PBS Plug® M Fluid Loss Control System Allows Operator to Achieve Multiple Key Operational Objectives and Major Savings by Successfully Controlling Total Losses in Highly Fractured Formations of Jurassic to Permian Age.

TBC-Brinadd’s PBS Plug® M Fluid Loss Control System was recently implemented in two different ADNOC Sole Risk (ASR) wells while drilling different troublesome formations in the Arabian Gulf, which are prone to losses. The first well (Well A) was drilled through the fractured Upper Khuff formation, and the second well (Well B) through porous Arabs and fractured Diyab/Jubaila groups. The application of the PBS Plug M system enabled the rigs to regain circulation and successfully drill to the total planned depth with less non-productive time attributed to curing losses. This case study was presented during ADIPEC 2017 technical sessions and published by the Society of Petroleum Engineers (SPE) under paper number SPE 188862.

The wells involved several different key objectives; however, zonal isolation and logging were critical to both. In addition, the ability to control losses, even at an acceptable rate for one of the wells, allowed the team to proceed with the critical logging program. If not mitigated, losses could have resulted in a well-control situation.

Controlling the losses on Well A allowed the first unimpeded logging suite, including high quality imaging, pressure sampling and avoidance of a liner run. After logging the section, drilling was resumed to the planned section total depth, and the liner was run and cemented successfully.

The application of the PBS Plug M system in Well B allowed multiple troublesome formations (Arabs/Diyab/Jubaila/Gulailah/Sudair) to be drilled as one interval and successful isolation of these zones. The losses were completely cured after applying this system in the correct zone. The total planned depth was attained and the casing landed and cemented.

The solution for these loss-circulation challenges when drilling was the development of a faster-setting, as well as flexible, crosslinking PBS Plug M system that could effectively bridge and/or adhere to the formation rock. The optimization also included extending thermal stability of the set plug to maintain a workable loss rate at the anticipated elevated temperatures and simulations to ensure the system would agglomerate and adhere to the limestone/dolomite rocks.

Pre-planning started nine months prior to drilling these wells in close cooperation between the operator, TBC-Brinadd and GCC. The predicted challenges ranged from managing losses to developing contingencies for total loss of circulation through the above-mentioned formations. Contingency systems were devised using a decision tree and rig instructions were prepared for every wellbore/scenario. The planning process included determination of a pumpable volume that would facilitate spotting this fluid loss system only once.

You can read more details about this successful application of PBS Plug M technology in the Middle East by reading the SPE Paper No. 188862, which can be downloaded from OnePetro® online technical library using this link.

* PBS Plug is a registered trademark of TBC-Brinadd, LLC

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