A new technique to estimate the hydrocarbon saturation in shaly. Examples with an exercise part sandstone reservoir, shaly sand interpretation, complex mineralogy of a carbonate reservoir. Petrophysical models and techniques for shalysand formation. Subject are the fundamental techniques of well loggingborehole geophysics and the interpretation of measured data formation evaluation. Development and field applications of shaly sand petrophysical models a dissertation submitted to the graduate faculty of the louisiana state university and agricultural and mechanical college in partial fulfillment of the requirements for the degree of doctor of philosophy in the department of petroleum engineering by milton n. Shaly sand interpretation using cecdependent petrophysical. Shaly sand interpretation qed pete 321, sections 501506 spring. Top 10 landmark papers in petrophysics and formation evaluation. It may also depend on the way the shale is distributed in the formation. In logging analysis, shaly sand formation evaluation estimates totalporosity, shale and quartz in shalequartz lithologydescription or clay and sand in clay sand lithologydescription, effectiveporosity and watersaturation. This course tackles the important and nontrivial problem of practical formation evaluation in shaly sand provinces. Conventional departures from archie conditions for petrophysical attribute delineation include shaliness, fresh formation waters, thinbed reservoirs, and combinations of these cases.
In this seminal paper, archie sets out not only to give a name petrophysics to the then. The conventional resistivity in a laminated shaly sand formation for the sand resistivity r sd of 20. On the application of simandoux and indonesian shaly sand resistivity interpretation models in low and high rw regimes k. In potential shalegas basins, due to limited data availability, volumetric evaluation of shaly sand formations is a challenging task for researchers, as well as for exploration and production companies, with the use of conventional well logs. The main emphasis during the course is on practical application rather than extensive discussion around the theoretical background. Well logging and formation evaluation sciencedirect. Integrated petrophysical evaluation applied to the. The grain density is used for deriving porosity from the density log. Then, the logs have represented an average of the log values over the shale and sand layers within the resolution of each log. Water saturation equations in shaly reservoir rocks ptrl3023. T total porosity phit, which includes the pore space in sand and shale. Of course, the hydrocarbon inplace is obtainable once porosity and water contents are estimated in the formation. Typically, the formation lithology included minerals which were termed clay or clay minerals. A method of shaly sand correction for estimating gas.
This evaluation is also very important to interpret for thin bed shalysand sequence. Hari kumar, ongc summary present paper is a relook at the oil industry practices in making use of the simandoux and indonesian shaly sand resistivity interpretation models for formation evaluation. An integrated formation evaluation approach for maximizing. Each of these can furnish a significantly different reservoir evaluation. The result of the evaluation was utilized to investigate the low productivity from some zones and its relation with depositional process and petrophysical properties.
In such a situation, archies model works very well. For a considerable time, shaly sand formation evaluation could not accurately quantify clay from standard well logs. The evolution of shalysand concepts in reservoir evaluation. 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. Shaly sand petrophysics training course petroskills aps. If these departures are unrecognized, water saturation can be overestimated, and this can result in loss of opportunity. Pnge 735 advance formation evaluation course description. Another problem found in reservoir is the presence of carbonates. Formation water resistivity r w regime for simandoux and indonesian models 2. Conventional wireline logs often fail to provide a reliable evaluation of reservoir quality and producibility in shaly mud formations, particularly in the shaly gas sand reservoirs of the rocky mountains which are characterized by low porosity i. The petrophysical work flow that is presented through the paper can be applied to other mature, complex shaly sand reservoir for formation evaluation. The laminations often have been too thin to be individually resolved by the logs. Connectivity equation and shalysand correction for. The importance of the interaction between seismology, geology, petrophysics and reservoir engineering will be emphasised and illustrated.
A practical guide asquith continuing education course notes series no. R ar o w m 1 where r o is the formation resistivity of watersaturated sediment, r w. This work presents a formation evaluation for two main santonian sequences of an important gas field composed of siliciclastic reservoirs in santos basin, eastern brazilian margin. As a means of investigating this unsatisfactory state of affairs, the development of thinking about the shaly sand problem has been mapped up to the present day. Review of existing shalysand models and introduction of a. Advanced formation evaluation in sandstone reservoirs. This leads to large uncertainties in the apparent sand resistivity even for. Shaly sand interpretation using cecdependent petrophysical parameters a dissertation submitted to the graduate faculty of the louisiana state university and agricultural and mechanical college in partial fulfillment of the requirements for the degree of doctor of philosophy in the department of petroleum engineering by kurniawan. Essential technical papers crains petrophysical handbook.
Hydrocarbon are stored only in pore space in sand matrix. This petroknowledge training course will explore the tools response to different lithologies and will help participants understand log readings, 37242. A practical guide aapg continuing education course note by asquitt, george b. Hydrocarbon saturation assessment of thick shaly sand reservoir. Formation evaluation and well log correlation petroleum. The conventional resistivity in a laminated shaly sand formation for the sand resistivity rsd of 20. Advanced methods for interpreting well logs, shaly sand analysis, and production logging methods. Electrical properties, petrophysics and formation evaluation. On the application of simandoux and indonesian shaly sand. The purpose of this book is to provide a series of techniques which will. Shaly sand formation evaluation using a single membrane.
Accuracy of shaly sand formation evaluation saudi aramco. Handbook of well log analysis for oil and gas formation. Openhole log analysis and formation evaluation, 2012 edition, by richard m. Dielectric measurements, nuclear magnetic resonance nmr and neutron derived spectroscopy are used. A practical guide aapg continuing education course note asquitt, george b. Toby darling, in well logging and formation evaluation, 2005. Part of the studies in fuzziness and soft computing book series studfuzz, volume 80. The first steps of using f d and the twocomponent model of shaly sands with variable density of mineral particles depending on shale content is a promising step in further development of this. What are the lower limits for porosity, permeability and upper limits for water saturation that permit profitable production from a particular formation or pay zone. Openhole log analysis and formation analysis book osti. Dielectric measurements in porous media and application to shaly formation revue delinstitut francais du petrole spwla reprint volume shaly sand p simandoux geology and geochemistry of oil and.
Subsurface and petrophysical studies of shalysand reservoir. Resistivity anisotropy techniques can provide estimates of sand resistivity and volume fraction, but good. Formation evaluation in thin sandshale lamination seeks first to determine sand resistivity, volume fraction, and porosity. In many fields with good quality carbonate reservoirs, evaluation is simpler than with sandstone because the shaly sand problem does not occur and beds tend to be thicker. Well logging pioneering research was hinged on the principle that. The presence of clay minerals and shale laminations strongly affects the physical properties of the reservoir rock and induce significant effects on the response of most logging tools. Geological survey scientific investigations report 20065121, 10 p. The following definition and petrophysics model are a typical shaly sand formation model which assumes. The course covers solutions for evalating various shaly sand reservoirs including technqiues and equations. In the application of these models to specific formations, industry follows no axiomatic approach in terms of critical factors such as 1.
A modified approach for volumetric evaluation of shaly sand. Comparing the results of different shalysand evaluation methods is dif. Purchase well logging and formation evaluation 1st edition. When heavier minerals are also present in the formation in variable amounts. Page 311 electrical conductivities in shaly sands i. Pdf formation evaluation of two given wells from mehsana field. Therefore, the effects of clay on porosity and resistivity logs were not accurately incorporated in shaly sands formation evaluation. The shaly sand problem is really a question of identifying, from logs, the degree to which the presence of clay degrades reservoir quality, because clay affects both porosity and permeability, if too much shale or clay is in a reservoir, production of hydrocarbons is suppressed by excessive reduction in permeability. The shale volume is about 9 percent and formation water resistivity for virgin zone is 0.
Basic open hole logging and formation evaluation foundation. Acknowledgements i would like to express my gratitude and thanks to cairn. Jan 30, 2007 typically, the formation lithology included minerals which were termed clay or clay minerals. Yet, no one method predominates within the industry. The interpretation of shaly sand formations has been recognized early as a. Examples with an exercise part sandstone reservoir, shaly sand interpretation, complex mineralogy of a carbonate reservoir help to understand the different methods and algorithms. The formation evaluation problem is a matter of answering two questions. The relationship between the resistivity index and the water saturation is also expressed in terms. A new equation is derived that directly relates shaly sand conductivity to the membrane potential. High new technology tools are contributing a lot to the evaluations of clastics formations. Theory and practice of measuring reservoir rock and fluid transport properties, fourth edition provides users with tactics that will help them understand rockfluid interaction, a fundamental step that is necessary for all reservoir engineers to grasp in. Well logs are usually the main tool of investigation and evaluation of the subsurface formations.
Wireline logs of four 4 wells from apete field were studied to delineate petrophysical. Shale is composed of silt, clay and their bounded water which will not flow. A valuable reference dedicated solely to well logging and formation. This course will be suitable for all geoscientists and engineers who will benefit greatly from exposure to advanced knowledge and expertise in formation evaluations in clastics. Shaly synonyms, shaly pronunciation, shaly translation, english dictionary definition of shaly. Choice of respective shale function v sh from gamma. Shale can exist in the form of laminae between which are layers of sand. The relationship between the resistivity index and the water saturation is also expressed in terms of a single membrane potential measurement. Then, the logs have represented an average of the log values over the shale and sand layers within the. Hari kumar, ongc summary present paper is a relook at the oil industry practices in making use of the simandoux and indonesian shaly. The way shaliness affects a log reading depends on the amount of shale and its physical properties. Find out more about basic formation evaluation from hot engineering on. This paper is intended to provide a better understanding of volumetric evaluation in unconventional shaly sand formations. Shaly material can be distributed in the formation in three ways.
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