Self-Powered Intelligent Data Retrieval Gauge for Unconventional Well Testing Using DFIT Technology

Abstract

Pressure transient testing has been the standard method used to obtain well information such as reservoir pressure, permeability, and skin in conventional reservoirs. However, with the shift towards unconventional, ultra-low permeability reservoirs, the only type of test that is economically practical for operators to use to determine reservoir and fracture properties is a diagnostic fracture injection test (DFIT). The DFIT provides a simple, cost-effective method for identifying fracture design parameters and essential reservoir properties in a relatively short period of time. Both fracturing and reservoir properties are critical inputs for proper fracture design, optimization, and reservoir characterization. When performing a DFIT, it is critical to use a high-quality pressure gauge that is thermally compensated, capable of one-second sampling and with a resolution of 0.01 psi. Detection of subtle pressure changes over a short period of time is essential in analyzing the fall-off data to determine reservoir characteristics accurately. The recently developed Self-Powered Intelligent Data Retriever system (SPIDR®) is an option for capturing accurate pressure data from the surface for use in DFIT analysis. This system provides a lower cost alternative that allows operators to view and download the data periodically during the fall-off without data interruption and without erasing the data. The downloads can then be reviewed to provide near real-time analysis, and also, will help determine when the test has been completed. A case study will be discussed that will show how data from a high-quality surface gauge mirrors that of bottomhole pressure gauges and can provide accurate DFIT analytical results more economically.