Well log correlation pdf

In 1980, i gave a talk at the aapg annual convention in denver, describing all of the correlation procedures that had been attempted at the time. Pdf welllog correlation using a backpropagation neural. Log correlation can be done in log to log mode or in the cross section. Automatic and simultaneous correlation of multiple well logs. Well log study and stratigraphic correlation of the cantuar. The gamma ray, resistivity and sonic logs characteristics were employed in the correlation analysis. Van wagoner search for other works by this author on. Correlation is flattened at top of the sahmah shale. Well log correlation, sahmah shale member geoarabia. Correlation of well logs as a multidimensional optimization. Recently, proponents of transgressive and regressive cycles, referred to as tr units, for regional correlation have included ryer 1983, busch and rollins 1984, busch et al.

Also included is a well log database that lists the location, available well logs, depths, and other pertinent information for each of the wells on the correlation section. We consider a variant of automatic correlation between well sections based on construction of. Formation evaluation and well log correlation petroleum. Correlation procedures between well logs and seismic reflection. Correlation example from a high accommodation setting. Well correlation the well section window allows displaying well logs in a specified order, with the available logs and well tops. Welltowell log correlation 423 a flexible set of rules and geologic models, which when applied to the data, serve to constrain the correlatioli within certain meaningful limits. The various openhole services offered by schlumberger are discussed in some detail, together with essential methods of interpretation and basic applications. Cross section software log correlation contour mapping. Presentation by loralee wheeler, ms, a graduate student in the center for wave phenomena at the colorado school of mines. Welllogging correlation analysis and correlation of well logs in rio grande do norte basin wells ricardo afonso salvador pernes march, 20 ricardo.

Stratigraphic correlation using well logs crewes research report volume 16 2004 1 well log study and stratigraphic correlation of the cantuar formation, southwestern saskatchewan shaohua li, charles m. Incremental correlation of multiple well logs following. Brookian sequence well log correlation sections and. We present a novel system for welltowelliog correlation using knowledgebased systems and dynamic depth warping techniques. The cost of matching the two wells is measured by the difference in the log values. Overview well log definition and its importance fundamentals of qualitative and quantitative log interpretation formation evaluation with well logs processing and interpretation of well log data conclusion 3. A well log curve is a sequential collection of one category of data, such as resistivity or gamma ray activity. Welllogging correlation analysis and correlation of well logs in rio grande do norte basin wells. Basic relationships of well log interpretation introduction this chapter provides a general introduction to well logging principles and methods that will be used throughout the book. Welltowell log correlation using knowledgebased systems. Siliciclastic sequence stratigraphy in well logs, cores. He goes on to provide a comprehensive summary of stratigraphic segmentations of well logs, automated correlation methods, and reservoir mapping and mod.

Welllogging correlation analysis and correlation of well. During the first 20 years, this correlation consisted. For the past 35 years, geologists and engineers have correlated electric and radioactivity logs. The most common logs used for this purpose are the gamma ray, the resistivity and the acoustic log. A well may have several logs, and a log may have several curves. In 1980, i gave a talk at the aapg annual convention in denver, describing all of the correlation procedures that had been attempted at.

This approach overcomes a major drawback inherent in previous methods, namely the difficulty in correlating missing or discontinuous rock units. Published in 1991, log interpretation principlesapplications provides a thorough background of log interpretation. Integration of well logs and seismic data for prospects. The accompanying illustrated data are from five wells and adjacent seismic lines. Basic well log interpretation chemistry physical sciences. Transgressive and regressive cycles have been used for regional correlation for at least 50 years. The text discusses how different log types measure various. Log correlation can be done in logtolog mode or in the cross section. Wireline logs can be divided into broad categories based on the physical properties measured. Stewart abstract this paper presents the results of a wireline log study on the cantuar formation of the. Petrel well correlation provides a clean correlation canvas on which to display logs, core images, seismic data, grid data, and even completions and simulation resultswhich can be played through time. Pdf jpas well log correlation and petrophysical interpretation of. Incremental correlation of multiple well logs following geologically optimal neighbors xinming wu 1, yunzhi shi, sergey fomel, and fangyu li2 abstract welllog correlation is a crucial step to construct cross sections in estimating structures between wells and building subsurface models. Basic well log interpretation free download as powerpoint presentation.

My first mentor, ko ko kyi, first taught me how to read and interpret well logs just by looking at the well log patterns. Multiple logs are used from each well, and the resulting. These coincide and are correlated with radioactive shales use of the. Well log correlation is an important step in geophysical interpretation, but as the number of wells increases, so does the complexity of the correlation process. Well log is one of the most fundamental methods for reservoir characterization, in oil and gas industry, it is an essential method for geoscientist to acquire more knowledge about the condition below the surface by using physical properties of rocks. The log may be based either on visual inspection of samples brought to the surface geological logs or on physical measurements made by instruments lowered into the hole geophysical logs. In the next section we describe the dynamic programming method used to perform the correlation algorithm. Regional well log correlation in the new mexico portion of the delaware basin introduction borehole geophysical logs provide records of stra tigraphy and structure in the northern delaware basin that are more detailed than previous data obtainable from incomplete coring and poor outcrop. Formation evaluation and well log correlation free download as powerpoint presentation. Overview well log definition and its importance fundamentals of qualitative and quantitative log interpretation formation evaluation with well logs processing and interpretation of well log data conclusion. The resistivity logs are in the middle and the porosity logs are on the right. Regional welllog correlation in the new mexico portion of the delaware basin introduction borehole geophysical logs provide records of stra tigraphy and structure in the northern delaware basin that are more detailed than previous data obtainable from incomplete coring and poor outcrop. Fine well to well correlation can be done with the horizon stack, thanks to the cross navigation and viewers synchronization. Gamma ray gr, selfpotential sp and deep induction log ild well logs were used for correlation analysis of four wells in osfield in the.

Besides the petrophysical aspect of well logs, their most important use. Log applications stratigraphic correlation formation tops quantitative oil, gas, water saturations porosity correlation with seismic data sedimentological studies reservoir modeling. Its just a common sense, stepbystep approach in interpreting any well logs. In large field studies, a computer can be used simply to reduce the time required to correlate zones of interest. We present a backpropagation neural network with an input layer in the form of a tapped delay line wich can be trained effectively. This spreadsheet contains data from a logging run of resistivity, natural gamma ray, density, neutron, and geochemical tools. Guidebook to the correlation of geophysical well logs within the st. These logging these logging tools record the level of naturally occurring ga mma ray emissions from the rocks. The well log cross section below is modified from plint 2000. Users can geosteer horizontal and highly deviated wells with schlumberger lwd tools in real time, and deviated wells can be displayed overlain. Us8065086b2 method for estimating missing well log data. The well log correlation model is obtained by constructing the optimal trajectory in the field of the function f x 1, x 2 and solving problem 3. Geol 332 lab 10 a well log correlation 4 page comprises upward.

A rulebased system for well log correlation onepetro. The simplest radioactive method in geophysical well logging is the natural gamma log. Preliminary study on the well logs revealed one major hydrocarbon bearing reservoir. Succeeding chapters 2 through 6 introduce the reader to specific log types. Log interpretation principlesapplications schlumberger.

The interval is from the upper cretaceous dunvagan. An interdisciplinary seminar for all earth scientists and engineers giving practical understanding of the principles and interpretation of geophysical well logs in research applications. A well log comprises data collected along the path of a hole in the ground. Jun 29, 2012 basic evaluation of south louisiana well log.

Log correlation this document shows you the best practices to correlate logs to seismic. The spontaneous and gammaray logs are displayed on the left side of the log. Jun 14, 2018 multiple welllog correlation aligns reference log data along common geologic time, and the cor relation coef. Formation evaluation and well log correlation swapnil pal imt geological technology indian institute of technology roorkee 2. The most important of these surfaces, and the first that should be identified when using logs, are maximum flooding surfaces mfs and transgressive surfaces ts. Besides the petrophysical aspect of well logs, their most important use has been correlation between wells. Multiple welllog correlation aligns reference log data along common geologic time, and the cor relation coef. Incremental correlation of multiple well logs following geologically optimal neighbors xinming wu 1, yunzhi shi, sergey fomel, and fangyu li2 abstract well log correlation is a crucial step to construct cross sections in estimating structures between wells and building subsurface models. In addition, a well to well correlation and reservoir quality assessment were undertaken. I propose a new method for automatic and simultaneous well log correlation that provides an optimal alignment of. The optimal line was constructed using an ant colony algorithm dorigo, 1992 and a wave algorithm lee, 1961. The log correlation can be done in both depth and time domains. Log correlation before correlating the well, we need to extract a wavelet so that a synthetic trace can be calculated.

Well trajectory coord shape of hole casing joints quality of cement etc reading in selley ch. Apr 15, 2016 correlation example from a high accommodation setting. The sections that follow initally focus on the well log response to shallow water clastics and then move on to their response to shallow water carbonates. Well log the continuous recording of a geophysical. Pdf well to well log correlation using knowledgebased.

Missing well log estimation by multiple welllog correlation. Stratigraphic correlation of well logs by computer techniques. Estimate sequences and systems tracts from the interpreted lithofacies using regional cross sections with well and outcrop data determine accommodation space changes from parasequence stacking. Other wells may not have a lithologic description but do have a geophysical log which can be correlated to a reference log. The high resistivity in the hasisrah sand in ata1 suggests the presence of hydrocarbon saturation. Process log processing log correlation and select the well. Then tool is raised through the entire well casing may prevent some logs from working logging speed. Computerassisted approaches to well log correlation are of interest to engineers and geologists for two reasons.

Well tops and horizon interpretation are checked and vertical differences automatically quantified in an interactive table. Siliciclastic sequence stratigraphy in well logs, cores, and. A log run for the purpose of correlating between wells. Click to correlate down the stratigraphic column or across multiple logs. The palaeodepositional environments in the field were deduced by combining gamma ray log trends with core data. Winlog ng multi well chart correlation hrh geology. Geol 332 lab 10 a well log correlation well logging. Regional welllog correlation new mexico portion the. Welllog correlation using a backpropagation neural network. Development of well logs established the discipline of subsurface geology as we know it today.

How to easily read a well log in 5 minutes or less using. Siliciclastic sequence stratigraphy in well logs, cores, and outcrops. Well correlation panel showing the completion and reservoir quality logs used in the unconventional well analysis workflow. Well log correlation, the stratigraphic framework, and the computer revolution. We will meet once a week and focus on the fundamentals of well logging methods, including electrical, nuclear, and acoustic measurements. The results of the well logs correlation connecting the four wells in the survey area is shown in. A description of the surfaces that bound and subdivide parasequence s and how they are identified on well logs. A path finding algorithm then traces through the matrix to define a function which maps the first well onto the second. Note the increased resistivity at the base of the shale in silt stringers in burkanah1. The study aims at using well log approach in establishing the sedimentary facies, their successions and environments of deposition in this field. Well logging, also known as borehole logging is the practice of making a detailed record a well log of the geologic formations penetrated by a borehole. Use winlog ng for 1d, ezcorrelate for 2d and the gravitas connector for petrel for 3d.

Click the window menu command and choose new well section window as shown in fig. Any depth calibrated log is ready for correlation with manual picks or autoposting of imported picks. Such holes are referred to as wells in the art of oil and gas exploration. The dynamic programming approach allows correlation across geologic structures, thinning beds, and missing or discontinuous units. Well log analysis for reservoir characterization aapg wiki.

Well to well log correlation 423 a flexible set of rules and geologic models, which when applied to the data, serve to constrain the correlatioli within certain meaningful limits. Use winlog ng for 1d, ezcorrelate for 2d and the gravitas connector for petrel for 3d visualisation. Regional welllog correlation new mexico portion the delaware. Concepts for highresolution correlation of time and facies authors j. Well log study and stratigraphic correlation of the.

Automatic and simultaneous correlation of multiple well. The list below, modified from vail outlines a suggested procedure for well log sequence analysis interpret depositional lithofacies on logs using cores and cuttings to calibrate the log. At the start of an interpretation of sequence stratigraphy using well logs one must first identify the predominant of sequence stratigraphic surfaces. Le nir i, van gysel n, rossi d 1998 crosssection construction from automated well log correlation. Scribd is the worlds largest social reading and publishing site.