Compositions: coating or plastic – Coating or plastic compositions – Inorganic settable ingredient containing
Patent
1998-03-06
1999-11-09
Marcheschi, Michael
Compositions: coating or plastic
Coating or plastic compositions
Inorganic settable ingredient containing
106781, 106785, 106776, 175 58, 175226, 175424, C04B 2816, E21B 2508
Patent
active
059806281
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a curable gypsum-containing composition for the production of a cured gypsum-based matrix, and a method for stabilization of unconsolidated core samples, according to the introductory of claims 1 and 9, respectively.
TECHNICAL BACKGROUND
In the production of gypsum articles, casting molds of gypsum and in building applications, such as for wall finishing, for example, it is known to use a solution/suspension of calcined gypsum, optionally added set accelerating or set retarding substances. A common feature of such curing gypsum systems is that the pot life or the time until gelation is about one half of the time to obtain full strength. The disadvantages of set retarding additives for gypsum/water compositions is that the compositions after application to a wall or into a mold, will creep or block the form for a long period of time. Some retarding substances require from 15 minutes to 8 hours to obtain a strength level allowing further processing or handling, dependent on the portion of the retarding substance. On the other hand, normal or set-accelerating additions to gypsum compositions may result in a short pot life since gelation may occur from one minute to fifteen minutes after the preparation of the composition. This may result in problems such as hardening in mixer units and pumps and lead to clogging or blocking of the equipment.
Accordingly, there is a need for a curable gypsum-based composition providing a gypsum composition ready for use, a composition having a long pot life but short setting time after application and preventing creep from for example a finished wall.
In another aspect, core samples are obtained from oil and gas drilling both off-shore and onshore by means of special drill heads provided with a central cylindrical bore. When the cylindrical bore or space extending form the drill head and a certain distance up the drill stein is full, the drill stem is withdrawn, and a so-called core sample is removed from the same. These core samples represent some of the most important material available for evaluation of the quality of the hydrocarbon-containing sedimentary rock types to be searched for. For that reason it is of considerable importance that the samples are protected from both mechanical and chemical strain to obtain correct values from the subsequent evaluation and analysis.
The geologists evaluation and analysis of the humidity properties of the sample, permeability, porosity and oil and water content, can provide the limits of the gas- and oil-containing layer thickness, the expected quantity of oil and/or gas to be produced, and the availability of the oil or gas. Therefore, it is important that these samples are as close in the reservoir to their original condition as possible, to provide a proper basis for both visual evaluation of the core material and subsequent analysis. In many cases, the samples are poorly consolidated and have to be protected from disintegration during transportation from the reservoir, during preparative cutting and drilling with diamond equipment and during the following analysis.
Presently, there are one of two important methods used to protect the cores mechanically during tansportation, core sampling and storage. These methods have different advantages and disadvantages:
1. Freezing core samples with liquid nitrogen
This method will stabilize all core samples containing water and oil since the sand is locked in a matrix consisting of ice and oil-based glass. However, because of the water expansion during freezing, the core material will often be damaged in the process. The damage is caused by the fact that the inherent weak bonds between the sand particles are broken (more or less) because of frost cracking during the freezing step. After cutting with a diamond saw in a frozen condition, the core samples are not suitable for geological evaluation as the samples have been reduced to more or less freely flowing sand. After drilling of test plugs, mounting and thawing in analysis equipment, this frost cracking also freq
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patent: 4661161 (1987-04-01), Jakacki et al.
patent: 4713115 (1987-12-01), Sato et al.
patent: 5273579 (1993-12-01), Tanaka et al.
patent: 5360074 (1994-11-01), Collee et al.
patent: 5855948 (1999-01-01), Mill et al.
Ardo Bjorn Arild
Hjelmeland Odd
Marcheschi Michael
Reslab AS
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