Jurassic-Lower Cretaceous in age.Its main lithology is siliceous shale,with a thickness of 30 m and TOC of 7% on average.Its TOC is generally above 4%,mainly falling on kerogens TypeⅠ-Ⅱ domain,with the maturity ranging from 0.5% to 1.1%.While Domanik formations,also called "Domanik facies" or "Domanik deposits" from the Paleozoic Upper Devonian (Russian stage-D₃ fr²) to Lower Carboniferous (Tournaisian-C₁t) in age,in the Volga-Urals and Timan-Pecher oil and gas provinces,are dark siliceous-clayey-bituminous limestones falling on kerogens TypeⅠ-Ⅱ domain,with an overall thickness of 100-600 m,TOC of 0.5-24%,and maturity ranging from 0.5% to 1.5% in the north-central part of Volga-Ural Basin.However,their gas production is mainly concentrated on the southern part of Caspian sea.Despite of the unfavorable impact due to the low international oil prices,the exploration and development of shale oil resources in Russia have never been stopped:146 vertical wells in the Bazhenov Formation were tested in 2016,with an average daily production rate of 10.8 t during the active days; meanwhile 36 horizontal wells were tested with an average daily production rate of 7.5 t during the active days.The Bazhenov technology center,set up by Gazprom in 2018,has cut down the time of hydraulic fracturing to 50%,and unit production cost to 40% in the development of Bazhenov oil.Moreover,the deve-lopment of shale oil resources in Russia can enjoy preferential policies like zero tax rate for mineral exploitations.Together with its existing favorable conditions,including abundant geological data for most oil fields,relatively short distances among these oil fields,and perfect infrastructures,the expectation is very positive for the future commercial development of shale oil in Russia.