致密砂砾岩岩性测井识别方法及应用

 以王府断陷小城子地区登娄库组和营城组为例,研究了致密砂砾岩岩性测井识别方法及其应用。利用录井岩性资料总结登娄库组、营城组各种岩性的组分,并提取2 个层组的主要岩性,登娄库组主要岩性为砂砾岩、砂岩和泥岩,营城组主要岩性为砾岩、砂砾岩和泥岩;分析不同岩性的测井响应特征,并提取2 个层组的岩性敏感参数,登娄库组为自然伽马、中子、声波时差和电阻率,营城组为自然伽马、中子和密度。利用SPSS 软件建立登娄库组和营城组的岩性Fisher 判别模型,将该模型应用于未参与建模的5 口井储层岩性的识别,识别准确率达86%,证明了该方法的可靠性。     

层间非均质砾岩油藏水驱油模拟实验

针对砾岩油藏层间非均质性强,开采过程中层间矛盾突出,剖面动用差异大,油藏整体采收率低的特点,以新
疆油田七区克上组砾岩油藏为例,开展了不同非均质程度模型恒压水驱油实验。结果表明：同一组并联水驱油实验
中,渗透率越高的岩芯越先启动,含水率上升越快,无水采收率越低,驱油效率越高;层间渗透率级差越大模型驱油效
率越低,与高渗岩芯相对渗透率级差大于8 的岩芯并联驱替不能启动;粗砂岩和含砾粗砂岩等单模态或双模态孔隙结
构岩芯驱油效率较高,砂砾岩和砾岩等复模态孔隙结构岩芯驱油效率较低;增大并联模型驱替压差后中低渗岩芯驱油
效率增大,含水率上升速度加快。     

含砾砂岩储层重复压裂新方法及机理分析

重复压裂技术广泛应用于老油田开发过程,尤其适用于致密砂岩、页岩等典型储层,而含砾砂岩储层中重复压裂方法的有效性还有待研究。针对重复压裂含砾砂岩储层产生复杂裂缝网络的压裂方法问题,基于动态载荷促进裂缝分叉、易渗透压裂液明显降低岩石有效应力的作用机理,本文提出“变排量、分阶段多压裂液组合”的重复压裂方法。为验证该方法的合理性,本文以人工预制的含砾砂岩试件为实验对象,通过变排量、分阶段注入不同性质压裂液进行了室内真三轴压裂模拟实验,总结了压裂机理。研究表明：变排量压裂方式产生的裂缝条数至少是定排量压裂方式产生裂缝条数的3倍;分阶段多压裂液组合压裂方法产生水力裂缝的条数是单一类型压裂液压裂产生裂缝条数的3倍。变排量、分阶段多压裂液组合的压裂方法将对含砾砂岩储层进行重复压裂产生复杂裂缝具有一定的借鉴意义。     

克拉玛依油田八区下乌尔禾组油藏水淹体四维描述

描述了块状特低渗透砾岩油藏水淹特征及水淹规律,并利用加密井水淹层解释结合动态分析定量描述了水淹体形态随时间的变化、进一步讨论了该类油藏的水驱机理,且对该区油藏的长期双线性渗流模型、裂缝控制水驱方向、水驱速度差异、裂缝的应力敏感性等进行了讨论。现场应用该成果,控制注水取得较好成效。     

岩石物理相在砂砾岩储层分类评价中的应用——以M1井区上乌尔禾组为例

玛湖凹陷M1井区上乌尔禾组砂砾岩储层非均质性强,孔隙结构和试油产能差异大,主控因素不明.利用岩心、薄片、测录井及试油等资料,对M1井区上乌尔禾组的沉积相、成岩相、裂缝相以及储层综合分类展开研究.结果表明,扇三角洲砂砾岩储层主要为重力流及牵引流2种成因类型,对应扇面河道、水下分支河道、泥石流3种沉积微相.可识别出弱成岩作用相、溶蚀相、压实致密相、方解石胶结相4种成岩相.沉积相与成岩相是影响该区储层的主控因素,依此将储层分为水下分流河道-弱成岩作用相、水下分流河道-溶蚀相、扇面河道-弱成岩作用相、扇面河道-溶蚀相、泥石流-压实致密相、砂砾岩方解石胶结成岩相6种岩石物理相.依据沉积相和成岩相对于储层的影响,将6种岩石物理相归纳为3种类型储层,其中Ⅰ类和Ⅱ类储层最好,Ⅲ类储层最差,胶结致密.该区岩石物理相与试油结果匹配好,可有效预测有利储层分布区.     

K-Ar dating of late Mesozoic volcanism and geochemistry of volcanic gravels in the North Huaiyang Belt, Dabie orogen: Constraints on the stratigraphic framework and exhumation of the northern Dabie orthogneiss complex

Two eruption episodes are identified through systematic field investigations and K-Ar dating of the lateMesozoic volcanic rocks in the North Huaiyang belt (NHB),Dabie orogenic belt, of which the earlier volcanic suitetermed Maotanchang Fm. (Fm.) occurring at Jinzhai,Xianhualing and Maotanchang, etc., was erupted from 149Ma to 138 Ma. The other named Xiaotian Fm. mainly dis-tributed at Xiaotian, Shucheng, etc., was formed between132 Ma and 116 Ma. During the eruption gap of the two vol-canic suites deposited a volcano-sedimentary conglomeratelayer, which are composed of the multi-compositional gravels, including the North Dabie orthogneiss complex (NDOC),volcanic gravels, etc. These volcanic gravels in the con-glomerate layer show identical geochemical and isotopic compositions (87Sr/86Sr(t) =0.7084-0.7092, (Nd (t) = 21.8-24.4) to the Maotanchang Fm. volcanic rocks (87Sr/86Sr = 0.7086-0.7102, (Nd = 19.2-24.4), but significantly distinct from those of Xiaotian Fm. (87Sr/86Sr = 0.7076-0.7084, (Nd = 17.2 - 19.2). K-Ar dating results of its underlying andoverlying volcanic sequences indicate that the conglomerate layers were deposite d at ~135 Ma. This suggests that the NDOC was rapidly exhumed to the surface dur ing or shortly before ~135 Ma and became the important provenance of the late Me sozoic volcano-sedimentary basins in the NHB. In combination with the regional v olcano-sedimentary correlation, we divided the Mesozoic stratigraphic sequence i n the NHB from base to top into Fanghushan Fm. (>160 Ma), Yuantongshan Fm. (/mid dle- lower segment of Sanjianpu Fm.) (160-149 Ma), Maotanchang Fm. (/Zhougongsh an Fm./upper segment of Sanjianpu Fm./Fenghuangtai Fm.) (149-135 Ma) and Xiaoti an Fm. (/Baidafan Fm./Heshidu Fm.) (135-116 Ma).     

Sedimentary environment of the Dajin conglomerate in Tibet, age of foraminiferan assemblages and their tectonic significance

The Dajin conglomerate, which is one of the most important sedimentary successions of the Xigaze forearc basin in Tibet, China, consists of deep-shallow marine tuffaceous turbidites and clastic rocks bearing Nummulites, Assilina, Alveolina and Lockhartia. These fossils are very similar to the foraminiferan in the Jialazi and Maila conglomerates, and those in Gangba and Dingri areas. They developed in the Eocene. By analyzing the spatial variation of Eocene sedimentary environments of Tibet Plateau and the foraminiferan in the Dajin conglomerate, we found that Eocene sedimentation should take place on both sides of the Yarlung Tsangpo suture, and the late Eocene tectonic uplifting should make the forearc basin expose out of the sea level and begin to receive nonmarine deposits.     

成都平原的晚新生代构造

根据成都平原晚新生代地层的展布、接触关系,以及与邻区的构造组合,对成都平原的基本构造格架进行了初步分析,描述了蒲江-新津断裂、大邑断裂、竹瓦铺断裂、绵竹断裂等晚新生代断裂,将成都平原的构造演化划分为6个阶段,对上述断裂的构造活动性与龙门山断裂带进行了分析对比.     

川西南段大邑地区深层碳酸盐岩油气成藏探讨

川西南段大邑地区所处的区域,其深层处于勘探的空白区,深入探讨该区海相油气成藏条件,不但能更新该区构造地质认识,也能为川西深层下一步油气勘探提供理论。基于研究区及周边钻井岩心、岩屑及地震等资料,对川西南段大邑地区深层油气地质条件进行综合分析。研究结果表明：(1)川西南段地层剥蚀至下寒武统筇竹寺组黑色泥页岩,该套烃源层广泛分布,为成藏提供了物质基础;(2)大邑深层发育多套储层,包括灯影组白云岩、栖霞组和茅口组白云岩、峨眉山玄武岩组玄武岩、嘉陵江组与雷口坡组白云岩,露头和探井都显示具有良好的储集条件;(3)纵向上发育中-下三叠统膏盐岩和巨厚的陆相碎屑岩盖层,具有很好的封挡条件。野外露头及钻井岩心中普遍可见储层大量沥青,说明形成过古油藏;(4)桐湾运动和加里东运动形成的不整合面在研究区叠加形成优质输导体系,加之大邑背斜带形成的有利纵向沟源断裂输导体系。大邑构造带古圈闭保持完整,与油气运移相匹配,有利于天然气的保藏,是未来深层天然气有利的潜在勘探区。     

砾岩储层注水开发后期高渗流通道成因特征及其识别

准噶尔盆地西北缘二叠-三叠系储层是洪积扇相砂砾岩体,油藏由于长期注水开发,后期形成了许多高渗流通道。从静态成因、工程动态成因角度总结了高渗流通道的形成原因,认为砾岩储层中高渗通道的主要成因有：沉积微相控制、微裂缝网络连通、沉积成岩作用程度弱（欠压实砂砾体弱胶结）、特殊的支撑砾岩岩石沉积结构、储层改造、长期注水微颗粒迁移、不同岩性沉积界面高渗通道、不整合面等8种。通过确定高渗透段的成因及其识别特征,将其嵌到单期水道内,建立高渗透层段的空间分布规律。高渗通道的开发动态特征为：高渗通道对应段吸水量高、高渗通道对应段吸水量随注水时间的延长而一般吸水量明显增大、高渗通道对应段地层压力从不明显到逐渐增高。由于储层高渗流通道的存在,导致注入水无法起到有效驱油作用,注入水无效循环严重影响了油藏注水开发效果。总结高渗流通道的特征并有效识别,是改善砾岩油藏储层开发效果的地质基础。