Features of Sandy Debris Flows of the Yanchang Formation in the Ordos Basin and Its Oil and Gas Exploration Significance

Sandy debris flow is a new genetic type of sand bodies,which has gained much attention in recent years and its corresponding theory is proved to be a significant improvement and even partial denial to the 'Bouma Sequence' and 'turbidite fan' deep-water sedimentary theories to some point. Oil exploration researchers are highly concerned with sandy debris flows for its key role in controlling oil and gas accumulation processes.In this article,by applying sandy debris flows theory and combining a lot work of core,outcrop observation and analysis plus seismic profile interpretation,we recognized three types of sedimentary gravity flows that are sandy debris flows,classic turbidites and slumping rocks in chang-6 member of Yanchang Formation in the deep-water area of central Ordos Basin.Among the three types,the sandy debris flows are the most prominent and possesses the best oil bearing conditions.On the contrary,the classic turbidites formed by turbidity currents are limited in distribution;therefore,previous Yanchang Formation deep-water sedimentary studies have exaggerated the importance of turbidite currents deposition.Further study showed that the area distribution of deep water gravity flow sand bodies in Yanchang Formation were controlled by the slope of the deep-water deposits and the flows had vast distribution,huge depth and prevalent advantages for oil forming,which make it one of the most favorable new areas for Ordos Basin prospecting.

Prospective prediction and exploration situation of marine Mesozoic-Paleozoic oil and gas in the South Yellow Sea

The South Yellow Sea Basin is a large sedimentary basin superimposed by the Mesozoic-Paleozoic marine sedimentary basin and the Mesozoic-Cenozoic terrestrial sedimentary basin, where no oil and gas fields have been discovered after exploration for 58 years. After the failure of oil and gas exploration in terrestrial basins, the exploration target of the South Yellow Sea Basin turned to the marine Mesozoic- Paleozoic strata. After more than ten years' investigation and research, a lot of achievements have been obtained. The latest exploration obtained effective seismic reflection data of deep marine facies by the application of seismic exploration technology characterized by high coverage, abundant low-frequency components and strong energy source for the deep South Yellow Sea Basin. In addition, some wells drilled the Middle-Upper Paleozoic strata, with obvious oil and gas shows discovered in some horizons. The recent petroleum geological research on the South Yellow Sea Basin shows that the structure zoning of the marine residual basin has been redetermined, the basin structure has been defined, and 3 seismic reflection marker layers are traceable and correlatable in the residual thick Middle-Paleozoic strata below the continental Meso-Cenozoic strata in the South Yellow Sea Basin. Based on these, the seismic sequence of the marine sedimentary strata was established. According to the avaliable oil and gas exploration and research, the marine Mesozoic-Paleozoic oil and gas prospects of the South Yellow Sea were predicted as follows.(1) The South Yellow Sea Basin has the same sedimentary formation and evolution history during the sedimentary period of the Middle-Paleozoic marine basin with the Sichuan Basin.(2) There are 3 regional high-quality source rocks.(3) The carbonate and clastic reservoirs are developed in the Mesozoic- Paleozoic strata.(4) The three source-reservoir-cap assemblages are relatively intact.(5) The Laoshan Uplift is a prospect area for the Lower Paleozoic oil and gas, and the Wunansha Uplift is one for the marine Upper Paleozoic oil and gas.(6) The Gaoshi stable zone in the Laoshan Uplift is a favorable zone.(7) The marine Mesozoic-Paleozoic strata in the South Yellow Sea Basin has the geological conditions required to form large oil and gas fields, with remarkable oil and gas resources prospect. An urgent problem to be addressed now within the South Yellow Sea Basin is to drill parametric wells for the Lower Paleozoic strata as the target, to establish the complete stratigraphic sequence since the Paleozoic period, to obtain resource evaluation parameters, and to realize the strategic discovery and achieve breakthrough in oil and gas exploration understanding.

BTEX anomalies used as indicators of submarine oil and gas reservoirs

It is a conventional method for petroleum prospecting to generally use paraffin hydrocarbon as basic indexes of oil and gas. This conventional geochemical technology, however, shows some limits in the prospecting as paraffin is vulnerable to influences from human and biologic activities. Consequently, BTEX （short for benzene, toluene, ethyl benzene and xylem, which are direct biomarkers） among aromatic hydrocarbon series has been taken into account for the oil and gas prediction. Domestic and foreign study results demonstrate that BTEX is hardly disturbed and can well indicate oil and gas reservoirs. Based on measured data from a South China Sea area, the present authors have used self-developed visual assessment software for petroleum prospecting has been used to process data, strip background anomalies, and outline significant BTEX anomalies. By comparison with stratigraphic profiles of the target area, it is confirmed that BTEX is a good indication of marine oil and gas during the petroleum prospecting.

Discovery of Palaeozoic Karsts in the Qaidam Basin and Their Oil and Gas Prospects

Objective Complex geological factors have been constraining the oil and gas exploration in the Paleozoic strata of the Qaidam Basin,although there are high-quality hydrocarbon source rocks.One of the most important reasons may be reservoir densification due to the multiple stages of destructive cementation,which has hindered our understanding of the Paleozoic petroleum enrichment rules in the Qaidam basin.In recent years.

New progress of microbial prospecting of oil and gas in China:Taking the Satellite Oilfield in Daqing as an example

The Microbial Prospecting of Oil and Gas(MPOG) is applied to the matured development area in the Satellite Oilfield in Daqing for the first time. And with the MPOG,the hydrocarbon accumulation regulation controlled by faults is interpreted,and the matured development area is extended out to western part. At the same time,four microbial anomalies are discovered. The MPOG results were verified by the hydrocarbon-bearing conditions of the 10 drilled wells within the following half a year,and the consistent rate is up to 80%,which add about 300×104 t of the explored petroleum-in-place. Through study and successful application of MPOG to the Satellite Oilfield,the basis of the application from the exploration to development field is substantially established,and standard system of microbial anomaly is more precisely built for the Satellite Oilfield,which provided an effective explanatory item for the studied and adjacent region,even for the whole Songliao Basin,and also a new technique for complicated reservoirs,especially for the later stage development of litho-reservoirs in China. Therefore,it must have profound influence upon the oil and gas exploration,especially upon the remaining oil,extension and reserves addition of the developed area in China.

DEFINITING AND ITS GEOLOGIC MEANING OF SOUTH-NORTH TREND FAULTED STRUCTURE BELT IN QIANGTANG BASIN, NORTH PART OF TIBET

There were more expounding to north—west (west) trend fault and north\|east trend fault within Qiangtang Basin, North Part of Tibet, in the past literature. With increasing of geophysical exploration data, nearly east\|west trend structure began to be taken note to. Since the year of 1995, by a synthetic study to geophysical and geological data, that south\|north trend faulted structures are well developed. These structures should be paid much more attention to, because they have important theoretical meaning and practical significance.1 Spreading of south\|north faulted structure belt According to different geological and geophysical data, the six larger scale nearly south\|north faulted structure belt could be distinguished within the scope of east longitude 84°～96° and near Qiangtang Basin. The actual location of the six belts are nearly located in the west of the six meridian of east longitude 85°,87°,89°,91°,93°,95° or located near these meridian. The six south\|north faulted structure belts spread in the same interval with near 2° longitude interval. The more clear and much more significance of south\|north trend faulted structure belts are the two S—N trend faulted structure belts of east longitude 87° and 89°. There are S—N trend faulted structure belts in the west of east longitude 83°,81°, or near the longitudes. The structure belts spreading features,manifestation,geological function and its importance, and inter texture and structure are not exactly so same. The structure belts all different degree caused different region of geological structure or gravity field and magnetic field. There is different scale near S—N trend faulted structure belt between the belts.

Structural Characteristics and Evolution of Jurassic Basins in the East of Middle Qilian Block

Structural characteristics of the Jurassic basins of Xining, Minhe, and Xiji in the east of middle Qilian were researched based on the data obtained by gravitational, magnetic, and seismic methods. The result shows that each of these three basins is an independent structural unit with a NW strike and being separated by upheavals. Two groups of faults with NW and NE directions are developed in the basin, which controls the formation and evolution of the (Jurassic basins). The NW faults are the main ones while the NE faults are the secondary for controlling the sedimentation. Of the three basins, the Minhe basin is the favorable prospecting area.

Prospects of borehole NMR instruments and applications Dedicated to Professor Chaohui Ye on the occasion of his 80th birthday

Borehole nuclear magnetic resonance(NMR)is a powerful technology to characterize the petrophysical properties of underground reservoirs in the petroleum industry.The rising complexity of oil and gas exploration and development objectives,as well as the novel application contexts of underground reservoirs,have led to increasingly demanding requirements on borehole NMR technology including instrument design and related processing methods.This mini review summarizes the advances and applications of borehole NMR instruments along with some future possibilities.It may be helpful for researchers and engineers in the petroleum industry to understand the development status and future trends of borehole NMR technology.

Prospects for Distributed Energy Systems in China Released in Beijing

On the afternoon of October 30, the international Energy Agency （IEA） and chinaSe.com held a joint press conference in Beijing for the release of an IEA report： Prospects for Distributed Energy Systems in China.

Deep structure of the Kumkol basin in the northern Tibetan Plateau and its resource environmental implications

The Kumkol basin is located in the northern Tibetan Plateau and is a closed plateau basin with an average altitude of>4000 m and an area of nearly 20000 km^(2). Its boundaries are limited by the Altyn Tagh fault, East Kunlun orogen and Qimantag orogen. Studying the deep structure of the Kumkol basin reveals 2 significant implications:(1) the basin has developed a large thickness of >7000 m Cenozoic continental sediments, recording the uplift history of the northern Tibetan Plateau, and(2)preliminary work indicates that the basin is likely to have oil and gas prospects. However, owing to the adverse natural conditions of the area and the strong tectonic activity in the Cenozoic, the latter of which was not conducive to hydrocarbon preservation,only regional geological mapping and petroleum exploration route surveys have been carried out, and there is no consensus on strata, structure and tectonic evolution. From 2021 to 2022, a deep seismic reflection profile implemented by the Second Tibetan Plateau Scientific Expedition and Research(STEP) project was the first high-resolution geophysical survey across the Kumkol basin. This study uses seismic reflection migration profiles, first-arrival wave tomographic imaging and previous research results to analyze the deep structure of the basin. The final merged model contains many features of tectonic and resource significance:(1) The Kumkol basin is ~90 km wide from north to south, with a basement depth of >9000 m. The main component is the Cenozoic continental deposits, which are divided into two major parts: the southern composite basin and the northern faulted basin. Owing to the later compression, the southern composite basin experienced significant deformation, but most parts still preserved their original sedimentary formations.(2) The structural deformation characteristics of the basin reveal a two-stage tectonic evolution process of the northern Tibetan Plateau in the Cenozoic: from the Oligocene to the Pliocene, the main mechanism was vertical differential uplift and subsidence, and after the Pliocene, it transformed to north-south compression and shortened deformation.(3) The strata, formation time, and source-reservoir-cap conditions of the Kumkol basin are similar to those of the Qaidam basin. If a breakthrough can be achieved, it is expected to expand the production capacity of the oil field in the Qaidam basin with a low-cost investment. Thus, further exploration is recommended.

二连盆地马尼特坳陷油气微生物勘探

在二连盆地马尼特坳陷哈日嘎构造进行油气微生物勘探 ,微生物勘探测网为 75 0m× 75 0m ,由德国MicroPro实验室进行微生物分析并界定异常范围。根据微生物识别出的石油异常分布可划分出 3个明显的含油前景区 ,试验区仅 2口探井 ,相对于现有的 2口井而言 ,微生物油气勘探的符合率为 10 0 % ,其效果是理想的。图 3表 1参 2 (袁志华摘 )

石油微生物学在中国科学院微生物研究所的发展

本文较详尽地综述了中国科学院微生物研究所50多年在涉及石油微生物学的科学研究成果,包括微生物勘探法和气态烃氧化菌、微生物与油气形成、有机酸的生产、油田微生物与提高采油量、微生物提高采油的现场应用。共引用了105篇文献。

新庄油田油气微生物勘探研究

将油气微生物勘探技术应用于新庄油田。通过该区的样品采集、实验、分析和研究,完成了油和气的微生物异常区的圈定,微生物异常显示与工区内已知4口探井的含油气情况基本吻合。以微生物异常为基础,结合研究区现有的区域地质概况、钻井和测井等资料,对新庄油田微生物异常圈定了3个明显的异常区,其中中部异常区为最有利的勘探区块,北部异常区为较有利的目标区块,东南异常区为可勘探的目标区块。根据新庄油田油气显示的微生物异常值特征,对含油气情况进行了初步解释,评价了新庄油田的油气远景,并与邻区的西峰油田相比,验证了该技术的实用性和可靠性。分析表明,油气微生物勘探技术特别适合于鄂尔多斯盆地,特别是地震效果不甚理想和岩性油气藏的地区。

渝东南渝页2井区页岩气微生物勘查

页岩气是一种非常规油气藏资源,利用油气微生物勘探(MPOG)技术寻找页岩气富集区域尚属首次,该技术可以有效圈定微生物异常,从而大大增加页岩气勘探的成功率。通过分析MPOG结果,结合微生物异常特征及地质解释,对渝东南渝页2井区页岩气有利富集区进行预测,并对其勘探前景作出了相应的评价。

微生物异常在镇泾油田找油中的应用

利用油气微生物勘探(MPOG)技术,对镇泾油田的1208组样品进行了分析,并结合工区已获得的地质资料,对镇泾油田含油气区和剩余油的分布进行了预测。结果表明:本工区微生物油异常分布连续性较好,异常平均值较高,油藏控制面积较大,可划分为四个主要区块;异常区沿水下分流河道"蜿蜒"分布,属于典型的岩性油藏;同时,有的区域已经过较长时间开采,但是微生物异常依然很明显,说明地下的剩余油较多,有进一步开发的价值。

阳信洼陷石油微生物勘探研究

运用油气微生物勘探技术中的石油微生物勘探技术,在阳信地区进行了采样和烃氧化菌的培养,通过该区的微生物异常分析,结合区内现有的区域地质资料,对研究工区的微生物异常区域进行了分析研究,并对其进行了分级排队,完成了工区内微生物异常辅助识别石油。在此基础上,建议加强对工区内沉积微相研究,以断层遮挡圈闭和鼻状构造为导向,再考虑评价部署的问题,这将大幅度提高勘探成功率。

大庆宋芳屯油田石油微生物勘探

叙述了油气微生物勘探(MPOG)的发展历史及发展趋势,较系统地论述了油气微生物勘探法的理论基础,包括物理(化学基础)和微生物学基础两方面。并详细地叙述了MPOG的原理,特别是轻烃"微泡上浮"的垂直运移机理。全面阐述了MPOG方法的实用运作过程,包括地质调查与样品采集、微生物实验技术、数据处理与指标系统、综合评价与远景预测等。论述了宋芳屯油田的MPOG结果,研究微生物异常区与地质构造位置、油井位置的吻合程度,检查微生物异常与现有勘探开发成果的符合率。剖析最有利勘探区重点油藏剖面上的微生物异常与下伏潜在的含油气地质构造的相互关系,对该区块的微生物异常及其勘探前景作了评价,进而提出了井位设计。