| 摘要: |
| 多种动力影响了天然气成藏过程，但不同地下环境中控制天然气运移聚集的主要动力不尽相同。对超压盆地 内天然气成藏过程中的动力进行了分析，并对我国30个典型超压环境中的天然气藏进行了剩余压力梯度统计，在此 基础上建立了剩余压力梯度与天然气聚集效率的关系。分析结果表明，超压盆地内天然气成藏过程中的动力可由 浮力梯度及剩余压力梯度的和来表示,至少有60%的成藏动力来源于剩余压力梯度。超压盆地中,不同级别的天然 '气聚集效率具有相应的动力(梯度)标准，中效天然气成藏过程中，源-储间剩余压力梯度须达到12 kPa/m;高效天然 气成藏过程的动力界限为18 kPa/m。我国大中型超压盆地中气藏成藏期间的剩余压力剖面可划分为散失型、弱压 差汇聚型和强压差汇聚型3种类型。其中散失型不具备指向储集层的运移动力,无法形成天然气藏;汇聚型可能形 成天然气藏，其剩余压力梯度控制了成藏效率。 |
| 关键词: 超压盆地 剩余压力梯度 天然气成藏 成藏动力 |
| DOI： |
| 分类号: |
| 基金项目:国家“973”重点基础研究发展计划项目(2007CB209503) |
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| Relationship between excess-pressure gradient and gas accumulation in overpressured basin |
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SUN Ming-liang1,LIU Guang-di1,LI Jian2
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(1. State Key Laboratory of Petroleum Resource and Prospecting in China University of Petroleum, Beijing 102249, China;2. Langfang Branch of Petroleum Exploration and Development Research Institute，PetroChina,Langfang 065007, Hebei Province, China )
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| Abstract: |
| Gas migration and accumulation were controlled by several forces, but the significance of each force was considerable difference in different geologic environment. Dynamic of gas migration was analyzed in overpressured basin. The relationship between excess-pressure gradient and gas accumulation efficiency was established by statistics of excess-pressure gradient in over 30 basins in China. The results show that dynamic of gas migration can be divided into two components including buoyancy and excess-pressure gradient, and at least 60% of gas migration dynamic comes from excess-pressure-differ-ence. In overpressured basin, gas accumulation efficiency correlates closely with excess-pressure gradient. It would take place moderately efficient gas accumulation event unless excess-pressure gradient is beyond 12 kPa/m. And only excess-pressure gradient was beyond 18 kPa/m, highly efficient gas accumulation would happen. In large and medium-sized overpressured basin of China, excess-pressure section in gas accumulation period can be divided into three types: scatter dynamic type, lower excess-pressure gradient afflux type and strong excess-pressure gradient afflux type. The excess-pressure section of scatter dynamic type does not have migration dynamic directing reservoir, and can not develop natural gas pool. The excess-pressure section of afflux type can develop natural gas pool, and the magnitude of excess-pressure gradient controls the efficiency of gas accumulation. |
| Key words: overpressured basin excess-pressure gradient gas accumulation accumulation dynamic |
