摘要
将钻井实测四川盆地五峰组—龙马溪组地层压力与现今构造分区、青藏高原各块体的向东运动速度进行综合对比,发现五峰组—龙马溪组地层压力宏观压力背景可能受燕山运动以来多期构造运动的影响,超压区主要位于川东高陡构造带与川南低陡构造带的主体部位。燕山—喜山期,华蓥山断裂带东侧发生强烈挤压,形成长条形高陡背斜与开阔向斜相间分布。现今的青藏高原各块体向东运动也可能对五峰组—龙马溪组地层压力系数宏观分布产生一定的影响。钻井勘探证明,四川盆地五峰组—龙马溪组地层沉积后,地层中有机质先生成原油,在异常地温梯度作用下,裂解为天然气。所以,烃类裂解导致流体膨胀是五峰组—龙马溪组地层异常压力的第二个因素。同时,地层压力宏观背景下的局部地区地层压力异常可能是页岩气保存条件的反映。在对五峰组—龙马溪组地层压力异常成因分析的基础上,将地层压力异常抽象为水平作用力与垂向作用力,采用反映横向作用与垂向作用的地震泊松比参数作为地层压力预测的基础参数,从而建立起泊松比地层压力预测方法。实际资料预测与后期钻井验证证明,泊松比地层压力预测方法适合四川盆地五峰组—龙马溪组页岩气地层压力预测,经多年试验与改进,该方法已在威远—长宁地区页岩气田勘探开发中得到广泛推广与应用,产生了巨大的经济效益与社会效益。到2019年,长宁页岩气田累计产量已达130亿方,广义泊松比地层压力预测方法是助推长宁页岩气田成为我国第一页岩气田的关键技术之一。
We compared the measured pressure coefficient of the Wufeng Longmaxi Formation,Sichuan Basin with the current tectonic division and the eastward movement velocity of the Qinghai Tibet Plateau,and found that the formation pressure of the Wufeng Longmaxi Formation might be affected by the multi-stage tectonic movement since the Yanshan Movement.The overpressure zone is located in the central areas of the high steep tectonic belt in eastern Sichuan and low steep tectonic belt in southern Sichuan.During the Yanshan Xishan period,the east side of the Huayingshan fault zone was strongly extruded to form a long strip-shaped high steep anticline and an open syncline.The eastward movement of various blocks of the Qinghai Tibet Plateau might also have influenced the pressure distribution in the Wufeng Longmaxi Formation.Drilling results showed that after the deposition of the Wufeng Longmaxi Formation in the Sichuan Basin,organic matters in the formation were transformed into crude oil and then cracked into natural gas under the action of abnormal geothermal gradient.Therefore,hydrocarbon cracking led to fluid expansion,which was the second causative factor of abnormal formation pressure in the Wufeng Longmaxi Formation.Meanwhile,local abnormal formation pressure may reflect the shale gas preservation condition.Based on the analysis of the formation pressure anomaly in the Wufeng Longmaxi Formation,the abnormal formation pressure was attributed to horizontal and vertical forces,and the Poisson's ratio formation pressure prediction method was developed based on Poisson's ratio calculation using seismic parameters.It is proved that this prediction method is suitable for predicting the shale gas formation pressure in the Wufeng Longmaxi Formation.After years of testing and improvements,this prediction method has been widely applied in the exploration and development of shale gas fields in the Weiyuan Changning area,bringing huge economic and social benefits.By 2019,the cumulative production of the Changning shale gas field ha
作者
井翠
郝龙
张婧
邓夏
於文辉
JING Cui;HAO Long;ZHANG Jing;DENG Xia;YU Wenhui(Sichuan Changning Natural Gas Development Co.,Ltd,Chengdu 610000,China;TerraMagis Energy Technology Co.,Ltd,Wuhan 430074,China)
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2021年第1期402-410,共9页
Earth Science Frontiers
基金
国家科技重大专项“长宁威远页岩气开发示范工程”项目(2016ZX05062006)。
