A hydrocarbon enrichment model and prediction of favorable accumulation areas in complicated superimposed basins in China

The geologic conditions of superimposed basins in China are very complicated. This is mainly shown by multi-phase structural evolution, multiple sets of source-reservoir-cap rock combinations, multiple stages of hydrocarbon generation and expulsion from source rocks, multi-cycle hydrocarbon enrichment and accumulation, and multi-phase reservoir adjustment and reconstruction. The enrichment, accumulation and distribution of hydrocarbon is mainly controlled by the source rock kitchen, paleo- anticline, regional cap rock and intensity of tectonic movement. In this paper, the T-BCMS model has been developed to predict favorable areas of hydrocarbon accumulation in complicated superimposed basins according to time and spatial relationships among five key factors. The five factors include unconformity surface representing tectonic balancing （B）, regional cap rock representing hydrocarbon protection （C）, paleo-anticline representing hydrocarbon migration and accumulation （M）, source rock kitchen representing hydrocarbon generation and expulsion （S） and geological time （T）. There are three necessary conditions to form favorable areas of hydrocarbon accumulation. First, four key factors BCMS should be strictly in the order of BCMS from top to bottom. Second, superimposition of four key factors BCMS in the same area is the most favorable for hydrocarbon accumulation. Third, vertically ordered combination and superimposition in the same area of BCMS should occur at the same geological time. The model has been used to predict the most favorable exploration areas in Ordovician in the Tarim Basin in the main hydrocarbon accumulation periods. The result shows that 95% of the discovered Ordovician hydrocarbon reservoirs are located in the predicted areas, which indicates the feasibility and reliability of the key factor matching T-BCMS model for hydrocarbon accumulation and enrichment.

Development unit division and favorable area evaluation for joint mining coalbed methane

Based on the productivity equation of coalbed methane (CBM) well, considering the impact of coal reservoir reformability on gas well productivity, the main production layer optimization index in the “three-step method” of optimal combination of production layers is corrected, and then the CBM production layer potential index is introduced to evaluate favorable areas for commingled multi-coal seam production. Through analysis of the key parameters of coal reservoirs affecting the CBM productivity index, a development unit division method for areas with multi-coal seams is established, and a quantitative grading index system is proposed. On this basis, the evaluation process of CBM development favorable area is developed: the mature 3-D modeling technology is used to characterize the reservoir physical properties of multi-coal seams in full-scale;the production layer potential index of each grid is calculated, and the production layer potential index contour under single-layer or commingled multi-layer production are plotted;according to the distribution of the contour of production layer potential index, the quantitative index of CBM development unit is adopted to outline the grade I, II, III coal reservoir distribution areas, and thus to pick out the favorable development areas. The practical application in the Yuwang block of Laochang in Yunnan proved that the favorable area evaluation process proposed can effectively overcome the defects of selecting favorable development areas only relying on evaluation results of a major coal seam pay, and enhance the accuracy of the evaluation results, meeting the requirements of selecting favorable areas for multi-coal seam commingled CBM production.

Characterization of favorable lithofacies in tight sandstone reservoirs and its significance for gas exploration and exploitation: A case study of the 2nd Member of Triassic Xujiahe Formation in the Xinchang area, Sichuan Basin

By using core,logging curves,and experiment data,favorable lithofacies types in the 2 nd Member of Triassic Xujiahe Formation in the Xinchang area,Sichuan Basin were classified,standard of the favorable lithofacies was established,planar distribution regularities of the favorable lithofacies were identified,and forming mechanisms of the favorable lithofacies and their control effect on production were examined.(1)The 2 nd Member of Xujiahe Formation has twelve types of lithofacies,among which multiple layer medium-coarse grain sandstone lithofacies,parallel bedding medium-coarse grain sandstone lithofacies,massive bedding medium-coarse grain sandstone lithofacies,inclined bedding medium-coarse grain sandstone lithofacies,and charcoal-bearing medium-coarse grain sandstone lithofacies with better physical properties and higher gas content are favorable lithofacies;they feature low gamma,low neutron porosity,low resistivity,and high acoustic travel time on logging curves.(2)The sedimentary process controls spatial distribution of sand bodies which are the material basis of the favorable lithofacies;post diagenetic fluids would differentially reconstruct the favorable lithofacies;tectonic activities and abnormal formation pressure made strata slide along the weakness plane,giving rise to fractures in different types of rocks,which can enhance the reservoir permeability significantly.(3)The development degree of favorable lithofacies is a major factor affecting stable production of gas well.

Structural characteristics of the basement and the prospective of favorable oil and gas blocks in the Tacheng basin

The Tacheng basin has been identified as a Carboniferous basement with a central uplift, sur- rounded by orogenic belts. This identification was based on the comprehensive analysis of field outcrops, regional magnetic and gravimetric data, skeleton seismic profiles, magnetotelluric profiles and drilling data. Here, we present gravimetric and magnetic data analyses of the basement structures of the Tacheng basin and its base formation. We also provide a magnetotelluric profile analysis of the structural features and tectonic framework of basin-mountain patterns. We use local geology, drilling data, and other comprehensive information to document the tectonic framework of the basement of the basin. Small-scale nappe structures are found in the northern basin, whereas stronger and more pronounced thrusting structures are found to the south and east of the basin. The basin is divided into four first-order tectonic units： a central uplift, a northern depression, a southeastern depression and a western depression. In addition, the Emin sag is suggested as a possible reservoir for oil and gas.

鄂尔多斯盆地南部旬-宜探区深部煤层气成藏条件与勘探潜力

在充分调研国内深部煤层气勘探研究成果的基础上,依据鄂尔多斯盆地南部旬-宜探区钻井、地震和煤心实验分析资料,分析深部石炭系太原组煤层分布、煤岩煤质、储层条件、保存条件及含气性等关键成藏要素,系统评价了旬-宜探区太原组煤层气成藏条件与勘探潜力。结果表明,旬-宜探区太原组煤层厚度大、横向分布稳定、煤阶高、灰分中等、含气性较好,具备良好的煤层气成藏条件;太原组煤层气资源量1754×10^(8) m^(3),具备良好的勘探潜力;旬-宜探区中东部煤层发育、含气量高、断裂不发育、煤层埋深相对较浅,为煤层气勘探有利区带;在有利区优选基础上,开展了煤层气老井复查,优选了PZ2井实施太原组煤层压裂试气,压后取得了较好效果,对该区下一步煤层气勘探具有参考意义。

地温梯度在塔里木盆地古生界热演化研究中的应用

塔里木盆地古生界烃源岩热史研究,特别是对超深古老烃源岩热演化认识存在较大争议,热演化阶段评价方法一直是困扰烃源岩热史研究的关键问题。调研结果表明,塔里木盆地寒武系古地温梯度变化在2.95~3.6℃/hm之间,按照生烃温度门槛值65℃计算,分别需要上覆地层厚度2203~1806 m,相差397 m,即2.58℃,温度差值较小。因此认为,塔里木盆地寒武系古地温梯度变化较小,可以忽略每期地温梯度取值上的差别,厚度可能是决定温度的主要因素;地层沉积与残留厚度可比较准确地获得,误差主要取决于剥蚀厚度的恢复。通过可靠获取的地层厚度、古地温梯度和剥蚀厚度等参数,以及烃源岩生烃图版,对塔里木盆地寒武系玉尔吐斯组烃源岩热演化阶段进行了评价;界定了关键期环满加尔坳陷的有效烃源岩及其分布,对玉尔吐斯组有效烃源岩及其规模生烃能力进行了预测和划分,并预测和划分了晚期成藏的有利区域。不同阶段有效烃源岩及其规模生烃量是每期成藏富集的关键,利用该方法避免了成熟度判识缺少可靠温标的问题,为塔里木盆地深层—特深层石油勘探和开发以及晚期成藏有利区的选择提供了重要的科学依据。

大宁-吉县区深部煤层气甜点特征及有利区评价

鄂尔多斯盆地东缘大宁-吉县地区,具备丰富的深部煤层气资源,是中国煤层气勘探开发老区,勘察面积高达5 784.175 km^(2).通过对大宁-吉县地区深埋在1 700~2 400 m范围内本溪组8#煤矿进行研究分析,总结出深部煤层甜点的储层性好、含气量高等特点,描述了煤层厚度、构造和水动力对煤层气富集的影响,并将丰度、含气量和煤层可压性综合指数等作为评价依据,对深部煤层地质工程的有利区进行评价,最终将地质工程甜点有利区划分为三类.

四川盆地东部下寒武统有效烃源岩与有利油气聚集区预测

为了评价四川盆地东部震旦系—下寒武统天然气勘探前景,在区域沉积--构造背景分析基础上,利用实测烃源岩总有机碳含量(TOC)、测井和二维地震数据,预测了下寒武统有效烃源岩;综合分析中三叠世末震旦系顶面古构造和下寒武统生烃中心分布,预测了有利油气聚集区。研究结果表明:晚震旦世至早寒武世强烈的沉积--构造分异导致在中上扬子地区形成台内断陷/裂陷槽、台内凹陷和台内凸起;四川盆地东部主要位于台内凸起,有效烃源岩厚度为50~150 m;习水—南川—石柱一带厚度小于30 m,有效烃源岩发育较差;平面上围绕四川盆地东部发育4个由裂陷槽和台内凹陷控制的烃源岩厚度中心及其对应的生烃中心,能够为震旦系—下寒武统提供充足的油气;四川盆地东部天然气勘探前景较好,川中古隆起及其围斜区是有利油气聚集区。

鄂尔多斯盆地马岭—乔川地区长6油层组油藏分布特征及控制因素

基于岩心观察、测井解释及开采数据分析,结合流体包裹体等测试,对马岭—乔川地区长6油层组的油藏分布特征及控制因素开展研究。研究结果表明,研究区油藏纵向上主要分布在长63油层段,长62、长61油层段含油性显著变差;平面上,长63油层段以L125,B452和L411井区为中心,油藏团块状分布,呈两条带沿北西南东向延伸,油层厚度主要在5~20 m之间,长62、长61油层呈孤立土豆疙瘩状分布,分布规模小。长6油层组油藏以岩性油藏为主,包裹体均一温度集中在70~90℃,荧光以黄褐色为主,结合区域埋藏史分析显示该区油藏充注为晚侏罗世和中-晚白垩世,表现为早期充注。长6油层组烃源岩厚度、距离,砂体砂质碎屑流砂体性质、物性和叠置类型是其形成油气藏的重要影响因素;长63油层段相比长62和长61油层段具有更靠近烃源岩,砂质碎屑流成因砂体分布广、孔渗条件好、叠置厚层砂体类型发育等优势。研究区最为有利油藏的勘探目标为长63油层段Y470,L374,B452等井区附近,有利勘探区面积达到517.28 km 2。

北方重要盆地油气资源战略选区调查工作进展

北方重要盆地蕴藏着丰富的油气资源,是我国陆上油气资源增储上产的重点地区。“十三五”以来,公益性油气地质调查聚焦国家需求,着力推进“四新”(即新区、新层系、新类型、新领域)油气调查与评价,强力支撑了油气体制改革,取得了塔西北沙井子构造带西段油气调查新发现,以及塔里木盆地数字化建设与选区评价、塔东北奥陶系、塔西北寒武系、三门峡盆地古近系和准东及其周缘地区石炭系油气基础调查等多项新进展;形成了数字盆地标准方案,塔里木盆地电阻率-极化率异常解释图版2项科技创新成果;支撑新疆地区油气勘查开采体制改革工作取得实效,助力企业在塔里木盆地东部超深层油气勘探快速实现新突破,有效推动地方经济和社会发展。

渤海湾盆地干热岩开发利用前景评估——基于开采优化数值模拟的认识

渤海湾盆地的大地热流高,5000 m埋深地层平均温度为175℃,热储岩性以低孔低渗的变质岩、火成岩为主,具备形成干热岩资源的条件。基于大地热流、岩石热导率、生热率等热参数,利用COMSOL软件建立三维水热耦合的干热岩开采模型、分析不同井间距、注采速率、布井方式等差异开采方案下在100 a内对热储层温度的影响随开发时间的变化,选取最优方案并估算干热岩资源。结果表明:注采速率一定时,随着开采时间的增加,开采井水温度下降速率与井间距成反比;当注采井间距一定时,注采速率越大,开采井水温度下降越快,发生“热突破”的时间越早;其他条件相同的情况下,“两采两注”布井方案比“一采一注”布井方案获得的热量更多,开采效率更高。基于上述认识,确定研究区最优开采方案为:年限50 a、井间距400 m、注采量90 m^(3)/h、“两采两注”方式。此方案下,可获得开采井水平均温度为172℃,对应全渤海湾盆地可采资源量为3.28×10^(19)J/a。以河北任丘市为例,按照民用住宅热负荷指标100 W/m^(2)计算,利用最优方案进行干热岩的开采,仅需157.75 km^(2)干热岩有利区即可满足全市居民供暖需求。因此,开发利用研究区干热岩资源,可增强华北地区能源供应保障能力,打造可持续发展的绿色低碳能源体系。

鄂尔多斯盆地府谷地区深部煤层气富集成藏规律及有利区评价

鄂尔多斯盆地东缘神府区块是典型深部煤层气田,资源丰富且勘探开发潜力巨大。2023年10月,神府深部煤层大气田成功申报探明地质储量超1100亿m^(3)。府谷地区位于神府区块中部,是最早深部煤层气生产试验区,但目前对其煤层气的富集成藏规律和勘探开发潜力的认识尚不清楚。综合应用地震、测井、钻井和煤岩测试等资料以查明该地区深部煤层气地质特征、富集成藏规律和有利区分布。结果表明:主力煤层4+5、8+9号煤发育稳定且厚度较大(4+5号煤:3.2~5.8 m;8+9号煤:8.7~13.5 m),有利层段主要分布在煤层中上部位置;宏观煤岩类型主要为光亮-半亮煤,煤体结构主要为原生-碎裂结构煤;受深成变质作用的影响,煤类以气煤、肥煤和焦煤为主,煤的变质程度处于热解生气的高峰期,煤储层表现出中-高含气量(4+5号煤:3.0~12.0 m^(3)/t;8+9号煤:7.5~18.5 m^(3)/t)和中-高含气饱和度(35.0%~115.0%)等特征;主力煤层属于低渗储层((0.01~0.09)×10^(-3)μm^(2)),孔隙结构主要以微孔和小孔为主。提出府谷地区煤层气为“挠褶-断层-水动力”富集成藏模式,煤层气富集区位于构造平缓区和斜坡带。建立深部煤层气地质-工程双甜点评价体系,识别出I类地质-工程甜点区位于东部和西南部,是研究区深部煤层气勘探开发首选区带。因此,该研究认识进一步丰富了深部煤层气富集成藏理论,对鄂东缘深部煤层气勘探开发实践具有重要指导意义。

松辽盆地南部王府断陷深部煤层气地质特征及有利区评价

松辽盆地南部王府断陷煤层气资源量丰富,但深部煤层气勘探程度较低,在煤层气地质特征、富集成藏主控因素及有利目标优选等方面缺乏系统研究,制约了该区煤层气勘探进程。为此,在系统分析煤系地质特征的基础上,明确深部煤层气成藏主控因素,建立有利区优选指标体系,预测煤层气富集有利区。结果表明:(1)王府断陷火石岭组宏观煤岩类型以光亮煤、半亮煤为主,具有低水分、低挥发分、低灰分的特征,镜质体最大反射率大于1.8%,孔隙率平均5.01%,CS38井计算的平均含气量为21.80 m^(3)/t。(2)王府断陷火石岭组火山喷发填平补齐沉积环境利于煤层发育,煤层主要发育于断陷双陡坡带之间与断陷中、东部的火山喷发的填平补齐效应形成的浅水区,形成了“填平补齐成煤模式”。此外,区内发育的大面积巨厚泥岩顶板与封闭断层使得煤层气得以富集保存。(3)王府断陷Ⅰ类有利区主要发育在断陷中部,煤层厚度大于5 m,断层断距<50 m,盖层厚度>80 m,气测全烃值>15%,具有较大勘探开发潜力;Ⅱ、Ⅲ类有利区主要发育在断陷的北部和南部,煤层厚度一般<5 m,盖层厚度<80 m,气测全烃值<15%,断层封闭性弱或不封闭,盖层厚度差异大,勘探开发风险较大。

安塞油田延安组储层特征及控制因素

安塞油田是鄂尔多斯盆地较为典型的油气富集带,浅层延安组油藏埋深浅,采出程度低,开发效果不佳。结合测井资料解释与岩心物性对延安组浅层油藏特征进行分析,进一步深化储层特征认识,进行有利区评价。结果表明:分流河道是延安组的有利储集相带;延安组储层孔隙度主要分布在14%~18%,渗透率约10.0×10^(-3)~80.0×10^(-3)μm^(2)。延安组油水分布复杂,沉积环境、成岩作用与储层物性共同作用的结果,构造和沉积相共同控制砂体空间展布特征,研究结果可为浅层延安组储层勘探开发提供合理建议。

车排子地区有利储层特征及控制因素

车排子地区属于准噶尔盆地西部隆起,分为车排子凸起东部和红车断裂带,车排子凸起区是石炭系、白垩系、古近系、新近系油气成藏的有利目标区(熊益学,2012;赵晓东等,2021)。其中P66井区,位于车排子地区的春风油田东北部,该区多口井获得工业油流,具有良好的勘探效果(杨志冬,2020),经过多年的勘探发现石炭系是重要的储层.

X油田长7致密油储层特征研究及有利区预测

X油田长7油藏是长庆油田第六采油厂的重点勘探区域,目前在该区域共完钻探井、开发井290余口。本文通过对该区探井的测井、录井、钻井以及试油等资料的系统整理,重点认识主要含油层系长7油层组的沉积微相及砂体展布特征,深入分析储层特征,明确油藏特征,开展有利区预测。研究结果表明:X油田长7岩性主要为灰色、灰绿色极细-细粒岩屑质长石砂岩,分选中等~好,次棱状磨圆;填隙物中黏土矿物以高岭石和绿泥石为主,碳酸盐矿物以铁方解石和铁白云石为主。研究区长7致密油储层非均质性为中等偏弱储层,整体以Ⅲ类储层分布为主,长7_(2)小层Ⅰ、Ⅱ类储层较为发育,为研究区优质储层。综合研究长7致密油储层优选建产有利区5个,新增地质储量1669.9×10^(4)t。为该区的整体规划、开发方案编制及区域探井部署提供了一定的地质依据。

思茅盆地页岩气地质条件及资源潜力分析

根据野外调查及样品测试,从富有机质页岩的地化特征、物性特征及保存条件等分析了思茅盆地页岩气地质条件。研究表明:思茅盆地发育下密地组、羊八寨组、挖鲁八组及和平乡组四套暗色页岩;其中,羊八寨组页岩累计厚度普遍大于100 m,TOC平均为1.06%~2.54%,R o平均为1.81%~3.47%,有机质类型主要为Ⅱ2—Ⅲ型,脆性矿物含量平均为49.5%,为思茅盆地页岩气有利层段。景谷洼陷南部和普文洼陷受深大断裂、地层抬升剥蚀、岩浆岩和变质岩带影响较小,盖层厚度大,页岩气保存条件相对较好。思茅盆地与相邻呵叻盆地具有相似的油气地质条件,具有一定的页岩气资源潜力,值得开展进一步的勘探研究工作。最后,综合考虑页岩分布、有机地化条件和保存条件,预测页岩气有利靶区主要位于勐班—德化及普文—象明一带。

海上L区低渗储层分类评价及有利区优选

海上L区目标层属于海上特低渗储层,为准确进行储层分类评价、指导储层有利区的优选,在统计借鉴已有低渗储层分类评价成果基础上,结合目标区低渗储层特征,厘定低渗储层分类评价参数,采用综合分类系数法完成低渗储层分类评价及有利区优选。研究认为L区目标层主要发育Ⅲ类储层,其次是Ⅳ和Ⅴ类储层,Ⅰ、Ⅱ类储层不发育,Ⅲ类储层连片分布的区域为储层有利区。研究结果可以较好地指导储层开发有利区的优选。

Sequence sedimentary evolution and reservoir distribution in the third and fourth members of Sinian Dengying Formation,Gaomo area,Sichuan Basin,SW China

Based on comprehensive analysis of cores,thin sections,logging and seismic data,the sequence stratigraphy and sedimentary evolution of the third and fourth members of Sinian Dengying Formation(Deng 3 and Deng 4 members for short)in the Gaomo area of Sichuan Basin were investigated,and the favorable zones for reservoir development in the Deng 3 Member and Deng 4 Member were predicted.(1)Two Type I and one Type II sequence boundaries are identified in the Deng 3 and Deng 4 members.Based on the identified sequence boundaries,the Deng 3 and Deng 4 members can be divided into two third order sequences SQ3 and SQ4,which are well-developed,isochronal and traceable in this area;the SQ3 thins from west to the east,and the SQ4 thins from northwest to southeast.(2)The sedimentary environment from the depositional period of SQ3 to SQ4 has experienced the evolution from mixed platform to rimmed platform,and the platform rimmed system on the west side is characterized by the development of platform margin microbial mound and grain shoal assemblages.The intraplatform area is a restricted platform facies composed of a variety of dolomites,and there are local micro-geomorphic highlands of different scales and scattered intraplatform mounds and shoals.(3)The Deng 4 Member reservoirs,with obvious facies-controlled characteristic,are mainly distributed in the upper part of high-frequency upward shallow cycle and the high-stand systems tract of the third-order sequence vertically,and are more developed in the platform margin belt than in the intraplatform belt,and more developed in the Gaoshiti platform margin belt than in the west Suining platform margin belt on the plane.(4)Three types of favorable reservoir zones of Deng 4 Member have been finely delineated with 3D seismic data;among them,the mound and shoal facies zones developed in the ancient highlands of the intraplatform are the first choice for the next exploration and development of the Deng 4 Member.

世界深水油气勘探形势分析与思考

利用标普全球、睿咨得等商业数据及各油公司的公开信息,对全球深水油气勘探趋势、深水油气发现特点、七大国际油公司深水油气勘探业务布局进行系统分析。结果表明:深水领域是当前全球油气勘探发现最重要的领域,被动大陆边缘盆地深水大发现油气田个数及储量均最多,深水油气大发现对海域新发现油气总储量的贡献最大。岩性油气藏发现越来越多,且油气发现主要分布于中—新生界;七大国际油公司广泛活跃在深水油气勘探和开发各个环节,并发挥着全球引领作用。结合多年对全球油气地质与资源评价形成的理论认识,提出未来有利的深水勘探领域主要集中在大西洋两岸、印度洋周缘、北冰洋周缘等3大领域。提出了开拓海外深水油气勘探业务的6点建议:拓宽多用户地震资料获取渠道,提高深水勘探科学选区水平;加大重点领域深水勘探项目获取力度;灵活进退勘探区块;以大权益获取区块,采用“双勘探模式”经营;加强与深水技术领先国际油公司的合作;提升商务运作能力,逐步实现“非作业者”向“作业者”转变。