四川盆地龙女寺构造龙王庙组储层特征及地震响应

2005年威远构造威寒1井龙王庙组获11×10⁴ m³/d的测试产量揭示了四川盆地内部龙王庙组勘探的突破。随着勘探的深入，川中磨溪—高石梯地区多口百万立方米气井的获得证实了龙王庙组巨大的勘探潜力。然而，龙女寺构造龙王庙组储层发育情况展现出与磨溪—高石梯（高磨主体）地区较大的差异，以传统“亮点”反射模式作为储层预测的指导思想已经无法满足现今勘探的需要。以龙女寺构造龙王庙组储层为例，借助已有岩心、薄片、测录井及地震资料，对区内龙王庙组储层与高磨主体地区龙王庙组储层进行对比研究，同时对储层的地震响应进行进一步的探索。研究表明：研究区龙王庙组发育局限台地沉积，颗粒滩相作为储层发育的最有利相带，最主要的储集岩类为颗粒云岩及晶粒云岩，储集空间包括粒间（溶）孔、晶间（溶）孔、溶洞等；研究区内储层表现出低孔低渗的特征，非均质性强，纵向展布差异大，横向可对比性差。对比分析“亮点”反射模式，采用波形聚类属性对储层进行平面分布预测，明确不同储层发育情况对应的波形特征。I类波形对应于储层发育于顶部，储层厚度>30 m；II类波形对应于储层发育于中部，储层厚度>20 m，或顶部中部发育2套相距20 m左右、厚度15 m左右的储层；I、II类波形为储层发育有利波形；III类波形对应储层较薄（<5 m）且储层呈薄互层状发育或储层欠发育；IV类波形对应储层欠发育；III、IV类波形为储层发育不利波形。该方法可有效地规避“假亮点”反射，预测结果与沉积相发育特征及实钻井储层发育情况吻合率高。

Reservoir characteristics and seismic response of Longwangmiao Formation of Longnvsi structure in Sichuan Basin

In 2005， the test production of 11×10⁴ m³/d of Longwangmiao Formation in Well Weihan 1 in Weiyuan structure revealed a breakthrough in the exploration of Longwangmiao Formation in Sichuan Basin. With the deepening of exploration， the acquisition of multi-million square gas wells in the Moxi-Gaoshiti area of the Sichuan Basin confirmed the huge exploration potential of the Longwangmiao Formation. However， the reservoir development of the Longwangmiao Formation in the Longnvsi area shows a large difference from the Moxi-Gaoshiti area. The “bright spot” reflection mode as the guiding ideology of reservoir prediction can no longer meet the needs of today's exploration. Taking the Longwangmiao Formation reservoir of the Longnvsi area as an example， the reservoirs of the Longwangmiao Formation and the Moxi-Gaoshiti area of the Longwangmiao Formation in the area were compared by means of existing cores， thin slices， logging and seismic data. And the seismic response of the reservoir was further explored. The research indicates that the Longwangmiao Formation in the study area mainly has limited sedimentary deposits， and the shoal subface is the most favorable face belt for reservoir development. The most important reservoir rocks are residual granulite and crystallite， and the reservoir space includes intergranular （dissolved） pores， intercrystalline （dissolved） pores and vugs. The reservoir has poor physical properties， showing low porosity and low permeability， strong heterogeneity， large differences in vertical distribution and poor horizontal comparability. Contrasting and analyzing the “bright spot” reflection mode， this paper uses the waveform clustering attribute to predict the reservoir distribution， and clarifies the waveform characteristics corresponding to different reservoir development conditions. Among them， the type I waveform corresponds to the development of the reservoir at the top， and the thickness of the reservoir is >30 m； the type II waveform corresponds to the development of the reservoir in the middle， and the thickness of the reservoir is >20 m， or two sets of reservoirs with a distance of about 20 m and a thickness of about 15 m in the middle and the top. The types I and II waveforms are favorable waveforms for reservoir development； type III waveform corresponding reservoirs are thin（<5 m） and the reservoirs are thinly interbedded or underdeveloped； type IV waveform corresponds to underdeveloped reservoirs； types III and IV waveforms are unfavorable waveforms for reservoir development. The method can effectively avoid the “false bright spot” reflection， the prediction results are in good agreement with the development characteristics of sedimentary facies and the development conditions of actual drilling reservoirs.