火山岩区断层封闭性的综合因子评价方法

基于火山岩区地质条件和断层封闭机制,依据断面正应力法,建立压实成岩断层封闭模式,结合断层面密度差法和断层紧闭指数法,建立岩性对接断层封闭模式。在此基础上,综合考虑断面正应力、断层紧闭指数、断层面密度差以及流体系数等因素,提出火山岩区断层封闭性的综合因子评价方法,并利用该方法评价准噶尔盆地西北缘火山岩区的断层封闭性。结果表明,火山岩区断层封闭性受断层级别的控制,即断层级别越高,综合因子越大,封闭性能越好,所控制的油藏规模越大;反之,断层级别越低,综合因子越小,封闭性能越差,所控制的油藏规模越小。评价结果与实际地质情况具有良好的吻合性,表明火山岩区断层封闭性综合因子评价方法具有较好的适用性。

Evaluation method of comprehensive factor of fault sealing in volcanic rock area

Based on geological conditions and fault sealing mechanisms in volcanic rock area, a fault sealing model of compaction diagenesis was established using the method of normal pressure on fault surface, and a fault sealing model of lithology juxtaposition was established based on density difference of fault surface and fault tightness index. An evaluation method of comprehensive factor of fault sealing in volcanic rock area was then carried out after taking normal pressure on fault surface, fault tightness index, density difference of fault surface and fluid index into consideration. The fault sealing in volcanic rock area of Karamay Oilfield is controlled by the fault level as a whole, namely, the better fault sealing leads to better comprehensive factor, and higher fault level, and eventually greater oil reservoir scale. The quantitative evaluation results compare well with the actual geological conditions, which suggests the wide applicability of the proposed method.