Abstract

A system has been developed based on a powerful portable microcomputer and an integrated data acquisition instrumentation package which allows real-time visualization of pumping well performance. The system integrates all the necessary elements to obtain a complete analysis of the performance of the pumping system which includes the pumping unit (beam or submersible), the wellbore, and the reservoir.

The data acquisition package consists of the necessary analog and digital input channels to process data from standard transducers such as pressure, temperature, rod load, displacement, etc., so that detailed surface unit performance curves such as dynamometer, speed, acceleration, power etc. performance curves such as dynamometer, speed, acceleration, power etc. can be obtained and analyzed. When the instrument is used in conjunction with an acoustic pulse generator and receiver, it digitizes and records the reflected acoustic signals which are digitally filtered and automatically processed to determine the liquid level. This is undertaken under program processed to determine the liquid level. This is undertaken under program control so that a recording of fluid level vs, time is obtained concurrently with the pumping performance parameters. Fluid level data is processed by the software to calculate bottom-hole pressure as well as flow processed by the software to calculate bottom-hole pressure as well as flow into and out of the well bore. Changing the well from flowing to shut in conditions allows recording of pressure buildup data which is then interpreted in terms of reservoir parameters. Alternatively, pump start-up after shutting in the well in for stabilization, provides draw-down testing capability. The analog/digital electronics system contains outputs of a 12 volts relay driver and also normally open/closed contacts for external control of gas-gun valves, motors, variable speed drives, casing vent valves, etc. These outputs are computer controlled and can be actuated depending upon input data, operator keyboard entry and/or time.

Graphic display of the various diagnostic parameters allows complete visualization of the performance of the whole pumping system including the reservoir, wellbore and pumping unit. The system can be used as a diagnostic tool to optimize pumping well performance on a periodic basis. The present performance of the well is compared to the performance recorded previously and in the case where significant changes are noted a more previously and in the case where significant changes are noted a more detailed analysis is undertaken. In critical well applications, the system can function as a stand-alone dedicated controller.

Well Performance Visualization

Figure 1 is a schematic diagram of the Well Performance Visualization System. This system is the integration of various surface measurement systems with well data base information and with software packages designed for diagnostic analysis of well performance. The system's objective is to yield an accurate and timely analysis of well performance for the present operating conditions and to predict the effect of operational changes on the well performance. Integration of these elements has been made possible only recently through the development of powerful microcomputers, portable digital data acquisition electronics, improved low cost sensors and transducers and PC-based software for analysis, data base management and graphics.

Well performance in the context of this paper addresses the complete well system including: the reservoir, the wellbore and the pumping components. Visualization of well performance then involves the ability to understand how these elements interact to yield the present conditions of pressure, flow rates, loads, efficiency, etc. and to be able to forecast the effect of changes in the variable operating parameters such as speed, stroke, surface pressure, on/off time, etc. and changes in the well configuration such as pump depth, rod sizes, surface unit geometry, well stimulation, etc. on the performance of the system.

For many years, the industry has had access to the individual components of the system: acoustic liquid level measurements, dynamometer measurements, well test data, pressure recorders, transient well test data, etc. The present system provides the means to integrate all these elements in a present system provides the means to integrate all these elements in a single system capable of providing the complete picture of the performance of the well. Figure 2 is a block diagram representation of the hardware and software configuration that implements the well performance visualization system.

Acoustic Well Soundings

Acoustic echo-ranging techniques to generate well soundings have been in effect for over fifty years to aid in the analysis of pumping wells. Early application was limited to determining the presence of liquid in the annulus above the pump.

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