Water saturation s w can be measured directly from a sealed core, which is an expensive method, or it can be calculated from the archie equation, which is less expensive. Archie, dual water, juhasz, waxmansmits, simandoux, and indonesia are available. The archie equation for clean formation can be expressed as follows. The video below is a quick tutorial on how to perform a water saturation calculation using danomics petrophysics software. The extensions of the archie resistivity equations for formation factor and water saturation to the case of shaly sands has been undertaken by many investigators over the last 45 years. Water saturation sw simandoux 1963 another well known equation to calculate water saturation is simandouxs equation 1963. The m exponent in carbonate petrophysics r e gene ballay, phd. This equation is best used in clean nonshaley reservoirs. This is caused by the additional electrical conductivity of the clay. Rw zone not considered in the petrophysical interpretation, unreliable values for rw. In petrophysics, archie s law relates the insitu electrical conductivity of a sedimentary rock to its porosity and brine saturation. If you have specialised petrophysical software, then by all means use it. Uncertainty analysis of archies parameters determination. Water saturation sw archie 1942 archie s equation is one of the most known ways to calculate water saturation.
Holmes established his own consulting practice, involving petrophysics, technical due diligence, consulting to the united nations worldwide, expert witness activities, and instructor to ihrdc and the university of brunei. Typical parameters for the archie equation for consolidated sandstones are a0. The most popular versions among interactive petrophysics users are 4. This software is an intellectual property of senergy group limited.
Water saturation from electric logs outline what is water saturation and why do we care. More than 30 different water saturation models have been proposed over that period, of which three or four are more popular than the others. The rest of the story gene ballay and nelson suarez. The application contains a set of useful functions for geologists, geophysicists, engineers and any other person interested in borehole geophysics, petrophysics or well log interpretation. Archie equation archie equation is the most famous equation used by petrophysicists to determine the water saturation in the reservoir in hand. Archie phit for organic shales, archie or simandoux for conventional systems with rw remapping in all cases. Archie s equation was improved throughout time by several researchers as winsauer 1952, carothers 1968, porter and carothers 1970, timur 1972, tixier etc. In 1998, michael combined consulting activities with software development, to form digital formation, inc.
You drive the order of actions and the amount of guidance provided. The archie equation may not apply at low sw values. This uses the same parameters used in other equations from other authors e. How to calculate rw and m porosity cementation exponent. The socalled archie equation is most readily expressed in the form below. Larionov, clavier, steiber, neutron, resistivity and from double shale indicators. This provides linear and nonlinear response functions for the wireline and lwd neutron tools of the major service companies.
The equations, which are known as the archie equations, relate the resistivity of a formation to the resistivity of the fluids saturating a formation, the porosity of the formation and the. Crains petrophysical handbook water saturation archie. Essay about archie equation petrophysics 6528 words. Archie s equation is the water saturation model for the determination of water saturation. Crains petrophysical handbook resistivity concepts. In 1952 archie stated in discussing the petrophysics of limestones, it is necessary to first classify them in a manner to portray as much as possible the essential pore characteristics of a reservoir. Application of archie equation in carbonate reservoir. To enroll in the full course visit log response course automatic transcription one of the methods thats now widely used is the archie s water saturation equation and all the derivative equations that have a shale corrections built in them based on archie s work. This rmf must be a continuous curve generated by extrapolating the. In an earlier note the m exponent in carbonate petrophysics we discussed the physical meaning and range of values of archie s m exponent. The choices of tools for the evaluation program are usually made by the. The quality of the water saturation values derived from the archie. This pc program was developed to work on windows xp, windows 7, windows 8 or windows 10 and is compatible with 32bit systems. The prototype equation relating rock porosity to various electrical properties of rock bears his name.
Archies equation, which assumes clean waterbearing formation. He logically traced the interconnections between rock type, porosity, permeability, fluid saturations, water salinity, hydrogen content, capillary pressure, natural radioactivity, response to neutron bombardment, spontaneous potential, and. The most commonly used water saturation equation is that created by gus archie in 1944. Petrophysics petro is latin for rock and physics is the study of nature is the study of the physical and. These equations are highly nonlinear and may give unreliable results. Tables 5 and 6 contain the solution of three regression equations, which give archie s parameters for the sandstone and carbonate samples.
Used by petrophysicists and log analysts in manual interpretation to have a quick look evaluation. He played the key role in identification of producible horizons at the giant elk city field in oklahoma, an episode which dramatically demonstrated for. S w can also be estimated using a graphical representation of the archie equation known as the pickett plot see also. Petrophysicists use cutoffs for calculation of average values that are. This is a 5 day course that covers wireline logging, mwdlwd and their specific applications for wellbore stability and includes 12 hours daily of workshop examples. This course will be suitable for all drilling engineers, directional drillers and other geoscientists associated with drilling. Work on thousands of wells with data located anywhere in the world, as an individual or as part of a team. The m cementation exponent is the adimensional power parameter for porosity in the archie water saturation equation, the simandoux equation, the indonesia equation, and others. From this discipline of petrophysics, archie s equation is.
While useful for a quick look this is a method which requires that we make a number of assumptions about the relationship between porosity and water resistivity. Petrophysics msc course notes resistivity theory dr. Danomics petrophysics and log analysis software uses robust petrophysical workflows so that users can get consistent and highquality results. The cementation factor of archie s equation for shaly sandstone reservoirs article pdf available in journal of petroleum science and engineering 232. In the original paper, the samples had water saturation greater than 15%. Here, denotes the porosity, the electrical conductivity of the fluid saturated rock, represents the electrical conductivity of the brine, is the brine saturation, is the cementation exponent of the rock usually in the range 1. The equation is then run through 5 times on each side.
The two recommended equations are the archie equation for clean reservoirs and the. The equations on the following pages convert the measurements commonly made in open uncased boreholes into the formation properties of scientific and economic interest to us. Water saturation is one of the final steps in the petrophysical workflow and will directly play into your calculations of inplace volumes. Around 1950 gus archie, working at shell oil, changed petroleum exploration by developing a theoretical foundation for elog interpretation based on certain electrical properties of rocks. Petrophysics and software development, and 3d analytical. Water saturation calculated from openhole resistivity measurements is a primary input to hydrocarbon reserves evaluation. A graphical solution to archie s equation so that plotting resistivity against porosity both on logarithmic scales will produce linear arrangements of the data. In the original work, archie proposed that m lay between 1. Considering rt is the true resistivity of the reservoir.
An ebook reader can be a software application for use on a computer such as microsofts. Pdf calculation of petrophysical properties for mishrif carbonate. Archie is perhaps best known for his contributions to petrophysics. This equation is not shale corrected, so it should not be. Using archie s law to find formation water resistivity seems like a simplistic approach to hydrogeology. Resistivity logging rt ro, waterleg rt ro, hydrocarbons archie s equations and using then to calculate water saturation when doesnt archie work. For the first time, archie set out clearly the waft and weave of the complex fabric that is petrophysics. This author included in his equation different physical rock properties and measurements from different well logs like tortuosity, water and formation resistivities, saturation exponent, and porosity. Determination of rw using different methods sp, rwa, pickett plot etc.
This technique is a mathematical manipulation of archie s formula and considers the equation in the form of three regression equations to get the three unknowns a, m and n. Top 10 landmark papers in petrophysics and formation. Sw water saturation of the uninvaded zone n saturation exponent, which varies from 1. Work the way you want with powerlog petrophysical software. Sw on the right is calculated initially from the archie equation using m and n in place of m and n. Applied formation evaluation and basic log analysis using. Reservoir evaluation is one of the critical tasks of any reservoir exploration and field development plan. Pdf the cementation factor of archies equation for.
Using archies law to find formation water resistivity. The higher the m, the higher sw water saturation this parameter m depends upon the pore space structure connectivity, the matrix consolidation, and the grains shape more than the size. Pdf the accurate calculations of petrophysical properties in carbonate. Water saturation archie model crains petrophysical handbook. Danomics petrophysics software water saturation in 10. Archie developed his famous equation to calculate, from well log parameters, the water saturation s w of the uninvaded zone in a formation next to a borehole. Log equation expression write your own can save this and share with others. The saturationheight modeling module provides coretolog integration via the following workflow.
This equation is not shale corrected, so it should not be used in shaly zones. Shale volume from single indicators like sp, gr corrections. The minimum log data required by the spreadsheetbased software are a porosity. Another possible way is to create a pseudo rxo curve by calculating it using archie s equation, assuming that the invaded zone is 100% flushed with mud filtrate with a resistivity of rmf. It usually works well with clean clastic sandstones and carbonate rocks. Sxo is calculated in the same way, with rxo replacing rt, and rmf replacing rw. The petrophysics of shales and organic rich shale associated with carbonates. Archie between the formation factor f and porosity phi, in which f 1 phi m, where the porosity exponent, m, is a constant for a particular formation or type of rock. The archie equation was the first empirical model built 1942 to estimate the water saturation in non conductive matrix rocks. Fluid levels within the reservoir formation water what is it composed of.
Hence use of the archie equation in shaly sands will result in too low a hydrocarbon saturation. Ppt deterministic petrophysics powerpoint presentation. We start with archie s water saturation equation and take the logarithm to obtain linear relationships between reservoir porosity and bulk resistivity. Common openhole petrophysics interpretation equations. The archie equation assumes that the matrix is nonconducting. The following equations are used for sw calculation.
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