Hydrocarbon saturation assessment of thick shaly sand reservoir. The relationship between the resistivity index and the water saturation is also expressed in terms of a single membrane potential measurement. Inverse of the electrical formation factor versus the porosity in. The course covers solutions for evalating various shaly sand reservoirs including technqiues and equations. Basic well logging and formation evaluation bookboon.
Petrophysical models and techniques for shalysand formation. Choice of respective shale function v sh from gamma. A valuable reference dedicated solely to well logging and formation evaluation. Well logging and formation evaluation oil and gas news. 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 water saturation distribution above the fwl in a reservoir is controlled by the balance of. Determination of shale volume and distribution patterns and effective porosity from well log data based on crossplot approach for a shaly carbonate gas reservoir. 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. This paper has been cited many times through the years, and books and training. Sandor, shell international exploration and production b. It may also depend on the way the shale is distributed in the formation. Formation water resistivity r w regime for simandoux and indonesian models 2. 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. Laminated shaly sand analysis and 3d saturation height modelling.
Hydrocarbon are stored only in pore space in sand matrix. In shaly sand zones having a high proportion of conductive dispersed shales. 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. On the application of simandoux and indonesian shaly sand. This course tackles the important and nontrivial problem of practical formation evaluation in shaly sand provinces. T total porosity phit, which includes the pore space in sand and shale. Landmark papers in well logging and formation evaluation. Shaly material can be distributed in the formation in three ways. The conventional resistivity in a laminated shaly sand formation for the sand resistivity rsd of. Shaly sand formation evaluation using a single membrane. In the application of these models to specific formations, industry follows no axiomatic approach in terms of critical factors such as 1. Packed with moneysaving and time saving strategies for the engineer working in the field. 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.
Scribd is the worlds largest social reading and publishing site. Shaly sand interpretation qed pete 321, sections 501506 spring. A practical guide aapg continuing education course note asquitt, george b. Each of these can furnish a significantly different reservoir evaluation. Advanced methods for interpreting well logs, shaly sand analysis, and production logging methods. Review of existing shalysand models and introduction of a. Pdf reservoir evaluation of shaly formations has long been a difficult task.
An integrated formation evaluation approach for maximizing. Advanced formation evaluation in sandstones next training. Of course, the hydrocarbon inplace is obtainable once porosity and water contents are estimated in the formation. Page 311 electrical conductivities in shaly sands i. The result of the evaluation was utilized to investigate the low productivity from some zones and its relation with depositional process and petrophysical properties. Quantitative log interpretation and uncertainty propagation of petrophysical properties and facies classification from rockphysics modeling and formation evaluation analysis using kernel principal component analysis to interpret seismic signatures of thin shaly sand reservoirs. The sand percentage here is generally less than 30%. This leads to large uncertainties in the apparent sand resistivity even for. Determination of shale volume and distribution patterns and.
A practical guide aapg continuing education course note by asquitt, george b. A new equation is derived that directly relates shaly sand conductivity to the membrane potential. Sharma center for petroleum and geosystems engineering, the university of texas at austin, cpe 2. The course covers solutions for evalating various shaly sand reservoirs including. In such a situation, archies model works very well. Dualwater method of shaly sandstone evaluation dual water model. I have yet to find the ideal petrophysics or formation evaluation text book. When heavier minerals are also present in the formation in variable amounts. Subject are the fundamental techniques of well loggingborehole geophysics and the interpretation of measured data formation evaluation. 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. Siyamak moradi 1, mohammad moeini 1, mohammad kamal ghassem alaskari 2 and elaheh hamed mahvelati 1.
On the application of simandoux and indonesian shaly sand resistivity interpretation models in low and high rw regimes k. Yet, no one method predominates within the industry. This leads to large uncertainties in the apparent sand resistivity even for relatively small volumes of laminar shale because the conventional resistivity measurements are made horizontally into the formation. Comparing the results of different shalysand evaluation methods is dif. Shaly sand petrophysics training course petroskills aps. The formation evaluation problem is a matter of answering two questions. The model showed that the conductivity of water saturated shaly sand co was directly related to the shaliness factor qv, conductivity of formation water cw, and porosity. A modified approach for volumetric evaluation of shaly sand.
In any petroleum province in the world where there are sandshale sequences, the geologist, engineer or log analyst confronts toe shaly sand problem. Shale can exist in the form of laminae between which are layers of sand. Water saturation equations in shaly reservoir rocks ptrl3023. 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 agbada formation consists of alternating sand and shales representing sediments of the transitional environment comprising the lower delta plain mangrove swamps, floodplain, and marsh and the coastal barrier and fluviomarine realms. Subsurface and petrophysical studies of shalysand reservoir. Shale is composed of silt, clay and their bounded water which will not flow. Responses of the three porosity logs in more complex. Petrophysical evaluation of shaly sand reservoirs in palouge.
Consequently, the methods and techniques in the shaly sand models can be used to improve petrophysical evaluation of shaly sand reservoirs. Shale is the most common, and certainly the most troublesome, rock type that must be drilled in order to reach oil and gas deposits. The way shaliness affects a log reading depends on the amount of shale and its physical properties. A valuable reference dedicated solely to well logging and formation. Summary formation evaluation from well logs in laminated shaly sands has often suffered from lack of proper. Shaly sand petrophysics inhouse training by petroskills.
This in turn makes seeking enhanced reservoir description of shaly sand. The conventional resistivity in a laminated shaly sand formation for the sand resistivity r sd of 20. Well logging and formation evaluation sciencedirect. As a result, a shaly sand with gas can look on the log as though the tool is in a liquid filled clean sand. An integrated formation evaluation approach for maximizing the value of mature shaly sand reservoir a case study from ravva middle miocene reservoir sudipto datta, bernd herold, tim osullivan, kausik saikia and vivek shankar, cairn india limited, kumar praveer, petrofac summary. This course can be conducted on site at your location exclusively for your staff. In lo g interpretation of shaly sand is used matrix densit y of quartz d. In thin lamination shalysand, fine grained of sand, silt and clay were. Toby darling, in well logging and formation evaluation, 2005. 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. Gas normally has little effect on the acoustic log, unless the formation is uncompacted.
The following definition and petrophysics model are a typical shaly sand formation model which assumes. 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. Pdf improved reservoir description of shaly sands using. The shale volume is about 9 percent and formation water resistivity for virgin zone is 0. Comprehensive coverage of the latest technologies and practices, including, troubleshooting for stuck pipe, operational decisions, and logging contracts. Openhole log analysis and formation analysis book osti. Integrated petrophysical evaluation applied to the. Formation evaluation in thin sandshale laminations. 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 will be suitable for all geoscientists and engineers who will benefit greatly from exposure to advanced knowledge and expertise in formation evaluations in clastics.
Openhole log analysis and formation evaluation, 2012 edition, by richard m. Basic formation evaluation university of southern california. Advanced petrophysics training in evaluation sandstone formations. Shaly synonyms, shaly pronunciation, shaly translation, english dictionary definition of shaly. Containing shale, a finegrained, impermeable, sedimentary rock composed of clays and other minerals, usually with a high percentage of quartz. R ar o w m 1 where r o is the formation resistivity of watersaturated sediment, r w.
Connectivity equation and shalysand correction for. Examples with an exercise part sandstone reservoir, shaly sand interpretation, complex mineralogy. Electrical properties, petrophysics and formation evaluation. Tongue of the castlegate sandstone, and mancos shale, eastern book cliffs, colorado and utah, usgs. The laminated shaly sand analysis lssa technique is a log analysis model specifically designed for the evaluation of thinbedded, lowresistivity sandshale sequences using vertical. The evolution of shalysand concepts in reservoir evaluation.
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