Analysis of Reservoir Sensitivity and Optimization of Drilling Fluid System in Block H9 of Tarim Oilfield

针对塔里木油田H9区块钻井过程中存在的储层损害问题,采用黏土矿物分析、扫描电镜及压汞法等方法,分析掌握了目标区块储层地质特征,并结合储层敏感性试验评价,明确了储层潜在敏感性损害因素,揭示了储层损害机理。结果表明,H9区块储层黏土矿物含量为10%~20%,具有中高孔渗特征,非均质性较好,且存在潜在的强速敏和强水敏性损害。针对现场用钻井液体系存在的抑制性、润滑性及储层保护效果存在的不足,室内优化了一套综合性能优良的KCl-聚合醇储层保护钻井液体系。通过模拟储层动态损害试验评价可知,储层岩心渗透率恢复值可达85%以上。现场试验结果表明,KCl-聚合醇钻井液体系可较好地抑制泥页岩水化膨胀分散,有效避免了井眼缩径、起下钻遇阻等井下复杂情况发生,保障了钻井施工高效、安全,且储层保护效果良好。

Petroleum Accumulation Associated with Volcanic Activity in the Tarim Basin —— Taking Tazhong-47 Oilfield as an Example

The discovery of the Tazhong-47 oilfield confirmed that it is realistic to explore oil and gas fields around igneous rocks in the Tarim basin. The favorable conditions for petroleum accumulation due to volcanic activity and igneous rocks formed during the activity show in two aspects. A) The contact surface of igneous rocks and the surrounding sedimentary rocks, like a vertical unconformity surface, formed the conduit of petroleum migration. Petroleum would accumulate once it encountered a trap in which the reservoir had fine porosity and permeability. B) It formed a trap barriered by igneous rocks, or changed or cut the original trap. In addition, volcanic rocks are a kind of potential reservoir, there are many such examples in the world, and oil also shows in the Permian igneous rocks in well Zhong-1 on Tazhong uplift. Petroleum accumulation associated with volcanic activity will be a new exploring field in the Tarim basin.

Burial Dissolution of Ordovician Granule Limestone in the Tahe Oilfield of the Tarim Basin,NW China,and Its Geological Significance

With a comprehensive study on the petrology, geology and geochemistry of some Ordovician granule limestone samples in the Tahe Oiifieid of the Tarim Basin, two stages of burial dissolution were put forward as an in-source dissolution and out-source dissolution based on macro-microcosmic petrology and geochemistry features. The main differences in the two stages are in the origin and moving pass of acid fluids. Geochemical evidence indicates that burial dissolution fluids might be ingredients of organic acids, CO2 and H2S associated with organic matter maturation and hydrocarbon decomposition, and the in-source fluid came from organic matter in the granule limestone itself, but the out-source was mainly from other argillaceous carbonate rocks far away. So, the forming of a burial dissolution reservoir resulted from both in-source and the out-source dissolutions. The granule limestone firstly formed unattached pinholes under in-source dissolution in situ, and afterwards suffered wider dissolution with out-source fluids moving along unconformities, seams, faults and associate fissures. The second stage was much more important, and the mineral composition in the stratum and heat convection of the fluid were also important in forming favorable reservoirs.

Types of Karst-fractured and Porous Reservoirs in China's Carbonates and the Nature of the Tahe Oilfield in the Tarim Basin

Almost all the oil and gas reservoirs developed in marine sedimentary strata of China have undergone processes of multi-phase reservoir formation and later modification. The irregular reservoirs are classified into three types as the Naxi, Tahe and Renqiu ones, increasing successively in the development degree of karstificated pores and fissures and the connection degree of independent reservoirs. In these reservoirs, the unity in the fluid feature, pressure and oil-gas-water interface also increases successively from the Naxi to the Renqiu type. The main body of Ordovician reservoirs of the Tahe Oilfield in the Tarim Basin is a network pool rather than a stratified, massive, stratigraphically-unconformed or weathering-crust one. The fluid nature of oil, gas and water, the interface positions and the pressures, as well as the dynamic conditions of fluids within the reservoirs during the production are all different from those in stratified or massive oil and gas reservoirs. Carbonates in the Akekule uplift and the Tahe Oilfield are assemblages of various types of reservoirs, which have an overall oil-bearing potential and obvious uneven distribution. Testing and producing tests are the major means to evaluate this type of reservoirs and acid fracturing improvement is a key link in petroleum exploration and development.

Hydrocarbon Inclusion Characteristics in the Cambrian-Ordovician Carbonates of the TS2 Well:Implication for Deep Hydrocarbon Exploration in the Tahe Oilfield,Tarim Basin,Northwest China

Going deep has been the strategy for the sustainable development of the Tahe Oilfield.Following the TS1 well in block 1,which revealed excellent combinations of hydrocarbon generation,migration and accumulation in the deeper parts of the Tarim Basin,the TS2 well was drilled to learn more about the prospectivity in the deeper parts of the main blocks of the Tahe Oilfield.Seventeen core samples were collected to perform fluid inclusion studies,including petrography,fluorescence microspectrometry,and microthermometry.The results show that the deeper parts of the Tahe Oilfield have a good hydrocarbon potential.The Cambrian source rocks can supply sufficient oil for not only the Cambrian reservoirs,but also for the Lower Ordovician reservoirs.The CambrianOrdovician carbonates reservoirs experienced at least three oil charging events and one late gas charging event.Oil accumulations formed in the early stage of basin evolution were likely destroyed in the late stage with deep burial,tectonic movements,or invasion of hydrothermal fluids.Therefore,the deep hydrocarbon exploration of the Tahe Oilfield,even the whole Tarim Basin,should focus on gas accumulations,although oil accumulations,especially in Cambrian reservoirs,cannot be neglected.

Water-Rock Interaction in Tarim Basin: Constraints from Oilfield Water Geochemistry

Oilfield waters from Cenozoic and Mesozoic terrestrial and Paleozoic marine environments in the Tarim Basin show no obvious difference in water chemistry except Br and isotopic compositions. The Paleozoic marine strata have higher Br concentrations than the terrestrial sediments, and the lack of obvious relationship between Br and Ⅰ suggests that Br is not, for the most part, derived from the degradation of organic matter. The oilfield waters are characterized by high TDS (total dissolved solids), ranging from 120000mg/L to 320000mg/L,relatively low Mg, high Ca, Sr, and CF relative to Br of evaporating seawater, suggestive of enhanced water-rock interaction. (Al (organic acid anions) concentrations are generally lower than 1500 mg/L with high values occurring over the temperature range from 95℃ to 140℃ ,in the Cambrian to Jurassic systems, and nearby unconformities. Organic acids are considered to be generated mainly from thermal maturation of kerogens during progressive burial of the Jurassic-Triassic and Cambrian-Ordovician systems, biodegradation of crude oils nearby unconformities, and thermochemical sulfate reduction in part of the Cambrian and Ordovician strata.High Al concentrations up to 3 mg/L to 5. 5 mg/L tend to occur in the waters of high OAA or petroleum- bearing intervals, suggesting the presence of organic complexing agents. Calculation by SOLMINEQ. 88 with updated database shows that AlAc2+ may account for more than 30%of the total Al. IsotoPic measurements (δD, δ18O) provide evidence for the following types of waters: diagenetically- modified connate meteoric water from the Jurassic and Triassic strata;diagenetically-modified connate marine water from the Cambrian and Ordovician strata; subaerially-evaporated water from the Cenozoic and Cretaceous strata; and mixed meteoric-evaporated or/and diagenetically modified connate water from the Carboniferous strata and reservoirs adjacent to the J/C and T/C unconformities. Those waters with very negativeδD values from -51. 30‰. to - 53. 80‰ (SMOW) and positive δ18 O values from 2. 99‰ to 4. 99‰(SMOW) in the continuous burial of the Cambrian-Ordovician system are explained to have resulted from hydrocarbon-water and water-rock interactions.

塔里木油田超深层钻井技术进展及难题探讨

当前,塔里木油田以超深特深层为代表的深地油气资源开发对满足我国经济发展需求和保障能源安全至关重要。经过数十年的探索和实践,塔里木油田创新形成了超深复杂井井身结构设计、超深难钻地层钻井提速、超深大斜度井水平井钻井、超深复杂地层钻完井液、超深复杂地层固井、高温高压井完整性、超深复杂井井控等一系列超深层钻井技术,保障深地油气勘探获得重大突破并创造多项纪录。伴随超深井数量持续增加,工程地质条件更加复杂,井下环境更加苛刻,超深层钻井过程势必面临新的工程难题和挑战,严重制约深地油气资源安全高效开发。为此,通过概括塔里木油田钻井工程技术发展历程,系统梳理了深地钻井工程技术取得的主要技术进展,并结合新的勘探开发形势与油气开发要求,指出了塔里木油田钻井工程技术从超深层迈入特深层新时期的焦点问题及攻关发展方向,为国内外深地复杂油气井安全高效钻进提供借鉴和参考。

Chemical Analysis of Water and the Resource of Br,K Prospects of Oilfield Brines from Ordovician and Carboniferous in Tarim,China

China is lack of bromine and potassium seriously.Oilfield brines is the headline goal of bromine and potassium resources exploration.Applicants grab 24oilfield brines samples from various wells of Ordovician

Donghetang Oilfield Comes on Stream in Tarim

Donghetang Oilfield,located in Kuche Coun-ty,Tarim.basin.of Xinjiang Uygur Au-tomonous Region,came on stream successfully on June 26,1994.Up to now,there are seven.oil wells,five water injections and 16 water source wells at the field site and a Central Treatment Plant(CTP)there.At this time,six oil wells began pro-duction,of which five by natural flow and one by electrical submersible pump.The field will produce:600000 tons per year of 0.8572 specific gravity oil at-13C pour point,which is buried in about 5800 meters underground.

塔里木盆地富满断控破碎体油藏储集类型特征与注水替油效果

塔里木盆地走滑断裂控制的超深油气藏是近年来中国油气勘探开发最重要领域之一,但目前该类型油藏的储集空间类型并不清楚,不同储集空间类型与注水效果关系不明确,严重制约了富满油田的高效开发。在充分分析野外露头、岩心、成像测井以及动态监测资料的基础上,系统剖析了断控破碎体的3种主要储集空间类型及其与注水效果的关系。提出了断控破碎体的概念,指出富满油田主要为断控破碎体油藏,研究结果表明:①断裂空腔型储集体主要分布在断裂带的核部,由断层滑动面产状变化引发内部体积调整形成了“空腔”型洞穴。埋藏条件下的储集空间相对较为封闭,内部孔隙空间较大,注水后原油置换率较高,部分油井动用储量的注水采收率可高达93%。②角砾间孔隙型储集体主要分布在断裂带的核部,由相邻的角砾相互支撑而形成角砾间不规则储集空间类型。该类储集体分布较为均匀,孔隙度中等,单位压降下的产液量较高,但是由于储集空间内部连接并不通畅,注水后置换率较低,需要研究探索构建立体结构井网来提高开发效果。③构造裂缝型储集体主要分布在断裂带的损伤带和过程带,在断层带的两侧和端部发育形成一定宽度的裂缝带。裂缝带周边也会发育少量孔隙,部分区域会形成一定的渗流优势通道,因此注入水的流失量较大,注水效果相对于断裂空腔型储集体较差。研究成果支撑了富满油田上产原油350×10^(4) t,可助推注水开发方案和提高采收率方案的优化,对同类型油藏高效开发具有重要的借鉴意义。

基于结构张量的走滑断裂破碎带地震识别——以富满油田超深层碳酸盐岩为例

塔里木盆地超深层奥陶系碳酸盐岩走滑断裂破碎带发现了丰富的油气资源,但由于超深层地震资料分辨率低,难以精准刻画走滑断裂破碎带,制约了走滑断控油气藏的高效评价与目标优选。根据富满油田走滑断裂破碎带的地震响应特征,在构造导向滤波基础上,利用结构张量方法计算特征值和特征向量,通过时窗选取与纵向厚度叠加加强反映沿断裂方向的投影能量,突出走滑断裂破碎带,刻画其边界与强度。结果表明:该方法更清晰地刻画了走滑断裂的分布,可以识别更小规模的走滑断裂;实现了超深层碳酸盐岩走滑断裂破碎带宽度与强度的刻画,可以用来评价走滑断裂破碎带的发育程度;将该方法应用于圈闭评价、井位部署、井轨迹设计、钻井监测等,大幅提高了钻探成功率与单井油气产量。

塔里木盆地富满油田走滑断裂带通源性评价

塔里木盆地走滑断裂带对油气藏形成具有控制作用,走滑断裂带与油源连通性对油气运移、聚集非常重要。基于3D地震资料,运用Riedel剪切离散元模型和完全塑性介质-应力上升函数模型,对塔里木盆地富满油田Ⅱ区块FI 17走滑断裂带油源连通性进行了评价。研究结果显示:①FI 17走滑断裂带海西晚期雁列断裂拖曳点深度(h)理论计算值远小于实测值,表明其走滑断裂T张破裂成因,而非R剪切断裂。②FI 17走滑断裂带通源深度平均达9~18 km,表明该断裂能够将其下伏埋深10 km以下的玉尔吐斯组烃源岩生成的油气直接输导至上覆奥陶系断(缝)溶体圈闭中聚集成藏。③FI 17走滑断裂带通源深度(H)自北而南增加,其断控形成油气藏中的原油密度、天然气干燥系数、油气充注期次及各期次贡献度与油源连通性密切相关,表明油源连通性对油气聚集具有控制作用。走滑断裂级别、走向分段性、活动强度和断穿地层不同,控制作用也不同。油源连通性会沿着走向发生显著变化,影响油气垂向输导效能。

超深层“断裂破碎体”概念和地质模式及其地震表征方法

“断裂破碎体”是塔里木盆地富满油田超深层碳酸盐岩储层的一种重要赋存类型。对于该类储集体,目前尚存在着概念不清晰和地质模式不明确、缺乏适用的地震表征方法等问题。为此,利用野外露头、钻井、地震和生产动态等资料阐述“断裂破碎体”概念的内涵,建立了超深层碳酸盐岩油气藏“断裂破碎体”四种地质发育模式,并形成了超深层碳酸盐岩“断裂破碎体”智能地震内部结构刻画技术。研究结果表明:①“断裂破碎体”具有三个方面的内涵,即发育背景主要为超深碳酸盐岩台内致密灰岩地层;在断裂破碎作用下,内部孔—渗储集性能较好,储集空间类型多样(主要包括断裂破碎角砾间孔、张扭作用形成的空腔以及中、高角度裂缝);油藏的通源、油气运移的输导有利,油藏高度可达千米,是超深层致密灰岩储层油气聚集的极为有利部位。②“断裂破碎体”发育六种断裂构型要素,组成了单一滑动面、压隆核带、张扭空腔、栅状缝网等四类内部结构模式。③采用“有条件的对抗深度学习网络”能够较好地刻画断裂破碎体内部结构,预测结果的地质意义较为明确,并与实际情况吻合。该成果在实际生产中得到了较好的应用,对“断裂破碎体”油藏的高效勘探与开发具有实用和推广价值。

塔里木盆地塔河北部“过溶蚀残留型”断溶体发育特征及其成因

为了研究塔里木盆地塔河北部强剥蚀区海西早期古岩溶洞穴发育特征,用古地貌恢复、岩溶水系统分析、测井-岩心洞穴识别和地震属性刻画等方法进行了YQ5井区的洞穴类型样式识别、缝洞结构刻画和洞穴成因演化研究。研究结果表明:YQ5井区在塔河油田Ⅱ号和Ⅲ号古岩溶台地北部的地势平缓区,总体为多期次岩溶叠加改造后的残留地貌,主要发育幅差较小的溶峰洼地、溶丘洼地和溶丘平原,南部发育NE向展布的峰丛垄脊沟谷。与塔河油田主体区及斜坡区不同,YQ5井区地下和地表水系的流向与地貌趋势不一致,岩溶水系统遭受构造作用破坏,导致补给、径流和排泄的岩溶水循环过程不完整。YQ5井区主要发育暗河型洞穴和“过溶蚀残留型”断溶体。暗河型洞穴充填较为严重,洞穴的有效储集空间受到破坏,影响油气开发效果。岩溶台地的构造抬升造成区域侵蚀基准面的下降,顺走滑断裂的垂向侵蚀作用有利于“过溶蚀残留型”断溶体的持续发育和保存,油气开发效果好。“过溶蚀残留型”断溶体的发育主控因素为走滑断裂、地层剥蚀强度和负向地貌。与塔河古岩溶台地演化过程一致,YQ5井区的岩溶演化经历深切曲流期、岩溶改造期和下渗断溶期3个阶段。暗河型洞穴被持续改造破坏,断溶体则持续建造。

变排量注替防漏固井技术在KS区块储层的应用

针对塔里木油田库车山前储层埋藏深、地层复杂、裂缝发育,安全密度窗口窄,对环空压力变化极为敏感,在固井施工过程中易发生井漏,导致整体固井质量较差,严重影响后期生产的问题。通过对现有传统固井工艺的主要技术特点和应用特点进行分析,基于塞流固井工艺的特点,提出了变排量固井工艺,进行了适应性评价,并提出了相应的固井设计方法。变排量固井设计包括雷诺数计算、流态判别、变排量施工参数设计、变排量施工对环空流体性能要求。现场应用实践表明:采用变排量注替防漏固井技术能有效地节约施工时间,降低施工风险,防止井漏,提高顶替效率,解决库车山前储层尾管固井地层裂缝发育、固井安全密度窗口窄、地层承压能力低等难题。

塔里木盆地塔河油田S80走滑断裂发育特征及其对奥陶系储层的控制作用

综合运用岩心资料、测井资料、单井漏失段宽度和漏失量数据,利用高精度三维地震数据,结合多层相干属性开展塔里木盆地塔河地区S80走滑断裂带精细解析,厘定了其空间展布特征、活动强度特性及活动期次,探讨了S80走滑断裂对奥陶系储层的控制作用。研究结果表明:①S80走滑断裂带沿走向可分为西带、中带和东带,3个分带整体具有纵向上由寒武系至奥陶系叠接段数量显著增多、段长和段宽明显增加的特点,平面上由SW向NE张扭段规模减小、压扭段规模增强、平移段逐渐消失。具有“中带断裂活动强、两侧断裂活动弱”的特征。②S80走滑断裂带活动主要经历了加里东中期、加里东晚期—海西早期、海西晚期和印支期—喜马拉雅早期4个阶段。加里东中期和加里东晚期—海西早期为主要活动期。为“前两期左行,后两期右行”的走滑性质。③围绕S80走滑断裂带发育洞穴型、复合型(裂缝-孔洞型、孔洞-裂缝型)以及裂缝型3类储层。溶蚀孔洞的发育与走滑断裂分段性活动密切相关,活动性强的压扭段、平移段及活动性弱的张扭段主干断裂周缘是溶蚀孔洞发育的有利部位。④中奥陶统一间房组压扭段裂缝线密度高,中奥陶统一间房组至中-下奥陶统鹰山组纵向上裂缝线密度显著降低,溶蚀能力局限性大。中奥陶统一间房组张扭段裂缝线密度适中,中奥陶统一间房组至中-下奥陶统鹰山组在纵向上裂缝均较发育,溶蚀孔洞数量和规模相对更大,为储层的有利发育区。

深层—超深层走滑断裂带储层流体来源与油气成藏过程研究——以塔里木盆地富满油田为例

以富满油田北部走滑断裂带深部储层孔洞缝充填脉体为研究对象,基于脉体的岩相学特征、微区稀土元素和Sr(锶)同位素、油包裹体荧光光谱、显微热力学和碳酸盐岩U-Pb同位素定年进行分析。结果表明:富满油田北部走滑断裂带发育2期方解石脉体,脉体来源于中下奥陶统海源地层水,未见氧化性流体侵入,表明深层—超深层油气晚期具有良好的封闭性。通过包裹体测温投点埋藏史结合碳酸盐岩低U-Pb同位素定年技术,厘定塔里木盆地富满油田北部走滑断裂带深层奥陶系存在3期油气充注过程,分别对应于距今(459±7.2)Ma(加里东中期)、(348±18)Ma(海西早期)和268Ma(海西晚期),富满油田北部深层—超深层碳酸盐岩油气成藏关键期为海西早期,且油气充注与断裂活动有较好的对应关系。

塔里木油田超深井压恢曲线异常分析及解决对策

针对塔里木油田超深井压力恢复测试,受试井压力计下深限制及井筒内多相流体重力分异、油水界面变动影响,压力恢复曲线经常出现“局部压力下降”、“直线”等异变特征,影响储层渗流能力、污染状况、边界特征分析,难以对储层进行准确描述。XX1-3井在压力恢复测试中压力恢复曲线出现“直线”异常特征,严重影响了解释精度及对储层的认识;通过分析井筒内油水界面变化对压力恢复曲线形态的影响,计算液面降落速度,合理设计压力计下入深度及关井时间,使测点压力变化与产层中部压力变化趋势相一致,较好地消除了液面移动造成的压力恢复曲线中“直线”段异常特征,从第二次压恢测试曲线中可以看出,压恢有效压力数据时长占比98.53%,提高了试井资料解释精度,加深了对地层压力、渗流能力、污染状况、边界特征等认识。为超深井中含水较高的油井压力恢复测试提供可借鉴方案,为油气藏开发方案的编制提供了可靠的理论依据。

塔里木油田富源井区深井超深井抗240℃高温钻井液体系研究

深井超深井的勘探开发已逐渐成为油气开发的主要对象,钻井液是深层超深层钻完井工程的核心技术,是钻井成功的关键之一。本文通过分析塔科1井的技术难点,对水基钻井液的降滤失剂、沥青封堵剂、抗高温抑制剂以及抗高温颗粒封堵剂进行了优选,形成了一套抗240℃高温的水基钻井液体系;并对钻井液体系进行评价。实验结果表明,钻井液体系在240℃高温下具有良好的流变性和降滤失剂性能,满足塔里木油田深井超深的钻井需求。

Geochemical characteristics and oil family classi-fication of crude oils from the Markit Slope in the southwest of the Tarim Basin, Northwest China

Based on the chromatograms of oils and saturated hydrocarbons, biomarkers and stable carbon isotope analyses, the geochemical characteristics and oil family Classification of crude oils from the Markit Slope in the southwest of the Tarim Basin were investigated. The results showed that crude oils from the Markit Slope are divided into two oil family Classification. Oils collected from the Bashituo oilfield in the western part of the Markit Slope are characterized by high contents of tricyclic terpanes, pregnane, and homopregnane, low contents of garmmacerane (G/H<0.20), dibenzofuran, and methyl cyclohexane, and light stable carbon isotopic values (the δ13C values of satu-rated hydrocarbons and aromatic components are less than -34‰ and -32‰, respectively), with the distribution type of steranes being C27>>C28<C29. Condensate oils collected from the Hetian River gasfield in the eastern part of the Markit Slope are characterized by low contents of tricyclic terpanes, pregnane, and homopregnane, high contents of garmmacerane (0.20<G/H<0.36), dibenzofuran, and methyl cyclohexane, and relatively heavy carbon isotopic values (δ13C of saturated hydrocarbons and aromatic components (> -32‰ and -30.6‰, respectively), with the distribution type of steranes being C27>C28<<C29. In addition, oils from Well Qu 1 have some characteristics similar to those of the above oils, with some special characteristics including high contents of β-carotenes and special distribution of steranes (C27<C28 <C29).