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致密砂岩气是非常规油气资源的重要组成部分,是当前技术条件下可动用程度最高的部分.致密砂岩气可分为连续型致密砂岩气和圈闭型致密砂岩气.通过系统地对比圈闭型和连续型致密砂岩气在运聚、分布上的地质、地化特征差异,并使用物理模拟实验揭示了连续型致密砂岩气呈近源累计聚集的动力学成因机制.研究表明:圈闭型致密砂岩气是天然气远距离运聚的结果,在天然气组分和碳同位素上都有很明显的分馏效应,具有良好的输导体系,形成了“常规圈闭汇聚、具有边底水、优质盖层封盖”的特征;连续型致密砂岩气是近源累计聚集的结果,天然气组分和碳同位素基本不产生分馏效应,同一地区碳同位素呈现离散性,表现出“连续分布、近源汇聚、气-水分布复杂或倒置”的特征.连续型致密砂岩气近源累计聚集是致密砂岩储层中近纳米级孔喉背景下天然气运移动阻力变化及平衡的结果.在天然气运移至气-水临界界面之前,气-水界面将天然气与地层水分为两个系统,天然气运移的动力是气体异常压力,浮力作用产生的基本条件不满足,运移阻力是上覆地层水压力和毛细管压力.连续型致密砂岩气圈闭可认为是非常规动力圈闭,其核心可概括为“(近)纳米级孔喉、气体活塞式推进、浮力基本不起作用、动阻力平衡决定气-水界面”.
Tight sandstone gas is an important part of unconventional oil and gas resources and is the most widely used part under the current technological conditions.Dense sandstone gas can be divided into continuous tight sandstone gas and tight sandstone gas.After the systematic comparison of trapped sandstone gas And the continuity of tight sandstone gas in the distribution and distribution of the geological and geochemical characteristics of differences, and the use of physical simulation experiments reveal the continuous tight sandstone gas accumulation near-source kinetic mechanism of formation.The study shows that trapped tight Sandstone gas is the result of long-distance natural gas migration and accumulation. It has obvious fractionation effects on both natural gas components and carbon isotopes. It has a good conductivity system and forms a “conventional trap assembly with edge-water and high-quality cap The results show that the continuous tight sandstone gas is the result of accumulation of near-source accumulations, and the composition and carbon isotope of natural gas do not produce any fractional effect. The carbon isotopes in the same area show the discrepancy, showing ”continuous distribution, near-source Convergence, gas-water complex or inversion. “Accumulation of near-source accumulation of continuous tight sandstone gas is the result of natural gas migration in tight sandstone reservoirs near the nanoscale pore throat The change of the resistance and the balance result.Before the natural gas is transported to the gas-water critical interface, the gas-water interface divides the natural gas and the formation water into two systems. The motive force of natural gas migration is the gas abnormal pressure, and the basic condition of the buoyancy effect is not The transport resistance is the water pressure and the capillary pressure of the overburden.The continuous tight sandstone gas trap can be regarded as an unconventional dynamic trap whose core can be summarized as ”(near) nano-pore throats, gas-piston propulsion, Buoyancy basically does not work, the balance of dynamic resistance determines the gas - water interface ".