ISSN 1004-4140
CN 11-3017/P

微重力技术在中深层气藏开发上应用:以新疆油田滴西121井区为例

Microgravity Monitoring Technology for Deep Gas-Reservoir Development based on Dixi 121 Wellblock in Xinjiang Oilfield

  • 摘要: 天然气富集差异会引起地下介质密度较大的变化,进而引起地表重力值的响应。微重力技术通过测量地表重力值来监测气藏开发区地下密度变化,从而推测气藏开发中的流体变化。微重力监测的重力异常分离提取对于精细刻画气藏开发层段的密度变化至关重要。优选深度递推法实现不同尺度重力场分离,提取得到可靠的剩余重力异常场,以新疆油田滴西121井区为例,结合钻探与生产动态数据,研究剩余微重力异常与储层特征的关系。本文实现将微重力技术应用于中深层储层的气藏开发,创新性地针对研究区地质情况建立砂地比正演模型,分析砂体厚度在剩余重力异常场中的响应情况。结果表明:微重力技术在中深层气藏开发中应用效果较好;气藏开发层段砂地比越高,剩余微重力异常越低,与正演认识相符,并与地震数据刻画的砂体分布规律一致。

     

    Abstract: The difference in natural-gas enrichment significantly affects the underground medium density and thus the surface gravity. Microgravity monitoring technology monitors the morphological changes of a gas-reservoir development zone by measuring the surface gravity to obtain the change information of gas-reservoir development. The separation and extraction of gravity anomalies in microgravity monitoring is necessitated to accurately characterize the changes in gas-reservoir development intervals. The depth recursive method is the preferred method for separating residual gravity anomalies of different scales and extract reliable residual gravity anomalies. Considering the Dixi 121 well area of Xinjiang oilfield as an example and using the dynamic data of oil and gas drilling and production, the relationship between residual microgravity anomalies and reservoir characteristics is investigated in this study. Additionally, microgravity monitoring technology is applied to the development of gas reservoirs in middle and deep reservoirs, and a forward modeling of sand-ground ratio is performed based on the geological conditions of the study area. Subsequently, the response of sand thickness to the residual gravity anomaly field is analyzed. The results show that microgravity monitoring technology is effective for the development of middle and deep gas reservoirs. A larger sand-ground ratio corresponds to fewer residual microgravity anomalies, which is consistent with the forward modeling and sand-body distributions described using seismic data.

     

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