RESERVOIR DATA ANALYSIS AT THE WELLSITE

Abstract

Current drill-stem test pressure-recording techniques rely on a pressure sensor, a chart recorder and a clock. Analysis and interpretation of this recorded data can only be done after the tool string is retrieved from the well.

The subject of this paper is a computer-based system that monitors, records, analyzes and displays at the wellsite, supplying the reservoir data necessary for the well operator to make a production decision about the well.

This system uses the capabilities of full-opening testing strings to provide instantaneous display of pressure and temperature information at the time intervals selected by the operator. Because the system provides a continuous stream of data (at selected intervals) the printer-plotter can display results of computer calculations and make graphs necessary for evaluation of the reservoir. The well operator can judge by the data received when the test can be terminated, and so could shorten significantly the rig time used for the test.

A conventional 'pressure vs. time plot' is made throughout the test, and Horner, Log-Log and 'pressure vs. square root of time plots' are available on operator demand. The well operator can also obtain calculations of the well's theoretical potential at the conclusion of the test or during any flow period after closed-in pressure data accumulate.