南海西北部莺歌海盆地HBJM39-1气田储层岩相划分与微相识别

以HBJM39-1-1、HBJM39-1-2A、HBJM39-1-3和HBJM39-1-4等4口井的取心资料为基础,结合层序地层学解释,深入分析了莺歌海盆地HBJM39-1气田储层的岩相沉积特征。研究表明,HBJM39-1气田储层岩相具有颜色深、粒度细、水动力条件弱、生物扰动强且发育风暴沉积等特点。通过地震地质解释、盆地古地貌以及岩心描述等分析研究证实,HBJM39-1气田储层形成于相对较深的沉积水体环境。莺歌海盆地上新世主要发育滨浅海相沉积,但根据古水体环境、生物遗迹相、岩相以及测井相等资料揭示,上新世莺一段至第四系乐东三段尚发育滨外亚相,不发育前滨及以上亚相沉积。同时,为了进行储层非均质性研究,以"泥"、"砂"截然不同的渗流、渗流屏障作用为主线,亦对滨外亚相等进行了进一步细分和较深入研究。

安塞油田长10_1储层成岩作用及岩相研究

安塞油田G52井区长101储层属低孔、中低渗—低渗储层,孔喉以中、细喉为主,具有粒度较粗,成分成熟度低,结构成熟度较高的特点。运用铸体薄片、X衍射、电镜扫描、镜质体反射率测定及物性分析等资料,研究了其成岩作用特征,确定成岩阶段主要处于中成岩的A期中亚期-B期。依据成岩作用类型及储层物性特征,划分出7种成岩相,其中强溶蚀成岩相和溶蚀成岩相孔隙度高、渗透率好、含油性好,是研究区最有利的油气储集相带;长石溶蚀—绿泥石膜胶结成岩相物性次之,含油性较差;压实固结成岩相、粘土矿物胶结成岩相、致密胶结成岩相和胶结成岩相物性最差,不利于油气储集。

基于水平井信息的辫状河岩相单元与砂体定量研究——以委内瑞拉奥里诺科重油带MPE3区块为例

采用直井信息进行砂体定量研究时,往往由于井间对比的不确定性,导致对砂体规模的认识存在较大的不确定性。水平井对储层砂体横向预测具有重要参考价值,这是常规直井难以达到的。因为水平井可以揭示砂体横向变化,从而为我们在砂体定量表征、岩相单元划分等定量化地质研究方面提供帮助。针对研究区辫状河储层特点,结合直井岩心、直井与水平井的测井信息,首先确定出4类岩相单元,进行直井与水平井岩相单元划分;然后结合直井与水平井信息,进行砂体定量研究,确定了心滩和辫状河道砂体的形态及发育规模,进而建立了心滩长宽比、心滩与河道宽度比、夹层与心滩宽度比等定量关系;随后以水平井钻遇砂体信息为约束,进行储层地震波阻抗反演;最后结合砂体定量表征与波阻抗反演结果,进行岩相单元的预测。研究结果表明:基于水平井信息可以精细刻画储层内部岩相分布特征,提高储层砂体定量研究与内部非均质性描述的精度;水平井段信息增加了参与地震储层反演的样点数量,从而减小了井间储层预测的不确定性,可以明显提高储层内部地震反演精度和可靠性,并可以提供更为可靠的储层岩相模型。

墨西哥湾天然气水合物富集特征与成藏机制——以WR313和GC955研究区为例

作为全球天然气水合物热点研究区,墨西哥湾水合物勘探研究已进行了数十年,特别是在WR313和GC955区集中开展了水合物富集成藏特征研究。基于大量水合物勘探成果,分析总结了这两个研究区水合物纵向上的分布特征、有利储层的岩相特征以及水合物富集成藏机制,从整体上反映了该海湾天然气水合物勘探研究的最新进展。WR313和GC955研究区水合物主要存在砂层孔隙充填型与泥层裂隙充填型两种赋存类型。较深部相对粗粒富砂层含有孔隙充填型水合物,饱和度通常大于80%,可高达95%;而较浅部泥层裂隙充填型水合物饱和度极低,平均饱和度一般低于5%。同时,讨论了水合物富集成藏研究面临的问题,强调水合物富集成藏是一个受诸多因素影响的复杂作用过程,指出在水合物富集区优选过程中,局部富砂体的识别应受到特别重视。

徐深气田火山岩气藏水锁效应

徐深气田火山岩气藏储层复杂,开发难度较大。为制定合理的气藏开发方案,提高单井产量和经济效益,减少开发过程对气藏的伤害,研究了不同孔隙类型火山岩气藏的全直径岩心水锁伤害机理。利用核磁共振T_2谱给出了不同孔隙类型储层自吸水和气相反排后滞留水分布规律,从微观角度解释了不同孔隙类型储层水锁伤害恢复快慢差别的原因。研究认为:火山岩气藏储层岩心含水饱和度随渗吸时间的延长而增加;储层大孔隙越发育则渗透率越高,微孔隙占比越大则渗透率越小;储层孔喉连通性越差,非均质性越强,则自发渗吸时岩心吸水量越小;连通性较差的大孔隙是残余气分布的主要孔隙空间;储层水锁伤害随气体反排孔隙体积倍数的增加而减小。

Automatic discrimination of sedimentary facies and lithologies in reef-bank reservoirs using borehole image logs

Reef-bank reservoirs are an important target for petroleum exploration in marine carbonates and also an essential supplemental area for oil and gas production in China. Due to the diversity of reservoirs and the extreme heterogeneity of reef-banks, it is very difficult to discriminate the sedimentary facies and lithologies in reef-bank reservoirs using conventional well logs. The borehole image log provides clear identification of sedimentary structures and textures and is an ideal tool for discriminating sedimentary facies and lithologies. After examining a large number of borehole images and cores, we propose nine typical patterns for borehole image interpretation and a method that uses these patterns to discriminate sedimentary facies and lithologies in reeI^bank reservoirs automatically. We also develop software with user-friendly interface. The results of applications in reef-bank reservoirs in the middle Tarim Basin and northeast Sichuan have proved that the proposed method and the corresponding software are quite effective.

Detailed sedimentary facies of a sandstone reservoir in the eastern zone of the Sulige gas field, Ordos Basin

Given sustaining exploration, the eastern zone of the Sulige gas field may soon become a key area of exploitation. In order to explore its genesis, types and distribution of the reservoir sandstones in the eastern zone of this gas field, we focused in our study on the provenance and detailed sedimentary facies of sandstone of the He8 （the eighth part of the Shihezi formation, Permian system） and Shanxil （the first part of the Shanxi formation, Permian system） members, based on core observations, analyses in petrography, granularity and logging. The results show that： 1） the sandstone provenance of Shanxil and He8 in the eastern zone of the Sulige gas field is from the north of the Ordos Basin, characterized by dual directions from the north and northeast. 2） The He8 and Shanxil members were deposited in a fluvial-delta sedimentary system. The He8 was mainly deposited in braided rivers, in- cluding braided channels, channel bars, levee and floodplain sub-environments, whereas the Shanxil Member was deposited in braided rivers and deltas, including braided channels, channel bars, floodplains, tributaries and inter-tributary sub-environments. 3） Sedimentary facies bands migrated in drastic fashion towards the basin from the Shanxil to the He8 Member. Base levels of sedi- mentation generally present a trend of small increases in-amplitude, large decreasing amplitudes and slow and gradual Increases. 4） The continuity of the reservoir sandbodies along the source direction is better than that perpendicular to the direction. Compared with Shanxil, both dimensions and continuity of the sandbodies in He8 are better from which we conclude that it is the most fa- vorable part of the reservoir.

Petroleum exploration of shallow marine deposit Carboniferous volcanic tuff reservoir in the western margin of Junggar Basin

In 2011, petroleum exploration of shallow marine deposits Carboniferous and volcanic tuff reservoir re- alized breakthroughs at Chepaizi slope in the western margin of Junggar Basin. Pal 61 well, with 855.7 949.6 m section, in the conventional test oil obtained 6 t/d industrial oil flow. The surface viscosity is 390 mPa. s （50 ℃）. The marine deposit of Carboniferous are deep oil source rocks and high-quality reservoir. Magma volcanic activity provides the basis for volcanic reservoir development and distribution. The weathering crust and secondary cracks developed volcanic tuff by strong rock weathering and dissolution of organic acids which has become top quality reservoir. Deep Permian oil-gas migrated and accumulated to high parts along Hong-Che fault belt and stratigraphic unconformity stripping. Permian and Triassic volcanic rocks or dense mudstone sedimentary cover as a regional seal for the late Carboniferous oil-gas to save critically. The seismic pre-stack time migration processing technologies for the problem of poor inner structures of Carboniferous were developed. Response of volcanic rock seismic and logging are obvious. The application imaging logging and nuclear magnetic technology achieved the qualitative identification and quantification of fracture description.

Temperatures of dolomitizing fluids in the Feixianguan Formation from the Northeastern Sichuan Basin

The discovery of natural gas reservoirs from the Triassic Feixianguan Formation in the Northeastern Sichuan Basin is an important breakthrough in the field of marine carbonate rocks for Chinese oil and gas exploration in recent years.Because of the dolomite-hosted reservoirs in the Feixianguan Formation,these dolomites and their formation mechanisms have been a research focus for sedimentary geologists and petroleum geologists.Based on the homogenization temperatures of fluid inclusions,oxygen isotopic composition and their calculated temperatures,and the burial and thermal history of the typical well,it is considered that the majority of dolomites are formed by low-temperature dolomitizing fluids in the Triassic Feixianguan Formation,Northeastern Sichuan Basin.Only a minority of dolomites are formed by high-temperature dolomitizing fluids.The ending depth interval of low-temperature dolomitizing fluids was about 1000-2500 m,of which the correspondingly ending timing interval was approximately from early-middle Middle Triassic to early-middle Late Triassic.The main depth interval of high-temperature dolomitizing fluids was about 3200-4500 m,of which the correspondingly main timing interval was approximately early-middle Middle Jurassic.The low-temperature and high-temperature dolomitizing fluids have different meanings to the formation and evolution of the pore volumes of dolomite reservoirs in the Feixianguan Formation,Northeastern Sichuan Basin.