论文详情
塔里木盆地顺北地区地表沙丘起伏大,地震信号吸收衰减严重,断溶体储集体埋藏深度大,纵横向非均质性强,因而断溶体(断裂、缝洞)成像精度不高、储层预测与圈闭描述难度大。为此,在该区系统开展了三维地震采集、目标处理、综合解释一体化技术攻关。首先,基于断溶体目标优化采集方案设计,采用中小面元、长排列、宽方位、高覆盖的观测系统,尽可能保护断裂绕射、缝洞体低频信息,提高采集数据质量;其次,在保幅、保真的前提下,建立了以“三层一带”精细速度建模为核心的断溶体成像技术,提高缝洞及不同尺度走滑断裂带的成像精度;再次,依据断溶体储层类型及反射结构特征,建立了走滑断裂带及断溶体储层地震识别模式,开展储层敏感属性分析,形成针对断溶体外部轮廓、内部不同类型储层的一系列储层预测及流体检测技术;最终,建立了“张量属性定轮廓、振幅属性定边界、融合雕刻定体积”的圈闭落实与描述技术,形成了“打主断、过异常、穿核部”目标优选与井轨迹优化设计技术。探区多口钻井实现了油气重大突破,证实了顺北沙漠区超深断溶体油气藏三维地震勘探技术的有效性及适用性。
Fault-related dissolution reservoirs are buried deeply in the Shunbei area of the Tarim Basin and exhibit a high heterogeneity.Moreover,the surface dunes fluctuate greatly,and the seismic attenuation is severe.This results in a low imaging accuracy of the fault-related dissolution body (fractures and fracture-vugs),and in difficult reservoir prediction and trap description.Therefore,an integrated exploration method consisting of three-dimensional seismic acquisition,target processing,and comprehensive interpretation was carried out systematically in the study area.First,the acquisition design scheme for fault-related dissolution bodies was optimized.The surveying scheme was characterized by small or medium-sized bins,long seismic spread,wide azimuth,and high coverage to preserve the diffraction from fractures and the low frequency information for fractures and cave bodies,thereby improving the quality of the acquired data.Second,on the premise of amplitude and fidelity preservation,velocity modeling and imaging techniques with preservation of amplitude and fidelity were implemented.The latter included pre-stack time migration and reverse-time depth migration imaging,to improve the imaging accuracy of fracture-vugs and strike-slip fault zones at different scales.Third,according to the types of fault-related dissolution bodies and the characteristics of the reflection configuration,the seismic identification patterns of strike-slip fault zones and fault-related dissolution reservoirs were identified,and the sensitive attributes of the reservoirs were analyzed.A series of reservoir prediction and fluid detection techniques for reservoirs located outside and inside fault-related dissolution bodies was developed.Finally,a technique for trap description was proposed,which uses the gradient structure tensor attribute to determine the outline,the amplitude attribute to describe the boundary,and the fusion engraving technique to determine the volume of the dissolution body.Moreover,a technology for target and well trajectory optimization was proposed,which aims at “drilling through the main fault,the seismic anomaly,and the core of the fault”.By carrying out several drilling wells great breakthroughs in oil and gas exploration have been made in the study area,thereby proving the validity and applicability of the three-dimensional seismic exploration technology for ultra-deep fault-related dissolution bodies in the Shunbei area.
中国石油化工股份有限公司科技攻关项目“顺北特深断溶体储集体地震关键技术研究应用”(P18040)资助。