Petro Matad spudded the Heron-2 development well in Block XX in Tamsag basin, eastern Mongolia, on Sept. 8. This is the first development well to be drilled on the Petro Matad-operated Heron field.
The field was discovered through the Heron-1 discovery well in 2019. It holds total oil in place potential of about 190 million bbl, the company said (OGJ Online, Mar. 24, 2020).
Heron-2 is being drilled by the DQE International rig 40106 and is about 800 m south of Heron-1. It is targeting the same reservoir units of the Cretaceous Lower Tsagaantsav formation that were proven productive in Heron-1. Heron-1 flowed at a maximum rate of 821 b/d of oil on test from a 12-m interval between 2,834 m and 2,846 m in an overall oil column of some 70 m. This was the third best test rate ever recorded in Mongolia, the company said.
Heron-2 will investigate the extension of the productive reservoir zone observed in the discovery well and will be drilled to a total depth (TD) of about 2,900 m. The reservoir is expected to be encountered at a similar depth to that in Heron-1 based on interpretation of 3D seismic data covering this portion of the Heron structure.
Drilling to TD is expected to take about 30 days following which wireline logging will be conducted to evaluate the productive potential of the reservoir. A well test and stimulation program are planned to be executed during the 2024 operational season. If successful, Heron-2 will be put on stream in either late 2024 or second-quarter 2025 after the winter operational shut down.
The construction permit for installation of production infrastructure at Heron-1 is at the final stage of the approval process. Negotiations are progressing with PetroChina and industry regulator Mineral Resources and Petroleum Authority of Mongolia (MRPAM) for processing, transport, and sales of Block XX production.
