油气藏水力压裂计算模拟技术研究现状与展望

水力压裂技术是油气藏尤其是页岩气开发中的核心技术,利用数值模拟方法进行压裂优化和产能预测又是水力压裂成功的关键。本文首先介绍了水力压裂技术的发展历程。然后从计算模型(二维模型、拟三维模型和全三维模型)和数值模拟方法(基于连续介质和基于非连续介质)两方面对油气藏开发领域的水力压裂计算模拟技术进行较全面的总结。最后,从以下3个方面指出现今研究的不足并提出了进一步的研究建议:(1)全三维模型的完善-全三维模型应当与真实的工程参数和监测数据结合,用于校正模型本身,而校正后的全三维模型又可预测和优化新的现场水力压裂作业; (2)数值模拟方法的选用-已有的水力压裂数值模拟方法种类繁多,需要针对各种方法的适用范围、计算效率和模拟效果等,进行全面的比较和优化; (3)页岩储层中天然裂缝网络的数值模拟-天然裂隙网络加剧了页岩储层力学性质的各向异性,同时水力裂缝沟通天然裂缝活化扩展是有利于储层的增渗增产,对压裂缝网的形态、尺寸和连通率等起着至关重要的作用。因此,数值计算过程中综合考虑页岩储层中天然裂缝与水力裂缝的相互作用,将是未来水力压裂模拟的热点。     

水中荧光计及其在海洋现场探测中的应用

本文描述了近几年来我们首次研制成功的３种类型的水中荧光计系统及其应用测量结果：１．用于水体混合扩散实验研究的水中荧光计，对罗丹明Ｂ浓度测量范围为１×１０－６～１×１０－１０ｇ／ｃｍ３；２．拖曳荧光计系统，能在２～８０ｍ水深内进行水平拖曳平稳地工作，拖曳速度为０～８ｋｎ，除检测罗丹明Ｂ外，还可检测无机悬浮物质的含量，检测范围为２～２０００ｍｇ／ｄｍ３；３．用于测量海中浮游植物体内叶绿素ａ浓度的水中荧光计，测量范围为１×１０－６～１×１０－９ｇ／ｃｍ３。用荧光法测量海中物质是近代新发展的一种简便、快速、灵敏度高、用途极其广泛的测量技术，有着重要的应用价值。     

Influence of ferric iron on phase equilibria in greenschist facies assemblages: the hematite‐rich metasedimentary rocks from the Monti Pisani (Northern Apennines)

We have investigated the effects of different Fe₂O₃ bulk contents on the calculated phase equilibria of low‐T/intermediate‐P metasedimentary rocks. Thermodynamic modelling within the MnO–Na₂O–K₂O–FeO–MgO–Al₂O₃–SiO₂–H₂O–TiO₂–O (MnNKFMASHTO) chemical system of chloritoid‐bearing hematite‐rich metasedimentary rocks from the Variscan basement of the Pisani Mountains (Northern Apennines, Italy) fails to reproduce the observed mineral compositions when the bulk Fe₂O₃ is determined through titration. The mismatch between observed and computed mineral compositions and assemblage is resolved by tuning the effective ferric iron content by P–XFe₂O₃ diagrams, obtaining equilibration conditions of 475 °C and 9–10 kbar related to a post‐compressional phase of the Alpine collision. The introduction of ferric iron affects the stability of the main rock‐forming silicates that often yield important thermobaric information. In Fe₂O₃‐rich compositions, garnet‐ and carpholite‐in curves shift towards higher temperatures with respect to the Fe₂O₃‐free systems. The presence of a ferric‐iron oxide (hematite) prevents the formation of biotite in the mineral assemblage even at temperatures approaching 550 °C. The use of P–T–XFe₂O₃ phase diagrams may also provide P–T information in common greenschist facies metasedimentary rocks.     

柴北缘冷湖构造带古近系沉积体系及演化特征

通过对柴达木盆地北缘西段重点探井的岩心观测、重矿物分析、测井数据及地震资料的分析，研究了冷湖构造带古近系沉积体系及演化特征和不同时期沉积微相及砂体的展布规律.结果认为，冷湖构造带古近系主要发育冲积扇-辫状河-辫状河三角洲-湖泊沉积体系，物源来自北东方向的小赛什腾山和赛什腾山附近.古近系路乐河组（E₁₊₂）沉积期，主要发育辫状河以及辫状河三角洲平原沉积，仅在靠近山前发育少量冲积扇沉积；至下干柴沟组（E₃）沉积时期，主要发育辫状河、辫状河三角洲平原、辫状河三角洲前缘及滨-浅湖沉积.古近纪时期冷湖构造带表现为一次较大规模的水进过程，纵向沉积继承性明显，很好地记录了这一沉积演化过程.这一沉积体系及演化过程有利于粗碎屑和细碎屑交互沉积，形成较好的储盖组合，为柴达木盆地冷湖构造带下一步的油气勘探提供了可靠的地质依据.     

Preliminary seismic hazard maps of Slovenia

The preparation of the preliminary seismic hazard maps of the territory of Slovenia has been based on an expansion of the basic approach laid out by Cornell in 1968. Three seismic source models were prepared. Two of them are based mainly on the earthquake catalogue using the Poissonian probability model. A map of seismic energy release and a map of earthquake epicenter density are used to delineate seismic sources in these models. The geometry of the third model which is based on a rough estimate of seismotectonic setting is taken from the probabilistic seismic hazard analysis of a nuclear power plant in Slovenia. Published ground motion attenuation models based on strong motion records of recent strong earthquakes in Italy are used. Test maps for variable and uniform b-values are presented. The computer program, Seisrisk III, developed by the U.S. Geological Survey is used.     

Late Quaternary diatom and sea level changes in estuarine plain of the Jiulong River

TheJiulongRiver,composedoftheWestStream,theNorthStreamandtheSouthStream(seeFig.1)isthesecondlargestriverinFujianProvince.ItsestuarineplainintervenesbetweenthetwqcitiesofXiamenandZhangzhou,withsouthern-subtropicoceanicmonsoonclimate-SofartherehasnotbeensystematicresearchontheLateQuaternarysea1evelchangesinthearea,andthispaperisintendedtodosomethingaboutit.DIAToMZoNESANDBIoFACIESOFZK5BoREHOLETheBoreholeZK5islocatedtothenortheastofHaichengTown,withcoordinateof24"24,32*N,ll7'5…     

Clinoform architecture and along‐strike facies variability through an exhumed erosional to accretionary basin margin transition

Exhumed basin margin‐scale clinothems provide important archives for understanding process interactions and reconstructing the physiography of sedimentary basins. However, studies of coeval shelf through slope to basin‐floor deposits are rarely documented, mainly due to outcrop or subsurface dataset limitations. Unit G from the Laingsburg depocentre (Karoo Basin, South Africa) is a rare example of a complete basin margin scale clinothem (>60 km long, 200 m‐high), with >10 km of depositional strike control, which allows a quasi‐3D study of a preserved shelf‐slope‐basin floor transition over a ca. 1,200 km² area. Sand‐prone, wave‐influenced topset deposits close to the shelf‐edge rollover zone can be physically mapped down dip for ca. 10 km as they thicken and transition into heterolithic foreset/slope deposits. These deposits progressively fine and thin over tens of km farther down dip into sand‐starved bottomset/basin‐floor deposits. Only a few km along strike, the coeval foreset/slope deposits are bypass‐dominated with incisional features interpreted as minor slope conduits/gullies. The margin here is steeper, more channelized and records a stepped profile with evidence of sand‐filled intraslope topography, a preserved base‐of‐slope transition zone and sand‐rich bottomset/basin‐floor deposits. Unit G is interpreted as part of a composite depositional sequence that records a change in basin margin style from an underlying incised slope with large sand‐rich basin‐floor fans to an overlying accretion‐dominated shelf with limited sand supply to the slope and basin floor. The change in margin style is accompanied with decreased clinoform height/slope and increased shelf width. This is interpreted to reflect a transition in subsidence style from regional sag, driven by dynamic topography/inherited basement configuration, to early foreland basin flexural loading. Results of this study caution against reconstructing basin margin successions from partial datasets without accounting for temporal and spatial physiographic changes, with potential implications on predictive basin evolution models.     

奥陶系宝塔组灰岩的环境相、生态相与成岩相

晚奥陶世宝塔组灰岩在上、中、下扬子碳酸盐沉积区分布极为广泛，因其层面上注记着不规则状、类似鸡冠花的形态特征，因而素以加引号的“龟裂纹灰岩”称之，以此代表宝塔组灰岩特有的沉积构造，以致于两者为同一词。宝塔组灰岩是地质历史中仅有的、唯一的在层面上具有特殊网纹的形态组构，其他时代的灰岩均无此特点，因而它是地质历史中的“时髦相”。形成这一组构可能有三个因素：一是盆地的沉积－构造背景，华南晚奥陶世为前陆盆地，前隆的结果使建筑在克拉通上的碳酸盐大平台构造掀斜，成为浅海中的深水盆地，为低能、慢速沉积的灰泥岩、泥灰岩提供了宽大而平坦的构造－沉积环境空间；二是深水环境中的生态和生物遗迹，由游泳型角石和与之能抗衡的大型软体生物在软底上和沉积物内留下活动的印迹；三是灰泥和泥质物成岩压实作用，叠加在印痕上，因此，宝塔组灰岩“龟裂纹”组构的形成是构造－沉积环境相、生态相和成岩相的产物。     

Garnet-bearing Granulite Facies Rock Xenoliths from Late Mesozoic Volcaniclastic Breccia, Xinyang, Henan Province

This paper presents the primary results of petrologic, mineralogical and petrochemical studies of garnet-bearing granulite facies rock xenoliths from Xinyang, Henan Province. These xenoliths, which are found in a pipe of late Mesozoic volcaniclastic breccia, are of high density (3.13-3.30 g/cm3) and high seismic velocity (Vp = 7.04-7.31 km/s), being products of underplating of basaltic magmas and had experienced granulite facies metamorphism. The underplating and metamorphism took place before the eruption of the host rock. Petrographical studies and equilibrium T-P calculations show that these xenoliths were captured at a 49 km depth and experienced at least a 16 km uplift before they were captured. The dynamics of the uplift could be related to the continent-continent collision between the North China plate and the Yangtze plate during the Triassic.     

Sedimentary response to the intracontinental orogenic process: insight from the anatomy of a small Mesozoic basin in western Yanshan,northern North China

ABSTRACT

The intra-continental orogeny and tectonic evolution of the Mesozoic Yanshan fold-thrust belt (YFTB) in the northern North China Craton (NCC) have been strongly debated. Here, we focus on the Shangyi basin, located in the centre of the YFTB. An integrated analysis of sedimentary facies, palaeocurrents, clast compositions, and detrital zircon dating of sediments was adopted to determine the palaeogeography, provenance, basin evolution, and intra-continental orogenic process. The Shangyi basin comprises the well-exposed Early–early Middle Jurassic Xiahuayuan Formation and the Longmen Formation, and the Late Jurassic–Early Cretaceous Tuchengzi Formation. Based on the 18 measured sections, five facies associations – including alluvial fan, fluvial, delta, lacustrine, and eolian facies – have been identified and described in detail. The onset of the Shangyi basin was filled with fluvial, deltaic, and lacustrine deposits controlled by the normal fault bounding the northern basin, corresponding to the pre-orogeny. In the Middle Jurassic, the cobble–boulder conglomerates of alluvial fan, as molasse deposits, were compatible with the syn-orogeny of the Yanshan movement, which played a critical role in northern North China and even East Asia. After the depositional break in the Middle–Late Jurassic, the Shangyi basin, controlled by the normal fault present in the north of the basin, re-subsided and quickly expanded southward with thick sedimentation, which is correlative with the post-orogeny. Combined with A-type granites, metamorphic core complexes, mafic dikes, and rift basins of the Late Jurassic–early Early Cretaceous present in the northern NCC and Mongolia, significant extension was widespread in the northern NCC and even in northeast Asia. Moreover, vertical changes of provenance indicate that the Taihang Mountain and the Inner Mongolia palaeo-uplift (IMPU) present at the west and north of the basin, respectively, experienced uplift twice in the Middle–Late Jurassic and Early Cretaceous, resulting in a regional depositional break.