Improvements to the fuzzy mathematics comprehensive quantitative method for evaluating fault sealing

Fuzzy mathematics is an important means to quantitatively evaluate the properties of fault sealing in petroleum reservoirs.To accurately study fault sealing,the comprehensive quantitative evaluation method of fuzzy mathematics is improved based on a previous study.First,the single-factor membership degree is determined using the dynamic clustering method,then a single-factor evaluation matrix is constructed using a continuous grading function,and finally,the probability distribution of the evaluation grade in a fuzzy evaluation matrix is analyzed.In this study,taking the F1 fault located in the northeastern Chepaizi Bulge as an example,the sealing properties of faults in different strata are quantitatively evaluated using both an improved and an un-improved comprehensive fuzzy mathematics quantitative evaluation method.Based on current oil and gas distribution,it is found that our evaluation results before and after improvement are significantly different.For faults in＂best＂and＂poorest＂intervals,our evaluation results are consistent with oil and gas distribution.However,for the faults in＂good＂or＂poor＂intervals,our evaluation is not completelyconsistent with oil and gas distribution.The improved evaluation results reflect the overall and local sealing properties of target zones and embody the nonuniformity of fault sealing,indicating the improved method is more suitable for evaluating fault sealing under complicated conditions.

Methods and Case Studies of Ultra-deep Fault Seal Evaluation

Fault seals are significant for petroleum exploration and production.This study summarizes the fault sealing impacting factors,including lithological juxtaposition,mud smearing,fault rocks and the fault plane stress states,as well as evaluation methods like Allan maps and Shale Gouge Ratio(SGR).The seal evaluation for a wrench fault focuses on its particular structural features.The evaluation methods were applied to the Jinma-Yazihe structure and the Shunbei oilfield.The source rock is the Xujiahe Formation of the Upper Triassic,the reservoirs and caprocks being of the Shaximiao Formation of the Lower Jurassic.The fault sealing evaluations in major faults proved the reservoir formation processes in the wells Jinfo 1(JF1)and Chuanya 609(CY-609),based on the editions of the Allan map showing lithological juxtaposition,the calculation of SGR showing mud smear and analyses of fault stress states.The analyses of stress states were also applied to Shunbei 5 strike-slip fault in the Shunbei area in Tarim Basin.The various sections along the fault were of different mechanical properties,such as compression and extension.Petroleum exploration has demonstrated that the extensional sections are more favorable for oil accumulation than the compressional sections.These evolutionary methods and other understandings will help in analyses of deep fault sealing.

Study on estimate method of wave velocity and quality fac-tor to fault seals

Based on ultrasonic test of fault rocks, the re-sponses for wave velocity and quality factor (Q value) to lithology, porosity and permeability of fault rocks and me-chanical property of faults are studied. In this paper, a new quantitative estimate method of fault seals is originally of-fered. The conclusions are as follows: (1) Wave velocity and Q value increase and porosity decreases with the increase in stress perpendicular to joint; (2) In compressive and com-presso-shear fault rocks that are obviously anisotropic com-pared with their original rocks, the wave velocity and Q value are greater in the direction parallel with foliation, and usually less perpendicular to it. In tensile and tenso-shear fault rocks that are not obviously anisotropic, the wave ve-locity and Q value are under that of original rocks; (3) In foliated fault rocks, the direction with minimal wave velocity and Q value is the best direction for sealing; on the contrary it is the best for flowing; (4) Structural factures develop mainly along foliation, the minimal wave velocity and Q value reflect the flowing capacity in parallel direction to fo-liation, and the maximal wave velocity as well as Q value reflect the sealing capacity in normal direction to foliation. The new estimate method is based upon contrast of wave velocity and Q value between fault rocks and their original rocks, and is divided into three parts that are respectively to identify rock’s lithology, to judge mechanic property of faults and to Judge sealing capacity of faults. Although there is vast scale effect between ultrasonic wave and seismic wave, they have similar regularity of response to fabric and porosity of faults. This research offers new application for seismic data and petrophysical basis for seismological estimation of fault seals. The estimate precision will be improved with the en-hancement of three-dimensional seismic prospecting work.

Limitation of fault-sealing and its control on hydrocarbon accumulation——An example from the Laoyemiao Oilfi eld of the Nanpu Sag

Based on previous studies on the internal structures of fault belts, the fault belts in the Laoyemiao Oilfield of the Nanpu Sag can be divided into three units, a crushed zone, an upper induced fracture zone and a lower induced fracture zone according to the log response characteristics. The upper induced fracture zone is characterized by the development of pervasive fractures and has a poor sealing or non-sealing capability. It therefore can act as pathways for hydrocarbon migration. The lower induced fracture zone consists of fewer fractures and has limited sealing capability. The crushed zone has a good sealing capability comparable to mudstone and can thus prevent lateral migration of fluid. Through physical modeling and comparing laboratory data with calculated data of oil column heights of traps sealed by faults, it is concluded that the fault-sealing capability for oil and gas is limited. When the oil column height reaches a threshold, oil will spill over from the top of reservoir along the lower induced fracture zone under the action of buoyancy, and the size of reservoir will remain unchanged. Analysis of the formation mechanisms of the fault-sealed reservoirs in the Nanpu Sag indicated that the charging sequence of oil and gas in the reservoir was from lower formation to upper formation, with the fault playing an important role in oil and gas accumulation. The hydrocarbon potential in reverse fault-sealed traps is much better than that in the consequent fault-sealed traps. The reverse fault-sealed traps are favorable and preferred exploration targets.

A Quantitative Study of Fault Zone Sealing

A fault is not simply a plane, but a zone consisting of a series of broken planes or lower faults. The greater the scale of faults, the wider and more complex the fault zone is. Fault-sealing properties are influenced by the fault zone itself, whose fault displacement, depth, net-to-gross-ratio of mudstone, fault plane angle, and fault mechanical properties play important controlling roles. The sealing of hydrocarbon by the fault zone depends on whether the fault zone can form a continuous sealing zone and if the pore throats connecting those fault zones are small enough. The concept of fault zone-sealing potential is proposed here, and a quantitative formula is established by using a great amount of practical statistical data as well as the fuzzy comprehensive evaluation method, which is a comprehensive characterization parameter to judge whether or not fault zones could seal oil hydrocarbon. The greater the value of the fault zone-sealing potential, the better sealed the fault is. For example, with increasing depth, the sealing degree of the Xin 68 Fault in the Dongxin 1 oilfield changes greatly, reflecting the complexity of fault-sealing properties.

Quantitative evaluation of lateral sealing of extensional fault by an integral mathematical-geological model

To evaluate the lateral sealing mechanism of extensional fault based on the pressure difference between fault and reservoir, an integral mathematical-geological model of diagenetic time on diagenetic pressure considering the influence of diagenetic time on the diagenetic pressure and diagenetic degree of fault rock has been established to quantitatively calculate the lateral sealing ability of extensional fault. By calculating the time integral of the vertical stress and horizontal in-situ stress on the fault rock and surrounding rock, the burial depth of the surrounding rock with the same clay content and diagenesis degree as the target fault rock was worked out. In combination with the statistical correlation of clay content, burial depth and displacement pressure of rock in the study area, the displacement pressure of target fault rock was calculated quantitatively. The calculated displacement pressure was compared with that of the target reservoir to quantitatively evaluate lateral sealing state and ability of the extensional fault. The method presented in this work was used to evaluate the sealing of F_(1), F_(2) and F_(3) faults in No.1 structure of Nanpu Sag, and the results were compared with those from fault-reservoir displacement pressure differential methods without considering the diagenetic time and simple considering the diagenetic time. It is found that the results calculated by the integral mathematical-geological model are the closest to the actual underground situation, the errors between the hydrocarbon column height predicted by this method and the actual column height were 0–8 m only, proving that this model is more feasible and credible.

断裂封闭性研究现状及发展趋势

断裂控油气作用主要表现在其对油气运移、聚集过程及分布规律的影响,其实质是断裂封闭性问题。断裂封闭性往往是受多种因素控制的,不同地区不同层系在不同地质时期的断裂封闭机制与封闭性主控因素差异较大。目前,断裂封闭性、封闭机理与评价方法还没有形成完整的研究体系,其评价的精度也有待提高。依据全面系统地调研断裂封闭性方面近年来的研究热点,归纳总结了断裂封闭机理,分析了断裂封闭主控因素,梳理了断裂封闭性评价方法,讨论了断裂封闭性研究中面临的实际问题,并提出了未来研究发展趋势。目前,断裂的封闭机理可以分为垂向和侧向封闭机理,前者包括断裂面封闭机理和断裂带排替压力差封闭机理,后者包括砂泥对接封闭机理、泥岩涂抹形成的侧向封闭机理和断裂带高排替压力封闭机理。断裂发育特征、断裂两盘岩性、应力场环境以及压实、胶结、溶蚀等成岩作用是影响断裂封闭性的主要因素,不同因素对断裂封闭性的作用方式不同,断裂在不同位置、不同时期的封闭性有着明显的差别。断裂封闭性评价研究方法可归结为以下4类:(1)传统地质学方法,包括定性分析和半定量分析;(2)数学地质方法,涵盖逻辑信息法、非线性映射分析法、模糊综合评判法、灰色关联分析法等;(3)构造应力场数值模拟及断裂封闭性相关参数计算法;(4)地球化学方法。碳酸盐岩地层断裂启闭机制与封闭性评价、应力和流体及其耦合作用对断裂封闭性的影响机制、多因素的断裂封闭性综合定量评价、断裂封闭性的时空演化及通源能力评估等是未来断裂封闭性研究的发展方向。

加权断层泥比率法(WSGR)定量判别断层封闭性——以苏北盆地高邮凹陷永安地区为例

断层封闭性评价是断块圈闭成藏条件分析的重要内容,在改进断层泥比率法基础上,提出了一种新的断层封闭性评价方法——加权断层泥比率法(WSGR)。首先,通过不同的地质模型开展断层泥比率法计算参数及影响因素分析,明确了断层断距、泥质含量及泥岩分布特征是泥岩涂抹的重要影响因素;并认为断层断距范围内,滑过目标位置的对置盘所有泥质含量都具有涂抹贡献,但不同点的涂抹贡献不同,距离目标位置越近泥质含量越高的对置盘泥岩点,其涂抹贡献越大。为此引入了一个新的表征参数——距离系数,定义为断层断距与各泥岩点到目标位置距离的差与断层断距的比值,来表征泥岩分布对泥岩涂抹的影响作用;在此基础上,构建了加权断层泥比率计算方法,定义为各点的泥质含量与距离系数的乘积之和再与距离系数之和的比值。利用加权断层泥比率法对苏北盆地高邮凹陷上含油气系统已知的油水层进行封闭性验证,认为当加权断层泥比率值大于0.6时,断层具有较好的封闭性,从而确定了该方法的封闭性判别标准。在高邮凹陷永安等地区始新统戴南组断层封闭性评价中取得了较好应用效果。

冀中坳陷文安斜坡顺向及反向断层侧向封闭性差异分析

为揭示含油气盆地中断层对油气成藏与分布的控制作用,以冀中坳陷文安斜坡为研究靶区,从顺向及反向断层控制油气富集部位及规模的差异出发,综合滑入断裂带内围岩成分及断裂带内部结构的不对称性等特征,分析不同配置类型断层的泥质含量与风险断距的差异及其对侧向封闭性的控制作用。研究结果表明:(1)在地层沉积环境相近的情况下,断层断距小于单层砂泥岩厚度和断层断距为单层砂泥岩层厚度的奇数倍时,反向断层目的点的泥质成分明显高于顺向断层;断层断距为单层砂泥岩层厚度的偶数倍时,反向断层目的点的泥质成分与顺向断层相等;在文安斜坡沙一段内反向断层的断层岩泥质含量平均值较顺向断层高6%。(2)为封闭较厚的上盘破碎带,顺向断层形成封闭时所需的临界断距明显大于反向断层,文安斜坡顺向断层风险断距的平均值约为反向断层的1.8倍。(3)理论与实例分析共同证实,反向断层更容易形成侧向封闭,这与油气主要富集在反向断层附近相吻合,但在文安斜坡内断层断距约为单层砂泥岩层厚度的偶数倍,断层岩泥质含量近似相等。这可能是导致文安斜坡顺、反向断层封闭烃柱高度近于一致的主要原因。上述结论可为油气田勘探开发提供有利的指导。

Features of the fault system and its relationship with migration and accumulation of hydrocarbon in Liaodong Bay

The fault system of Liaodong Bay developed extensively under the control of the Tanlu Fault. The fault system can be grouped into strike-slip faults of grade Ⅰ, trunk faults of grade Ⅱand branch faults （induced faults） of grade Ⅲ respectively based on its developmental scale. The faults of grade Ⅰ and Ⅱwere deep, early and large while the faults of grade Ⅲwere shallow, late and small. The formation, evolution and distribution features played a significant role in controlling the migration of oil and gas in both horizontal and vertical directions. The fluid transfer in the fault system occurred in the process of faulting. The strike-slip and trunk faults moved actively forming predominant pathways for oil and gas migration. The branch faults, with weak activity, generally controlled the development of traps and were beneficial for the accumulation and preservation of oil and gas. The faults of grade Ⅰ and Ⅱ formed the major migration pathways for oil and gas, but their fault activity rates appeared to vary along their strikes. The zones with a relatively low fault activity rate might be favorable for oil and gas accumulation. When the activities of strike-slip, trunk, and branch faults came to a halt, the fault seal behavior had a vitally important effect on the accumulation of oil and gas. The controlling role of the fault over fluid distribution was further analyzed by calculating the fault activity quantitatively.

复杂断块油藏滚动增储关键技术

PL油田为大型复杂断块油田,主要含油层位为新近系明化镇组和馆陶组,储层受浅水辫状河三角洲、曲流河沉积控制。该油田经过20年的开发,已进入双高阶段,寻找优质接替储量,保证稳产上产成为油田开发的主要矛盾。开发实践证明,油田边部断块油底之下潜力受制于控藏断层的封闭能力;开发老区潜力分布在隐性断层控制的正向微构造单元,受断层开启性和隐性断层双重因素控制.

基于断层岩压实成岩程度指数的断裂侧向封闭时空分布预测方法及其应用

为了研究含油气盆地受断裂控制圈闭中油气分布规律,在断裂侧向封闭机理及与断层岩压实成岩程度之间关系研究的基础上,通过断层岩压实成岩程度指数空间分布和断裂侧向封闭所需的最小断层岩压实成岩程度指数,确定断裂侧向封闭空间的分布;通过不同地质时期断层岩古压实成岩程度指数恢复和断裂侧向封闭所需的最小断层岩压实成岩程度指数,确定断裂侧向封闭时间的分布;二者结合建立了一套基于断层岩压实成岩程度指数的断裂侧向封闭时空分布预测方法,并利用其预测渤海湾盆地歧口凹陷大张坨断裂在沙河街组一段(沙一段)下亚段内断裂侧向封闭的时空分布。结果表明:除了西部端部外,大张坨断裂其余部位在沙一段下亚段内的皆为封闭部位;从距今1.17 Ma至现今,大张坨断裂在沙一段下亚段内皆处于封闭状态,较有利于下伏沙河街组三段(沙三段)源岩生成油气在大张坨断裂处沙一段下亚段内聚集与保存;与已知大张坨断裂处沙一段下亚段的油气富集规律相吻合。研究成果证实了该方法用于断裂侧向封闭时空分布预测是可行的。

飞机调温活门卡滞故障分析及改进措施

调温活门是飞机加温系统中的重要部件,能控制加温气体流量,进而实现座舱温度调节。调温活门故障会直接导致飞机加温系统功能失效,影响乘客体验,还制约了飞机通勤频率。根据调温活门的结构形式以及工作原理,并从密封形式、零件材料、转轴尺寸等方面分析故障产生的原因,并提出了改进措施,有效地消除了故障,并确保系统功能正常,可为其他类似问题的分析和解决提供参考。

游梁式抽油机的常见故障及解决措施

通过分析游梁式抽油机的基本原理以及其在石油工业中的重要性,探讨了常见故障对游梁式抽油机性能和经济性的影响。研究发现,液压系统故障、密封装置失效和游梁磨损是影响抽油机正常工作的主要故障。这些故障会导致抽油机的抽吸能力和工作效率下降,增加能源消耗和维修成本。为此,本研究旨在通过深入研究游梁式抽油机的原理、故障及其影响,提出相应的改进措施和维护策略,以改善抽油机的性能和经济性。本研究的意义在于提高石油工业的生产效益和经济效益,增强我国石油工业的技术水平和竞争力。

基于四维动态地质力学的碳酸盐岩储气库承压能力分析

盖层动态密封性和断层动态密封性是储气库的主要评价指标,对储气库的安全运行具有重要意义。针对储气库盖层与断层静态评价体系的不足,以国内华北地区某碳酸盐岩型储气库为背景,结合测井资料开展岩石力学实验,建立岩石力学动静态参数转换模型和储气库四维地质力学模型,反演地质体初始应力场,开展储气库地质体承压能力分析,获得储气库在注采条件下的四维动态应力场信息(三维应力场在时间维度下的信息)。四维地质力学计算结果表明,当前上限压力(47 MPa)下盖层及断层破坏风险较低,当储气库上限压力提高到49 MPa时,盖层及断层仍然没有发生破坏,结合地面压缩机运行能力,确定储气库上限运行压力为49 MPa。四维动态应力场的建立为储气库的提压扩容提供了科学理论依据。

渤中8-4油田“S”型走滑转换带特征及其对浅层油气侧封的控制作用

新构造运动在渤海海域表现强烈,形成了渤中凹陷特有的走滑构造体系和浅层油气藏。前人研究集中在走滑运动论证和走滑转换带类型探讨上,缺乏对走滑构造带控藏作用的精细研究。利用地震资料,结合油田实例,探讨了渤中8-4油田走滑转换带特征和对油气侧封的控制作用。研究认为,渤中8-4油田主断裂为“S”型走滑转换带,发育释压带和增压带两类转换带。释压带地层陡,圈闭不发育,是油气由深向浅的充注段;增压带地层缓,背形特征清晰,低幅断鼻、断块圈闭集中发育,为油气汇聚区。建立了走滑断裂封闭指数以定量表征走滑转换带的侧封能力,通过近20个油田的统计分析,认为可以把走滑断裂封闭指数4作为走滑断层侧封的临界值。该成果为富砂背景下的浅层油气勘探工作提供了一种新的方法和思路。

催化裂化装置富气压缩机干气密封优化改造

陕西延长石油(集团)延安炼油厂100万t/a催化裂化装置富气压缩机所采用的串联式干气密封系统在运行过程中故障率高,不能适应设备运行要求,通过将串联式改造为双端面式型干气密封,提高干气密封效果,提高了设备运行可靠率。

离心机在氟化锂生产中的应用及故障分析处理

离心机关键零部件可以概括如下:机座、主机、转鼓、翻盖、主轴、刮刀、料层控制器、电机传动系统、液压控制系统、电控系统等;离心机主要用于反应后液体物料中含固体颗粒介质的洗涤、两相分离的设备,在氟化锂生产中主要用于脱碳工序后产生的碳酸锂料浆的过滤分离、洗涤作用。其目前广泛运用于制药、精细化工、食品和化工等行业。根据高纯氟化锂生产中离心机的应用实践,对离心机常见设备故障进行举例说明并对其易产生故障处理做以简要浅析。

船用机械密封常见故障形式及预防措施研究

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