地球物理测井方法原理和应用ppt课件.ppt

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1、地球物理测井方法原理和应用,总目录第一讲： 绪 论第二讲：普通电阻率法测井第三讲：聚流电电阻率测井第四讲: 自然电位测井方法原理及应用第五讲：感应测井第六讲: 声波测井第七讲: 自然伽马测井方法原理及应用第八讲 : 中子测井方法原理及应用,第一讲： 绪 论一、地球物理测井的基本概念二、地球物理测井能解决什么问题?三、地球物理测井包括哪些内容？四、地球物理测井的发展历史五、地球物理测井在地球物理 探测技术中的位置,矿场地球物理油矿地球物理钻井地球物理勘探地球物理测井:钻孔中进行的各种地球物理探测方法的统称.1927年由法国Schlumbeger公司的创始人Schlumbeger兄弟俩创立的.,地

2、球物理测井是用各种专门的仪器放入井内,沿井身测量井孔剖面上各种物理参数随井深的变化曲线,并根据测量结果进行综合解释,用于判断岩性、确定油气层及其它矿藏的一种间接手段.测井工作分为两个阶段:野外资料录取阶段和资料处理解释阶段.,The borehole environment,The borehole environment in which logging measurements are made is of some interest from the standpoint of logging tool designs and the operating limitions placed

3、 upon them. it is important in terms of the disturbance it causes in the surrounding formation in which properties are being measured.,The Borehole Environment,Some characterization of the borehole environment can be made using the following set of generalizations:Well depths The deviation of the bo

4、rehole, which is between and onshore, and between and offshore.The temperature, at full depth, ranges between and F The drilling fluid, or mud. The salinity of the drilling mud ranges between 3000 and 200,000 ppm of NaCl ,This causes invasion of a porous and permeable formation by the drilling fluid

5、.,The Borehole Environment,To account for the distortion which is frequently present with electrical measurements, a simplified model of the borehole/formation has evolved ,which is shown schematically in Fig. 2-4,It considers the invaded formation of interest, of resistivity to be surrounded by “sh

6、oulder” beds of resistivity the mudcake of thickness and resistivity The next annular region of diameter is the flushed zone whose resistivity is donated by the uninvaded or virgin zone with resistivity,Figure 2-4. Schematic model of the borehole and formation used to describe electric logging measu

7、rements and corrections.,第一讲： 绪 论一、地球物理测井的基本概念二、地球物理测井能解决什么问题?三、地球物理测井包括哪些内容？四、地球物理测井的发展历史五、地球物理测井在地球物理 探测技术中的位置,可以解决的问题:油气储层的评价问题相关的地质问题工程问题及地层的机械性能油气开发问题为地面地球物理勘探资料解释提供参数与其它资料结合进行储层空间描述与盆地分析,Introduction,This section presents a general overview of the problem of log interpretation and examines the

8、 basic questions concerning a formations potential hydrocarbon production which are addressed by well logs. The borehole environment is described in terms of its impact on the electrical logging measurements, and all of the qualitative concepts necessary for simple log interpretation are presented.

9、The log format conventions are presented , and an example is given which indicates the process of locating possible hydrocarbon zones from log measurements . The process of extracting petrophysical parameters from the logging measurements is the subject of subsequent chapters.,Rudimentary Well Site

10、Interpretation,Log interpretation, or formation evaluation, requires the synthesis of logging tool response physics, geological knowledge and auxiliary measurements or information to extract the maximum petrophysical information concerning subsurface formations. In this section, a subset of this pro

11、cedure is considered :well site interpretation This subset refers to the rapid and somewhat cursory approach to scanning an available set of logging measurements, and the ability to identify and draw some conclusion about zones of possible interest.,Rudimentary Well Site Interpretation,The most impo

12、rtant questions to be answered by well site interpretation are: 1.Does the formation contain hydrocarbons? 2.If so, what is the quantity present? 3.Are the hydrocarbons recoverable? In order to see how logging measurements can provide answers to these questions, a few definitions must first be set o

13、ut. 1. porosity is that fraction of the volume of a rock which is not matrix material and may be filled with fluids. Fig.2-1 illustrates a unit volume of rock,The pore space has a fractional volume denoted by , the matrix material occupies the remaining fraction of the volume,Rudimentary Well Site I

14、nterpretation,Figure2-1. A unit volume of formation showing the porosity and the fractional pore volume of water .The fractional volume of hydrocarbons is .,Note: the fractional volume occupied by the water is given by the product , and the total fraction of formation occupied by the oil by,2. Water

15、 saturation , is the fraction of the porosity which contains water. This fractional volume is also indicated in Fig.2-1.3. Oil saturation , is given by,Rudimentary Well Site Interpretation,Since one of the principal logging measurements used for the quantification of hydrocarbon saturation is electr

16、ical in nature, it is necessary to mention some of the terminology used to describe these measurements. The resistivity of a formation is a measure of the ease of electric conduction .Resistivity, a characteristic akin to resistance, is discussed in much more detail later. Replacing the conductive b

17、rine of a porous medium with essentially nonconducing hydrocarbons can be expected to impede the flow of current and thus increase its resistivity.,Rudimentary Well Site Interpretation,The resistivity of the undisturbed region of formation , is denoted by is derived from measurements that yield an a

18、pparent resistivity. These measurements can then be corrected, when necessary, to yield the true formation resistivity. In the region surrounding the well bore, where the formation has been disturbed by the invasion of drilling fluids, the resistivity can be quite different from . This zone is calle

19、d the invaded or flushed zone,and its resistivity is donated by .,Rudimentary Well Site Interpretation,Two other resistivities : 1. the resistivity of the brine, which may be present in the pore space . 2. the resistivity of the filtrate of the drilling fluid, , which can invade the formation near t

20、he well bore and displace the original fluids.,Rudimentary Well Site Interpretation,Returning to the three questions which must be addressed by well interpretation, refer to Fig.2-2, which attempts to show the interrelationships implicit in the questions site.,Figure 2-2 A schematic representation o

21、f the logging measurements used and the petrophysical parameters determined for answering the basic questions of well site interpretation,The first task is to identify the clean zones. The task is routinely accomplished through two measurements: GR and SP.,The second step is to answer the question :

22、”Can the formation contain hydrocarbons?” This condition will be possible only if the formation is poros. Three curves from three different types of measurements will give porosity information. They are commonly referred to as the density, neutron, and sonic curves.,Rudimentary Well Site Interpretat

23、ion,Once a porous, clean formation is identified, the analyst is faced with deciding whether it contains hydrocarbons or not. This analysis is done in quite an indirect way, using the resistivity of the formation. Basically, if the porous formation contains conductive brine, its resistivity will be

24、low. If , instead, it contains a sizable fraction of nonconducting hydrocarbon, then the formation resistivity will be rather large.Another common resistivity measurement, which is used to get some idea of the recoverability of hydrocarbons in the following way.,Rudimentary Well Site Interpretation,

25、If the then the original formation fluids are present in the so-called invaded zone, indicating that no formation fluid displacement has taken place. if the resistivity of the invaded or flushed zone corresponds to the resistivity expected for the formation invaded with the drilling fluid, then the

26、drilling fluid has displaced the original fluid(some of which may be hydrocarbon). Therefore the formation fluids are moveable and will probably be producible.,第一讲： 绪 论一、地球物理测井的基本概念二、地球物理测井能解决什么问题?三、地球物理测井包括哪些内容？四、地球物理测井的发展历史五、地球物理测井在地球物理 探测技术中的位置,地球物理测井包括的内容： 测井的方法原理 测井仪器与采集技术 测井的处理解释及应用根据观测的物理量的性质

27、分： 电以研究岩石的电学性质为基础的方法 声以研究岩石中的声波传播特性为基础的 方法 核以研究物性的原子物理及核物理性质为 基础的方法 其它热、重力、磁、地层几何分布特征,Qualitative Interpretation,In this rapid overview, the basic rules for interpretation are given,without explanation. The reasons behind them are presented in later chapters.For the moment, consider this to be a rec

28、ipe for answering the three basic questions of Fig.2-2, from the phenomenological behavior of the measurement cures presented next.,Qualitative Interpretation,In order to assess the formation for shaliness, two indicators can be used: the gamma (GR) and the spontaneous potential (SP). Three logging

29、devices yield a value of porosity. That is density tool, the neutron tool and the sonic tool.The presence of hydrocarbon is inferred from the value of the formation resistivity .,Qualitative Interpretation,A summary of these relations is found in Table 2-1,Reading A Log,Reading a log with ease requi

30、res familiarity with some of the standard log formats, which are shown in Fig.2-6. The top illustration shows the normal linear presentation,The middle figure shows the logarithmic presentation for track 2and 3. Four decades are drawn to accommodate the electrical measurements, which can have large

31、dynamic ranges.The bottom illustration is a hybrid scale with a logarithmic grid on track 2 and a linear one in track 3. Electrical measurements that may spill over from track 2 into track 3 will still be logarithmic even though the indicated scale is linear.,Reading A Log,Figure 2-6. Standard log p

32、resentation formats,Figure 2-7.Presentation of SP and GR headings used for clean formation determination,Reading A Log,Fig.2-7 shows the typical log heading presentation for several of the basic logs that will be used shortly. The upper two presentations show two variations for the SP, which is alwa

33、ys presented in track 1. the SP becomes less negative for increasing shale, this will be seen to correspond to deflections of the SP trace toward the right for increasing shale content. The bottom presentation shows the caliper and the GR, which are also generally presented in track 1. The GR curve

34、will also produce curve deflections to the right for increasing shale content. Thus the two shale indicators can be expected to follow one another as the shale content varies.,Reading A Log,One of the resistivity log headings is shown in Fig.2-8 ,The particular tool associated with this format is re

35、ferred to as the dual induction .The trace coded for ILD corresponds to the deepest resistivity measurement and will correspond to the value of when invasion is not severe. The curve marked ILM is an auxiliary measurement of intermediate depth of penetration and is highly influenced by the depth of

36、invasion. The curve marked SFLU corresponds to the resistivity of the invaded zone,Figure 2-8. The induction log heading and schematic of the formation, with three zones corresponding approximately to the simultaneous electrical measurements of different depths of investigation,By combining the thre

37、e resistivity measurements, it is possible to compensate for the effect of invasion on the ILD reading.,Reading A Log,In Fig.2-9, three typical headings for the three types of porosity devices are indicated.The top heading shows the format for porosities derived from neutron and density measurements

38、 simultaneously The middle example shows, in addition, the correctin curve for the density log, which can be used to get some idea of the mudcake and rugosity of the borehole encountered during the density measurement .The bottom heading is for the sonic trace with the apparent transit time increasi

39、ng to the left .,Figure 2-9. Log headings for the porosity devices.,Reading A Log,For the neutron and density logs, another point to be aware of the matrix setting .This setting corresponds to a rock type assumed in a convenient preinterpretation that establishes the porosity from the neutron and de

40、nsity device measurements .In both examples shown in Fig.2-9,the matrix setting is listed as SS, which means that the rock type is taken to be sandstone .If the formations being logged are indeed sandstone, then the porosity values recorded on the logs will correspond closely to the formation of the

41、 actual formation . if the actual formation matrix is different,say limestone,then the porosity values will need to be shifted or corrected in order to obtain the true porosity in this particular matrix.,第一讲： 绪 论一、地球物理测井的基本概念二、地球物理测井能解决什么问题?三、地球物理测井包括哪些内容？四、地球物理测井的发展历史五、地球物理测井在地球物理 探测技术中的位置,地球物理测井的发

42、展历史:方法原理及仪器方面：第一阶段:普通电阻率及自然电位等少数几种方法；第二阶段:研究由视参数确定岩层电性参数的方法 （横向测井方法）第三阶段:提出一系列带聚焦和贴井壁的测井方法；第四阶段:综合参数解释模型的提出及成像仪的研究开发；仪器的自动化程度： 手动半自动模拟自动模拟数字记录 程控数字记录,第一讲： 绪 论一、地球物理测井的基本概念二、地球物理测井能解决什么问题?三、地球物理测井包括哪些内容？四、地球物理测井的发展历史五、地球物理测井在油气勘探开发中 的位置,地球物理测井在油气勘探开发中的位置：勘探阶段：普查（地质、重磁、电磁、地震）详查（地质、电磁、地震）确定目标钻探地球物理测井测试

43、、开发；开发阶段：测试、开发测井储层精细研究,Examples Of Curve Behavior And Log Display,The first example is the SP, which is shown over a 150interval in Fig.2-10. Sections of log with greater SP deflection(i.e., with a more negative value than the shale base line) are taken as clean, or at least cleaner,zones. One clean

44、 section is the zone between 8510 and 8550.,Figure 2-10. An SP log over a clean section bounded by shales,Examples Of Curve Behavior And Log Display,Note the similarity between the GR trace of Fig.2-11 and the SP trace of Fig.2-10.In the clean sections.Note also that the caliper, in this example, fo

45、llows much of the same trend. This trend results from the fact that the shale sections can “wash out,” increasing the borehole size compared to the cleaner sand sections that retain their structural integrity.,Figure 2-11. A GR and caliper log over the same section as Fig.2-10,Examples Of Curve Beha

46、vior And Log Display,The shallow, deep, and medium depth resitivity curves are indicate. In the zone below 5300, a possible water zone is indicated. At a depth of 5275, a possible hydrocarbon zone is noted. It is clear that the deep resistivity reading (ILD) is much greater than in the supposed wate

47、r zone. However, this increase in resistivity may not be the result of hydrocarbon presence. A decrease in porosity could produce the same effect for a formation saturated only with water.,Figure 2-12. An induction log over a section which might be interpreted as a water zone with a hydrocarbon zone

48、 above it,Examples Of Curve Behavior And Log Display,Fig.2-13 shows a typical log of a neutron and density device in combination. In addition to the density porosity estimate and the neutron porosity, the compensation curve is also shown. This curve is the correction which was applied to the density

49、 measurement in order to correct for the mudcake and borehole irregularities.,Figure 2-13.Sample neutron and density logs which has been converted to sandstone porosity.,Examples Of Curve Behavior And Log Display,The presence of gas may be extremely easy to spot from a comparision of the neutron and

50、 density logs. In the simplest of cases, gas is indicated in any zone in which the neutron porosity is less than the density porosity. Fig.2-14 shows sections which exhibit this behavior. Shale produces the opposite effect . The neutron porosity may far exceed the density porosity, as can be seen in