四川盆地中三叠统雷口坡组中发育多种类型的钾盐矿藏,是我国找钾的重点目标层系.磨溪气田雷口坡组地层卤水富含K、Li、Br、B元素,定性为中低矿化度KCl、LiC1、Br-、B2 O3等超标的优质化工原料水,显示出较好的钾盐勘探前景.地震资料解释结果表明,磨溪气田雷口坡组一段的第一亚段(雷一1)顶面表现为一个完整的长轴背斜形态,断层不发育.富钾卤水发育在背斜的翼部,而天然气则占据了背斜的核部,二者共同贮存在雷一1亚段溶蚀孔洞发育的滩相白云岩中,构成了典型的同层型气钾复合矿藏.借鉴含油气系统的概念,将富钾卤水的形成、聚集及后期保存等影响卤水型钾矿形成全过程的各种因素总结归纳为6大关键要素,即钾的物质来源,储层物性、封盖条件、圈闭条件、运移方式和保存条件.在乐山—龙女寺古隆起形成和演化的背景下,确定构造圈闭形成时间,分析优质储层发育有利因素以及后期保存条件,并按照各要素在时空上的搭配关系,动态地分析雷口坡组同层型气钾复合矿藏的形成过程.烃类物质和卤化物都是地下水所含的特殊物质,在地下水动力场的作用下,地层水在雷口坡组内部向着川中地区的继承性发育的古构造高点——磨溪背斜持续运移.被运移而来的由蒸发浓缩的古海水和石膏脱水形成的初始富钾地层水不断捕获下伏绿豆岩释放的钾离子,使得钾离子二次富集成藏.在地层水运移和气藏压力的共同作用下,形成气在上、富钾卤水在下的复合矿藏.长期继承性发育的古隆起不仅是油气聚集的有利部位,亦是二次运移、聚集的富钾卤水矿藏发育部位.本次研究成果为四川盆地及其他类似盆地的"气钾兼探"工作提供了一种新的方法和思路.

川南地区Y101区油气资源丰富,主要产气层下二叠统茅口组岩溶缝洞发育.储集层厚度小,横向非均质性强,与上覆上二叠统龙潭组岩性速度差异大,形成"两谷夹一峰"的强反射界面,对茅口组岩溶储集体产生屏蔽效应,导致岩溶储集体地震响应识别困难.为此,建立一套基于模型正演的频率域子波重构和波形分解技术进行岩溶储集体地震响应识别,首先,根据研究区钻井资料、测井资料和地层结构建立茅口组岩溶储集体模型,采用基于有限差分法的声波波动方程进行正演模拟;然后运用多子波分解的频率域子波重构和波形分解技术去除强反射界面,实现岩溶储集体地震识别.川南地区Y101区的应用效果验证了该方法的有效性;基于模型正演的频率域子波重构和波形分解技术能够消除强反射界面的屏蔽影响,储集层地震响应与钻井吻合度较高.

川南YJ向斜区YJ2井在茅口组钻遇石灰岩岩溶储层,测试获高产工业气流,日产量为58.8×104 m3,展现出川南向斜区茅口组岩溶储层巨大的勘探潜力.文中基于YJ向斜区高品质三维地震资料和典型新老钻井井震标定,结合模型正演,研究了茅口组内幕岩溶储层和表层岩溶储层的地震响应特征;优选均方根振幅地震属性,预测了内幕岩溶储层和表层岩溶储层的分布.研究表明,茅口组储层的主控因素为颗粒滩相沉积、东吴期岩溶改造和燕山-喜山期构造裂缝.研究成果为川南地区茅口组拓展勘探领域提供了重要支撑.

Abstract The Cambrian Longwangmiao Formation in the Sichuan Basin, southwest China, mainly comprising of dolomites, is one of the most ancient production layer in the world. Recently, Anyue gas field was discovered in the Leshan-longnvsi paleo-uplift in the central Sichuan Basin, and become the oldest gas field in the carbonate rocks in a single structural system in China. The reservoir is mainly distributed in the shoal grain dolomite, which is always controlled by the sedimentary environment. The conventional well correlation and sedimentary facies analysis might result in difficulty of carbonate shoals distribution and reservoir description in the gas field. Hence, how to characterize the geometry and distribution of carbonate shoals is critical for gas exploration and development. In our study, we completed an interpretation of 1172km2 3D seismic data in the field by means of all reflectors auto-tracking method. The method, combining density-based spatial clustering with waveform similarity clustering algorithm, can automatically track and interpret all reflectors within the 3D seismic cube. As a result, 18 local horizons, characterized by a shingled progradational configuration, were recognized within the Longwangmiao Formation. Synthetic seismograms suggest that these parallel oblique progradational sets were considered as carbonate shoals. The Longwangmiao Formation is consisted of stacked multistaged carbonate grainstones deposited on the shoals within the platform. These shoals, which grow towards northwest, are approximately distributed surrounding the Leshan-Longnvsi paleo-uplift. Stacked and widely distributed shoal grainstone reservoir is formed on the uplift. Our study suggests that the paleo-uplift mainly controls the shoal distribution in the study area, which provides important clues for gas exploration.

The clastic reservoir of the 2nd member of the Xujiahe formation is the typical lithological reservoir in PL area, the favorable reservoirs with strong heterogeneities are controlled by the depositional procession and it's difficult to predict through the seismic data.The seismic facies is plotted on the framework of seismic stratigraphy of the 2nd member of Xujiahe formation.Based on logging data,the hummocky- lenticular seismic facies is favorable,which is interpreted as underwater distributary channel.In order to predict the favorable sand distribution,the all-reflector auto-tracking method is applied. We speculate that Qianzhong ancient land and Jiangnan ancient land may be the source of the Xujiahe formation in central Si-chuan basin.The later well test results prove most industry gas wells locate in the hummocky-lenticular seismic facies,which indicate the accuracy of this research.

AY地区构造位置位于四川盆地川中古隆起平缓构造区中部,为一南东—北西向倾斜的单斜。综合地质、测井等资料,对研究区上三叠统须家河组展开了地震层序地层研究。研究结果表明,地震同相轴的上超方向、层序等T0厚度、下切河谷走向等信息指示了物源区可能位于研究区的南部或东南部。据薄片资料的岩屑成分排除了紧邻研究区东南部的泸州古隆起作为物源区的可能性。推测研究区须家河组物源区位于研究区南部或东南部的"黔中古陆"或"江南古陆"。该项研究成果对于四川盆地上三叠统须家河组的下一步勘探具有指导意义。

Influenced by the complex surface structures and subsurface geologic conditions,the seismic data acquired in the Kuqa Depression,Tarim Basin,is commonly featured by low signal-to-noise ratio and low quality of seismic profiles,which constrains petroleum exploration and development in the study area.During the DK 2D seismic acquisition in the Kuqa Depression,the wide line survey system and long geophone array receiving(9 strings of detectors used for huge thick loess accumulation zones,while 3 strings of detectors in three parallel lines used for complicated mountainous zones with ancient rocks at surface) were adopted as the core acquisition techniques,the detailed surface survey was performed,and seismic engineering remote sensing technique was used to select rational shot points and receiving points.In addition,the effective folds on geologic targets were enlarged,and the shooting and receiving conditions were enhanced.These measures helped increase the signal-to-noise ratio of single shot records and improve the quality of seismic sections.High-quality seismic data could thus be provided for identifying the structures in the Kuqa Depression.Successful pilot tests show that this technical approach can be popularized and applied in other areas with similar conditions.