New perspective of Miocene marine hydrocarbon source rocks in deep-water area in Qiongdongnan Basin of northern South China Sea

Drilling wells reveal that the organic matter abundance of Miocene marine source rocks in shallow water area of the Qiongdongnan Basin is relatively low with poor hydrocarbon generation poten- tial. However, in some drilling wells of deep water area close to the central depression belt, Miocene marine source rocks with better organic matter abundance and hydrocarbon generation have been found, which have achieved better source rock standard based on the analysis of geochemical charac- teristics. Although there are no exploratory wells in deep water area of the research region, through the comparative analysis of geochemical data of several typical exploratory wells respectively from shallow water area in the basin, central depression belt margin in deep-water area of the basin and Site 1148 of deep sea drilling in the South China Sea Basin, it reveals that the tendency of the quality of source rocks becomes positive gradually from delta to bathyal environment, which then becomes negative as in deep oceanic environment. Owing to the lack of terrestrial organic matter input, the important controlling factors of Miocene marine source rocks in the Qiongdongnan Basin are ocean productivity and preservation conditions of organic matter. The element geochemistry data indicate that the tendency of the paleoproductivity and the preservation conditions of organic matter become positive as water depth increase from shallow area to bathyal area close to central depression belt. So it is speculated that there must exist high quality source rocks in the central depression area where the preservation conditions of organic matter are much better. Besides, in theory, in oxygen-poor zone of oceanic environment at the water depth 400–1 000 m, the preservation conditions of organic matter are well thus forming high-quality marine source rocks. The result- ing speculation, it is reasonable to consider that there are high hydrocarbon generation potential source rocks in bathyal environment of the Qiongdongnan Basin, especially at the water depth 400– 1 000 m.

The Relationship between Tectonic Subsidence and BSR of Upper Neogene in the Deep-Water Area of the Northern Continental Slope, South China Sea

BSR （Bottom Simulating Reflector） occurs widely in the strata since the late Miocene in the deep-water area of the northern continental slope of South China Sea （SCS）. It is an important seismic reference mark which identifies the gas hydrate and its distribution influenced by the tectonic movements. Single-point basin modeling was conducted using 473 points in the study area. To discuss the relationships between the tectonic subsidence and BSR, the volume and rate of tectonic subsidence in each geological time have been simulated. The results show that there are three tectonic accelerate subsidence processes in the study area since the late Miocene, especially since 1.8Ma the tectonic subsidence accelerates more apparently. Since the Late Miocene to Pleistocene, the rate of tectonic subsidence in deep-water underwent a transformation from weak to strong. The ratio of tectonic subsidence to the total subsidence was relatively high （65-70%）. Through the superposition of the BSR developed areas and the contours of tectonic subsidence in this area, it was discovered that more than 80% of BSR tend to be distributed at the slope break or depression-uplift structural transfer zone and the average tectonic subsidence rate ranges from 70 m/Ma to 125 m/Ma.

Chemical kinetics evaluation and its application of natural gas generation derived from the Yacheng Formation in the deep-water area of the Qiongdongnan Basin,China

The natural gas generation process is simulated by heating source rocks of the Yacheng Formation, including the onshore-offshore mudstone and coal with kerogens of Type II2-III in the Qiongdongnan Basin. The aim is to quantify the natural gas generation from the Yacheng Formation and to evaluate the geological prediction and kinetic parameters using an optimization procedure based on the basin modeling of the shallow-water area. For this, the hydrocarbons produced have been grouped into four classes（C1, C2, C3 and C4-6）. The results show that the onset temperature of methane generation is predicted to occur at 110℃ during the thermal history of sediments since 5.3 Ma by using data extrapolation. The hydrocarbon potential for ethane, propane and heavy gaseous hydrocarbons（C4-6） is found to be almost exhausted at geological temperature of 200℃ when the transformation ratio（TR） is over 0.8, but for which methane is determined to be about 0.5 in the shallow-water area. In contrast, the end temperature of the methane generation in the deep-water area was over 300℃ with a TR over 0.8. It plays an important role in the natural gas exploration of the deep-water basin and other basins in the broad ocean areas of China. Therefore, the natural gas exploration for the deep-water area in the Qiongdongnan Basin shall first aim at the structural traps in the Ledong, Lingshui and Beijiao sags, and in the forward direction of the structure around the sags, and then gradually develop toward the non-structural trap in the deep-water area basin of the broad ocean areas of China.

Movement characteristics of Karst water in a deep mining area

In order to study the movement characteristics of groundwater in a deep mining area and solve the dispute of the distri- bution rule of hydro-chemical zoning which is contradicted by lixiviation water zoning in a horizontal direction, we directed our attention to the source of deep groundwater, its seepage and hydro-chemical characteristics in a typical mining area. We used a neotectonic water-control theory, chemical and isotope methods, as well as a method for analyzing dynamic groundwater conditions. The results indicate that 1) Karst water in the deep and medium parts of this mining area is recharged by vertical leakage through neotectonic fractures rather than seepage along strata from subcrop parts or surrounding flows; 2) from surface to deep leakage paths, the variation in the types of chemical groundwater agrees with the normal lixiviation water distribution rule and the age of mixed groundwater increases; 3) the water-rich zones along neotectonic fractures correspond with water-diluted zones in a hori-zontal direction; 4) the leakage coefficient and water capacity of aquifers increases during the flow process of Karst water along the antidip direction (from west to east) and 5) Karst water in shallow mining areas forms a strong runoff belt along strikes and quickly dilutes the water from deep and medium mining areas. Overall, chemical and dynamic water characteristics actually agree with in terms of the entire consideration for differences in vertical leakage and abnormalities in the zone of water chemical distribution, along a horizontal runoff direction.

Petroleum geology controlled by extensive detachment thinning of continental margin crust: A case study of Baiyun sag in the deep-water area of northern South China Sea

The relationships between crustal stretching and thinning,basin structure and petroleum geology in Baiyun deep-water area were analyzed using large area 3D seismic,gravity,magnetic,ocean bottom seismic(OBS),deep-water exploration wells and integrated ocean drilling program(IODP).During the early syn-rifting period,deep-water area was a half-graben controlled by high angle faults influenced by the brittle extension of upper crust.In the mid syn-rifting period,this area was a broad-deep fault depression controlled by detachment faults undergone brittle-ductile deformation and differentiated extension in the crust.In the late syn-rifting period,this area experienced fault-sag transition due to saucer-shaped rheology change dominated by crustal ductile deformation.A broad-deep fault depression controlled by the large detachment faults penetrating through the crust is an important feature of deep-water basin.The study suggests that the broad-deep Baiyun sag provides great accommodation space for the development of massive deltaic-lacustrine deposition system and hydrocarbon source rocks.The differentiated lithospheric thinning also resulted in the different thermal subsidence during post-rifting period,and then controlled the development of continental shelf break and deep-water reservoir sedimentary environment.The high heat flow background caused by the strong thinning of lithosphere and the rise of mantle source resulted in particularities in the reservoir diagenesis,hydrocarbon generation process and accumulation of deep-water area in northern South China Sea.

极端环境隧道建造面临的主要问题及发展趋势

聚焦艰险山区、深水海域与城市敏感区3类极端环境,全面梳理和总结了在此环境下隧道建造面临的主要问题、相关技术突破和未来发展趋势。针对艰险山区中极高地应力、高地温、高海拔以及活动断裂带等极端条件,总结分析围岩和隧道的变形机制、破坏机制及防护措施,并指出未来可通过大数据、机器学习等手段建立更精准的预测模型,以实现隧道建造过程的实时监控和风险评估;针对深水海域中高水压、高烈度地震、强侵蚀环境等极端条件,分析多因素耦合下沉管法及盾构法隧道管片及接头的劣损和破坏机制,总结提升其力学和耐久性能的主要技术措施,并提出未来仍需针对海底隧道管片接头的防水、抗震及抗侵蚀性能开展更深入的研究,以形成完整的理论和技术体系;针对城市敏感区隧道穿越既有隧道、敏感建构筑物、地下障碍物等挑战,总结分析盾构法和顶管法施工环境响应规律、地层变形评估方法和控制技术措施,提出未来可采用机器学习等技术辅助隧道建设,以提升预测和控制的准确性,减小建设过程对城市环境的扰动。目前,相关研究成果为极端环境下的隧道工程建设提供了重要支撑,但部分技术仍需进一步在实践中完善并形成规范,以指导后续的工程建设;而随着新一代信息技术的发展,未来隧道建造必将朝着数字化、智能化、自动化的方向发展,从而保障极端环境下隧道建设的安全、绿色、高效。

深水中大型气田滚动勘探技术体系与成效——以琼东南盆地中央峡谷A边际气田为例

为了促进琼东南盆地中央峡谷深水A边际气田开发,引入目标搜索研究、目标评价研究、目标钻探研究等完整气田滚动勘探技术体系。A边际气田目标搜索除利用传统的区带油气潜力目标搜索技术外,提出评价过程目标搜索技术,共搜索了5个油气潜力区块,并优选A4构造进行油气目标评价。从圈闭解释与落实、圈闭烃类检测两方面对A4构造油气成藏主控因素开展研究。A4构造中部预测优势含气区具有强振幅属性、低密度、低速度、低纵波阻抗、低纵横波速度比等有利含气信息特征,总体为Ⅲ类AVO异常,且能够升级HL_0气组控制天然气地质储量,部署滚动探井A4-1井实施钻探,在黄流组钻遇气层超20 m,莺歌海组二段钻遇可疑气层近10 m,获得天然气探明地质储量近30亿立方米,钻探效果好。滚动勘探研究在深水A边际气田的应用,不仅有效地促进了A边际气田后续滚动勘探活动,而且证实了滚动勘探同样适用于深水油气勘探。

珠江口盆地超深水区LW21-A井烃源岩分子地球化学特征与油气成因

珠江口盆地超深水区勘探程度低,珠四坳陷仅LW21-A井有油气发现,通过对其进行系统地特征分子地球化学测试与分析,揭示了所钻遇烃源岩的类型和发现油气的成因。该钻井揭示,文昌组和恩平组发育海相(海侵)泥岩和微咸水浅湖相(近海湖盆)泥岩;LW21构造气藏中存在海相(海侵)和湖相2类凝析油;LW21构造气藏中天然气主要成分为CO_(2),属于CO_(2)气藏,含一定量烷烃气;CO_(2)主要是无机幔源型成因气,烷烃气主要是油型气与海相生物气的混合型干气。这一认识对珠江口盆地超深水区珠四坳陷带的进一步评价和勘探决策具有重要意义。

新形势下中非油气合作建议

非洲油气资源丰富,随着近年陆续在毛里塔尼亚、莫桑比克、南非、纳米比亚等国家发现大型油气田,油气储量规模进一步增大,非洲西海岸北段、东非、南非成为勘探新兴区域。近年来受局部区域政局动荡、已发现剩余油气可采储量品质变差、天然气商业化困难等因素影响,非洲油气生产形势低迷。经过近30年的发展,中非油气合作已具备一定规模,但对标国际大型石油公司,无论是生产项目还是勘探项目,仍有一定差距。伴随俄乌冲突加剧,地缘政治变化,拥有大量油气资源的非洲在全球的能源地位日益凸显。同时国际石油公司由于能源转型,纷纷缩紧非洲投资,这给中资石油公司在非洲的进一步发展提供了机遇。建议中资石油公司要加大前期勘探投入,聚焦前沿成藏区带,力求获得大面积、大资源量、经济效益可观的勘探目标;着力提升海上深水-超深水区域的研究能力和作业能力;积极关注非洲LNG产业发展,优化资产结构;同时要正确认识非洲非资源风险,提升风险防范能力。

近海深水区混凝土半潜型浮式风机一体化计算与耦合动力特性分析

[目的]文章旨在探索10 MW级半潜型浮式风机的一体化计算方法并分析其在40~50 m近海深水区的耦合动力响应特性。[方法]以10 MW混凝土半潜型浮式风机为例,构建一体化时域数值计算模型,统计分析其额定发电和极端工况下的平台动力响应和系泊张力特征。[结果]平台水平运动主要受波浪荷载、风荷载和系泊刚度特性的影响,最大水平运动和系泊张力发生在生存工况,垂向运动主要受波浪荷载影响,摇摆运动的均值主要受风荷载影响,上述浮式风机动力响应均满足设计指标。[结论]一体化数值计算方法较好地考虑浮式风机耦合动力特性,由于水深限制,近海深水区的海上漂浮式风机对水平运动约束和系泊非线性问题的优化更为重要,响应极值主要发生在极端工况,上述结论为此类漂浮式海上风机基础结构的研究与设计工作提供了一定的参考。

面向“23·7”特大暴雨的北京市门头沟、房山、昌平流域单元划分

2023年7月末至8月初,北京市受台风影响,遭遇了历史罕见的特大暴雨并引发流域性特大洪涝灾害,造成了重大损失和影响。特大暴雨落区主要集中在西部山区,其中门头沟、房山、昌平区受灾严重,为快速响应灾后重建规划需求,本文提出基于2m分辨率的地形数字高程模型(DEM)数据、数字正射影像图(DOM)、沟渠、道路、2010年第一次水务普查成果等多源数据,面向深山区、浅山区的流域提取方法,应用于北京市受灾区域,划定了房山、门头沟、昌平区的山区流域单元,并基于流域单元数据进行了村庄及特大暴雨时期的人口分析等应用研究。经过试验证明,本文与传统水文模型提取算法相比,提取结果更符合实际地形,也和第一次水务普查成果进行比对,证明了本研究方法的可靠性。

深水区浅覆盖层锚桩法钢栈桥设计及施工

从钢栈桥的设计理念出发,结合具体的工程案例,对深水区浅覆盖层区域钢栈桥的设计施工进行了探讨,对照使用区域的实际情况,采用锚桩法栈桥施工技术。经计算,栈桥的强度和刚度能够满足工程的施工要求,栈桥整体的稳定性可以得到保障。对钢栈桥锚桩法的施工流程和技术要点进行了讨论,顺利实现了施工目标。

Experimental Simulation Study of the Dominant Enrichment Area of Terrestrial Organic Matter in the Shallow-Delta Sedimentary System of the Yacheng Formation in the Qiongdongnan Basin

Shallow-delta sedimentary systems receive both terrestrial and marine organic matter. As oil and gas exploration activities determine that the source rocks of the deep-water area of the Qiongdongnan Basin, northern South China Sea, are generally rich in and even dominated by terrestrial organic matter, this has led many researchers to examine the rules governing terrestrial organic matter enrichment in shallow-delta sea sedimentary systems. However, the deep burial of source rocks in deep-water areas and the relatively small amount of drilling undertaken have greatly restricted the study of these rules. In this study, the ‘forward modeling' research method was used to observe and analyze the deposition and preservation of terrestrial organic matter through flume experiments, where the depositional results were carefully depicted and sampled. The total organic carbon content of selected samples was measured and when combined with qualitative observations and quantitative comparison results, the dominant enrichment areas of terrestrial organic matter were identified. The experimental results show that the overbank parts of the delta front, the dune countercurrent surface, the low-lying parts, the delta front slope area and the shallow-prodelta sea area are where terrestrial organic matter is predominantly enriched. This provides an important basis and guidance for the prediction of the development areas of marine source rocks with terrestrial input in the deep-water areas of the Qiongdongnan Basin.

陕蒙矿区深部开采导水裂隙带发育特征与高度预测方法

导水裂隙带发育高度是矿井防治水及安全开采的重要依据。由于陕蒙矿区地层沉积环境和沉积过程的特殊性,使得该区域导水裂隙发育高度与传统认识差别较大。考虑到目前围绕陕蒙矿区导水裂隙带发育高度计算方法缺失问题,以鄂尔多斯市营盘壕煤矿2217工作面为工程背景,采用UDEC模拟研究了不同开采进度下导水裂隙带发育规律及演化特征,分析了大能量事件与导水裂隙带发育的关联关系,进而基于GA-SVR算法,建立了区域导水裂隙带发育高度精准预测方法。结果表明:直罗组砂岩巨厚的特性使得其在覆岩运动中表现出坚硬岩层的特点,裂隙带在其下充分发育,稳定后也形成“马鞍形”;微震监测数据能精准反映区域导水裂隙带发育高度,预测相对误差仅为3.90%;建立的导水裂隙带高度预测模型的决定系数R^(2)为0.81,相对平均误差r为14.55%,预测精度显著优于经验公式(R^(2)<0,r=59.57%)。研究成果对于陕蒙矿区保水开采与安全生产设计及矿井水防治具有重要的实践意义。

合水地区Z183区块长7_(1)深水重力流储层宏观非均质性及影响因素

为解决致密储层开发中因非均质性造成的小层突进与平面舌进等问题,根据岩心、高压压汞、测井等资料,采用储层地质方法,从层内、层间与平面3个方面描述了合水地区Z183区块长7_(1)储层的宏观非均质性,并探讨其影响因素。结果表明,区块内存在2类层内夹层,其中泥质夹层分布相对较广。区块内可识别4类砂体构型,间隔叠加厚砂—薄泥互层型分布最广。区块内砂质碎屑流成因砂体分布范围最广。研究区储层整体具有强非均质性,其物性变化主要受砂质碎屑流微相与压实作用的影响。

蒙陕深埋煤层首采工作面顶板富水性和涌水量差异研究

针对蒙陕接壤区存在水文地质条件不清、水害问题多发、水资源漏失严重等问题,通过分析区内呼吉尔特矿区4个矿井首采工作面顶板地质水文地质特征、回采过程中涌水量变化及差异性,查清了矿区煤炭开采初期扰动下的水文地质条件,结果表明:四个矿井首采工作面涌水量,均随着工作面回采呈逐渐增加趋势,其中葫芦素和巴彦高勒矿井首采工作面最大涌水量分别为645.0 m^(3)/h和494.0 m^(3)/h,且七里镇砂岩含水层不同区域存在富水性差异,导致涌水量的增加呈台阶式,波动性较大,与该区域七里镇砂岩含水层厚度较薄、富水性较弱的特征一致;门克庆和母杜柴登矿井首采工作面最大涌水量分别为1372.0 m^(3)/h和938.0 m^(3)/h,且七里镇砂岩含水层整体富水性较强、富水性较均一,涌水量的增加呈平稳增加态势,波动性较小,与该区域顶板七里镇砂岩含水层厚度较大、富水性较强的特征一致。

四川盆地简阳地区二叠系火山碎屑岩储层特征与成岩演化

火山碎屑岩油气藏作为重要的非常规油气藏,对油气增储上产具有重要的意义。通过岩心观察,综合薄片鉴定、QEMSCAN扫描、X射线衍射、物性分析、包裹体测温及碳氧同位素分析等资料,系统分析了四川盆地简阳地区二叠系火山碎屑岩储层特征及其成岩演化过程。研究结果表明:(1)简阳地区二叠系火山碎屑岩储层岩石类型主要包括火山角砾熔岩、凝灰熔岩和熔结火山角砾岩,整体物性都较好,孔隙度为0.78%~32.00%,平均为16.67%,渗透率为0.001~2.680 mD,平均为0.125 mD,属于高孔低渗储层,储集空间以次生孔隙和裂缝为主,包括脱玻化孔、基质溶蚀孔及溶蚀缝等类型。(2)研究区发育多种成岩作用,主要有熔结、压实、脱玻化、胶结及溶蚀作用等。(3)研究区经历了同生成岩、表生成岩与埋藏成岩3个阶段,成岩演化受深部热液、大气淡水及有机酸流体的共同影响,一方面流体活动造成热液矿物或碳酸盐胶结物的沉淀对储层物性起破坏性作用;另一方面热液流体促进油气运移,酸性流体的溶蚀改造作用对储层孔隙发育起建设性作用。

西南山区某深埋长大隧道水文地质特征及突涌水危险性分析

西南山区某隧道处于龙门山断裂带西南段内,区域地质构造作用强烈,地形地貌及岩溶水文地质条件复杂,突涌水成为制约隧道勘察设计和安全施工的重大难题。本文采用现场水文地质调查、水化学成分测试、理论分析计算等方法分析了隧道的岩溶发育程度和岩溶发育规律;依据岩溶水补径排条件,划分了工程区水文地质单元;在水文地质分区的基础上,进行了隧道涌水量预测和隧道涌突水危险性评价。研究结果表明:(1)该隧道二叠系栖霞组(P_(1)q)、奥陶系中统宝塔组(O_(2)b)为强富水性,泥盆系养马坝组(D_(2)y)、泥盆系中统观雾山组(D_(2)g)、志留系下统纱帽组(S_(2)s)、志留系下统罗惹坪组(S_(2)l)为中等富水性,晋宁澄江期斜长花岗岩(γ_(2))、震旦系下统安山岩段(Zaα)以及志留系,泥盆系地层中的砂岩和泥岩为弱富水性;(2)该隧道高危险突涌水段650 m,占比4.42%;中危险突涌水段5879 m,占比39.98%;较危险突涌水段7742 m,占比52.64%;低危险突涌水段435 m,占比2.96%。本文研究成果对西南山区铁路岩溶区高压富水隧道勘察设计和施工具有重要参考价值。

琼东南盆地深水区宝岛21-1气田天然气来源及输导体系

宝岛21-1气田的发现是琼东南盆地宝岛凹陷近30年以来油气勘探取得的最大突破,打开了勘探新局面,有关其天然气来源和输导体系的认识,对宝岛凹陷进一步勘探具有重要意义。以宝岛21-1气田为主要研究对象,采用油气地球化学及断裂体系刻画等手段,详细分析了天然气组成、碳同位素特征和凝析油生物标志化合物特征,精细刻画了主控断层几何形态和运动学特征,并分析了其对天然气富集的贡献。结果显示,宝岛21-1气田具有重烃气含量高、干燥系数低及碳同位素轻的特点,与Y13气田和L17气田具有明显差异,揭示除陆源有机质的贡献外,还有明显的腐泥型有机质贡献,主要为海相藻类的贡献。宝岛21-1构造经历了3期油气充注,断裂与陵水组三段三角洲砂体构成了高效输导体系,断裂形态与差异活动性控制油气汇聚-输导,使该构造所在位置成为优势聚集区。建立了紧邻生烃主洼,沿“大型构造脊+断面脊汇聚,长期活动的大型沟源断裂与三角洲砂岩配置高效输导”的天然气富集模式,为宝岛凹陷及琼东南盆地勘探提供重要依据。

叠后多属性在潜山断裂系统描述中的应用研究

南海北部深水区白云凹陷区域毗邻生烃超压带,成藏条件优越,拥有巨大的勘探潜力,同时深层潜山圈闭发育,潜山内幕裂缝带是油气运移通道。因此,针对深层潜山有利圈闭预测是该区油气勘探的一个重要方向。受构造作用及风化作用的影响,潜山内幕地震响应特征表现为杂乱反射、弱反射和空白反射的特点,这无疑增加了储层预测的难度。针对上述问题,论文充分利用叠后地震数据开展多属性分析,并在此基础上形成了一套分级分尺度的叠后地震潜山储层预测方案及技术流程。该方法主要依据断裂尺度大小与地震数据分辨率的相对大小关系,将断裂划分为大尺度断层、亚断层和微断裂,并利用不同叠后地震属性来分级描述。首先,在人工构造解释的基础上,利用叠后地震数据的本征值相干属性来刻画亚断裂,并在滤波处理的基础上,采用倾角增强、断层增强和线性增强对大尺度断裂进行精细刻画。其次,对比分析曲率属性体和最大似然属性,优选最大似然属性对中小尺度微断裂进行刻画,确定裂缝发育区。最后,在分级刻画的基础上进行多属性叠合刻画微断裂发育带。选取南海北部深水区白云凹陷东潜山勘探区进行了实际应用,通过对不同尺度大小的断裂目标体进行不同属性的描述和多属性叠合解释,提高了对潜山微断裂发育带的刻画精度,确定了潜山有利储层目标区域。实际数据应用结果表明:叠后多属性断裂系统描述方案可以很好地进行断裂型储层的分级描述,并在地质认识的基础上确定优质目标区。论文提出的分级分尺度储层断裂刻画方案可在其他类似的潜山油气勘探开发中应用。