基于地震多属性分析的吉尔嘎朗图凹陷煤层气富集区预测

Prediction of CBM enriched area in Jirgalangtu Sag based on the seismic multiple-attribute analysis

吉尔嘎朗图凹陷煤层厚度和含气性具有垂向变化大、横向变化快的特点,煤层气富集区预测成为生产难题。对于煤层预测,优选基于相控的地质统计学反演方法提高预测煤层厚度的精度;对于煤层含气性预测,由于单一属性预测含气性具有一定局限性,利用地震多属性融合技术提高煤层含气性预测精度,融合后的平面预测结果与实际钻井数据吻合率达91%。结合煤层厚度和煤层含气性2个重要评价指标,实现该区煤层气富集区的预测,认为工区东南部缓坡带为较好的煤层气富集区,为后续井位优化部署提供依据。

The coal seams in Jirgalangtu Sag are characterized by a great vertical change and rapid horizontal change for the thickness and gas-bearing property,so the prediction of the coalbed methane enrichment area has become the production problem.For the coal seam prediction,the geostatistical inverting method based on the phase control was optimized to enhance the precision of the prediction of the coal seam thickness;for the gas-bearing property prediction,due to the limitation of the single-attribute prediction of the gas-bearing property,with the help of the seismic multi-attribute fusion technology,the precision of the prediction of the coal-seam gas-bearing property was enhanced,and moreover the coincidence rate between the planar predicted results and actual drilled data after the fusion was up to 91%.Combined with the two important evaluating indexes i.e.the coal seam thickness and gas-bearing property,the prediction of the CBM enriched area in this area can be realized.It is considered that the southeast gentle slope zone is much better CBM enriched area,which provides the evidence for the follow-up optimized arrangement of the well location.