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.

Microbial Gas in the Mohe Permafrost, Northeast China and its Significance to Gas Hydrate Accumulation in Permafrost across China

The Mohe permafrost in northeast China possesses favorable subsurface ambient temperature, salinity, Eh values and pH levels of groundwater for the formation of microbial gas, and the Mohe Basin contains rich organic matter in the Middle Jurassic dark mudstones. This work conducted gas chromatography and isotope mass spectrometry analyses of nearly 90 core gas samples from the Mk-2 well in the Mohe Basin. The results show that the dryness coefficient(C1/C1–5) of core hydrocarbon gas from approximately 900 m intervals below the surface is larger than 98%, over 70% of the δ13 C values of methane are smaller than-55‰, and almost all δD values of methane are smaller than-250‰, indicative of a microbial origin of the gas from almost 900 m of the upper intervals in the Mohe permafrost. Moreover, the biomarker analyses of 72 mudstone samples from the Mohe area indicate that all of them contain 25-norhopane series compounds, thereby suggesting widely distributed microbial activities in the permafrost. This work has confirmed the prevailing existence of microbial gas in the Mohe area, which may be a potential gas source of gas hydrate formation in the Mohe permafrost. This result is of great significance to gas hydrate accumulation in the permafrost across China.

Study on the distribution characteristics of faults and their control over petroliferous basins in the China seas and its adjacent areas

As one of the main controlling factors of oil and gas accumulation,faults are closely related to the distribution of oil and gas reservoirs.Studying how faults control petroliferous basins is particularly important.In this work,we investigated the plane positions of major faults in the China seas and its adjacent areas using the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)of the Bouguer gravity anomaly,the fusion results of gravity and magnetic anomalies,and the residual Bouguer gravity anomaly.The apparent depths of major faults in the China seas and its adjacent areas were inverted using the Tilt-Euler method based on the Bouguer gravity anomaly.The results show that the strikes of the faults in the China seas and its adjacent areas are mainly NE and NW,followed by EW,and near-SN.Among them,the lengths of most ultra-crustal faults are in the range of 1000–3000 km,and their apparent depths lie between 10 km and 40 km.The lengths of crustal faults lie between 300 km and 1000 km,and their apparent depths are between 0 km and 20 km.According to the plane positions and apparent depths of the faults,we put forward the concept of fault influence factor for the first time.Based on this factor,the key areas for oil and gas exploration were found as follows:the east of South North China Basin in the intracontinental rift basins;the southeast region of East China Sea Shelf Basin,the Taixinan and Qiongdongnan basins in the continental margin rift basins;Zhongjiannan Basin in the strike-slip pull-apart basins;the Liyue,Beikang,and the Nanweixi basins in the rifted continental basins.This work provides valuable insights into oil and gas exploration,mineral resource exploration,and deep geological structure research in the China seas and its adjacent areas.

Geologic-Geophysical Indicators of the Deep Structure of Zones of Geothermal Anomalies for Allocation of Channels of the Deep Heat and Mass Transfer

On the basis of the analysis of field thermogeochemical data along abnormal zones of a thermal stream in the Bukhara-Khiva, oil-and-gas region of the Turan (Tegermen, Chagakul, Shimoly Alat, Beshtepa) was succeeded to obtain important data on a deep structure of sites. Data of gas-chemical and geothermal observations show about confinedness of abnormal concentration of methane to zones of the increased values of the temperature field the measured values of temperatures (Tegermen Square and others). On geoelectric section mines 2-D of inversion of the MT-field depth of 4000 m are lower, among very high-resistance the chemogenic and carbonate deposits of the Paleozoic is traced the subvertical carrying-out abnormal zone. This zone is identified as the channel of a deep heat and mass transfer with which hydrocarbon (HC) deposits are connected. It is shown that electro-investigation when using a geophysical complex can and has to become “advancing” at exploration by oil and gas.

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.

A Mutant Strain of a Surfactant-Producing Bacterium with Increased Emulsification Activity

As reported in this paper, a strain of oil-degrading bacterium Sp - 5 - 3 was determined to belong to Enterobacteriaceae, which would be useful for microbial enhanced oil recovery (MEOR). The aim of our study was to generate a mutant using low energy N+ beam implantation. With 10 keV of energy and 5.2× 1014 N+/cm2 of dose - the optimum condition, a mutant, S-34, was obtained, which had nearly a 5-fold higher surface and a 13-fold higher of emulsifica-tion activity than the wild type. The surface activity was measured by two methods, namely, a surface tension measuring instrument and a recording of the repulsive circle of the oil film; the emulsification activity was scaled through measuring the separating time of the oil-fermentation mixture. The metabolic acid was determined as methane by means of gas chromatography.

The surface geochemical exploration of oil and gas in the Gangbatong-Ya'anxiang and the Dongqiao-Nam Co of the Qinghai-Tibet region

Due to the complexity of geological background and the adverseness of natural geographical environment in the Qinghai-Tibet Plateau,it is very difficult to carry out petroleum geological study in this region. The Qinghai-Tibet Plateau is the only blank space of petroleum exploration on a large scale. The authors carried out the surface geochemical exploration of oil and gas in the Gangbatong-Ya'anxiang and Dongqiao-Nam Co of the Qinghai-Tibet region. Based on the data of actual detection and experiments in the studied area,the characteristics of concentration and profile distribution of the main geochemical exploration indicators(total adsorbed hydrocarbon,altered carbonate,thermal released mercury,etc.) were discussed. The origin of hydrocarbon was also discussed. Moreover,the oil and gas potential of different sections in the Qiangtang Basin and the Biru Basin were evaluated,which could provide references for the exploration and prediction of oil and gas in this region. The concentrations of total adsorbed hydrocarbons in the Ya'anxiang of Suoxian County-Zadong of Baqing County and the Jiecha-Dangxiong of Anduo County in the Qinghai-Tibet region are high,averaging 312.64 μL·kg-1 and 164.36 μL·kg-1. Their altered carbonate concentrations are relatively low,averaging 0.11% and 0.56%. Their concentrations of thermal released mercury are relatively high,averaging 13.09×10-9 and 1.94×10-9. Geochemical exploration results in fact reflect hydrocarbon information in the underground,which are mainly petroleum associated gas and over-matured cracking gas. The Jiecha-Charenluma and the Xiamaya'ertong-Suoba sections in the Qiangtang Basin are the most favorable ones for oil and gas and the Ekou-Zadong section is relatively favorable one,while the Nam Co and the Zigetangcuo-Dongqiao sections in the Biru Basin are the favorable ones for oil and gas,and the Jiang Co-Nading Co and the Ya'anxiang-Ya'ertong sections are relatively favorable ones.

黄骅坳陷港西构造西端歧81断块微生物异常研究

油气微生物勘探(MPOG)技术作为一种新的地表油气勘探方法,以其直接、有效、多解性小且经济等优势日益受到全球油气勘探界的重视。将油气微生物勘探技术应用于港西地区,得出油气分布规律,其基本上为油异常区,且未连片分布,而气异常区基本为背景值区。结合区域地质资料、油气井资料以及生物灰岩分布规律等信息,分析歧81断块的主控因素,揭示该断块的油气成藏规律。通过较成熟开发区的异常区与研究区内其它异常区的微生物异常值进行对比,研究区内异常区的微生物异常值的平均值均没有前者高,合理直观地了解了歧81断块的含油气远景。最后指出其主要储层,同时进行了含油性预测,应优先在异常值较强烈的区域进行勘探,并确定了有利的布井点位,从而大大降低勘探风险。

油气微生物勘探技术在大庆升平油田的应用

油气微生物勘探(MPOG)成本低廉、简便快速、多解性小,根据它可检测微生物异常区,可以评价和预测下伏油气藏的存在和性质,能适用于大庆升平油田。笔者等在大庆升平油田内,以微生物异常为基础,结合已有的区域地质资料、钻井和测井等资料,对微生物异常区域进行了分析研究,并圈定了一个明显的异常区。通过升平油田微生物异常区与邻区的异常对比,对升平油田的油气远景进行了初步探讨。最后在以微生物异常为主要前提下,结合区内断层、地质特征以及整体部署,共建议了2口控制评价井,并经过钻井实践所证实,2口井的含油气性与微生物异常预测结果均吻合。依据微生物勘探结果,为升平油田新增了探明石油地质储量,充分显示了油气微生物勘探技术的巨大应用前景。

松辽盆地西部杜75块油气微生物勘探研究

在松辽盆地西部杜75块应用油气微生物勘探,结合区域沉积相分析,对研究区进行了分流河道砂体、河口砂坝以及远砂坝等有利储集砂体的预测。根据油气微生物异常分布特征,明确了研究区的油气富集规律,即油气基本上分布于构造较宽缓的平台区域,或是具有微幅鼻状构造处,或是在水下分流河道分流处,为现场勘探提供了可靠的决策依据。同时,对研究区乃至整个松辽盆地西斜坡的岩性油气藏勘探奠定了基础。

微生物油气勘探技术及其应用

介绍了地表微生物油气勘探技术的基本原理、常用指标和异常模式。总结了地表微生物油气勘探技术数十年来的发展概况与应用现状。通过具体实例分析了微生物油气勘探技术在未开采区和成熟探区油气勘探中的应用价值:在未开采区,可以筛选出有利的含油气区,特别是与地震勘探结合,可对地震探明构造的含油气远景进行评价,是判断地震探明构造是否存在烃类充注的可靠工具;在成熟探区,通过微生物储层评价可绘制地下含油气储层最可能的分布模式,识别老产区中的漏失产层以及老油井的扩边范围,是老区复查的重要勘探手段。

内蒙洪特地区化探与油气微生物勘探应用

通过采用化探及油气微生物勘探新技术,对内蒙洪特地区进行了油气勘探研究。化探综合异常分析研究表明,本研究区有2个异常区,即西南化探异常区和东北化探异常区。油气微生物综合异常分析研究,可将本研究区划分为3个异常区,即中南微生物异常区、东北微生物异常区和西南微生物异常区。研究表明,化探和油气微生物勘探结果,不仅与研究区内已完钻井的含油气性相符,而且与随后完钻的各井的含油气性亦相符。在本研究区,化探与油气微生物勘探结果呈现互补关系,如将二者叠合运用,这样将会大大提高油气勘探成功率。

石油微生物勘探技术在滨北地区的应用

将油气微生物勘探新技术应用于滨北地区进行取样,并进行了烃氧化菌培养。通过该区微生物异常分析,结合该地区沉积相、构造反射层等资料,认为该地区断层不发育,没有形成有效圈闭。分析结果表明,该区油气顺斜坡带向上运移,在工区内沿运移通道存留部分油气,其余的油气继续沿斜坡向上运移,在富拉尔基形成浅层稠油油藏。经过综合研究,指出了不同的油气富集区。

松辽盆地泰康隆起东翼杜20-3井区油气微生物勘探

采用油气微生物勘探技术对松辽盆地泰康隆起东翼杜20-3井区进行油气勘探分析。以微生物异常为基础,结合工区内现有的区域地质、钻井和测井等资料,并根据油气微生物异常的分布情况,明确了研究区的油气富集规律,同时完成了工区内石油微生物异常区的圈定。从本工区内的沉积相、反射层构造等深线的展布、以及与邻区的异常对比等方面入手,详尽地分析了工区内的油气远景,给出结论和勘探建议:该工区的油气远景较差,基本上为油异常区;工区内勘探程度较低,需要加强综合研究,确定含油层系,从而为勘探区块评价和探井井位设计提供依据,进一步认识整个研究工区的油气富集规律。

阿拉新气田东部汤池构造油气微生物评价应用研究

油气微生物勘探法(MPOG)是地表勘探法的一个分支,主要研究近地表土壤层中微生物异常与地下深部油气藏的相关关系。在阿拉新气田东部汤池构造区,以微生物异常为基础,对微生物异常区域进行了分析研究,初步评价了该井区内的油气资源潜力。结果表明:工区内微生物异常分布非均匀,但有五处相对较大的微生物异常区,且连片性较好,表明油气潜力较大;异常区由南向北呈由弱变强的趋势;且工区内基本为油异常,气异常几乎为背景值状态,结合区域地质资料给出了勘探建议。并部署了了五口评价建议井。

镇泾油田红河105—1057井区微生物异常与含油气性关系

油气微生物勘探(MPOG)是地表油气藏评价的一个分支,主要研究近地表土壤层中微生物异常与地下深部油气藏的相关关系,它以成本低廉,简便快速,多解性小的特点,在镇泾油田得到充分的验证。在镇泾油田内,以微生物异常为基础,结合已有的区域油气地质、钻井和测井等资料,对微生物异常区域进行分析研究,重点解释说明了镇泾油田红河105—1057井区长821小层与油气异常的关系,并圈定出2个异常区,其异常连片分布,异常区的异常平均值较高,反映本工区内油藏控制面积较大。本工区天然气微生物异常整体水平较低,且基本上与油藏微生物异常区吻合,异常区零星分布,表明本工区的天然气多系原油溶解气。最后对工区油藏分级评价,并根据微生物勘探结果和地质特征等综合因素,在工区部署3口建议井。

柴北缘马海构造马10井区天然气微生物勘探

柴北缘构造较为复杂,研究工区各断块含油、含气前景区显得尤为重要。通过在柴北缘马海构造马10井区进行的油气微生物勘探,采取550组样品进行天然气微生物数量及活性分析,得出该区的油气分布规律和分布范围,通过微生物异常值的分析得出马10井区微生物异常基本上为气异常,但没有大范围连成片,而油异常区几乎为背景区值。通过较成熟开发区的异常区与研究区内其他异常区微生物异常值进行对比,研究区内异常区的微生物异常值的平均值均没有前者高,合理直观地了解了马10井区的含油气远景。结合该区的区域地质资料,对马10井区进行含气预测,并部署了一口评价建议井。

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。

港西构造西端油气微生物勘探研究

在港西地区进行了油气微生物采样和烃氧化菌的培养,结合其他资料,对研究工区的微生物异常区域进行了分析并进一步绘制了油气微生物异常分布图。将划分的8个微生物异常区与已探明的成熟开发区进行比较,并进行了分级,提出了最有利的勘探区块1号异常区。

微生物异常探索江汉盆地江陵凹陷万城断裂带北部油气富集规律及有利区

江汉盆地江陵凹陷万城断裂带北部研究区,地表条件复杂,地震和钻井施工困难,油气富集规律还不甚清楚。因此,试图通过微生物找油方法,最小成本最高效率,以探明本研究区的油气富集规律。研究区面积约230.0 km2,采集样品间距南北500 m×东西250 m,共采集并分析了样品2354个。研究表明,微生物异常主要分布在万城断层的东侧,其中微生物气异常零星分布,异常较弱,无独立气藏。在综合地质等资料的基础上,微生物异常分布特征表明,万城断裂带显示了来自北西和北东向的双向物源,油气来源于梅槐桥洼陷,属近源成藏。万城断裂带东侧和坡折带低位扇砂体是油气有利富集区,前景较好,主要为古近系新沟咀组成藏。万城断裂带西侧有小面积油藏,可能系白垩系成藏。最后,对微生物异常区进行了分级评价,指明了重点攻关区、评价有利和较有利区,对大幅降低勘探风险和提高勘探成功率,具有重大的社会经济效益和深远的现实意义。