重力流沉积砂岩的成因、改造及油气勘探意义

发布时间：2018-11-01 20:51

【摘要】：在前人研究基础上,结合最新研究成果,以深水砂岩形成为线索,讨论重力流沉积砂岩成因机制以及后期底流改造作用,分析争议问题,探讨解决方法,并揭示油气勘探意义。重力流沉积砂岩成因机制复杂,将浊流严格定义为紊流支撑,悬浮沉降的重力流,有利于砂岩成因机制解释及砂体分布预测。具有正粒序构造的砂岩为浊流成因,块状砂岩和逆粒序砂岩为砂质碎屑流成因。浊流砂岩沉积在平面上向四周散开,形成朵叶状砂体,碎屑流砂岩沉积沿流体搬运方向展布,形成舌状砂体。重力流沉积受后期底流改造而形成含牵引流构造的砂岩,但牵引流构造不是底流改造砂体所特有的标志,需结合砂体分布特征及沉积环境加以鉴别。水道内重力流沉积受底流影响,天然堤不对称发育,水道发生单向迁移,砂体平面展布范围变大,但砂体垂向厚度变小。同时,受底流改造的天然堤之间会形成局部负向地形,为后期水道、朵体有利沉积场所,易形成连续垂向叠置砂体。深水砂岩预测需将重力流沉积和底流改造结合起来。
[Abstract]:On the basis of the previous studies and the latest research results, taking the formation of deep-water sandstone as a clue, this paper discusses the genetic mechanism of gravity flow sedimentary sandstone and the late remolding of bottom flow, analyzes the controversial problems, discusses the solutions, and reveals the significance of oil and gas exploration. The formation mechanism of gravity flow sedimentary sandstone is complicated, and the turbidity flow is strictly defined as the gravity flow supported by turbulent flow and suspended subsidence, which is helpful to explain the genetic mechanism of sandstone and predict the distribution of sand body. The sandstone with normal grain sequence structure is turbidite origin, block sandstone and reverse grain sequence sandstone are sandstone clastic flow origin. The turbidite sandstone deposits are dispersed around the plane to form a leaf-like sand body, while the clastic flow sandstone deposits are distributed along the direction of fluid transport, forming a tongue sand body. The gravity flow deposition was transformed by the late bottom flow to form sandstone with traction flow structure, but the traction flow structure is not the special mark of the bottom flow reconstruction sand body, which needs to be identified in combination with the distribution characteristics of sand body and the sedimentary environment. The gravity flow deposition in the channel is affected by the bottom flow, the natural dike is asymmetrical, the channel is migrated in one direction, and the horizontal distribution range of the sand body becomes larger, but the vertical thickness of the sand body becomes smaller. At the same time, the local negative topography will be formed between the natural embankments modified by the bottom flow, which is the late waterway, the flower body is favorable for deposition, and it is easy to form continuous vertical superimposed sand bodies. Deep-water sandstone prediction needs to combine gravity flow deposition with bottom flow transformation.
【作者单位】：陕西省地质调查中心;中国石油勘探开发研究院;中石油煤层气有限责任公司忻州分公司;中国石油华北油田分公司勘探开发研究院;
【基金】：中国石油天然气股份有限公司重大科技项目“海外海洋勘探技术与有利目标评价研究”(2014D-0908)
【分类号】：P618.13

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