RIASSUNTO
SPE Members
Abstract
The main objectives in introducing automated chemical handling system were:
1. To provide more effective product mixing.
2. To minimize chemical losses through inefficient sack cutting operations or broken sacks during transport and storage.
3. To improve the working environment.
The three rigs that Norsk Hydro equipped with automated mud mixing reduced chemical losses to almost zero. This is because the sack cutting operation was totally mechanized. In addition, the arriving sacks were inspected before being processed. Broken sacks or obviously old material was returned to the supplier.
The mixing operation offshore has been computerized and this ensures that accurate and even dosing of additives occurs.
The working environment has been vastly improved both onshore and offshore. The sack-opening operation and mixing process are totally enclosed. Even the empty sacks ar automatically compressed into plastic ""sausage skins"" that allow no exposure to the atmosphere.
Manhandling of sacks is eliminated. The only exception is mixing of lost-circulation or stuck-pipe pills. Due to the relatively smaller quantities of chemical used, these are mixed manually.
Introduction
The offshore oil industry has frequently been criticized for lagging behind comparable land based industry.
Manufacturers of products requiring high degrees of accuracy in a chemical mixing operation have been using automated handling and mixing techniques for many years.
The chemical industry has over 30 years experience of powder handling. Norsk Hydro initiated a pre-study to see if this experience could be transferred to the offshore mud mixing process.
The prestudy arrived at the following conclusions:
1. More effective and correct product additions could be achieved through automated mixing. Fish-eyes, over and under-treatment could be avoided.
2. Additive consumption could be reduced by minimized losses during sack cutting. Losses through broken sacks would be reduced to zero.
3. The work environment would be improved through the elimination of manual handling, reduced contact with the chemicals and minimization of dust pollution.
Based on these conclusions Norsh Hydro decided to introduce automated chemical handling and mixing offshore, which consists of the following main components.
- Chemical filling stations located on the onshore supply base, where mud chemicals are transferred to dry bulk or liquid transport/feed tanks, which are transported offshore to be connected to the rig's mixing system feeding stations.
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