Large-scale Tazhong Ordovician Reef-flat Oil-Gas Field in the Tarim Basin of China

The Tazhong reef-fiat oil-gas field is the first large-scale Ordovician organic reef type oil-gas field found in China. Its organic reefs were developed in the early Late Ordovician Lianglitag Formation, and are the first large reefs of the coral-stromatoporoid hermatypic community found in China. The organic reefs and platform-margin grain banks constitute a reef-flat complex, mainly consisting of biolithites and grainstones. The biolithites can be classified into the framestone, baffiestone, bindstone etc. The main body of the complex lies around the wells from Tazhong-24 to Tazhong-82, trending northwest, with the thickness from 100 to 300 m, length about 220 km and width 5-10 km. It is a reef-flat lithologic hydrocarbon reservoir, with a very complex hydrocarbon distribution： being a gas condensate reservoir as a whole with local oil reservoirs. The hydrocarbon distribution is controlled by the reef complex, generally located in the upper 100-200 m part of the complex, and largely in a banded shape along the complex. On the profile, the reservoir shows a stratified feature, with an altitude difference of almost 2200 m from southeast to northwest. The petroleum accumulation is controlled by karst reservoir beds and the northeast strike-slip fault belt. The total geologic reserves had reached 297.667 Mt by 2007.

Source Rocks for the Giant Puguang Gas Field,Sichuan Basin:Implication for Petroleum Exploration in Marine Sequences in South China

Detailed geochemistry studies were conducted to investigate the origin of solid bitumens and hydrocarbon gases in the giant Puguang gas field. Two types of solid bitumens were recognized： low sulfur content, low reflectance （LSLR） solid bitumens in sandstone reservoirs in the Xujiahe Formation and high sulfur content, high reflectance （HSHR） solid bitumens in the carbonate reservoirs in the Lower Triassic Feixianguan and Upper Permian Changxing formations. Solid bitumens in the Upper Triassic Xujiahe Formation correlate well with extracts from the Upper Triassic to Jurassic nonmarine source rocks in isotopic composition of the saturated and aromatic fractions and biomarker distribution. Solid bitumens in the Feixianguan and Changxing formations are distinctly different from extracts from the Cambrian and Silurian rocks but display reasonable correlation with extracts from the Upper Permian source rocks both in isotopic composition of the saturated and aromatic fractions and in biomarker distribution, suggesting that the Permian especially the Upper Permian Longtan Formation was the main source of solid bitumens in the carbonate reservoirs in the Feixianguan and Changxing formations in the Puguang gas field. Chemical and isotopic composition of natural gases indicates that the majority of hydrocarbon gases originated from sapropelic organic matter and was the products of thermal cracking of accumulated oils. This study indicates that source rock dominated by sapropelic organic matter existed in the Upper Permian and had made major contribution to the giant Puguang gas field, which has important implication for petroleum exploration in marine sequences in South China.

Accumulation Mechanisms and Evolution History of the Giant Puguang Gas Field,Sichuan Basin,China

Solid bitumens were found throughout the carbonate reservoirs in the Puguang gas field, the largest gas field so far found in marine carbonates in China, confirming that the Puguang gas field evolved from a paleo-oil reservoir. The fluid conduit system at the time of intensive oil accumulation in the field was reconstructed, and petroleum migration pathways were modeled using a 3-D model and traced by geochemical parameters. The forward modeling and inversion tracing coincided with each other and both indicated that oils accumulated in the Puguang-Dongyuezhai structure originated from a generative kitchen to the northwest of the Puguang gas field. The deposition of organic-rich Upper Permian source rocks dominated by sapropelic organic matter in the Northeast Sichuan Basin, the development of fluid conduit system that was vertically near-source rock and laterally near-generative kitchen, and the focusing of oils originated from a large area of the generative kitchen, were the three requirements for the formation of the giant paleo-oil reservoir from which the giant Puguang gas field evolved. The Puguang gas field had experienced a three-stage evolution. The post-accumulation processes, especially the organic-inorganic interaction in the hydrocarbon-water-rock system, had not only profoundly altered the composition and characteristics of the petroleum fluids, but also obviously changed the physicochemical conditions in the reservoir and resulted in complicated precipitation and solution of carbonate minerals.

Mesozoic-Cenozoic Tectonics of the Yellow Sea and Oil-Gas Exploration

The purpose of the present study was to study the tectonics of the Yellow Sea. Although oilgas exploration has been undertaken for more than 30 years in the southern Yellow Sea, the exploration progress has achieved little. There are three tectonic periods with near N-S trending shortening and compression （260-200 Ma, 135-52 Ma and 23-0.78 Ma） and three tectonic periods with near E-W trending shortening and compression （200-135 Ma, 52--23 Ma and 0.78 Ma） at the Yellow Sea and adjacent areas during the Mesozoic and Cenozoic. The lndosinian tectonic period is the collision period between the Sino-Korean and Yangtze Plates, which formed the basic tectonic framework for the Yellow Sea area. There were strong intraplate deformations during the Yanshanian （200-135 Ma） and Sichuanian （135-52 Ma） periods with different tectonic models, which are also the main formation periods for endogenic metallic mineral deposits around the Yellow Sea. The three tectonic periods during the Cenozoic affect important influences for forming oil-gas reservoirs. The Eocene-Oligocene （52-23 Ma） is the main forming period for oil-gas sources. The Miocene-Early Pleistocene （23-0.78 Ma） was a period of favorable passage for oil-gas migration along NNE trending faults. Since the Middle Pleistocene （0.78 Ma） the NNE trending faults are closed and make good conditions for the reservation of oil-gas. The authors suggest that we pay more attention to the oil-gas exploration at the intersections between the NNE trending existing faults and Paleogene- Neogene systems in the southern Yellow Sea area.

Porosity Formation and Evolution of the Deeply Buried Lower Triassic Feixianguan Formation, Puguang Gas Field, NE Sichuan Basin, China

The deeply buried shoal dolomite reservoirs of the Lower Triassic Feixianguan Formation, giant Puguang Gas Field, NE Sichuan Basin, are exceptionally porous. The influences of diageneses on pore evolution are studied. Through petrologic investigation, diagenetic phases are divided into four stages, i.e., near-surface, pre-oil window, oil window, and gas window. The Adobe Photoshop system is used to quantify the rock texture components, porosity constitutions and the influences of diageneses on reservoir porosity. Porosity evolution curves are quantitatively recovered. The Feixianguan reservoir porosities are mainly created by early meteoric dissolution, dolomitization, and organic acids dissolution. Dissolution during deep burial is insignificant. Pores are formed in near-surface and pre-oil window stages and effectively preserved till present. This result may be of great significance to the further exploration of deeply buried carbonate reservoirs not only in NE Sichuan Basin, but also around the world.

InSAR技术在普光气田地质灾害调查中的应用

普光气田高含硫化氢的集输管道经常需穿越一些地形地质条件复杂区域,这些地区通常又是地质灾害的高发区,不同类型的地质灾害威胁着管道的安全运行。通过雷达卫星数据对普光气田集输站场和集输管道周边滑坡进行了地表形变探测,共探测出32处地质灾害点;结合光学遥感影像目视解释和现场勘查^([1]),对普光气田103集气站南侧、胡家阀室、毛坝1井—1#阀室管线西侧共3处典型滑坡形变特征进行了详细分析。结果显示,该区域地质灾害变形速率受降雨的影响较大。调查结果能够对普光气田地质灾害防控工作提供重要的决策依据。

New Model of Predicting Remaining Recoverable Reserves and Application in the Oilfield

As a significant inducement during the development of oil and gas,the role of remaining recoverable reserves is more observable especially in the later phase of development of oilfield.Depended on the production decline method in petroleum reservoir engineering,a new model of predicting recoverable and remaining recoverable reserves has been

四川盆地普光高含硫气田长周期高产稳产关键技术

普光气田是我国探明储量最大的高含硫气田,储层以礁滩相为主,具有非均质性强、边水能量强、高含硫等特点,面临礁滩储层地震预测精度低、气藏边水推进快、产能快速递减、硫沉积逐步析出、气井产能和气藏储量动用效果差等一系列技术难点和挑战。为此,针对普光气田开发面临的难点和挑战,全面、系统总结了自“十三五”以来,为实现气田长周期高产稳产而开展的技术攻关与矿场实践。研究结果表明:①建立了台内滩储层预测岩石物理量版,提出了有效动用对策,研发了“自转向清洁酸+降阻滑溜水+缝内暂堵”造复杂缝酸压工艺,实现了超深礁滩相低品位台内滩储层有效动用;②建立了礁滩相储层气水前缘运动方程,研发了新型抗硫三元复合泡排剂、高抗硫超高膨胀率比桥塞,设计了过油管注塞堵水工艺,实现了高含硫气井全生命周期控水稳气;③揭示了高含硫天然气单质硫析出机理,建立了高含硫气藏硫沉积分布模型,研发了快速分散型溶硫剂,配套射流冲洗工艺,形成了井筒硫沉积治理技术。结论认为,普光气田目前边水突进导致剩余气分布复杂、硫沉积逐渐从井筒扩展到地层、井口压力接近外输压力,下一步需要开展剩余气精细描述与挖潜、精准堵水、储层硫沉积治理、集输系统增压开采等技术攻关,以期进一步改善气田开发效果进而提高采收率。

普光气田大湾-毛坝构造飞仙关组天然裂缝发育规律

普光气田进入开发中后期,天然裂缝的发育特征决定着开发井的调整和控水政策的制定,目前,针对大湾-毛坝构造飞仙关组天然裂缝的研究尚未系统开展。文中利用野外露头、岩心、薄片和成像测井资料,评价了研究区天然裂缝的发育类型和参数特征,结合叠前叠后地震属性,进一步明确了天然裂缝的控制因素和分布规律。研究表明:大湾-毛坝构造天然裂缝走向以近东西向为优势方位,以斜交-高角度裂缝为主;天然裂缝发育特征受构造、岩性、沉积微相和成岩作用控制,白云岩中天然裂缝发育密度大于灰岩,方解石和白云石的胶结作用和有机质充填更有利于天然裂缝发育。预测结果表明,断层附近、毛坝构造褶皱枢纽附近以及大湾构造褶皱枢纽-翼部的转折端为天然裂缝密度高值区。根据天然裂缝发育规律,并结合含气性预测结果,可以明确气井水侵规律,进而为制定合理的复产措施提供依据。

普光气田超深高含硫水平井开发测井先导性试验

针对普光气田超深高含硫水平井开发测井施工时井口安全控制风险极大,对测井设备及仪器材质、井口控制系统和腐蚀防控等要求苛刻这一问题,文中借鉴前期高含硫直井和小斜度井开发测井的经验做法,论证并优选了连续油管输送存储式测井工艺,即符合国际标准NACE MR 0175的HS90连续油管,最高工作压力70 MPa的井口高压防H2S控制系统,工作压力上限103 MPa且外部材质为AISI4130-4135合金的测井仪器。根据高含硫气井井下工况条件,开展了测井设备及仪器实验研究和模拟评价;在P101H井开展先导性试验,安全顺利完成了我国第1口超深高含硫水平井开发测井施工,验证了该测井设备及仪器的可靠性和安全性。研究成果为类似气田水平井安全有效地进行开发测井施工提供了工艺技术和经验借鉴。

普光气田天然气净化装置运行总结

高含硫气田天然气因硫化氢、二氧化碳含量高,物料毒性、腐蚀性强,大大加剧了天然气净化装置的安全、环保风险。普光气田作为国内首个自主开发投产的高含硫气田,其天然气净化厂自2009年投产至今,已安全平稳运行14 a,外输天然气1 200亿m^(3),外销硫磺2 400万m^(3),均达到国标最高质量等级要求,腐蚀速率控制在0.020 mm/a以下,外排烟气SO_(2)质量浓度低于200 mg/m^(3),万立方米原料气综合处理能耗低于6 400 MJ,无安全、环保事故发生。在腐蚀防护、安全控制、环保提标、提质增效等方面建立了系列成套技术,为高含硫气田的成功开发及投产提供了技术支持和借鉴。

普光气田长兴组礁滩体精细刻画及认识

针对普光气田长兴组礁滩体分布规律认识不清楚、台缘礁气水关系复杂的问题,开展了长兴组礁滩体地震识别及台缘礁内幕精细刻画工作。通过井震精细标定,明确了礁滩体储层地震响应特征,利用多属性分析等手段对长兴组礁滩体进行宏观识别,结合最新古地貌恢复结果分析了礁滩体平面展布规律;利用瞬时相位与波阻抗反演结果对台缘生物礁群的内幕结构进行了精细刻画,并结合生产动态资料分析了单礁体储层的连通性。结果表明:长兴组发育台缘礁群与台内礁滩复合区2类礁滩体,礁滩复合区的分布受到台缘礁间水道控制,宽水道对应礁滩复合区面积大,窄水道对应礁滩复合区面积小,平面上呈近似扇形分布;台缘礁群在长兴组中上部可识别2期次50个单礁体,呈现5类不同的叠加发育模式,并且2期次的单礁体储层互不连通,同一期次侧向叠置的单礁体储层普遍连通。研究结果对普光气田长兴组下步勘探及开发具有一定指导意义。

普光气田套管补贴用抗硫膨胀管及其性能测试

受到高酸性物质的影响,普光气田部分套管变形井后期可能会出现套管腐蚀穿孔或漏失的问题。目前,膨胀管补贴技术正是解决这一问题的有效办法。文中在优选抗硫膨胀管材质的基础上,设计了普光气田Ф177.8 mm套管补贴用抗硫膨胀管,建立了膨胀管膨胀过程非线性接触有限元模型,分析了膨胀管膨胀后的径向变形量、残余应力分布和膨胀力变化的规律;搭建了膨胀管膨胀性能测试系统,对膨胀管膨胀后的螺纹连接密封性能、硫化橡胶密封性能和悬挂力进行了测试和分析。研究表明:抗硫膨胀管膨胀后螺纹连接抗外压值达到了30 MPa,螺纹连接抗内压值为50 MPa,膨胀管硫化橡胶的密封压力为30 MPa,膨胀后一组硫化橡胶的悬挂力接近200 kN。这为Ф177.8 mm套管膨胀管补贴现场施工参数的优选提供了参考,同时还可以为川东北乃至其他高酸性气田的后期开发提供技术储备。

普光高含硫气田钢丝作业技术探究

通过对普光高含硫气田钢丝作业技术的探究,介绍了普光高含硫气田的概况及钢丝作业技术的定义,进一步分析了钢丝作业技术在普光高含硫气田中的应用特点,总结出了其主要难点,分析了其存在的问题,并提出了相应的技术策略和应对措施。

四川盆地普光大型气田的发现与勘探启示

普光气田是四川盆地近期发现的规模最大、埋藏最深、资源丰度最高的气田。在对普光气田的勘探及气藏基本特征研究的基础上,笔者总结了普光大型气田的发现与勘探启示,即成熟盆地的勘探需要有新思路;勘探技术是促进勘探发展的技术保障;大型富油气盆地油气成藏类型多,成藏条件复杂,立体勘探能有效降低勘探风险。

四川盆地普光大型气藏基本特征及成藏富集规律

普光气田是在四川盆地近期发现的规模最大、埋藏最深、资源丰度最高的气田,2005年初向国家储委上交飞仙关组探明储量1144×108m3,普光气田已初步落实的三级储量超过3500×108m3。普光气田下三叠统飞仙关组储层岩性以单一的白云岩为主,发育鲕粒白云岩、残余鲕粒白云岩等储层;储层物性以中孔中渗、高孔高渗储层为主,为优质储层。深埋藏条件下的孔隙形成可能与深部热水溶蚀作用有关。临近主力生烃凹陷、优质储层发育、适时的古隆起可能是普光大型气田形成的有利条件。

川东北地区海相碳酸盐岩油气成藏作用及其差异性--以普光、毛坝气藏为例

对普光气藏与毛坝气藏的成藏要素、天然气和沥青特征、气源、成藏演化和成藏机制等进行对比分析,研究川东北地区海相碳酸盐岩油气成藏作用的差异性及其原因。普光飞仙关组、长兴组气藏与毛坝长兴组气藏的成藏作用具有较大的相似性,但毛坝飞仙关组气藏成藏作用在时间、空间和天然气成分上却有明显差异。川东北地区气藏具有多层系源和多转化源,表现为各气藏具有明显的来源差异。海相碳酸盐岩地层中受特殊沉积相带控制的特殊储集层的发育对油气藏分布具有重要的影响;多旋回叠合盆地复杂的构造演化背景在宏观上控制油气成藏要素,从根本上制约成藏规律和成藏机制,是导致海相碳酸盐岩差异成藏的根本原因。

空气钻井技术在普光D-1井的应用

为提高钻井速度,缩短钻井周期,加快普光气田开发进程,在普光D-1井的上部陆相地层的564．0～3002．0m井段进行了空气钻井试验。分析了普光气田进行空气钻井的可行性,详细介绍了普光D-1井空气钻井的施工情况,并对空气钻井的效果进行了评价。普光D-1井空气钻井试验结果表明,普光气田在上部陆相地层采用空气钻井可以提高钻井速度,缩短钻井周期,达到加快开发进程的预期目的。

空气钻井安全钻进特性分析

空气钻井技术被钻井界认为是提高钻井速度、缩短钻井周期的一项实用性技术。与常规钻井液钻井技术相比,空气钻井在提高机械钻速、避免地层伤害、避免地层漏失方面具有明显优势,在控制地层压力、地层流体流入能力等方面存在不足。总结出了影响空气钻井安全钻进的"十大"因素,即井眼清洁、地层出水、井眼稳定、井下着火和爆炸、井斜控制、井控问题、气侵早期监测、钻具的腐蚀及冲蚀、钻具断裂和钻井液转换,并对上述因素进行了详细的分析。普光气田空气钻井实践证明了空气钻井技术的优势,但同时也暴露出一些问题。只有全面理解和掌握了空气钻井技术,才能充分发挥其优势和潜力,加快普光气田及周边区块的勘探开发步伐。

普光气田气体钻井钻具失效原因分析及预防措施

气体钻井技术虽然大幅度提高了普光气田上部陆相地层钻井速度,但屡次出现钻具失效事故,不仅影响钻井速度,而且威胁井下安全。分析了钻具失效规律,并通过宏观分析判断钻杆为疲劳和腐蚀疲劳断裂,钻铤为疲劳断裂。从气体钻井自身因素、钻柱运动(包括公转和纵向共振)、钻具腐蚀、钻井方式、钻铤弯曲强度比不足等方面分析钻具失效原因,提出使用空气锤钻井技术、加强钻具探伤、优化钻具组合和钻井参数、缓解钻具腐蚀、加强钻柱振动监测等预防措施。指出应加强气体钻井钻具失效的微观机理、钻柱运动与动力学、岩屑对钻具的冲蚀磨损、钻具腐蚀、消除钻柱公转等方面的研究以预防钻具失效。