黄骅坳陷古生界潜山储层沥青成因判识

正黄骅坳陷古生界潜山是大港油田重要的油气勘探领域,近年来,先后在王官屯、乌马营潜山古生界发现油气流,且均为石炭—二叠系煤系源岩供烃成藏,如王官屯潜山王古1井二叠系石盒子组发现天然气,同位素特征判断为煤成天然气。这些发现拓展了古生界潜山的勘探领域,表明了石炭—二叠系煤系烃源岩的油气充注范围不仅仅局限于奥陶系碳酸盐岩储层,石炭—二叠系的碎屑岩储层也可以充注成藏,证实了古生界潜山具有更大的油气勘探价值。随着勘探进程与理论认识的不断深化,     

基于概率积分法的潜山型地裂缝空间预测方法研究

苏南地区锡北镇地裂缝灾害活跃,且为典型的基岩潜山型抽水沉降地裂缝。以无锡锡北镇杨墅里地裂缝为研究对象（31.703174°~31.705488°N,120.452707°~120.453410°E）,基于非连续介质理论,运用概率积分方法建立基岩潜山条件下的抽水沉降裂缝空间预测数学模型。运用该理论模型计算得出基岩潜山上覆岩土体的差异性沉降规律、地表倾斜程度及地表曲率变化规律,并指出地表倾斜程度与地表曲率为地裂缝易发位置的重要评价指标。将地裂缝空间预测数学模型计算出的沉降规律、地裂缝发生位置等结果与物理模型试验结果进行对比研究,结果显示：1）当W"（x）=0时,地表倾斜函数取得极值,此时x=±0.8 m,表明距模型左边界2.6 m与4.2 m处地表倾斜程度最大,差异性沉降最为明显。2）当W"'（x）=0时,地表曲率函数取得极值,x=0,表明在距模型左边界3.4 m处地表曲率最大,为拉应力集中位置。3）模型试验地裂缝集中发生2.4~2.6 m、3.3~3.5 m和3.9~4.2 m这3处;基于概率积分方法的潜山型地裂缝空间预测结果与物理模型试验结果基本一致。预测模型能够合理解释物理模型试验中潜山山腰及潜山山顶三处地裂缝的发生位置,验证了其正确性,为地裂缝空间预测方法提供了新的研究思路。

     

古潜山热储开发对地面沉降的影响机制研究

古潜山是中国水热型地热的主要富集区,具有分布广、潜力大、开发利用条件好等特点,同时也是中国地面沉降相对严重的地区.廓清古潜山区地面沉降的影响机制是区域地下水资源以及地热资源的合理规划与开发利用的基础.本文从地面沉降的机理出发,以雄安新区为例,从第四系厚度、黏性土含量、水位变化、土体固结性、地下水的越流补给以及地下水开采...     

Formation conditions and reservoir-forming models of the Ordovician buried hill reservoirs in the Jizhong depression

The buried hill in the Jizhong depression contains abundant petroleum reserves and are important production areas. The Ordovician buried hill has restricted the discovery of new oil and gas exploration targets because of its strong reservoir heterogeneity and complex reservoir-controlling factors. Based on a large volume of core, thin section, logging, seismic, and geochemical data and numerous geological analyses, the reservoir-forming conditions and modes were systematically analyzed to guide the exploration and achieve important breakthroughs in the Yangshuiwu and Wen’an slope buried hills. The study revealed that three sets of source rocks of the third and fourth members of the Shahejie Formation from the Paleogene and Carboniferous-Permian were developed in the Jizhong depression, providing sufficient material basis for the formation of buried hill oil and gas reservoirs. The reservoir control mechanism involving the three major factors of “cloud-karst-fault” was clarified, and karst cave, fracture fissure-pore, and cloud pore type reservoir models were established, thereby expanding the exploration potential. Controlled by the superposition of multi-stage tectonic processes during the Indosinian, Yanshanian, and Himalayan, two genetic buried hill trap types of uplift-depression and depression-uplift were formed. Based on the analysis of reservoir-forming factors of the Ordovician buried hill, three buried hill oil and gas reservoir-forming models were identified: low-level tectonic-lithologic composite quasi-layered buried hill, medium-level paleo-storage paleo-block buried hill, and high-level paleo-storage new-block buried hill. Comprehensive evaluations indicate that the reservoir-forming conditions of the low-level tectonic-lithologic composite quasi-layered buried hill in the northern portion of the Jizhong depression are the most favorable and that the Sicundian and Xinzhen buried hills are favorable areas for future exploration.     

冀中坳陷奥陶系潜山油气藏形成条件与成藏模式

冀中坳陷潜山是增储上产的重要领域,奥陶系潜山由于储层非均质性强、控藏因素复杂,因此一直制约着油气勘探的新发现。基于大量岩心、薄片、测井、地震及地球化学数据和地质分析的基础上,对其成藏条件及成藏模式进行了系统分析,指导杨税务潜山、文安斜坡潜山勘探取得重要突破。研究表明：冀中坳陷发育古近系沙三段和沙四段以及上古生界石炭—二叠系3套烃源岩,为潜山油气藏的形成提供了充足的物质基础;明确了碳酸盐岩“云化-岩溶-断裂”三主因叠合控储机理,建立了岩溶孔洞型、断裂孔缝型和云岩孔隙型3种储层模式,拓展了勘探空间;受印支期、燕山期、喜山期多期构造作用叠加控制,形成了先隆后凹型和先凹后隆型两种成因潜山圈闭类型。通过奥陶系潜山成藏要素分析,总结出3种潜山油气成藏模式：低位构造-岩性复合准层状潜山成藏模式、中位古储古堵块状潜山成藏模式和高位古储新堵块状潜山成藏模式。综合评价,目前冀中坳陷北部低位构造-岩性复合准层状潜山成藏条件最为有利,泗村店潜山和新镇潜山是下一步勘探的有利方向。     

A parallelizable method for two‐phase flows in naturally‐fractured reservoirs

A parallelizable, semi‐implicit numerical method is proposed for the study of naturally‐fractured reservoir systems. It has proved to be computationally efficient in producing accurate numerical solutions for the dual‐porosity model for immiscible, two‐phase flow in such reservoirs. The method combines hybridized mixed finite elements, a new version of the modified method of characteristics, a sophisticated operator‐splitting procedure for separating the pressure calculation in the fractures from that of the saturation, another operator splitting to handle the interaction of the matrix blocks and the fractures, and domain decomposition iterative procedures for both the pressure and the saturation. It permits moderately long time steps for the pressure and the saturation in the fractures and matrix blocks by using short, inexpensive microsteps to treat the transport portion of the saturation equation in the fractures. This paper is devoted to the formulation of the method and a discussion of numerical results for five‐spot and vertical cross‐section examples.     

海拉尔盆地贝尔凹陷基岩断层相关裂缝发育特征及模拟实验研究

海拉尔盆地基岩潜山油藏的发现拓宽了大庆油田外围油田勘探的领域,裂缝是贝尔凹陷基岩潜山油藏的主要储集空间之一。为查明潜山裂缝发育特征与分布规律,根据大量岩心观察统计资料,研究了裂缝类型、密度、宽度、充填期次等发育特征及基岩断层发育特征。研究表明,贝尔凹陷基岩发育3类断裂:即早期伸展断裂、早期伸展中期张扭长期活动断裂和早期伸展中期张扭晚期反转长期活动断裂。二者的几何学特征、距断层距离及成像测井资料均表明,裂缝主要是断裂构造活动过程中形成的,基岩断层活动的多期性造成了裂缝发育的复杂性。为验证断层对裂缝的控制作用,进行了物理模拟实验,实验结果表明,伴生裂缝主要发育于断层面两侧,距离断层面越远,裂缝密度变小,岩层厚度、断移速率、岩性变化、距断面距离等因素对裂缝发育均有一定的控制作用。     

吉华1地区潜山变质岩储层裂缝发育特征及综合评价

天然裂缝是吉华1潜山变质岩储层重要储集空间和主要的渗流通道,其发育程度影响着潜山油气运移、聚集、保存和单井产能。利用岩心、薄片以及成像测井等资料,对吉华1潜山变质岩储层裂缝的分布特征进行了定量表征,明确了影响研究区变质岩储层裂缝发育的主控因素,最后运用多信息融合和数值模拟等方法对裂缝的分布进行了综合评价。吉华1潜山变质岩储层主要发育以中-高角度为主的构造裂缝,裂缝大多未充填或半充填,裂缝有效性好。岩心宏观裂缝线密度主要分布在8~14条/m之间,平均为12.39条/m。宏观裂缝孔隙度大多分布在0%~2%,微观裂缝孔隙度大多分布在0.6%~1.2%。宏观和微观裂缝增加了研究区变质岩储层的储集空间,同时增强了储层的连通性,充当油气充注的运移通道。岩石矿物成分和断层是影响研究区裂缝发育的主要因素。浅色矿物中的裂缝线密度高于深色矿物,同时随着距断层距离的增大,裂缝的线密度明显降低,裂缝的线密度随着距断面距离的增加呈负指数函数递减的趋势。通过岩心和成像测井标定,建立了多信息融合的常规测井裂缝识别方法,裂缝发育段比值与岩心裂缝密度正相关,裂缝识别吻合率达64.02%。结合应力场数值模拟,对裂缝分布规律进行综合评价。     

多属性融合定量储层预测方法研究与应用——以廊固凹陷杨税务潜山为例

杨税务潜山位于廊固凹陷北部,裂缝孔隙型储层发育,地质综合研究表明该区处于油气运聚的有利方向,但由于其储层埋藏深,地震资料成像精度低,常规属性预测有效储层难度大,多解性强.本文在充分分析已钻井地球物理响应特征的基础上,优选了对有效储层响应敏感的3个属性——平均振幅、方差属性、弧长属性,并计算有效储层厚度与优选属性之间的相...     

An evolutionary system for exploitation of fractured geothermal reservoirs

In this work, we present a novel methodology to integrate one of the most advanced technique for modeling fractured media for underground systems with a semantics-based genetic programming technique. The objective of the study is to develop a global framework to forecast the temperature of fractured reservoirs. The numerical method used to solve the physical equations is able to handle different fracture distributions without changing the background computational grid, i.e. the mesh of the rock matrix, as well as letting geometrically uncoupled the one co-dimensional fracture meshes. In the context of temperature forecasting, the use of a recently defined variant of genetic programming is taken into account for finding (quasi-)perfect solutions with high probability and for generating models able to produce near optimal predictions also on unseen data. The proposed computational intelligence technique integrates, in a recently developed version of genetic programming that uses semantic genetic operators, a “greedy” crossover and a self tuning algorithm. Experimental results confirm the suitability of the proposed method in predicting the correct temperature distribution in probes inside the domain.     

Large‐scale poroelastic fractured reservoirs modeling using the fast multipole displacement discontinuity method

An effective approach to modeling the geomechanical behavior of the network and its permeability variation is to use a poroelastic displacement discontinuity method (DDM). However, the approach becomes rather computationally intensive for an extensive system of cracks, particularly when considering coupled diffusion/deformation processes. This is because of additional unknowns and the need for time‐marching schemes for the numerical integration. The Fast Multipole Method (FMM) is a technique that can accelerate the solution of large fracture problems with linear complexity with the number of unknowns both in memory and CPU time. Previous works combining DDM and FMM for large‐scale problems have accounted only for elastic rocks, neglecting the fluid leak‐off from the fractures into the matrix and its influence on pore pressure and stress field. In this work we develop an efficient geomechanical model for large‐scale natural fracture networks in poroelastic reservoirs with fracture flow in response to injection and production operations. Accuracy and computational performance of the proposed method with those of conventional poroelastic DDM are compared through several case studies involving up to several tens of thousands of boundary elements. The results show the effectiveness of the FMM approach to successfully evaluate field‐scale problems for the design of exploitation strategies in unconventional geothermal and petroleum reservoirs. An example considering faults reveals the impact of reservoir compartmentalization because of sealing faults for both geomechanical and flow variables under elastic and poroelastic rocks. Copyright © 2015 John Wiley & Sons, Ltd.     

Ensemble clustering for efficient robust optimization of naturally fractured reservoirs

In the development of naturally fractured reservoirs (NFRs), the existence of natural fractures induces severe fingering and breakthrough. To manage the flooding process and improve the ultimate recovery, we propose a numerical workflow to generate optimal production schedules for smart wells, in which the inflow control valve (ICV) settings can be controlled individually. To properly consider the uncertainty introduced by randomly distributed natural fractures, the robust optimization would require a large ensemble size and it would be computationally demanding. In this work, a hierarchical clustering method is proposed to select representative models for the robust optimization in order to avoid redundant simulation runs and improve the efficiency of the robust optimization. By reducing the full ensemble of models into a small subset ensemble, the efficiency of the robust optimization algorithm is significantly improved. The robust optimization is performed using the StoSAG scheme to find the optimal well controls that maximize the net-present-value (NPV) of the NFR’s development. Due to the discrete property of a natural fracture field, traditional feature extraction methods such as model-parameter-based clustering may not be directly applicable. Therefore, two different kinds of clustering-based optimization methods, a state-based (e.g., s _w profiles) clustering and a response-based (e.g., production rates) clustering, are proposed and compared. The computational results show that the robust clustering optimization could increase the computational efficiency significantly without sacrificing much expected NPV of the robust optimization. Moreover, the performance of different clustering algorithms varies widely in correspondence to different selections of clustering features. By properly extracting model features, the clustered subset could adequately represent the uncertainty of the full ensemble.     

Heterogeneity preserving upscaling for heat transport in fractured geothermal reservoirs

In simulation of fluid injection in fractured geothermal reservoirs, the characteristics of the physical processes are severely affected by the local occurence of connected fractures. To resolve these structurally dominated processes, there is a need to develop discretization strategies that also limit computational effort. In this paper, we present an upscaling methodology for geothermal heat transport with fractures represented explicitly in the computational grid. The heat transport is modeled by an advection-conduction equation for the temperature, and solved on a highly irregular coarse grid that preserves the fracture heterogeneity. The upscaling is based on different strategies for the advective term and the conductive term. The coarse scale advective term is constructed from sums of fine scale fluxes, whereas the coarse scale conductive term is constructed based on numerically computed basis functions. The method naturally incorporates the coupling between solution variables in the matrix and in the fractures, respectively, via the discretization. In this way, explicit transfer terms that couple fracture and matrix solution variables are avoided. Numerical results show that the upscaling methodology performs well, in particular for large upscaling ratios, and that it is applicable also to highly complex fracture networks.     

Application of the two-stage Markov chain Monte Carlo method for characterization of fractured reservoirs using a surrogate flow model

In this paper, we develop a procedure for subsurface characterization of a fractured porous medium. The characterization involves sampling from a representation of a fracture’s permeability that has been suitably adjusted to the dynamic tracer cut measurement data. We propose to use a type of dual-porosity, dual-permeability model for tracer flow. This model is built into the Markov chain Monte Carlo (MCMC) method in which the permeability is sampled. The Bayesian statistical framework is used to set the acceptance criteria of these samples and is enforced through sampling from the posterior distribution of the permeability fields conditioned to dynamic tracer cut data. In order to get a sample from the distribution, we must solve a series of problems which requires a fine-scale solution of the dual model. As direct MCMC is a costly method with the possibility of a low acceptance rate, we introduce a two-stage MCMC alternative which requires a suitable coarse-scale solution method of the dual model. With this filtering process, we are able to decrease our computational time as well as increase the proposal acceptance rate. A number of numerical examples are presented to illustrate the performance of the method.     

轮南奥陶系潜山表层岩溶储层的分布特征

轮南古潜山位于塔里木盆地塔北隆起轮南低凸起中部地区,主要岩溶层位是奥陶系鹰山组与一间房组,轮南古潜山的形成条件和表生岩溶作用时间与中国南方的桂林岩溶存在极其相似之处。本文通过研究轮南地区古风化壳表层岩溶带发育分布特征及其形成影响因素,认为:表层岩溶带主要分布于距古风化面以下0～40m范围内,此带范围内岩溶缝洞系统相对比较发育,岩溶缝洞系统具有一定连通性,属岩溶储层较为发育的部位,岩溶储层有效储集空间主要是溶蚀孔洞、小规模溶洞和溶蚀裂缝;表层岩溶带发育与古岩溶地貌及古水动力条件具有密切关系,岩溶地貌类型或水动力条件不同,表层岩溶带发育厚度、岩溶形态与岩溶缝洞系统发育规模、岩溶缝洞系统充填特征也不同。      

车镇地区下古生界碳酸盐岩潜山岩溶模式初探

构造分析和地层研究表明,潜山范围内岩溶垂向发育有限,但是潜山周缘岩溶深度很大。采用岩石学、地球化学分析等方法,对研究区岩溶作用进行了深入分析。共识别出3期岩溶作用,即寒武系冶里亮甲山组-凤山组沉积期岩溶、加里东期岩溶和印支燕山期岩溶。初步探讨了3期岩溶机制:沉积期古岩溶受控于沉积、成岩作用,以大气水、海水混合白云石化作用所形成的储集空间最为有利;加里东期古岩溶介质为大气水,以地表溶蚀为主,岩溶缝、孔、洞多为后期石炭-二叠系泥岩所充填;印支燕山期古岩溶为研究区主要岩溶发育期,受构造运动、内幕地层控制,岩溶介质主要为大气水,混有地下热液影响。     

Gas-oil gravity drainage mechanism in fractured oil reservoirs: surrogate model development and sensitivity analysis

Computational Geosciences - In this study, a surrogate model is developed based on single porosity modelling approach to predict the gas-oil gravity drainage recovery curves. The single porosity...     

梯级水库群联合优化调度函数研究

构建了制定梯级水库群联合优化调度函数的"优化-拟合-再优化-随机仿真"框架:首先建立梯级水库群优化调度模型,通过确定性动态规划方法得到最优样本;然后对最优样本进行多元线性回归分析得到联合调度函数;并基于模拟调度结果采用非线性规划方法直接修正调度函数;最后通过水文随机模拟技术生成径流系列,进一步检验、评价所得调度函数的效率。以清江梯级水库群长期优化调度为对象进行实例研究,计算结果表明:对于1951-2005年实测径流系列,梯级水库群联合优化调度函数较常规调度方案年均增加发电量2.03亿kW·h,增幅达2.79%;对于两种随机模拟方法生成的水文径流系列,年均发电量分别提高了1.74%和2.36%,经济效益显著。     

准噶尔永进地区深部储层的保存与发育机理

随着油气勘探向深部发展,在深部寻找优质储层是一个亟待深入研究的问题。永进地区位于准噶尔腹部中石化中部3区块,勘探目的层埋藏深,大于5000m,储层多为低孔-特低孔低渗-特低渗储层,因此,在该地区深部寻找相对优质储层具有重要的理论意义和勘探意义。该地区发育区域性不整合,即J/K不整合。在不整合形成期间,大气淡水具有高的流速和相对开放的流体环境,可以溶蚀易溶矿物并将溶蚀产物带离出溶蚀区;颗粒包壳可以抑制石英加大和碳酸盐矿物沉淀,保存原生孔隙和形成的次生孔隙;永进地区油气充注早,早期的油气充注改善了流体成岩环境,抑制胶结作用,同时,其携带的有机酸溶蚀易溶矿物,产生次生孔隙,油气早期充注从两个方面改善储层。