Deep transient testing without flowing proves productivity

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Mexico, North America, Offshore

Deep transient testing (DTT) in a large reservoir offshore Mexico enabled more efficient operations while maintaining safer well control and without the need to flow the well to a barge. As a result, the operator confirmed reservoir quality and proved productivity to declare commercial discovery.

Reservoir testing to assess producibility in Mexico without flaring typically requires hydrocarbons to be flowed and disposed in barges. The operator searched alternatives to derisk reservoir characterization while reducing the time and cost associated with conventional testing without compromising local requirements for reserves classification.

The operator successfully conducted three DTTs to characterize and prove flow potential in three different sands and collect six pure samples, ensuring safer well control without the need to flow to a barge. The total operation lasted 5 days per the plan. In the longest transient flow, the dual-packer system was used for testing as the source flowing device, with the 3D radial probe for observation. In the two other transient flows, additional flow units were tested and flow capacity was estimated. The results were combined into a well deliverability assessment that enabled the operator to prove flow capacity.

Plot showing transient test station details
Transient test station details showing close to 18 h of data acquisition with two large flows and buildups. The flow rate reached close to 100 cm3/s as shown in the plot on the left, and the final buildup data lasted close to 10 h.
Log-log plot modeling results of the vertical interference
Modeling results of the vertical interference between the dual-packer source (blue curves) and 3D radial probe observation (gray curves). The model match of both pressure transients enables obtaining horizontal and vertical permeability with confidence.
Products Used