Corcovo Norte

1. Project Overview

Pluspetrol S.A. (PPT) requested Anddes to carry out drilling and installation services for groundwater monitoring wells in order to monitor groundwater at different oil and gas fields located in the provinces of La Pampa, Mendoza, and Neuquén.

According to the characteristics of each field, the estimated groundwater table depth — determined through indirect methods — and the requirements of the respective regulatory authorities, the final drilling depth ranged between 8 and 70 meters. The casing was installed using 3” and 4” diameter PVC pipes, protected at the surface with a wellhead and a cement base.

During each drilling operation, soil samples were collected every meter, recording and describing the lithological profile encountered. In wells where the groundwater table was identified, well development was performed until stabilization of the parameters was achieved, after which groundwater samples were collected following the appropriate purging process.

2. Project Challenges

This project involved both technical and logistical challenges.

From a technical standpoint, one of the main challenges was implementing a drilling methodology that ensured sample representativeness while preventing cross-contamination. The drillings were carried out using a down-the-hole hammer with air injection, employing a multipurpose drilling rig. These activities were performed under complex conditions due to the presence of cemented conglomeratic strata, large sand deposits, and, in some cases, underground interferences typical of operational areas.

Regarding logistical challenges, the geographical distribution of the drilling sites required the mobilization of equipment and tools across long distances. These activities were planned and executed under strict safety conditions and with constant monitoring.

3. Our Approach and Solutions

To address these challenges, an integrated approach was adopted based on:

• Comprehensive review of existing documentation for each site.

• Detailed field surveys and verification of the absence of underground interferences.

• Analysis and interpretation of analytical results from soil and groundwater samples.

• Joint evaluation with the client of technical and economic criteria to define the work plans.

This approach combined the technical expertise of the Anddes Argentina team with operational flexibility and a strong commitment to continuous improvement, ensuring safe work conditions for personnel, equipment, and facilities at each field.

4. Results Achieved

The activities carried out resulted in the following outcomes:

• Drilling of wells and installation of groundwater monitoring wells at variable depths (between 5 and 60 meters below ground level).

• Characterization of soils and subsurface profiles encountered.

• Groundwater characterization at selected sites.