Water Input Profile Determinations on Injection Wells in Secondary Recovery Fields

Abstract

Abstract The knowledge of the distribution of input water in injection wells is important to the success of water flood secondary recovery projects. The presence of thief formations, the lack of complete well history, and improper completion methods all contribute to diverting the flood water from the producing horizon. Through the use of known tools and procedures, input profiles can be obtained. The interface velocity procedure coupled with caliper and correlation logs give satisfactory input profiles. These provide the data to detect the presence of the undesirable conditions and for the method of correction. Under normal conditions the correlations between profile data and permeability data from cores is good. Introduction The application of secondary recovery methods to oil production has spread rapidly throughout the oil fields of the United States. This has created a desire for greater knowledge of the behavior of the oil reservoir under a secondary recovery program. In the case of water flooding projects and particularly during the early stages of pilot flood work, it is important to know the water is being directed through the proper zone. In a recent paper on secondary recovery water flood projects which had been classified as unsuccessful, it was shown that a considerably larger quantity of water had been injected than fluid recovered. This indicated that the flood water was going into zones which were not part of the oil reservoir. Confirmation of this was not established since no attempt had been made to determine the distribution of the input water into the zone being flooded. The need for this type of information on many water flood projects has caused the secondary engineers to seek means of obtaining this data in an effort to better understand and evaluate their various floods. This would require a procedure which would work satisfactorily on wells completed either through perforations, open hole, or shot hole under the following water flooding conditions, namely:Surface injection of flood waters under pressure;Surface injection of flood waters at atmospheric pressure;Dump flood wells using water for flooding from a zone above the oil reservoir. In addition, any tool involved would have to be small enough to work through 2-in. tubing, since a large number of injection wells have tubing in them. In some cases it is not desirable and in others it is not possible to remove it.