奥连特盆地隐蔽油藏高效滚动勘探开发方法技术及应用——以厄瓜多尔14和17区块为例

Efficient progressive exploration and exploitation technology for subtle reservoirs in the Oriente Basin and its applications to blocks 14 and 17 in Ecuador

厄瓜多尔14和17区块位于奥连特盆地前渊带,主要含油层系为Napo组的M1,U和T段。现已开发油田进入高含水阶段,资源接替面临挑战。通过基于趋势面驱动的叠后地震数据连片一致性处理、时-频衰减高精度合成记录标定和解释及各向异性变速成图,精细刻画了低幅度构造,发现了一批低幅度构造油藏。采用分频迭代去噪拾取薄层弱反射系数,以其重构的叠后宽频有效信号为约束,采用相控波形非线性反演,定量预测了埋深3 000 m的2~5 m厚潮汐水道砂岩,发现了多个M1超薄层岩性油藏。依据区域水动力条件、低幅度构造油藏油-水界面趋势及油藏能量特征,发现了LU水动力油藏并滚动扩边。通过观察大量岩心薄片,发现海绿石在石英砂岩储层中呈胶结物和颗粒两种赋存状态,建立了海绿石双组构测井解释体积模型,评价并识别了UT低电阻率油藏。基于热带雨林地表和隐蔽油藏特点,按照“整体部署、分批实施、跟踪评价、及时调整”的策略,实现滚动勘探、评价和快速建产,探井和评价井成功率大于90%。

In blocks 14 and 17 of Ecuador,both situated in the foredeep zone of the Oriente Basin,the main oil-bearing strata comprise the M1,U,and T members of the Napo Formation.The developed oilfields in these blocks have entered a high water-cut stage,posing challenges to resource replacement.The trend surface-driven,post-stack consistent processing of seismic data,the time-frequency attenuation-based calibration and interpretation of high-precision synthetic seismograms,and anisotropic-variable-velocity mapping,are jointly applied to finely characterize lowamplitude structures,with many low-amplitude structural reservoirs discovered.Thin layers' weak-reflection coefficients,determined through frequency-division iterative denoising,contribute to the reconstruction of effective poststack broadband signals.With these signals as constraints,we quantitatively predict 2-to 5-m-thick tidal channel sandstones at a burial depth of 3 000 m through a seismic phase-controlled nonlinear inversion of waveforms,identifying several ultra-thin lithologic reservoirs in the M1 member.Based on regional hydrodynamic conditions,the oil-water contact trends of low-amplitude structural reservoirs,and the energy characteristics of reservoirs,we determine hydrodynamic oil reservoirs in the LU member and perform step-out drilling.The observation of numerous thin sections from cores reveals the presence of glauconites as cements and particles in the quartzose sandstone reservoirs.Accordingly,a dual-component volume model of glauconites for log interpretation is developed,allowing for reservoir evaluation and identification of low-resistivity reservoirs in the UT member.Based on the characteristics of tropical rainforest surfaces and subtle reservoirs in the subsurface,we achieve progressive exploration,evaluation,and rapid production onstream following the strategy of “overall deployment,batch-wise implementation,tracking and evaluation,and timely adjustment”,with a success rate of over 90 % for both exploration and appraisal wells.