川西北部地区中二叠统茅口组岩溶储层特征研究

川西地区中二叠统茅口组在多个构造获得突破,但前期受勘探程度及资料限制,对茅口组储层研究相对较少,这制约了下一步勘探工作,因此开展川西北部茅口组储层特征研究是有必要的。基于此,本文根据钻井、化验分析、地震等资料,结合动静态资料重新评价茅口组储集类型,取得了以下三点认识:①川西北部地区中二叠统茅口组储集岩类主要为亮晶生物(屑)灰岩、粒屑灰岩、含生屑泥晶灰岩、白云岩、白云质(豹斑)灰岩。具有孔、洞、缝等多种储集空间,它们在空间上相互有机搭配形成了孔洞缝相结合的储渗空间。②川西北部茅口组气藏并不只是单一的裂缝性气藏,应以裂缝—孔洞型气藏为主,只有找准缝洞系统发育区,才能获得较好储量规模及勘探开发效果。③有利滩相是储层发育的基础,受岩溶作用改造后的有利地貌区是控制储层分布的主要因素。     

四川盆地西部中二叠统茅口组油气地质条件及勘探潜力

四川盆地西部中二叠统茅口组为碳酸盐岩浅水缓坡相沉积,高能浅滩亚相颗粒岩发育。茅口组沉积末期,研究区古表生岩溶作用强烈,有利于岩溶储层发育。中二叠统发育栖霞组和茅口组碳酸盐岩、梁山组泥质岩等多套烃源岩,烃源岩厚度大,品质较好;各套烃源岩从中三叠世末起相继达到生烃高峰,资源潜力大。茅口组中上部发育两类储层:裂缝-孔洞型(或裂缝型)储层和白云岩孔隙型储层。钻井及露头剖面揭示茅口组含气性好。高能滩相沉积区与岩溶斜坡带叠合区是茅口组储层发育的有利地区。茅口组之上的区域盖层发育,保存条件好。认为川西地区茅口组具有良好的天然气勘探前景。     

川西北地区下二叠统茅口组储层特征

对川西北地区下二叠统茅口组野外露头和钻井岩心等资料的分析表明,储层段主要为茅口组三段,孔隙度平均为0.895%,渗透率平均为1.696×10-3μm2,总体属于低孔低渗储层。储集岩的类型可分为白云岩、生物碎屑灰岩及泥—粉晶灰岩三类,储集空间主要为晶间孔、晶间溶孔、粒内溶孔、粒间溶孔和裂缝(主要为构造缝)。将储集空间划分为孔隙(直径小于2 mm)、孔洞(直径大于或等于2 mm)及裂缝三大类,其中溶蚀孔洞为茅口组最主要的储集空间,裂缝是重要的渗滤通道。沉积相带和成岩作用是控制储层发育的主要因素,台地高能生物滩最有利于储层发育,白云石化作用和溶解作用是主要的建设性成岩作用。     

黔南坳陷平塘甘寨二叠系茅口组沉积相与储层特征分析

通过铸体薄片、物性测试、扫描电镜等资料,对黔南坳陷平塘甘寨二叠系茅口组沉积相与储层特征进行深入分析,认为贵州平塘甘寨茅口组主要的岩石类型为亮晶-微晶生屑灰岩、生物灰岩、微晶灰岩、内碎屑亮晶灰岩、硅质岩、瘤状灰岩和含燧石灰岩等。茅口组生物种类较多,有介形虫、腹足、腕足、三叶虫、藻类、棘屑、蜒、珊瑚、海百合茎等。上述岩石学特征和生物组合指示平塘甘寨地区中二叠统茅口组为开阔碳酸盐台地沉积环境,包括台内滩和滩间两个亚相。储层特征分析结果表明,茅口组储集空间以晶间溶孔和晶间孔为主,具有明显的低孔低渗特征。局部溶蚀孔、构造裂缝相对较发育,对改造储层的孔渗性有重要的贡献。储层类型为碳酸盐岩裂缝-孔隙型储层,储层质量及发育部位受沉积相、成岩作用和构造活动多因素的控制。     

多孔介质储层表征技术在塔中地区上奥陶统礁滩储层中的应用

多孔介质储层表征技术应用岩心分析、测井分析、地震分析、岩样实验分析、生产动态分析等多种分析方法,表征不同尺度储集空间及其组合特征,最终评价有利储层。应用该技术,识别塔中地区北斜坡奥陶系良里塔格组孔隙型、孔洞型、孔隙-孔洞型、缝洞型和孔缝洞型5类储层,并表征了各类储层的孔喉结构、孔渗性和产能特征。结果表明：孔隙-孔洞型储层的孔喉结构发育大孔大喉的孔喉结构,优于孔隙型和孔洞型储层;裂缝对各类储层起到改善作用,裂缝的发育增加了储层孔渗性和连通性;储层产能特征受储层类型及规模影响,台缘孔缝洞型、孔隙-孔洞型储层以高产稳产为特征,台内缝洞型储层以中产较稳产为特征,台内孔洞型储层以中低产不稳产为特征。各类储集空间组合类型中,台缘孔缝洞型、孔隙-孔洞型储层是最有利储层,台内缝洞型是目前台内勘探的主要类型,台内孔隙型、孔洞型储层在裂缝发育情况下可以形成潜力储层。     

四川盆地北部中二叠统茅口组碳酸盐岩斜坡沉积及其油气勘探意义

在露头分析的基础上,结合钻井和地震资料,提出四川盆地中二叠统茅口组发育碳酸盐岩斜坡相沉积。其典型岩性为深灰色砾屑灰岩,砾屑成分以生物碎屑泥晶灰岩为主,局部地区见亮晶生物碎屑灰岩、造礁生物和重力滑动变形构造,砾径变化范围大;次要岩性为含钙屑浊积岩的深灰色薄层泥晶灰岩。中二叠统从栖霞组开阔台地相到茅口组斜坡相的演化,说明茅口组沉积时期构造活动加强,导致盆地北部及其他区域都有可能发生相带的分异。茅口组地震剖面上的厚度由南向北明显增厚,且具有楔形反射的特征,印证了盆地北部斜坡相的南区发育有台地边缘高能相带,这一认识有利于对四川盆地茅口组构造-岩相古地理的重建以及有利相带和储层的预测。     

川西北中二叠统茅口组储层特征及成因

对四川盆地西北部钻井岩心、露头剖面样品的宏观及微观岩石学特征研究认为,川西北茅口组储层类型主要为生屑灰岩,储集空间主要为生物格架孔、粒间溶孔、粒内溶孔、溶蚀孔洞及裂缝。茅口组储层的发育主要受到沉积微相、古岩溶作用及构造作用等因素控制。其中沉积微相是储层形成的物质基础,古岩溶作用是储层形成的关键因素,而构造裂缝是储层改善及连通的重要因素。     

塔河油田西南部地区中—下奥陶统碳酸盐岩储层缝洞发育特征与分布

岩溶-裂缝是塔河油田西南部地区上奥陶统覆盖区中—下奥陶统碳酸盐岩储层主要储集空间类型。依据岩心观察、显微镜薄片鉴定、扫描电镜、钻井、深浅侧向和FMI成像测井等资料,综合识别了中—下奥陶统储层裂缝和孔洞发育段,认为该区储层缝洞发育特征与塔河油田主体区有较大的不同,其主要的储集空间类型为半充填—未充填的构造缝和溶蚀扩大缝,且以高角度斜裂缝和垂直裂缝为主,低角度裂缝较少;微裂缝和中缝发育,大裂缝和孔洞总体不发育,利用储层多因素综合评价方法指出了研究区内裂缝和孔洞发育的有利地区。     

顺托果勒奥陶系一间房组超深层灰岩储层类型及储集空间定量表征

顺托果勒地区位于塔里木盆地北部坳陷带顺托果勒低隆起之上。该区中奥陶统一间房组发育台地相碳酸盐岩沉积,地层厚度为168～220m,埋深主要在6300～7850m,超深层储层是研究的关键。经过系统的岩心、铸体薄片、电镜观察和岩心微纳米CT检测分析,发现该套储层以致密灰岩储层为主,包括砂屑灰岩、凝块灰岩、藻粘结灰岩和藻灰岩等岩石类型。储集空间包括生屑遮避孔、铸模孔、粒内孔、晶内孔、微裂缝和溶蚀孔洞,其中粒内孔是主要储集空间类型。物性分析和储集空间的三维定量表征表明,储层以台内滩相亮晶藻屑砂屑灰岩和凝块灰岩为最好,孔隙度主要为2%～4%,少量可达12.14%;其次是藻粘结灰岩和藻灰岩。构造热液交代作用形成蚀变灰岩,发育溶蚀孔洞、微孔隙和微裂缝,构成良好储集空间体系,从而形成优质储层,这对超深层天然气勘探具有重要价值。     

四川盆地中三叠统-上三叠统马鞍塘组天然气藏特征和有利勘探地区

四川盆地中三叠统雷口坡组勘探已近40年,但迄今为止只发现了两个大中型气藏.近年来,雷口坡组钻井油气显示活跃,展示了良好的勘探前景.四川盆地中三叠统气藏储层主要位于底部雷一段、顶部雷三一雷四段,天然气主要来源于上二叠统龙潭组和上三叠统须家河组烃源岩,各气藏天然气组分特征也不尽相同,储集空间均以各类次生溶蚀孔隙为主,多为低-中孔低渗的孔隙型或裂缝一孔隙型储层.气藏盖层发育,均具备良好的直接盖层和区域盖层条件.上三叠统马鞍塘组储层主要位于其顶、底部的(藻)砂屑灰岩和泥晶灰岩,烃源岩和盖层与雷三、雷四段成藏条件相似.本文将四川盆地中三叠统一上三叠统马鞍塘组生储盖组合特征概括为两种类型:1)上二叠统龙潭组烃源岩+雷一-雷二段滩相储层+雷口坡组膏盐盖层;2)上三叠统烃源岩+雷三-雷四段-马鞍塘组底部(礁)滩相储层和(或)风化壳古岩溶储层+上三叠统泥质盖层.将来的油气勘探应更加重视对第二组合的关注.龙门山中南段前缘地区应是中三叠统雷三一雷四段和上三叠统马鞍塘组油气勘探最有利的地区.     

Unity of the national and the international in the socio-cultural development of the peoples of the USSR

International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.     

Report of the restudy of the defined global stratotype of the base of the Silurian System

The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs.     

Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth

It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T ₃ = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.     

The Tendencies of the Development of the Mineral-Resources Sector at the Turn of the Century

Important tendencies in development of the world mineral-resources sector at the beginning of the 21st century were an increase in production and consumption of mineral materials differentiated by types of metals and nonmetallic mineral raw materials, by countries and regions, as well as the concentration of the production of mineral raw materials in a small number of countries, and a reduction in industrial reserves of minerals in the world economy, even at the current stage of their extraction. These tendencies should be taken into account in working out a strategy for development of the Russian mineral raw-material base.     

Causes of the famine among the rural population of the Sahelian zone of the Sudan

Taking the example of W Sudan, an analysis of the climatic incidents leading to the two recent famine disasters is made. On this natural background, the human side is investigated. Focus is directed towards the fragile economic structure of the famine-prone population groups. An early-warning system for famine in the Sahelian Zone is proposed taking grain production and storage, livestock development and the relationship between the prices of livestock and grain as major indicators.     

东濮凹陷北部沙河街组三段中亚段沉积环境分析

东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。     

On the consistency of proposed models for the Pyrenees with the structure of the eastern parts of the belt

The structure of the eastern Pyrenees consists mainly of south-directed thrusts involving basement and cover rocks. An antiformal stack developed by the piling up of basement thrust sheets which outcrop in the Axial zone. These structures account for a thin-skinned thrust model rather than a vertical fault model in which the Axial zone would be essentially autochthonous, and the North-Pyrenean fault the axial plane of a fan thrust system. New data from the Eastern Pyrenees and the thin-skinned model suggest that(1) the structure east of the Pedraforca nappe is similar to that of the Central Pyrenees; (2) the cover rocks of the South-Pyrenean units and of the Axial zone-after restoration—built up a northwards-thickening prism consistent with the existence of a unique Pyrenean sedimentary basin during Mesozoic time; (3) the Axial zone is only a complex antiformal stack developed as a part of South-Pyrenean system related to the Paleogene thrusting-tectonics. The Axial zone palaeogeographic area had no special meaning during Mesozoic time.     

The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads

In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.