Effects of Certain Gums and Starches on Filtration of Salt-water Muds at Elevated Temperatures
- Frank Perkins (Louisiana State U.) | Benjamin C. Craft (Louisiana State U.)
- Document ID
- Society of Petroleum Engineers
- Transactions of the AIME
- Publication Date
- December 1943
- Document Type
- Journal Paper
- 248 - 252
- 1943. Original copyright American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Copyright has expired.
- 1.11 Drilling Fluids and Materials, 4.1.2 Separation and Treating, 1.14 Casing and Cementing
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- 186 since 2007
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The wall-building properties of salt-water muds can be maintained at hightemperatures by additions of gum karaya, gum ghatti, gelatinized starch, orcommercially prepared starch. A germicide should be used to preventfermentation.
The behavior of drilling mud has received special attention from thepetroleum industry within the past few years in numerous research projectsdealing with such subjects as chemical treatment, gelation, and filtrationcharacteristics.
The importance and control of filtration, or water loss, is readilyapparent. It affects the analysis of side-wall cores and interpretation ofelectric logs; it controls to a large extent the work of primary cementing,reduces the amount of expensive fishing, and permits the running of longstrings of casing.
It has been found that among the many factors that have an adverse effect onfiltration, the presence of electrolytes, in general, and of salt, inparticular, is outstanding. The effect is one of flocculation of the colloidsdue to neutralization of the negative charges on the clay particles. Thisreaction is further increased on the Gulf Coast because high temperaturesreduce dispersion to a minimum, causing increased
flocculation in both fresh-water and saltwater muds. The problem of reducingwater loss in salt-water muds by the addition of gums and starch at atmospherictemperature has been investigated, and many successful field tests in WestTexas indicate its solution. From the work of Byck it is concluded that noexisting method will permit an approximate determination of the filtration rateat high temperatures from data taken at room temperatures. Filtration should bemeasured at the temperature actually anticipated in the well, or at least at anumber of lower temperatures and extrapolated over a small range.
A laboratory study has been made of the chemicals available for thefiltration characteristics of salt-water muds at high temperatures, and the useof germicides to prevent fermentation.
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