Surface Indicating Pressure, Temperature and Flow Equipment

A surface indicating pressure, temperature and flow instrument that employsvariable frequency sensing elements has proved useful in evaluating flowcharacteristics of wells. Relative productivity of individual oil and gas sandsin a given well can be analyzed at several back pressures. The variable frequency sensing elements are an improvement in sensitivityand accuracy and make possible observation of temperature and pressurevariations that have not been possible heretofore. The surface indicatingfeature results in a more direct approach to solving problems and eliminatesmany assumptions. All three subsurface factors are evaluated, and correlation between themresults in a direct means of analyzing reservoir and well conditions. Surveys have been used to evaluate well performance, locate gas entry inhigh ratio wells and to investigate gas injection and water floodingconditions. Introduction In a flowing well that is open to a multiple number of producing sands withvarying characteristics, it is valuable to know which sands are producing fluidat a given back pressure and in what relative quantity. Core studies couldqualify an interval as productive, and reserves would be computed on thisbasis. Unless the well is produced so that the interval does contribute, irreparable damage to the interval can occur. It is generally accepted that theoptimum condition of production of oil in an oil well will be, if the objectiveis to produce the largest amount of oil at the least cost, to produce oil atsuch rates of flow that the decline of production and the intrusion of edgewater should be uniform as between all portions of the producing horizonsproducing into the well. An indirect approach to this problem does not alwaysresult in a timely practical answer. To insure a correct answer, the conditionshould be measured as directly as possible, while the well is being produced.The PTF equipment was developed with this objective. Measurements of allvariable factors that can be associated with fluid movement, to a high degreeof dependability and accuracy, was a design requirement. Initial field use has indicated that sufficient data can be obtained withthe instrument to answer the questioned conditions in a reasonable length oftime and at a reasonable cost. A description of the instrument, the principals of operation, and the fieldexperience are discussed herein. T.P. 3080