Ultra Sour Wells Testing and Blending with Other Wells Within Facility Limits with Excellent Collaboration of Upstream and Downstream Team Contributed Towards Sustainability Targets
Authors: Siddiqui Muhammad Ali , Subaihi Maad Hasan Qayed , Hosini Abdullah Alhaj Al , Janahi Mohammed Ibrahim Al , Pangestu Yohannes Fisher , Agarwal Anubhav , Alhajeri Ahmed Mohsen Abdulla Faraj , Ahmad Zeeshan , Ahmad Mubashir , Alhammadi Reem Mohamed , Thabit Muhammad , Shinde Kaustubh Dhananjay , Alhefeiti Maryam , Ahmed Sami Ullah Bashir , Hoot Abdulrahman Mohamad Al , Al-Hammadi Yousef Abdulrahman , Alhmoudi Ahmed Abdulla Saif , Orekie Uchenna Christopher 
Published: November 2024

In general exploration & appraisal of new reservoirs involves flaring operations. Well testing operation of sour wells by flaring or flowing through existing pipeline networks with limitations is always considered highly challenging in the brownfield. Ultra-sour appraisal well testing operation considered to be complex in nature and may be resulted serious concern due to toxic gasses and their immediate effects. The wells are in congested developed fields and special consideration regarding social risk analysis and mitigation to be considered for operations. Apart from social risk there could be flow assurance issues due to scale deposition in the surface network during testing. Therefore, it is required to test the facilities to handle high H2S reservoir and blending with the low H2S content stream.

To appraise the ultra-sour reservoir, extensive HAZOP (Hazard and Operability study) reviews and a blending study were carried out in-house. Multiple blending scenarios were developed real-time to ensure that H2S & CO2 remained within facilities limit.

Below is the stepwise approach followed to achieve all objectives in line with our sustainability targets.

Initial blending estimates based on Compositions and remote manifold stations (RMS's) / compression stations (Cs's) profiles. Proposed sour gas blending ratios are calculated in such a way so that the net effect of H2S at the compressor station common suction header (post mixing) will remain within limit, any increment shall be managed through negotiating production from less sour wells. Afterwards developing the baseline for the project, a detailed technical discussion was carried out with the downstream team. In this regard, the facility integrity team confirmed the integrity and adequacy of existing gas surface facilities & compressors.

A detailed HAZOP review was conducted on the temporary well testing set-up along with the flowline. All recommendations were closed out prior to operations commencement. As a study outcome operation, frequent sampling was recommended at compressor stations and remote manifolds. Detailed Social risk studies and social risk management were also part of project and all control were implemented prior to kick off the project.

Multiple wells were successfully appraised along with the significant reduction of GHG emissions. Moreover, the appraisal wells were generating revenues as they were producing through the facilities. All objectives were in-line with our vision of 100x decarbonization, unconventional gas & preserving the ecosystem.

This paper will elaborate on the integrated & excellent collaboration between upstream and downstream teams for inline testing of ultra-sour well without flaring considering the operational, Safety, and subsurface aspects. There are two important aspects of the case study. First Wells were commissioned and produced through facilities without any flaring operations which complimented the sustainability mandate. It created new venues for sour reservoir development and steps closer to gas self-sufficiency.