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Collaborating Authors
The Log Analyst
William Grady Halbert, Jr. June,1962 (Editor's Note: This is a condensation of Mr. Hnlbert's pmer, omitting the tabulated data, many of the plots of data, the very detailed and thorouqh discussion of results, and the biblioeraphy. Some of the rest has been cut of references to the omitted tables and graphs.?'his rather arbitrary shorteninq was due to space limitations; readers needing more detailed information are referred to the Library of the University of Texas, where the conplete renort is on file.) IMTRODUCTICN The identification of beds of different litholopical types in well logeins; is made from interpretation of the Spontaneous Potential (5.P.) curve. It is well known that S.P. deflections to the low, or negative, potential side of the log stones are characteristic of porc;us and permeable beds such The magnitude of the deflection opposite a porous, permeable bed is referred to as the "SP" and is a measurement of the tctal ohmic drop in the borehole fluid. Investigations of the SP have revealed it to be a combination of electrochemical, electrokinetic, and contact potentials. In conventional log interpretations# only electrochemical components are considered. When the logged SP for a particular bed is less than the static or true electrochemical potential because of borehole and bed thickness effects, empirical adjustments developed by Doll may be applied. However, no method for correcting borehole potentials which are greater than static potentials has been devised.
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
A nomograph is an alignment chart which enables one, by use of a Straight edge, to determine the values or dependent variables of equations for which the independent variables are given. These charts have been used in many fields, including quantitative well log analysis, as a quick and easy means of obtaining desired information.
The formation factor vs. porosity relationship is given by F=a/0m, where F = formation factor, 0 = porosity, and a and m are constants related to many textural properties of the formation rock. Average values generally used for the constants are a = 1.00 for m = 1.8 to 2.0, or a = 0.62 for m = 2.l 5. Figure 1 shows the graphical plot of F vs. 0 for a rectangular system
Many investigators have shown that fluid is lost to permeable strata during normal drilling operations. The fluid may be the mud itself or the filtrate from the mud. Agreement is genera1 that mud will invade fissures, channels, and other large openings in the formation whereas the filtrate will invade the rock itself. Many investigators have pointed out the detrimental effect of the filtrate, or water, on the producing characteristics of oil or gas wells.
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
The predominant negative charge of the shale framework attracts and allows the passage of cations but repels and prevents the passage of anions. When the formation water and mud have different electrolyte concentrations, a larger number of cations will pass from the more concentrated fluid than from the less concentrated fluid. The net effect of this cationic migration is the development of a positive charge in the less concentrated fluid. The resulting potential difference that exists across the shale partition is the membrane potential. It appears that drilling mud and/or its filtrate commonly makes contact with formation waters through the invaded zone in a permeable bed., Since nothing separates the fluids, both cations and anions are able to transfer from either liquid to the other, Such transfer is well illustrated by sodium chloride, The sodium ions have a stronger affinity for water than do the chloride ions; therefore the anions travel faster through the water, This migration of the chloride ions gives rise to a negative charge in the less concentrated of the two fluids, The resulting difference is the liquid junction potential, Thus liquid junction potentfa3 is attributed to differential ionic migration through the boundary between mud filtrate and connate water. It is proposed to simulate such an environment as might be conducive to the generatrim of thhsrpptential, However, according to the conditions of the experiment, there will be no definite boundary between the filltrate and the salt solution when they are mixed. Despite the absence of this boundary, the situation is still that of filtrate in diredt contact with fornation water.
- North America > United States > Texas (1.00)
- North America > United States > Oklahoma (1.00)
- Europe (0.94)
- Geology > Mineral > Silicate > Phyllosilicate (0.53)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.44)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Treatment (0.41)
If this objective is to be accomplished, the in permeability of the joint between the cement and casing must be with acceptable limits. However, from field experience, it is the opinion of the authors that the quality of this joint has diagnostic value in appraising the effectiveness of the over-all cement job. Here we will discuss those properties of this joint that can be measured with an acoustic device known as a Cement tween Bond Logging took. An attempt will be made to show a correlation be the measurements made by this device and the ability of the joint to conduct fluid longitudinally in the borehole. If an acoustic generator is placed inside of a string of pipe and the sound energy is forced into the casing, the pipe will conduct this enera away from its generator.
LOG INTERPRETiiTION OF SECONDARY SALT DEPOSITION MISSISSIPPI N LIMESTONES ROOSEVELT COUNTY, MONThNA by John H. Wetzel Master's Thesis, University of Texas Salt sections in the upper portion of the Mississippian Charles formation in northeastern Montana are well known. Less publicized, however, is the occurrence of secondarily deposited salt in porous lower Charles and underlying Iverson carbonates. Plate I indicates the gamma ray, self potential, guard-type,!#velocity"
Editor's Note: The article that follows is abstracted from the thesis Dresented to the Faculty of the Graduate School of the Univer sity of Texas in partiai fulfillment of the requirments for the degree of Master of Science in Petroleum Engineering, May, 1959. Any resemblances between this article and a paper presented at the last annual convention is intentional. Inspite of the fact thst this thesis served as the basis for Mr. Hilchie's recent paper, it was felt by the editorial staff that the original thesis differed sufficiently from the paper presented at the convention to merit its inclusion in this News Letter. Furthermore, this fits into the current program of the News Letter to notify the members of the vast reservoir of information available that is un-published in the field of logging. ABSTRACT Quantitative interpretation of well logs in fractured and vuggy reservoirs require specialized techniques.
- North America > United States > Texas > Permian Basin > Midland Basin > Big Lake Field > Ellenburger Formation (0.99)
- Africa > Namibia > Kalahari Desert > Kavango Basin > PEL 073 > Karoo Formation > 6-1 Well (0.99)
General Crude Oil Company Rr, Leonard Lipson Consultant, Houston Editores Note: The technical note that follows is abstracted from a Thesis presented to the faculty of the Department of Petroleum Engineering of the University of Houston in partial fulfillment of the requirements for the degree of Master of Science in Petroleum Engineering in June, 1960. That this Technical Note is not the original thesis, but rather an abstracted condensation thereof should always be kept in mind by the reader, No effort was made to rewrite any part of the thesis in order to make the reading smoother in bridging the gaps caused by omitting sentences, or even whole paragraphs. SUMMARY slyz;ing The object of this research was to develop a simplified technique of an electrical logs for the Gulf Coast Area. The method developed in this research persnits obtaining a reliable porosity and water saturation value for the uncontaminated Bone of a sandstone formation with porosities in excess of 18 per cent. These values may be calculated from the information recorded on the self potential curve and the 16 and 64 inch normal resistivity curves of the standard electrical log, The water saturation is obtained by solving Archiefs saturation fornula.