in Asia, the Middle East, North Sea and Africa.
ynamic reservoir data are a key enabler for oil and gas operators to prove reserves and maximize hydrocarbon recovery. However, traditional well testing approaches, where a job is planned, executed and interpreted in a linear fashion, can limit operators from obtaining the optimal amount of data during the well test. Furthermore, this approach is inefficient and rigid, significantly increasing the time operators spend between acquiring data and making key field development decisions.
For many decades, the linear well testing approach remained unchanged until the introduction of wireless telemetry about 10 years ago. Wireless telemetry enables acoustic data to be transmitted across downhole repeaters from the downhole gauges to surface in real time. Prior to this innovation, the only way to gather real-time data was through a wireline deployment during the drillstem test (DST), which increases risk and cost.
While wireless telemetry, combined with a conventional DST tool string, enabled some data acquisition flexibility for real-time data interpretation, it stopped short of providing operators with the ability to acquire dynamic data for making actionable field development decisions in real time. To achieve this, operators needed a way to enhance the flexibility of well testing operations by increasing the control of the downhole tool string.
The wireless tools are united via Muzic wireless telemetry, providing bi-directional feedback of tool position for operational control and enhanced capabilities. The digital tool string is customized for the operator’s reservoir evaluation objectives.
During field tests of the live downhole reservoir testing platform in Asia, the Middle East, North Sea and Africa, the digital tool string was customized for each operator’s reservoir objectives. A common thread across each test was a complex reservoir environment. The digital tool string provided the flexibility for the operators to make actionable decisions in their workflows. This enabled them to acquire the dynamic data they needed while overcoming challenges, including, but not limited to, shallow reservoir depths, fluid compressibility issues, low bubble point pressure, crew optimization and rig time reduction.
The wireless dual valve incorporated an independently operated test valve and circulation valve providing isolation within the tubing and from tubing to annulus, respectively. Since it did not require pressure pulse for activation, the operating envelope was ideal for a shallow reservoir environment. It provided full well integrity and control throughout the reservoir test.
The wireless quartz gauges provided continuous real-time data, which through digital workflows and connected operations allowed the operator to make informed decisions toward optimization of the reservoir test.
The wireless correlation tool used gamma ray measurement incorporated into the digital tool string and transmitted to surface via the wireless telemetry. The addition of this tool reduced the overall correlation time, reduced the personnel on board by eliminating the three-person wireline crew and avoided running wireline into the tool string, hence decreasing HSE risk.
During the first DST, the operator opted to run both correlation methods to evaluate the use during the rest of the multiwell test campaign. The results shown in Figure 2 proved accurate to the cased-hole correlation within 1 ft, which satisfied the operator’s requirements. The entire correlation was completed in 1 to 2 hours, saving approximately 10 hours of rig time per well test operation.