威远五峰组—龙马溪组页岩岩相展布及对水平井产量的影响

通过对威远地区14口评价井或导眼井五峰组—龙马溪组地层开展系统的笔石生物地层、岩相地层、测井响应、地球化学、元素地球化学等特征分析，证实了威远地区五峰组—龙马溪组古隆起的发育，指出古隆起发育控制页岩的厚度及岩相展布，明确优质页岩展布受古隆起发育控制，并提出水平井井位优化部署建议。主要结论如下:1）从生物地层、岩性地层、电性特征、地层厚度等方面证实在Z4-Z1—WY1—W5—WX井一带存在（水下）古隆起；2）不同时期地层分布及岩相主要受古隆起发育控制，隆起区及周边地层厚度薄，黏土矿物或碳酸盐矿物含量高，坳陷区沉积厚度大，硅质矿物含量高；3）威远地区五峰组页岩沉积期物源多来自其西部或北部，鲁丹阶早期以生物成因石英为主，物源较少，鲁丹阶晚期物源可能来自川南的黔中古陆，不同的物源方向意味着沉积体系的变化；4）鲁丹阶早期（LM1~LM3）地层储层品质最优，产量高，其储层参数平面展布受隆起发育控制，拗陷区域储层品质最好。建议以鲁丹阶早期地层为目标靶体实施水平井，优先部署该层段厚度较大区域水平井，尽量避开隆起发育区。

Lithofacies and Distribution of Wufeng Formation?Longmaxi Formation Organic-rich Shale and Its Impact on Shale Gas Production in Weiyuan Shale Gas Play,Southern Sichuan Basin,China

Paleo-uplift in the Weiyuan area was confirmed in this study by analysis of the graptolite biostratigraphy， lithofacies， logging response， geochemistry and element geochemistry at 14 wells in the Wufeng Formation?Longmaxi Formation. The thickness and lithofacies distribution of the shale are controlled by the paleo-uplift. The study clarifies that the distribution of high-quality shale was controlled by the paleo-uplift and puts forward some suggestions regarding the optimization of horizontal well location. It was concluded that: （i） The biological strata， lithological strata， electrical features and stratum thickness indicated that the （underwater） paleo-uplift was first discovered in the area of wells Z4-Z1-WY1-W5-WX. （ii） The stratigraphicand lithofacies distribution during different periods was mainly controlled by paleohigh development. The shale strata are thin in the paleo-uplift and adjacent areas， with high clay or carbonate mineral content. Thick shale containing siliceous minerals occurs in depressed areas. （iii） The sediment sources at wells WF2?WF4， LM1?LM3 and LM4?LM5 were central Sichuan ancient land， authigenic quartz and central Guizhou ancient land； the different provenances indicate changes in the sedimentary system. （iv） The best reservoir quality occurs in the early Ludan stage （LM1?LM3）. The reservoir properties were controlled by paleo-uplift， with the best reservoirs in depressed areas. LM1?LM3 strata are recommended as the target horizon. It is also recommended that horizontal wells be give priority in the thicker LM1?LM3 strata.