Fracture network types revealed by well test curves for shale reservoirs in the Sichuan Basin,China

Pressure buildup testing can be used to analyze fracture network characteristics and conduct quantitative interpretation of relevant parameters for shale gas wells,thus providing bases for assessing the well productivity and formulating proper development strategies.This study establishes a new well test interpretation model for fractured horizontal wells based on seepage mechanisms of shale reservoirs and proposes a method for identifying fracturing patterns based on the characteristic slopes of pressure buildup curves and curve combination patterns.The pressure buildup curve patterns are identified to represent three types of shale reservoirs in the Sichuan Basin,namely the moderately deep shale reservoirs with high pressure,deep shale reservoirs with ultra-high pressure,and moderately deep shale reservoirs with normal pressure.Based on this,the relationship between the typical pressure buildup curve patterns and the fracture network types are put forward.Fracturing effects of three types of shale gas reservoir are compared and analyzed.The results show that typical flow patterns of shale reservoirs include bilinear flow in primary and secondary fractures,linear flow in secondary fractures,bilinear flow in secondary fractures and matrix,and linear flow in matrix.The fracture network characteristics can be determined using the characteristic slopes of pressure buildup curves and curve combinations.The linear flow in early secondary fractures is increasingly distinct with an increase in primary fracture conductivity.Moreover,the bilinear flow in secondary fractures and matrix and the subsequent linear flow in the matrix occur as the propping and density of secondary fractures increase.The increase in the burial depth,in-situ stress,and stress difference corresponds to a decrease in the propping of primary fractures that expand along different directions in the shale gas wells in the Sichuan Basin.Four pressure buildup curve patterns exist in the Sichuan Basin and its periphery.The pattern of pressure buildup curves of shale reservoirs in the Yongchuan area can be described as 1/2/→1/4,indicating limited stimulated reservoir volume,poorly propped secondary fractures,and the forming of primary fractures that extend only to certain directions.The pressure buildup curves of shale reservoirs in the main block of the Fuling area show a pattern of 1/4/→1/2 or 1/2,indicating greater stimulated reservoir volume,well propped secondary fractures,and the forming of complex fracture networks.The pattern of pressure buildup curves of shale reservoirs in the Pingqiao area is 1/2/→1/4→/1/2,indicating a fracturing effect somewhere between that of the Fuling and Yongchuan areas.For reservoirs with normal pressure,it is difficult to determine fracture network characteristics from pressure buildup curves due to insufficient formation energy and limited liquid drainage.

Application of laser scanning for rock mass characterization and discrete fracture network generation in an underground limestone mine

Terrestrial laser scanning(TLS) is a useful technology for rock mass characterization. A laser scanner produces a massive point cloud of a scanned area, such as an exposed rock surface in an underground tunnel,with millimeter precision. The density of the point cloud depends on several parameters from both the TLS operational conditions and the specifications of the project, such as the resolution and the quality of the laser scan, the section of the tunnel, the distance between scanning stations, and the purpose of the scans. One purpose of the scan can be to characterize the rock mass and statistically analyze the discontinuities that compose it for further discontinuous modeling. In these instances, additional data processing and a detailed analysis should be performed on the point cloud to extract the parameters to define a discrete fracture network(DFN) for each discontinuity set. I-site studio is a point cloud processing software that allows users to edit and process laser scans. This software contains a set of geotechnical analysis tools that assist engineers during the structural mapping process, allowing for greater and more representative data regarding the structural information of the rock mass, which may be used for generating DFNs. This paper presents the procedures used during a laser scan for characterizing discontinuities in an underground limestone mine and the results of the scan as applied to the generation of DFNs for further discontinuous modeling.

Characterization and formation mechanisms of fractures and their significance to hydrocarbon accumulation: A case study of Lower Ordovician mid-assemblage Formations in central Ordos Basin, China

The lower Ordovician mid-assemblage Formations in the central Ordos Basin of China host prolific gas resources,and most hydrocarbon reserves are stored in naturally-fractured reservoirs.Thus,fracture pathway systems may have a significant impact on reservoir performance.This article focuses on the core-and laboratory-based characterization of fractures.Through the developmental degrees,extended scale,output state and filling characteristics of various types of fractures,the results show that there are three distinct fracture types:1)nearly vertical fractures,2)oblique fractures,and 3)horizontal fractures.Based on a systematic study of the characterization of reservoir space,the main geologic setting of natural gas accumulation and the regional tectonic background,type 1 is mainly driven by the tectonic formation mechanism,and type 3 and parts of low-angle fractures in type 2 are induced by the diagenetic formation mechanism.While recovered paleopressure for methane-rich aqueous inclusions trapped in fracture-filling cement indicates that the fracture opening and growth are consistent with gas maturation and charge and such high-angle fractures in type 2 are caused by the compound formation mechanism.The fractures to hydrocarbon accumulation may play a more significant role in improving the quality of reservoir porosity.Furthermore,connected fractures,dissolved pores and cavities together constitute the three-dimensional pore-cave-fracture network pathway systems,with faults serving as the dominant charge pathways of highly pressurized gas in the study area.Our results demonstrate that protracted growth of a pervasive fracture system is not only the consequence of various formation mechanisms but also intrinsic to quasi-continuous accumulation reservoirs.

A novel production data analysis method for multi-fractured horizontal wells with infill well-caused fracture interference

Tightening the well spacing for unconventional tight reservoirs is an efficient technique to enhance oil and gas recoveries.Infill well-caused fracture connection between wells is widely reported in the field with small well spacing.This will make it difficult to make formation evaluation and fracture characterization between wells compared to single well cases.In this paper,a novel production data analysis(PDA)method is proposed for fracture characterization with the consideration of interwell fracture connections after the hydraulic fracturing of the infill.The PDA method is based on a semianalytical model,in which the small-scaled fractures are treated with the concept of stimulated reservoir volume(SRV).Thus,the fracture connections between wells are classified into three types,including SRV,fractures,and both SRV and fractures.The physical model is discretized into several linear flow regions,so the mathematical model can be solved semianalytically.An integrated workflow is proposed to analyze the production data for the wellpad,and three steps are mainly included in the workflow,including PDA for the parent well before infill,PDA for the parent well after infill,and PDA for the infill well.In each step,the production performance in the early linear and bilinear flow regimes are analyzed with approximate solutions in the square and fourth root-of-time plots.Because only the relationship between unknown model parameters can be obtained with the approximate solutions,history matching to the production data in log-log plots is further used to determine each unknown parameter.The PDA method is benchmarked with a synthetic case generated by the numerical simulator tNavigator and a field case from Southwestern China.The results show that both good matches and precise parameters can be obtained with the proposed PDA method.The connected fracture number will not be sensitive in PDA when the wells are connected with high-conductive dSRV.The innovation of this paper is that a practical method is provided for PDA analysis of well groups with fracture connection,and it will be a good technique for fracture characterization and well-interference analysis for tight formations.

Surface characteristics analysis of fractures induced by supercritical CO_(2)and water through three-dimensional scanning and scanning electron micrography

Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyzed the fracture surface characteristics induced by supercritical carbon dioxide(SC-CO_(2))and water in open-hole and perforation completion conditions under triaxial stresses.A simple calculation method was proposed to quantitatively analyze the fracture surface area and roughness in macro-level based on three-dimensional(3D)scanning data.In micro-level,scanning electron micrograph(SEM)was used to analyze the features of fracture surface.The results showed that the surface area of the induced fracture increases with perforation angle for both SC-CO_(2)and water fracturing,and the surface area of SC-CO_(2)-induced fracture is 6.49%e58.57%larger than that of water-induced fracture.The fractal dimension and surface roughness of water-induced fractures increase with the increase in perforation angle,while those of SC-CO_(2)-induced fractures decrease with the increasing perforation angle.A considerable number of microcracks and particle peeling pits can be observed on SC-CO_(2)-induced fracture surface while there are more flat particle surfaces in water-induced fracture surface through SEM images,indicating that fractures tend to propagate along the boundary of the particle for SC-CO_(2)fracturing while water-induced fractures prefer to cut through particles.These findings are of great significance for analyzing fracture mechanism and evaluating fracturing stimulation performance.

The Production and Fracture Characteristrics of Particles in Radial Sliding Bearing

Based on the running characteristics,the experimental results show that wear particles appear on the normal running stage.The fractural characteristics of wear particles were investigated, it is found there exists a relation between the wear characters and bear conditions.

New insight into fracturing characterization of shale under cyclic soft stimulation:A lab-scale investigation

The cyclic soft stimulation(CSS)is a new method of reservoir reforming for which the mechanism of fracturing crack propagation is ambiguous with regard to the alternating fluid pressure.This study aims to provide a comprehensive understanding of the fracturing mechanical characterizations of CSS under different magnitudes and amplitudes of the alternating fluid pressure.Acoustic emission(AE)is recorded to investigate the damage evolution under CSS based on the b value analysis of AE.Experimental results reveal the difference of pressure in a crack under different cyclic fluid pressure conditions.The AE results show that the maximum radiated energy under CSS tends to be reduced with the increase in the amplitude and magnitude of the alternating fluid pressure.The finishing crucial touch is that the crack extending criterion under CSS is proposed,which combines the injection parameters,the rock properties and in-situ stress.According to the crack extending criterion,the fluctuation fluid pressure causes the reduction of a critical crack extending pressure,and the CSS causes the crack to initiate and propagate under low fluid pressure.Under a higher-value magnitude of alternating fluid pressure,the cyclic times of CSS is less for the crack initiation.In supplement to the crack extending criterion,a distinct relationship between the radiated energy and the cyclic fluid pressure also is established based on the energy dissipation criterion.These new findings provide an insight into the determination of crack extending criterion under CSS for efficiently implementing shale fracturing.

The application study on the multi-scales integrated prediction method to fractured reservoir description

In this paper,we implement three scales of fracture integrated prediction study by classifying it to macro-（ 1/4/λ）,meso-（ 1/100λ and 1/4λ） and micro-（ 1/100λ） scales.Based on the multi-scales rock physics modelling technique,the seismic azimuthal anisotropy characteristic is analyzed for distinguishing the fractures of meso-scale.Furthermore,by integrating geological core fracture description,image well-logging fracture interpretation,seismic attributes macro-scale fracture prediction and core slice micro-scale fracture characterization,an comprehensive multi-scale fracture prediction methodology and technique workflow are proposed by using geology,well-logging and seismic multi-attributes.Firstly,utilizing the geology core slice observation（Fractures description） and image well-logging data interpretation results,the main governing factors of fracture development are obtained,and then the control factors of the development of regional macro-scale fractures are carried out via modelling of the tectonic stress field.For the meso-scale fracture description,the poststack geometric attributes are used to describe the macro-scale fracture as well,the prestack attenuation seismic attribute is used to predict the meso-scale fracture.Finally,by combining lithological statistic inversion with superposed results of faults,the relationship of the meso-scale fractures,lithology and faults can be reasonably interpreted and the cause of meso-scale fractures can be verified.The micro-scale fracture description is mainly implemented by using the electron microscope scanning of cores.Therefore,the development of fractures in reservoirs is assessed by valuating three classes of fracture prediction results.An integrated fracture prediction application to a real field in Sichuan basin,where limestone reservoir fractures developed,is implemented.The application results in the study area indicates that the proposed multi-scales integrated fracture prediction method and the technique procedureare able to deal with the strong heterogeneity and multi-scales problems in fracture prediction.Moreover,the multi-scale fracture prediction technique integrated with geology,well-logging and seismic multi-information can help improve the reservoir characterization and sweet-spots prediction for the fractured hydrocarbon reservoirs.

Dynamic behavior and fracture mode of TiAl intermetallics with different microstructures at elevated temperatures

Experimental studies were conducted on the tensile behaviors and fracture modes of TiAl（Ti-46.5Al-2Nb-2Cr） alloys with near gamma（NG） equiaxed and near lamellar（NL） microstructures over a temperature range from room temperature to 840 ℃ and a strain rate range of 0.001-1 350 s-1.The results indicate that the alloys are both temperature and strain rate dependent and they have a similar dependence.The dynamic strength is higher than the quasi-static strength but almost insensitive to high strain rate range of 320-1 350 s-1.The brittle-to-ductile transition temperature（BDTT） increases with increasing strain rates.NG TiAl yields obviously,while NL TiAl does not.Below BDTT,as the temperature increases,the fracture modes of the two alloys change from planar cleavage fracture to a mixture of transgranular and intergranular fractures,and finally to totally intergranular fracture.

Integrated petrophysical log characterization for tight carbonate reservoir effectiveness: A case study from the Longgang area, Sichuan Basin, China

Ultra-low porosity and permeability, inhomogeneous fracture distribution, and complex storage space together make the effectiveness evaluation of tight carbonate reservoirs difficult. Aiming at the carbonate reservoirs of the Da＇anzhai Formation in the Longgang area of the Sichuan Basin, based on petrophysical experiments and logging response characteristics, we investigated the storage properties of matrix pores and the characteristics of fracture development to establish a method for the characterization of effectiveness of tight reservoirs. Mercury injection and nuclear magnetic resonance （NMR） experiments show that the conventional relationship between porosity and permeability cannot fully reflect the fluid flow behavior in tight matrix pores. Under reservoir conditions, the tight reservoirs still possess certain storage space and permeability, which are controlled by the characteristic structures of the matrix porosity. The degree of fracture development is crucial to the productivity and quality of tight reservoirs. By combining the fracture development similarity of the same type of reservoirs and the fracture development heterogeneity in the same block, a three-level classification method of fracture development was established on the basis of fracture porosity distribution and its cumulative features. According to the actual production data, based on the effectiveness analysis of the matrix pores and fast inversion of fracture parameters from dual laterolog data, we divided the effective reservoirs into three classes： Class I with developed fractures and pores, and high-intermediate productivity; Class II with moderately developed fractures and pores or of fractured type, and intermediate-low productivity; Class III with poorly developed fractures and matrix pores, and extremely low productivity. Accordingly log classification standards were set up. Production data shows that the classification of effective reservoirs is highly consistent with the reservoir productivity level, providing a new approach for the effectiveness evaluation of tight reservoirs.

Performance-based fractal fracture model for complex fracture network simulation

The paper presents a novel hydraulic fracturing model for the characterization and simulation of the complex fracture network in shale gas reservoirs. We go beyond the existing method that uses planar or orthogonal conjugate fractures for representing the ＇＇complexity＇＇ of the network. Bifurcation of fractures is performed utilizing the Lindenmayer system based on fractal geometry to describe the fracture propagation pattern, density and network connectivity. Four controlling parameters are proposed to describe the details of complex fractures and stimulated reservoir volume（SRV）. The results show that due to the multilevel feature of fractal fractures, the model could provide a simple method for contributing reservoir volume calibration. The primary-and second-stage fracture networks across the overall SRV are the main contributions to the production, while the induced fracture network just contributes another 20% in the late producing period. We also conduct simulation with respect to different refracturing cases and find that increasing the complexity of the fracture network provides better performance than only enhancing the fracture conductivity.

Dynamic fluid transport property of hydraulic fractures and its evaluation using acoustic logging

The existing acoustic logging methods for evaluating the hydraulic fracturing effectiveness usually use the fracture density to evaluate the fracture volume, and the results often cannot accurately reflect the actual productivity. This paper studies the dynamic fluid flow through hydraulic fractures and its effect on borehole acoustic waves. Firstly, based on the fractal characteristics of fractures observed in hydraulic fracturing experiments, a permeability model of complex fracture network is established. Combining the dynamic fluid flow response of the model with the Biot-Rosenbaum theory that describes the acoustic wave propagation in permeable formations, the influence of hydraulic fractures on the velocity dispersion of borehole Stoneley-wave is then calculated and analyzed, whereby a novel hydraulic fracture fluid transport property evaluation method is proposed. The results show that the Stoneley-wave velocity dispersion characteristics caused by complex fractures can be equivalent to those of the plane fracture model, provided that the average permeability of the complex fracture model is equal to the permeability of the plane fracture. In addition, for fractures under high-permeability(fracture width 10~100 μm, permeability ~100 μm^(2)) and reduced permeability(1~10 μm, ~10 μm^(2), as in fracture closure) conditions, the Stoneley-wave velocity dispersion characteristics are significantly different. The field application shows that this fluid transport property evaluation method is practical to assess the permeability and the connectivity of hydraulic fractures.

基于计算机视觉的岩石裂隙识别表征与软件研制

岩石裂隙特征是评判岩体结构及其完整性的核心指标,也是评估岩石工程安全稳定性的重要因素。针对岩石裂隙识别,采用深度学习方法,通过引入混合注意力机制对Unet模型进行了改进,有效提高了岩石裂隙识别的精度。针对交叉岩石裂隙的分离与特征提取,提出了一种基于迹线方向判定的裂隙分离与表征算法,依据裂隙分离的结果形式,采用重合追踪法或断裂追踪法分离交叉裂隙骨架,继而使用微分累加法、方框法、线性回归法求得裂隙的长度、宽度及倾角等几何特征指标。基于提出的算法,研制了一套具有图形用户界面的岩石裂隙图像智能识别与表征软件系统,实现了从深度学习模型参数选择、模型训练、裂隙识别、量化分析到结果可视化的完整功能。最后对岩石裂隙识别与分离表征算法的性能进行了评判,结果表明,改进Unet模型对复杂分布的裂隙识别效果最好,其总体识别性能要优于其他网络;骨架分离算法对常见类型交叉裂隙能够取得预期结果,表征算法对分离裂隙与交叉裂隙的表征精度高,对实际岩石裂隙图像的应用效果较好。研究成果可为基于计算机视觉的岩石工程试验与岩体结构检测技术研发提供参考依据。

深部煤储层孔裂隙结构对煤层气赋存的影响-以鄂尔多斯盆地东缘大宁-吉县区块为例

深部煤储层孔隙–裂缝结构对深部煤层气资源潜力评价和勘探开发具有重要意义。选取鄂尔多斯盆地东缘大宁–吉县区块DJ57井本溪组5个煤岩样品为研究对象,在煤岩煤质参数测试的基础上,采用气体吸附法、高压压汞法和微米CT扫描等测试手段,对深部煤储层中的纳米级孔隙-微米级裂缝进行多尺度定量表征,综合评价不同尺度的孔裂隙结构特征。再结合渗透率和甲烷等温吸附试验,探讨了微观孔裂隙对深部煤储层中煤层气的赋存和渗流的影响。研究结果表明:基于多种孔隙表征方法对深部煤储层孔裂隙进行多尺度定量表征,其孔裂隙体积分布类型主要以“U”型为主,呈现出微孔与微裂缝并存双峰态,主要集中在0.3~1.5 nm和>100μm的范围内。其中,微孔(<2 nm)、介孔(2~50 nm)、宏孔(50 nm~10μm)和微裂缝(>10μm)体积平均分别占总孔裂隙体积的80.18%,6.70%,1.65%和11.47%。随着微孔发育而吸附气量呈增大的趋势,微孔可以提供大量吸附点位,为深部煤层气的吸附和赋存提供场所。随着微裂缝发育而游离气量呈增大的趋势,微裂缝可以提供大量储集空间,为深部煤层气的富集提供空间条件。此外,微裂缝在三维空间中相互连通,形成网状结构,连通性强。随着微裂缝越发育,煤储层渗透率越大,微裂缝增强了煤层气的渗流能力。纳米级孔隙和微米级裂隙发育特征分别控制着深部煤层气吸附能力和开发潜力。

超深断控碳酸盐岩油藏空间结构表征技术与工程实践

在积极推进深地工程的背景下,超深断控缝洞型碳酸盐岩成为油气勘探开发的重点领域,而超深走滑断裂精准解译、缝洞体内部构型建模、断控油气藏储量雕刻评估、高效井位部署及提高采收率等是制约超深领域“增储上产”的重要科学问题与技术挑战。本文基于区域应力场研究、露头剖析、三维地震解译、物模数模,全面构建了涵盖动力学、运动学、几何学,分期、分级、分性质、分带、分层的“三学五分”断裂构造解析技术,据此阐明了走滑断裂纵向分层、横向差异分段特征,揭示了走滑断裂控储、控藏、控油气富集等地质规律,发现了超深断控缝洞型10亿吨级大油田。依据动/静态资料,精细刻画了断控缝洞体内部构型,通过“井震”结合实现了断控缝洞型油气藏量化表征,形成了相应的高效井位部署、油气储量雕刻评估等技术系列,支撑了富满油田10亿吨级油气储量的发现与落实。依据断控油气藏的定量刻画结果,针对性提出了提高采收率技术对策,推动了富满5×106t大油田的高效建设,形成了超深断控碳酸盐岩“增储上产”范例,可为我国类似油气藏的开发“上产”提供借鉴。

缝洞型碳酸盐岩油藏流体流动表征方法探讨

塔里木盆地缝洞型碳酸盐岩油藏储集空间尺度差异大、流动复杂,很多学者认为渗流理论不能解决其流动表征问题,应该用管流理论解决。为厘清这一问题,从管流与渗流的概念、单相流流动特征及数学表征方法、油水两相流流动特征及数学表征方法3方面,研究了管流与渗流的关系,在此基础上,分析了管流方程描述缝洞型碳酸盐岩油藏流体流动的可行性,并对缝洞型碳酸盐岩油藏流体流动的表征方法进行了探讨。结果表明,从研究的角度,渗流可视为小尺度复杂管道管流;单相流时,管流存在层流、紊流两种流态,渗流也存在层流、紊流两种流态,层流状态,描述管流与渗流的方程是统一的,紊流状态,二者的描述方程不一致,但都是考虑惯性力的影响;两相流时,管流存在多种流型,渗流因尺度小、流型简单,管流基于流型建立了不同的流动表征模型,渗流利用相渗曲线解决两相流问题。说明,管流与渗流并不“冲突”,渗流即是小尺度复杂管道管流,只是由于学科不同、研究对象不同,对流体流动采用了不同的表征方法。缝洞型碳酸盐岩油藏描述不确定大,受油藏描述精度和研究范围的制约,现有管流的处理方法并不适用描述缝洞型碳酸盐岩油藏流体的流动。缝洞型碳酸盐岩油藏的流体流动表征问题应该在渗流力学的架构内,部分借鉴管流的处理方法来解决。

页岩储层构造裂缝活动期次及开启性研究进展与展望

随着我国在非常规油气领域的研究不断深入和技术手段不断提高,页岩油气勘探开发工作取得了显著进展。大量生产实践结果表明:页岩储层裂缝是影响油气富集、高产和稳产的关键因素,页岩储层中裂缝的存在不仅可以改善储层的物性,还有利于后期的压裂改造。特别是储层中发育的构造裂缝,其活动期次与开启性的研究对于揭示页岩油气富集规律、保存条件等具有重要意义。早期对于页岩储层裂缝的研究集中在裂缝分类、识别与表征、裂缝发育主控因素分析与分布预测及建模等方面,而对于裂缝的形成时间与活动期次厘定、裂缝开启性的主控因素、裂缝开启与闭合机理、裂缝开启程度定量表征研究相对薄弱,制约了我国盆内页岩油气的高效勘探开发。为此本文在充分调研了国内外页岩储层构造裂缝研究成果的基础上,围绕页岩储层构造裂缝活动期次及开启性这一主题,重点梳理了页岩裂缝期次划分、充填脉体定年、开启性主控因素分析及开启程度定量表征方面的研究进展。裂缝活动期次的划分方法可分为两类:地质定性分析和裂缝充填物地球化学示踪分析。在实际应用中,上述方法只能得到裂缝活动期次相对的先后顺序,且会受到埋藏史、热史等基础地质资料精度的影响,其应用存在一定局限性。裂缝中脉体多为碳酸盐岩矿物和石英,高精度微区原位U-Pb定年技术的出现,使得厘定不同组系裂缝脉体形成的绝对年龄成为可能,避免了由于热史、埋藏史认识差异带来的流体活动时间的多解问题。影响构造裂缝开启性的主控因素较多,不仅受到岩石本身特性的影响,还受到现今地应力、地层流体压力等因素的控制。裂缝中广泛分布的纤维状充填物岩石学特征记录了晶体的生长过程,此类特殊的晶体形态是裂缝曾经存在多期活动的证据,揭示了裂缝多次开启闭合的演化过程。目前主要应用开度这一参数来表征裂缝的开启程度,或是通过计算及实验获取裂缝开启压力间接表征其开启性。在总结并分析上述研究成果后指出了页岩储层构造裂缝活动期次及开启性研究中存在的关键问题及发展趋势,旨在丰富和完善页岩油气储层研究的理论和方法体系,为我国页岩油气的构造保存条件和富集机理研究提供重要的科学依据。

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。

150例人工髋关节置换病因学特征分析

目的探讨人工髋关节置换的病因学特征,为人工髋关节置换防治提供依据。方法回顾性分析150例人工髋关节置换患者的相关住院资料,采用秩和检验、卡方检验对不同年龄、病因、相关基础疾病等数据进行统计学分析。结果150例患者中,多数为年龄65岁以上的老年患者,女性平均年龄显著高于男性(P<0.05);本研究中,女性患者所占比例虽高于男性,但差异无显著性;在性别分组中,手术侧别和骨折类别具有统计学意义,尤以股骨颈骨折为最常见的原因(P<0.05);接受髋关节置换的患者普遍伴有基础性疾病,骨质疏松和关节疾病最常见,其次为高血压、脑卒中和2型糖尿病。结论人工髋关节置换与患者年龄、骨折类别及是否存在并发症等因素密切相关。

页岩储层多尺度天然裂缝表征与三维地质建模:以四川盆地平桥构造带五峰组龙马溪组页岩为例

天然裂缝是页岩储层重要的储集空间和渗流通道,查明天然裂缝类型及其空间展布特征是页岩气勘探开发的重要基础之一。基于地震、露头、岩心观察、测井和微观测试分析等资料,重点考虑裂缝对页岩气富集高产的控制作用,将页岩储层天然裂缝分为大尺度、中小尺度和微尺度3类,明确了各尺度裂缝表征与建模方法和应用效果。(1)大尺度裂缝通过叠后地震属性表征,中小尺度裂缝以岩心、成像测井和地震属性预测相结合的方法表征,微尺度裂缝通过岩心描述、扫描电镜观测等方法表征,明确了各尺度裂缝发育密度、开度、产状和充填状况等特征。(2)大尺度裂缝通过输入叠后地震属性表征参数,采用确定性建模方法建立大尺度裂缝DFN模型;中小尺度裂缝以单井成像测井解释数据为先验信息,以多信息融合的裂缝概率体为空间约束建立裂缝密度体,采用随机模拟方法建立中小尺度裂缝DFN模型;微尺度裂缝建模以微观测试分析获取的微裂缝参数为基础,井资料与TOC等主控因素属性体结合建立微裂缝密度体,采用随机模拟方法建立微裂缝DFN模型。(3)以四川盆地平桥构造带页岩气为例,开展了页岩储层不同尺度裂缝表征与三维地质建模工作,明确了不同尺度裂缝的发育位置、规模和产状特征,刻画了不同尺度裂缝的空间位置、倾角、方位角、几何尺寸、发育密度等属性特征,形成了多尺度页岩储层天然裂缝表征与建模技术,为页岩气藏数值模拟提供了较可靠的模型依据。该方法建立的平桥构造带页岩储层三维地质模型及其模拟结果与地质认识、生产数据吻合较好,对页岩气田开发具有参考价值。