Saudi Arabia: Significant time saving and exceptional data accuracy proved with Target DISCOVERY Well Test Tool with providing real-time shut-in formation evaluation
Tool in operation:
The candidate well was an exploration oil well in Saudi Arabia. Build-up shutin formation testing was planned on three different zones to determine well productivity and reservoir characteristics.
The operation required tool capability to perform acid stimulation, nitrogen lifting and shut-in build up test of the formation in a single run. Downhole pressure and temperature data was to be displayed real-time at surface throughout the operation.
The operation was planned executed with the new Target DISCOVERY™ Tool, conveyed on Coiled Tubing (CT) and controlled from surface via the CT internal cable.
The Target DISCOVERY™ Tool is an alternative to conventional testing methods utilising downhole shut-in tools, typically installed on electric wireline and timer/memory based.
Using the Target DISCOVERY™ gives distinct advances over the conventional technology, such as real time observation of downhole pressures and temperatures during flowing and shut-in periods. This greatly supports the decision-making process when evaluating the performance of exploration wells and fields. In addition, stimulation operations can be easily integrated into the process, allowing the evaluation of the well’s performance before and after, effectivly without multiple runs.
The Target DISCOVERY™ consists mainly of a single packer, slips and a shut-in valve. All tool functions are controlled from surface via the CT internal cable. Well flow can be directed around the tool with the packer not set and through the tool with the packer set and the shut-in valve open in the open position.
Real-time casing-collar-perforations-locator (CCPL) was used for depth correlation and to assure accurate tool placement. At position the electrical operated slips were set and confirmed to be anchored inside the casing.
Each zone was flow tested with and without the packer being set. The electric downhole shut-in valve is multi-cycle and was closed several times to obtain build-up pressures and temperatures in real-time.
The downhole data was available instantly throughout all processes of the operation. Two of the zones were stimulated and then tested again as a result of the availability of the downhole reservoir data real-time. Direct comparison between the zone’s capabilities before and after the stimulation was available in real-time. This opportunistic approach was available to the operator, due to the unique combination of electrical, mechanical and hydraulic capabilities enabled by the Target DISCOVERY™ Tool conveyed on electric CT and far exceed the operating envelop of the conventional wireline technology.
Target DISCOVERY™ completed the operation in less time compared to the conventional method, significantly reducing the operational cost for the operator. High accuarcy real-time data throughout the operation was used to optimize the operation giving better and more data for the reservoir evaluation.