Theory and Application of Well Analysis

Abstract

FUNDAMENTALS OF WELL ANALYSIS A well analysis program is an area where any oil company can make money immediately. It appears that most well analyses are performed by large oil companies that have large computer facilities. However, in order to use these facilities, a great deal of effort is required on the part of the engineer or technician. Quite often, the engineer could make a few calculations with a small calculator and have the answer to the problem. This requires that the engineer understand the basic principles of the pump, rod string, and pumping unit operation Equipment to obtain the necessary data has been hard to use and required considerable time. Usually, the pumping system had severe problems before the time and effort would be spent to analyze it. Now, equipment is available that will allow the engineer or technician to obtain the data easily and make an analysis in a few minutes. Of primary importance is a thorough understanding of the operation of a modern oil well pump. Fig. 1 is a schematic drawing of such a pump. There are three main components of an oil well pump: the standing valve (SV), the traveling valve (TV), and the pump barrel. The SV is located in the bottom of the pump barrel and opens or closes, depending on the relationship between the Pressure Pl and P3. The TV is located in the plunger and opens or closes, depending on the relationship of the Pressures P2 and P3. Pressures P2 and P3.The operation of the pump is as follows. Assume that the pump plunger is at its lowest point and is starting to move upward. As the point and is starting to move upward. As the pump plunger stops and begins to move upward, pump plunger stops and begins to move upward, the TV closes because Pressure P2 is the same as Pressure P3, and the weight of the TV causes it to fall into its seat. With the TV closed and moving upward, Pressure P3 is reduced. When the pressure difference between Pl and P3 is large enough, the SV will be forced open. This allows well fluid to flow into the pump barrel. As the plunger rises, the pump barrel continues to fill. Note that the reason for the pump barrel filling was the plunger moving upward, which reduced Pressure P3. When the plunger stops its upward movement at its plunger stops its upward movement at its topmost position, Pressures Pl and P3 equalize and the SV closes because of its own weight. When the plunger, starts down, it will be forced into the fluid in the pump barrel, which will cause Pressure P3 to increase above Pressure P2, thus opening the TV. P2, thus opening the TV.