利用声波时差研究异常孔隙流体压力释放次数及深度的方法

A method for studying release times and depths of abnormal pore fluid pressure of mudstone.

大庆石油学院, 黑龙江大庆163318

Daqing Petroleum Institute,Daqing 163318,China

异常孔隙流体压力对油气的生成、运移、聚集和储存具有控制作用,因此研究异常孔隙流体压力的释放次数和深度有助于提高油气藏的预测精度。为此,利用声波时差对泥岩异常孔隙流体压力的释放次数和深度进行了研究。首先对泥岩异常孔隙流体压力形成的机制和条件进行了分析,探讨了泥岩异常孔隙流体压力的形成和演化规律；然后利用声波时差资料,根据泥岩破裂与异常孔隙流体压力释放之间的关系,建立了研究泥岩异常孔隙流体压力释放次数和深度的方法；最后,利用该方法研究了松辽盆地古龙凹陷古11井青山口组和嫩一段、嫩二段泥岩异常孔隙流体压力的释放次数和深度。研究结果表明,古11井青山口组和嫩一段、嫩二段泥岩均经历了3个异常孔隙流体压力释放过程,形成了扶余、杨大城子和萨尔图、葡萄花、高台子等油层；目前正处于第4次演化阶段,具有较高的异常孔隙流体压力,有利于油气在扶余、杨大城子和萨尔图、葡萄花、高台子的聚集与保存。研究结果与古龙凹陷中部含油气组合的油气成藏条件相符合,表明利用声波时差来研究泥岩异常孔隙流体压力释放次数和深度的方法是可行的。

Based on the analysis of formation mechanism,condi- tions,and evolution laws of abnormal pore fluid pressure, a method studying release times and depths of abnormal pore fluid pressure of mudstone by interval transit-time was established according to relation between cracking of mud- stone and release of abnormal pore fluid pressure.The method was applied in studying release times and depth of abnormal pore fluid pressure of K_? and K_? mudstone in Gu 11 well of Gulong Sag in Songliao Basin.The results is as following:①abnormal pore fluid pressure of mud- stone in K_? and K_? released 3 times in well Gull and both of them are in the fourth evolution stages now;②the second and the third release of abnormal pore fluid pressure occurred in K_? mudstone and the third release occurred in K_? according with their main expelling period respec- tively,they are favorable for generating hydrocarbon by expelling from source rock.③There exist high abnormal pore fluid pressure in mudstone of K_? and K_?,which is favorable for oil-gas to accumulate and preserve in S,P,G reservoirs.The results were coincident with the actual oil- gas accumulation conditions in middle oil-gas bearing com- bination,it is proved to be practical to study release times and depths of abnormal pore fluid pressure.