渤海海域火山热流体及其对碳酸盐岩优质储层的控制作用

渤海海域火山活动频繁，为了落实火山热液活动对碳酸盐岩储层的影响，利用岩心、铸体薄片、扫描电镜、碳氧同位素、锶同位素、稀土元素和流体包裹体等分析手段，对渤海海域火山热流体活动特征及其对古生界碳酸盐岩储层的改造作用进行了研究。渤海海域火山热液流体主要受断裂控制，主要成分包括幔源成因的岩浆并携带大量的CO₂、H₂S等气体；建立了碳酸盐岩储层中火山热液活动的标志，包括热液诱导缝、热褪色，鞍形白云石（渤海海域首次发现）、硅质结核、柱状自生石英和脉状黄铁矿等典型热液矿物。受热液作用影响的方解石具有δ18O值异常低、87Sr/86Sr值异常高、轻稀土元素富集及Eu正异常等特征，盐水包裹体均一温度远高于地层温度。火山成因热液流体在沿断裂进入碳酸盐岩围岩过程中，促使围岩产生了大量诱导缝，发生热液白云岩化作用，产生大量的晶间孔，磷灰石包壳、硅质结核等热液矿物对先存的孔缝具有一定的支撑和保护作用，火山热液流体沿孔缝进入，进一步对碳酸盐岩进行溶蚀改造，形成大量的溶蚀孔隙，储层物性大大改善，提升了碳酸盐岩储层的储集性能。 

Volcanic hydrothermal fluid activity and its influence on carbonate reservoirs in Bohai Sea area

Volcanic activity is frequent in the Bohai Sea. Hydrothermal fluid activity and its reformation effect on Paleozoic carbonate reservoirs were studied based on core, cast thin section, scanning electron microscopy, carbon and oxygen isotopes, strontium isotope and rare earth elements in combination with fluid inclusion analysis to study the influence of volcanic hydrothermal activity on carbonate reservoirs. The hydrothermal fluid in the Bohai Sea was controlled by fractures. The main ingredients of hydrothermal fluid include a large amount of CO₂ and H₂S gas from the earth mantle. Properties indicating hydrothermal fluid activity included induced joints by hydrothermal fluid, typical rock heat bleaching and typical hydrothermal minerals such as saddle dolomite (first discovered in the Bohai sea area), siliceous nodules, columnar authigenic quartz and veined pyrite. The calcites growing under the influence of hydrothermal fluid are featured by low δ18O value, high 87Sr/86Sr, light rare earth enrichment and Eu positive exception, and the homogenization temperatures of salt water inclusions are obviously higher than the formation temperature. When volcanic hydrothermal fluids flowed along faults, a large number of hydrothermally induced fractures were formed in carbonate reservoirs, and hydrothermal dolomitization took place in large intergranular pores. Hydrothermal minerals such as cladding of apatite and siliceous nodules supported and protected the previous apertures. Volcanic hydrothermal fluids flowed along the apertures, forming a large number of dissolution pores in carbonate rocks, which improved carbonate reservoir porosity.