控制碳酸盐岩油藏单井产能的主要地质因素分析——以哈萨克斯坦北特鲁瓦油田KT-I油层组为例

目前国内外针对控制碳酸盐岩油藏单井产能主要地质因素研究还较少。本文以哈萨克斯坦北特鲁瓦油田KT-I油层组为例,基于岩芯分析、测井解释成果、储层微观表征与生产动态分析等资料,宏观上从沉积作用、成岩作用、构造作用以及微观上从储层岩性、储层类型、物性、有效厚度等两方面对单井产能主控因素进行了研究。研究发现单井产能主要受孔隙体积、渗透率与储层有效厚度的直接影响,而孔隙体积及孔隙空间类型受岩性、沉积微相与成岩相控制。在碳酸盐岩中,裂缝的发育可极大程度地改善孔隙连通性,从而增加渗透率,而其发育受断裂作用与构造变形及成岩作用、岩性控制。研究各种地质因素对碳酸盐岩单井产能的控制作用,可为制定初次油气开发方案提供有效的指导,为调整开发方案和老区扩边勘探、滚动开发提供更为可靠的依据。     

鄂尔多斯盆地榆林气田山西组2段砂岩成岩作用及孔隙演化

榆林气田下二叠统山西组2段为一套辫状河三角洲沉积,储集岩主要为石英砂岩、岩屑石英砂岩,平均孔隙度5.36%,平均渗透率4.58×10-3μm2,是典型的低孔低渗储层。以岩心观察为基础,结合薄片鉴定、扫描电镜、阴极发光及物性分析等资料进行研究,认为山2段砂岩经历了压实作用、胶结作用、交代作用、溶解作用、粘土杂基的充填作用等多种成岩作用,目前已达到晚成岩阶段A期。成岩作用是控制该区储层物性的关键因素,孔隙演化经历了原生孔隙的破坏、次生孔隙的形成和次生孔隙的破坏三个阶段。各类次生孔隙占总孔隙度的55.3%,其中岩屑溶孔18.4%,粒间溶孔10.8%,晶间孔26.1%。     

柯坪地区下志留统储层性质及控制因素

野外露头浅钻取样分析发现,柯坪地区志留系下统柯坪塔格组的储层性质与塔北及塔中地区差别较大。柯坪地区的砂岩储层以粉细粒岩屑砂岩为主,处于晚成岩A2期,孔隙度主要为2%~6%,平均4.47%,渗透率主要为(0.01~0.1)×10-3μm2,平均0.06×10-3μm2,属于特低孔特低渗储层,而塔北及塔中地区以低孔低渗和中孔中渗为主。研究表明柯坪地区成岩压实、石英次生加大是储层物性的主控因素,储层经历长期深埋藏和短期浅埋藏,使成岩压实减孔率达30.4%;胶结作用所减少的孔隙量一般为1.5%~8%,致密胶结段可达10%~11%,石英次生加大所减少的孔隙量一般2%~4%,致密胶结段可达6%~8%;溶蚀作用及次生裂缝对储层物性改善不大,一般增孔量4%左右;成岩中后期强烈挤压构造运动对储层性质有重要影响。储层演化史表明晚二叠世、晚白垩世—早第三纪是油气聚集成藏期,随后遭后期构造运动破坏,油气逸散或发生氧化作用,柯坪塔格组含沥青砂岩即是这一过程的产物。     

靖边气田北部中奥陶统马家沟组五_4~1储层沉积微相组合与储层非均质性控制因素

中奥陶统马家沟组上部马五41储层是鄂尔多斯盆地靖边气田主力产气段,根据该层段的岩石学特征和沉积构造等,可划分为3个亚相以及9个微相组合。该储层的储集性能具有强烈的非均质性,微观上表现为低孔低渗,以微细喉、细喉为主;纵向上表现为反韵律、随机韵律、均质韵律3种韵律模式,平面上表现为平均岩心孔隙度、渗透率分布的非均一性。沉积微相及微相组合差异性是控制岩石孔隙发育的基础,成岩作用决定了孔隙发育的程度,古岩溶地貌类型对储层分布有着明显制约作用,最终导致该区储集性能在纵横向上的非均质性。     

茶尖岭矿区后水矿化点铜银多金属成矿条件分析及远景初探

茶尖岭矿区后水矿化点铜银多金属矿属于浅成热液脉型成因,通过矿床形成的热源、水源、矿源的信息标志分析了后水矿化点铜银多金属成矿条件。认为该矿化点铜银多金属成矿的热源、水源、矿源条件均较充足,指出找矿有利地段。     

Reviews of the Destruction and Preservation of Primary Porosity in the Sandstone Reservoirs

埋藏条件下原生孔隙的破坏与保存机制是含油气盆地砂岩储层质量研究的一个核心领域,其在油气地质学研究中的意义不言而喻。与次生孔隙的形成与保存机制相比,影响原生孔隙破坏与保存的因素有着其特殊的复杂性和多样性。在总结国内外研究进展的基础上,试图深入理解不同成岩机制在砂岩储层原生孔隙破坏与保存中的意义和作用,包括破坏机制（如机械压实、胶结作用等）和保存机制（如地层超压、颗粒包膜、盐体侵位和烃类占位等）。目前难以实现砂岩储层质量钻前准确预测的一个困难在于无法明确原生孔隙演化的动力和过程,将来成岩作用、流体作用、沉积过程和盆地演化的更紧密结合可能是解决砂岩储层原生孔隙破坏与保存机制研究中最有希望的发展方向之一。     

Syn- and post-sedimentary controls on clay mineral assemblages in a tectonically active basin,Andean Argentinean foreland

In the northern part of the Calchaquí Valley (NW Argentina), Palaeogene Andean foreland sediments are represented by a 1400-metre-thick continental succession (QLC: Quebrada de Los Colorados Formation) consisting of claystones, siltstones, sandstones, and conglomerates representing sedimentation in fluvial-alluvial plains and alluvial fan settings. To understand the main syn- and postsedimentary variables controlling the clay mineral assemblages of this succession, we have studied the fine-grained clastic sediments by X-ray diffraction and electron microscopy, along with a detailed sedimentary facies analysis, for two representative sections. In the northern section, the whole succession was sampled and analysed by XRD, whereas in the second section, a control point 15 km to the south, only the basal levels were analysed. The XRD study revealed a strong contrast in clay mineral assemblages between these two sections as well as with sections in the central Calchaquí Valley studied previously. In the northernmost part of the study area, a complete evolution from smectite at the top to R3 illite/smectite mixed-layers plus authigenic kaolinite at the bottom, through R1-type mixed-layers in between, has been recognized, indicating the attainment of late diagenesis. In contrast, the clay mineral assemblages of equivalent foreland sediments cropping out only 15 km to the south contain abundant smectite and micas, subordinate kaolinite and chlorite, and no I/S mixed-layers to the bottom of the sequence. Early diagenetic conditions were also inferred in a previous study for equivalent sediments of the QLC Formation cropping out to the south, in the central Calchaquí Valley, as smectite occurs in basal strata. Burial depths of approximately 3000 m were estimated for the QLC Formation in the central and northern Calchaquí Valley; in addition, an intermediate to slightly low geothermal gradient can be considered likely for both areas as foreland basins are regarded as hypothermal basins. Consequently, the attainment of late diagenesis in the northernmost study area cannot be explained by significant differences in burial depth nor in geothermal gradient in relation to the section 15 km to the south nor with the central Calchaquí Valley. The formation of R3 mixed-layer I/S and authigenic kaolinite in the northern study area was most likely controlled by the circulation of hot, deep fluids along the reverse faults that bounded the Calchaquí valley. These faults were active during the Cenozoic, as evidenced by the syndepositional deformation features preserved in the studied sediments. Stress could also have been a driving force in burial diagenesis at the R3 mixed-layer I/S stage in these young continental sediments.     

从江污牙白钨矿地质特征及成因浅析

从江污牙白钨矿,分布在吉羊穹状背斜北缘,赋存于摩天岭花岗岩外接触带甲路组一段下部的电气石—黑云母化石英千枚岩中。白钨矿的产出总是与特定的构造环境和蚀变特征联系在一起,并严格受其控制,本文试图从分析污牙白钨矿床的基本地质特征入手,探索该矿床的成因及指出下步找矿方向。     

云南金江小石将军铜矿床地质特征分析

以云南东川金江小石将军铜矿床为主要研究对象,对小石将军铜矿床区域地质、矿区地层、构造、岩浆岩、控矿因素、矿体特征、围岩蚀变等地质特征认真、详细观察、分析,结合东川知名矿床地质特征进行对比研究,将矿床成因类型初步厘定为沉积变质叠加热液改造型矿床。