Stability control of surrounding rocks for a coal roadway in a deep tectonic region

In order to effectively control the deformation and failure of surrounding rocks in a coal roadway in a deep tectonic region, the deformation and failure mechanism and stability control mechanism were studied. With such methods as numerical simulation and field testing, the distribution law of the displacement, stress and plastic zone in the surrounding rocks was analyzed. The deformation and failure mechanisms of coal roadways in deep tectonic areas were revealed: under high tectonic stress, two sides will slide along the roof or floor; while the plastic zone of the two sides will extend along the roof or floor,leading to more serious deformation and failure in the corner of two sides and the bolt supporting the corners is readily cut off by the shear force or tension force. Aimed at controlling the large slippage deformation of the two sides, serious deformation and failure in the corners of the two sides and massive bolt breakage, a ‘‘controlling and yielding coupling support'' control technology is proposed. Firstly, bolts which do not pass through the bedding plane should be used in the corners of the roadway, allowing the two sides to have some degree of sliding to achieve the purpose of ‘‘yielding'' support, and which avoid breakage of the bolts in the corner. After yielding support, bolts in the corner of the roadway and which pass through the bedding plane should be used to control the deformation and failure of the coal in the corner. ‘‘Controlling and yielding coupling support'' technology has been successfully applied in engineering practice, and the stability of deep coal roadway has been greatly improved.

Mechanism of stepwise tectonic control on gas occurrence: A study in North China

To gain an understanding of gas occurrence, distribution is the fundamental basis for preventing gas disasters. Presently, how tectonic structures control gas occurrence remains problematic. This study proposes the theory and elucidates the mechanism of stepwise tectonic control on gas occurrence according to the characteristics of gas occurrence and the patterns of gas distribution in coal mines in North China. On the one hand, tectonic compression and shearing lead to stress concentration and thus deform the coal and reduce the coal seam permeability, further contributing to gas preservation. On the other hand, tectonic extension and rifting lead to stress release and thus improve the coal seam permeability, further contributing to gas emission. Therefore, the distribution zones of tectonic compression, ubiquitous coal deformation, and gas accumulation have been step-wisely revealed, and the coal-gas outburst proneness zones are finally identified. The proposed theory of step-wise tectonic control on gas occurrence is of practical significance for gas prediction and control.

Tectonic Control of the Reykjanes Geothermal Field in the Oblique Rift of SW Iceland:From Regional to Reservoir Scales

This paper presents a multidisciplinary structural analysis of the Reykjanes Peninsula where Holocene deformation of a young oblique rift controls the geothermal processes in presence of a transform segment. The new structural map from aerial images and outcrops is correlated with selected surface and subsurface data and shows a complex pattern: NNE extensional rift structures, N-S dextral and ENE sinistral oblique-slip Riedel shears of the transform zone, and WNW and NW dextral oblique-slip faults. Shear fractures are more common, and along with the NNE fractures, they compartmentalise the crustal blocks at any scale. The fractures are within two ENE Riedel shear zones, indicating a minimum 7.5 km wide transform zone. The greatly deformed Southern Riedel Shear Zone is bounded to the north and the south by the 1972 and the 2013 earthquake swarms. This shear zone contains the geothermal field in a highly fractured block to the west of a major NW structure. Some of the deformations are: a) clockwise rotation of rift structures by the 1972 earthquake zone, inducing local compression;b) magma injection into extensional and oblique-slip shear fractures;c) reactivation of rift structures by transform zone earthquakes;d) tectonic control of reservoir boundaries by WNW and ENE shear fractures, and the distribution of surface alteration, fumaroles, CO2 flux, reservoir fluid flow and the overall shape of pressure drawdown by N-S, ENE, WNW/NW and NNE fractures. Results demonstrate the role of seismo-tectonic boundaries beyond which fault types and density change, with implications for permeability.

Dynamo Speed Control and Tectonics—Modeling Earth as a Shunt Wound DC Machine

The Sun’s slow periodic flux transfer to the Earth, the low frequency of Schumann Resonance, and the fixed DC voltage of the capacitor direct us toward direct current (DC) machines for electrical modeling purposes. The Earth exhibits dual characteristics of a motor generator set by motoring the mechanical Earth around its axis, while at the same time generating energy for its spherical capacitor. It follows that electrical and mechanical output of the Earth are powered by the magnitude of the flux transfer events, the constant DC voltage supply and any potential nuclear contribution within the core. Like an induction furnace, powerful magnetic flux from the Sun partially melts the outer iron core of the Earth and magnetizes the inner solid iron core. The solid inner magnetic core acts as a rotating armature similar to a DC machine. All electrical machines experience no load and full load power loss while in operation. Speed control of large rotating DC machines is well understood and has been applied in industry for over a century. Speed can be changed either by varying the field resistance and/or the armature resistance. The characteristic of a constant speed DC machine is such that a change in field resistance will cause a compensatory change in armature resistance to maintain velocity. In the case of the earth, a decrease in armature resistance results in an increase in volume of the iron core, which may result in greater seismic and volcanic activity. Climate change may be the direct result of changes in soil and sea water resistance, which we lump together as field resistance.

Tectonic Control of the Theistareykir Geothermal Field by Rift and Transform Zones in North Iceland:A Multidisciplinary Approach

This paper presents a multidisciplinary structural analysis of a 165 km2 area in the Northern Rift Zone and the Tjörnes Fracture Zone of Iceland, and unravels the tectonic control of the Theistareykir geothermal field and its surroundings. About 10729 fracture segments (faults, open fractures, joints) are identified in the upper Tertiary to Holocene igneous series. The segments were extracted from aerial images and hillshade, and then analyzed in terms of number of sets, geometry, motions, frequency, and relative age. The correlation with surface geothermal manifestations, resistivity, earthquakes, and occasional well data reveals the critical regional and local fractures at the surface, reservoir level and greater depth. The main conclusions of this study are: 1) The structural pattern consists of N-S rift-parallel extensional fractures and the Riedel shears of the transform zone striking NNE, ENE, E-W, WNW and NW, which compartmentalize together the blocks at any scale. 2) The en échelon segmentation shows strike and oblique slips on the Riedel shears, with a dextral component on the WNW and NW planes and a sinistral component on the NNE to ENE faults. 3) Fractures form under the influence of the transform mechanism and the effect of rifting becomes significant only with time. 4) The WNW dextral oblique-slip Stórihver Fault of the transform zone has a horsetail splay that extends eastwards into the geothermal field. There, this structure, along with few NW, ENE, NNE and N-S fractures, controls the alteration, alignment of fumaroles, emanating deep gases. These fractures also rupture during natural or induced earthquakes. 5) The resistivity anomalies present en échelon geometries controlled by the six fracture sets. These anomalies display clockwise and anticlockwise rotations within the upper 8 km crustal depth, but at 8 km depth, only three sets (the N-S rift structures, and the E-W and the NW Riedel shears) are present at the rift and transform plate boundaries. Results of this study are relevant to resource exploration in other complex extensional contexts where rift and transform interact.ööö

Tectonic Fractures in Tight Gas Sandstones of the Upper Triassic Xujiahe Formation in the Western Sichuan Basin,China

The western Sichuan Basin, which is located at the front of the Longmen Mountains in the west of Sichuan Province, China, is a foreland basin formed in the Late Triassic. The Upper Triassic Xujiahe Formation is a tight gas sandstone reservoir with low porosity and ultra-low permeability, whose gas accumulation and production are controlled by well-developed fracture zones. There are mainly three types of fractures developed in the Upper Triassic tight gas sandstones, namely tectonic fractures, diagenetic fractures and overpressure-related fractures, of which high-angle tectonic fractures are the most important. The tectonic fractures can be classified into four sets, i.e., N-S-, NE-, E-W- and NW-striking fractures. In addition, there are a number of approximately horizontal shear fractures in some of the medium-grained sandstones and grit stones nearby the thrusts or slip layers. Tectonic fractures were mainly formed at the end of the Triassic, the end of the Cretaceous and the end of the Neogene-Early Pleistocene. The development degree of tectonic fractures was controlled by lithology, thickness, structure, stress and fluid pressure. Overpressure makes not only the rock shear strength decrease, but also the stress state change from compression to tension. Thus, tensional fractures can he formed in fold-thrust belts. Tectonic fractures are mainly developed along the NE- and N-S-striking structural belts, and are the important storage space and the principal flow channels in the tight gas sandstone. The porosity of fractures here is 28.4% of the gross reservoir porosity, and the permeability of fractures being two or three grades higher than that of the matrix pores. Four sets of high-angle tectonic fractures and horizontal shear fractures formed a good network system and controlled the distribution and production of gas in the tight sandstones.

Characteristics of Mesozoic-Cenozoic tectonic diagenesis in the Kuqa area of the Tarim Basin,China

Tectonic diagenesis is a common and important geological phenomenon. We can fully understand the diagenesis of compressional basins through studying tectonic diagenesis. In this paper, we presented the tectonic diagenetic characteristics in the Kuqa area of the Tarim Basin by integrated method of geological analysis and paleotectonic stress. The results showed that the Mesozoic-Cenozoic tectonic diagenesis affected sandstone compaction evolution mainly through physical mechanisms. It showed characteristics of abrupt change and nonthermal indicator (it means that sandstone compaction can not be explained by thermal diagenetic compaction alone because actual sandstone compaction was larger than thermal compaction), which were different from the thermal and fluid diagenesis. Compared with thermal diagenesis, tectonic diagenesis had a typical tectonic compaction in very short time, and many phases of tectonic deformation showed multiple abrupt changes of compaction. There are obvious differences between tectonic and thermal diagenetic compaction, leading to sandstone compaction being larger than the thermal compaction under the same thermal evolution stage in the areas where tectonic deformation happened. The stronger the tectonic deformation, the more obvious the difference. Tectonic process changed the stress distribution through changing the tectonic deformation styles, resulting in different tectonic diagenesis effects. Therefore, tectonic diagenesis of Mesozoic-Cenozoic in the Kuqa area can be divided into four types including rigid rock restraint, fault ramp, low angle fault slippage, and napping.

Tectonic development of subtle faults and exploration in mature areas in Bohai Sea,East China

Based on the theory of structural analysis,the characteristics and structural patterns of subtle faults are studied using 3D seismic data of the Bohai Sea to analyze the development process and origin of the subtle faults.A method of identifying subtle faults is proposed,forming a complete system for analyzing origins of subtle faults in the Bohai Sea.The complex strike-slip fault patterns under the strike-slip and extension stress background,diverse formation rocks,and strong neotectonic movement are the reasons for the development of subtle faults.According to the tectonic origin and development location,the subtle faults in Bohai Sea can be divided into 12 types in the three categories of strike slip dominant,extension dominant and strike slip and extension composite,and the different types of subtle faults occur in different regions of the Bohai Sea.Unreasonable variation of sedimentary stratum thickness,inherited distortion or even abrupt change of stratum occurrence,zonation of plane fault combination and the variation of oil-water system in the same structure with no-lithologic change are the important signs for identifying subtle faults in Bohai Sea.The subtle faults greatly enlarge the size of the structural trap groups,and areas with dense subtle faults are often active area of hydrocarbon migration and accumulation and favorable exploration zones,which have strong control on the hydrocarbon accumulation.The identification method for subtle faults has guided the exploration in the mature areas of Bohai Sea effectively,with a number of large and medium oil and gas fields discovered,such as Bozhong 29-6 and Penglai 20-2.

Tectonic Characteristics and Emplacement Mechanism of Dayishan Granite in Hunan Province, China

Dayishan granite, a significant metallogenic-rock body located in Shaoyang-Chenxian tectonomagmatic belt of Hunan Province, was controlled by 'Dayishan-type' fault pattern. Based on the study of tectonic setting and geological features of the grantie, it is concluded that the tectonic system controlling magmatic emplacement is a shear folded-fauted zone which resulted from NW-trending convergent strike-slip faulting. The close relationship between the temporal-spatial distribution, emplacement mechanism of Dayishan granite and the strike-slip faulting is detailed.

A STEP-BY-STEP INTEGRAL METHOD FOR ACTIVELY CONTROLLED STRUCTURES

A new active control method was proposed, in which the analytical control law was deduced by using a step by step integral method to differential equation of motion under the condition of static error being zero. This control law is terse in mathematical expression and convenient for practical use. The simulation results demonstrate that the proposed method can provide much more remarkable peak response reduction of seismically excited structures than the classical LQR method.

青藏高原1990年以来的M_W≥6.5强震事件及活动构造体系控震效应

深入认识青藏高原陆陆碰撞-挤出构造体系作用下的强震活动特点及未来强震活动趋势,对于区域防震减灾具有重要科学意义。统计分析青藏高原及邻区1900年以来的M≥6.0强震活动发现,青藏高原自1950年西藏墨脱—察隅8.6级大地震以来正处于新一轮相对缓慢的地震能释放期,但1990年以来的强震发生率和地震释放能显示出逐步增高趋势,并可能预示下一轮地震能快速释放期的临近。活动构造体系控震分析表明,青藏高原陆陆碰撞-挤出构造体系中的“多层次挤出-旋转活动构造体系”构成了1990年以来新一轮M_W≥6.5强震活动的主要控震构造,尤其是其中的巴颜喀拉挤出构造单元的强震活动最为显著,指示其目前正处于构造活跃状态,而且这一状态可能仍将持续。综合研究认为,在区域强震活动趋势分析中,充分认识活动构造体系控震效应,将有助于更好地分析判断区域未来强震时空迁移过程及最可能出现的构造部位。考虑到当前强震活动过程中,青藏高原“多层次挤出-旋转活动构造体系”的未来强震活动趋势仍会持续,需要重点关注挤出块体边界上3条大型左旋走滑断裂带,阿尔金—祁连—海原断裂系、东昆仑断裂带和鲜水河—小江断裂带的未来强震危险性,其次是断块内部断裂。

页岩储层非构造裂缝研究进展与思考

随着我国对非常规油气勘探理论的完善和技术的提高,页岩油气勘探开发不断获得突破,其战略地位也在不断上升。页岩储层的品质通常是制约其资源潜力的主要因素,其中裂缝是页岩油气富集、高产、稳产的关键。因此裂缝作为富有机质页岩储层重要的储集空间和渗流通道,其相关研究一直都是该领域内的重点。我国页岩储层内天然裂缝大量发育,而非构造裂缝同样比较发育,对页岩油气的富集和保存评价亦具有重要意义。目前对页岩储层构造裂缝的研究比较深入,而对页岩非构造裂缝的研究则相对薄弱。为此本文在充分调研近年来国内外页岩非构造裂缝研究成果的基础上,重点梳理了非构造裂缝的分类、识别与表征、主控因素、期次及演化序列等方面的研究进展。页岩储层非构造裂缝以成因和形态复杂、分布不规则、尺度较小为特征,依据成因机制差异可将其分为成岩缝、异常高压缝、层理缝和表生缝4个大类,它们的识别与表征目前主要还停留在定性描述的阶段;尽管不同类型的非构造缝主控因素存在差异,但均在不同程度上受控于沉积作用、成岩作用、矿物组分及含量、岩石力学性质,呈现出一定的共性。综合分析并指出了页岩储层非构造裂缝研究的关键问题及发展趋势:一是基于页岩储层岩心、薄片、成像测井、常规测井的典型特征,结合先进图像技术,建立不同类型不同尺度非构造裂缝综合有效识别与定量化表征新方法。二是针对页岩储层非构造裂缝的形成发育具有“多成因类型、多控制因素、多期次演化”的特点,并且页岩非构造裂缝的形成与演化与“古温压、古流体、古成岩”过程联系紧密。据此提出了利用页岩储层非构造裂缝中普遍存在的方解石等充填物的流体地球化学、同位素地球化学(C,O,Sr)及微区原位同位素年代学(U-Pb,Sm-Nd)等先进实验分析技术,综合确定页岩储层非构造裂缝形成时间和活动期次及演化序列是未来研究的关键手段。三是由页岩储层非构造裂缝发育程度与单因素主控因素之间的定性-半定量分析,向多个主控因素耦合控制下的非构造裂缝发育程度的定量研究方向发展,即采用数学方法确定不同主控因素对于裂缝发育程度影响的权重,并构建适合我国页岩非构造裂缝发育程度的综合指数与多个主控因素之间的定量关系模型。

多期构造应力控制走滑断控储层发育机理与差异性研究——以塔里木盆地顺北地区为例

塔里木盆地顺北油气田发育典型走滑断控缝洞型储层。区别于受原始沉积相带控制的基质孔洞、受岩溶改造的洞穴等储集类型,走滑断控缝洞型储层的形成主要受断裂活动期构造应力导致的破裂作用控制。为研究走滑断裂多期活动背景下构造应力控制的断控储层发育机理与分布规律,综合应用野外、岩心、测录井、地震及钻井动态等资料,开展不同走滑断裂、同一走滑断裂沿走向不同部位、垂向不同层系断控储层发育特征表征,并结合应力场数值模拟手段开展多期构造应力恢复,预测断控储层发育的主要时期与分布规律。结果表明,走滑断裂活动期不同分段内部应力状态差异显著,其中拉分段内部以张应力为主,主要派生张性裂缝;压隆段内部以挤压应力为主,派生裂缝类型多样。顺北地区勘探目的层奥陶系一间房组顶面断控裂缝主要在加里东中期Ⅲ幕及加里东晚期—海西早期发育,海西中—晚期及之后裂缝基本不发育,且滑移距大的顺北18号断裂带较顺北1号断裂带派生裂缝开度、密度更高。走滑断控储层具有“簇状”结构特征,断裂活动期不同分段内部应力状态控制储层结构差异,拉分段“空腔”多,以“双簇”结构为主,核带规模大,压隆段核带结构多,以“多簇”结构为主,分割性强;走滑断裂活动期应力强度控制储集空间类型与规模,小型断裂储集空间以裂缝为主,大型断裂带发育核带结构,断控储层规模与断裂活动强度呈正相关关系;断控裂缝发育主要受断裂早期活动控制,晚期由于地层埋深增大,岩石不易破裂,新派生裂缝发育较少。

苏北盆地盐城凹陷盐③断裂带构造演化及其控圈作用

盐(3)断裂带位于苏北盆地盐城凹陷中,断裂带及周边区域发生过多期伸展-走滑复合的构造演化,控制圈闭的时空有效性。为阐明这些构造圈闭对油气差异聚集的影响,需先明确盐(3)断裂带在各时期的演化过程,并研究构造变形对圈闭的控制作用。本文基于盐城凹陷高精度三维地震资料,揭示主要断层和周边褶皱的几何学形态和运动学特征;结合断距回剥法定量恢复断层分段生长过程,进一步利用古构造图分析各期次的褶皱变形规律,解析各期次构造演化性质以及控圈作用。结果表明,盐(3)断裂带经历3个主要演化阶段:(1)泰州—阜宁期(K_(2)t—E_(1)f_(4))NW向伸展控制盐(3)正断层西段孤立生长、东段发生软连接,此时主干断裂的控陷作用不明显,圈闭不发育;(2)阜宁期末发生短期快速的压扭作用,造成盐(3)断层再活动,同时形成一系列的NW向共轭剪切断层,此时沿着盐(3)断裂带形成了一系列的圈闭;(3)戴南—盐城期(E_(2)d-Ny)发生SN向东强西弱的伸展,控制盐(3)断裂带东部再活动,并对圈闭进行调整。整体而言,盐城凹陷的构造活动强度具有“早强晚弱,东强西弱”的差异性,随着研究区构造应力场的不断变化,圈闭的构造幅度、面积逐渐缩小,构造高点也逐渐往SW向转移。

构造煤层顶板爆破跨界面致裂增透机制研究及应用

深部煤炭开采地质条件恶化,原生煤在多期构造运动作用下形成松软低渗高瓦斯构造煤层,煤层钻孔施工困难,爆破增透产生的裂隙不发育且易于重新压实。针对目前构造煤层顶板爆破致裂增透关键技术没有得到根本突破问题,构建试验模型进行煤层顶板爆破相似模拟试验和数值分析,监测跨界面应力波传播和宏观三维裂隙演化形态,再现了爆破应力波传播和煤岩体内部损伤破坏过程。研究表明:(1)构造煤层爆破损伤范围主要集中在爆破孔和煤层上下煤岩交界面附近煤体;构造煤顶板爆破产生跨界面致裂卸压裂纹,爆破损伤沿爆破孔向四周岩体扩展,最后蔓延到煤层底板,爆破孔位置和上部煤岩交界面以及煤层内部的损伤较为严重。(2)爆破应力波从构造煤层顶板传播到煤岩交界面时发生波的透射和反射,透射的压缩应力波破坏煤体;反射的拉伸应力波反作用于煤岩交界面区域岩体。(3)爆破累积损伤产生的跨界面交叉裂纹卸压,使顶板岩层裂隙和构造煤层裂隙贯通,有利于构造煤层的瓦斯垂向运移流动和卸压瓦斯抽采。现场应用表明,煤层顶板爆破瓦斯抽采纯量及其浓度快速上升,瓦斯抽采纯量从爆破前的0.07 m^(3)/min提高到1.73 m^(3)/min,体积分数从10.46%上升到68.50%,并且长时间维持在较高水平。研究成果可为深部构造煤层瓦斯高效抽采提供理论基础和技术支持。

碳酸盐岩储层高精度构造应力场模拟与裂缝多参数分布预测方法及其应用

构造裂缝是碳酸盐岩的主要储集空间之一,局部应力导致的构造破裂是影响裂缝发育的重要因素。基于有限元方法的构造应力场模拟已成为构造裂缝预测的重要方法,但尚未能解决模型设置与实际地质情况相差较大、最优边界条件获取效率低以及构造裂缝发育的主控因素不清晰等问题。①引入非均质岩石力学模型构建方法和自适应边界条件约束算法以提升应力场模拟的精度,根据储层破裂率和断裂活动性等参数定量表征储层裂缝发育特征;②定量探讨走滑断裂变形特征的差异和应力扰动对构造裂缝发育的影响,优选控制构造裂缝发育的最强因素构建碳酸盐岩裂缝型储集体发育指数并定量研究其主控因素;③以储集体发育规模预测为基础,结合单井裂缝测井和岩心解释成果,建立不同级别碳酸盐岩裂缝型储集体的地质模式。将该方法在中国塔里木盆地顺北地区18号断裂带及邻区奥陶系碳酸盐岩储层中应用。结果表明,张扭段、平移段与压扭段的裂缝发育程度依次降低。地层变形幅度越大,裂缝发育程度越高。储层岩石力学参数、距断裂的距离、水平两向应力差、应力非均质性系数和综合破裂率被用于构建裂缝型储集体发育指数,其分级结果与实际地质情况匹配度较高。

黔西北青山铅锌矿床构造控矿机理及其对深部找矿的启示

【研究目的】青山铅锌矿床地处扬子地块西南缘的黔西北矿集区威宁—水城成矿亚带中段,严格受构造控制,资源潜力巨大。基于前期资料综合分析及野外地质调研,发现矿区构造成生发展过程和构造控矿机理不清、深部找矿勘查方向不明等问题制约了找矿突破。【研究方法】本文应用矿田地质力学理论和方法,通过大比例尺构造剖面精测、不同方向控矿构造力学性质鉴定与不同期次、序次构造筛分,结合区域构造应力场变化特征,揭示了构造控矿机理。【研究结果】自印支期以来,该区的主压应力方向主要历经了北东-南西向→北西-南东向→北东-南西向→近东西向的转变过程,依次形成了早北西构造带、北东构造带、晚北西构造带、南北构造带(构造体系)。通过成矿构造解析及其与成矿关系讨论,厘定了北东构造带为该矿区的成矿构造体系,揭示了构造分级控矿规律:北西向威宁—水城断裂、威水背斜为矿区的一级控矿构造,控制了威宁—水城矿化带或矿田的展布;威宁—水城断裂扭动作用派生的北西向断裂F1、F2,控制了矿床(矿体群)的分布,为矿区的二级控矿构造;F1、F2断裂间的层间断裂破碎带,直接控制了矿体的形态和产状,为三级控矿构造;矿体旁侧的节理裂隙带控制矿脉,为四级控矿构造。【结论】青山铅锌矿床构造分级控矿规律明显,主要受四个等级的控矿构造控制,并形成了与其相对应的4种矿化样式。

沁水盆地郑庄区块残存煤层气的埋深和构造综合控气模式分析

煤层含气量是影响煤层气勘探开发的重要条件.实际生产中,煤储层地质条件十分复杂,含气量往往受多个因素综合控制.以沁水盆地郑庄区块3^(#)煤层为研究对象,分析其含气量分布特征及控气地质因素,得到以下结论:郑庄区块煤层含气量较高,其分布特征受煤层埋深和构造条件综合作用;在构造条件不发育地区,煤层埋深通过改变储层温度和压力控制煤层气的产生和保存,随着埋深增加,煤层含气量先增加后降低,逐渐由强压力敏感性转变为强温度敏感性;在构造发育区域,煤层含气量受埋深和构造条件综合作用,构造条件通过改变煤层埋深和储层封闭能力引起煤层气的运移逸散,褶皱和断层作用改变煤层埋深,为煤层气运移提供驱动力,伴生的节理是煤层气的运移通道,其走向和密度控制煤层气的运移方向和程度,运移目标区的埋深等储层特征影响煤层气的最终保存.

构造作用对常规-非常规油气连续聚积耦合成藏控制机制——以川东南平桥地区为例

为探索川东南平桥地区构造作用对常规和非常规气藏成藏过程的动态控制作用及差异,基于地震、地质和包裹体等资料,根据断层相关褶皱理论,系统剖析了该区构造特征及演化过程、常规气藏和非常规气藏动态成藏过程及构造对两者影响的差异性,建立了典型常规—非常规油气连续聚集耦合成藏模式。平桥地区位于川东南SE-NW前展式递进变形带中,受多套滑脱层和江南—雪峰造山带联合控制,发育断展构造和背冲构造。平桥背斜构造形成于燕山期。中燕山期,受江南—雪峰构造体系前展式扩展影响,研究区发生NE向强烈断褶作用。晚燕山期—喜马拉雅期川中隆起阻挡和青藏高原隆升使平桥背斜不断抬升;寒武系筇竹寺组和奥陶系五峰组—志留系龙马溪组烃源岩在早燕山期及以前主要经历了长期的埋藏生烃,中燕山期构造变形扩展至研究区,常规气藏储层(洗象池群)、盖层、油气圈闭及运移均受到影响,气藏保存条件较差。非常规气层被改造成为背斜构造,页岩气向背斜核部聚集,整体保存条件较好。晚燕山期—喜马拉雅期,地层隆升泄压,两类气藏保存条件继续变差。因此,构造作用对常规气藏和非常规气藏成藏控制差异体现在控制方式和改造时间上:中燕山期侧向供烃是常规气藏成藏的关键;晚白垩世构造活动改造和晚燕山期—喜马拉雅期构造抬升影响了页岩气的保存。

淮北煤田钱营孜矿井控煤构造特征及其动力学背景分析

钱营孜矿井位于淮北煤田宿县矿区的西部,毗邻徐宿弧形推覆构造南段的外缘带。为认识该矿井构造变形与演化规律、动力学机制以及指导未来资源探采方向提供重要地质依据。利用最新的矿井地质勘探与生产资料,对钱营孜矿井开展构造格架和控煤构造样式分析,划分矿井构造期次,讨论构造发育的区域大地构造背景。结果表明,矿井内石炭纪-二叠纪含煤地层总体呈一轴向NNE、向SSW仰起的宽缓向斜;矿井内断裂构造非常发育,逆断层数量大于正断层,2类断层的走向均以NE至NNE向为主,其次为NS向;矿井构造格架显著受控于数条NS向至NE向的大型断层,自西向东受南坪断层、F_(22)、F_(17)、DF_(200)及双堆断层等主干断层的分割,呈现东、西分带特征;矿井控煤构造样式可以划分为挤压、伸展和走滑3个类型,以及逆冲牵引褶皱、对冲式构造、冲起构造、叠瓦状构造、地堑、地垒、阶梯状断层、正花状构造、羽状雁列式构造9个亚类型;构造组合分析表明,F_(17)断层除逆冲活动之外,还存在显著的平移活动。矿井构造可划分为5期,从早到晚分别为:轴向NNE的冯家向斜、近NS向逆断层、NNE向逆-左行平移断层及NE向逆断层、近NS向正断层、NE向正断层。矿井内第1,2期缩短构造分别是印支期华北克拉通与华南板块汇聚过程中的前陆变形及随后陆-陆碰撞造山变形的影响结果;第3期压扭性构造与西太平洋区伊泽奈崎板块早白垩世初向东亚大陆边缘快速斜向俯冲有关;第4,5期伸展构造则是早白垩世以来中国东部强烈伸展背景下发育而成。