Introducing SOLA: Shallow Opti Light Architecture (SOLA) as a New Well Architecture Strategy in Pertamina Hulu Mahakam (PHM) to Achieve a Roadmap of Cost-Effective Drilling
Authors: Sinaga H. A. , Yudhatama M. A. , Agriawan C. 
Published: August 2024

Tunu Shallow Zone (TSZ) in Mahakam delta is confronted with an economic challenge stemming from declining production levels. In order to address this predicament, it is imperative to implement a series of continuous improvement measures and proactive initiatives aimed at augmenting production levels and aligning them with the costs associated with drilling operations. A zeal of initiative roadmap is a cause to be chased.

The implementation of an efficient well design holds the potential to yield substantial cost reductions and enhance drilling efficiency. The introduction of the SOLA initiative represents a novel optimization strategy aimed at achieving sustainable drilling practices by replacing the existing Shallow Light Architecture (SLA) well design framework within the Mahakam Development. This approach entails the deployment of a slimmer & light architecture, thereby facilitating a steeper learning curve ensuring the secure and efficient delivery of wells. SOLA initiative utilizes a 9 1/2-inch open hole for the surface section and a 6-inch open hole for the production section in order to optimize well architecture. The 9 1/2-inch hole in surface section SOLA facilitates enhanced drilling efficiency in contrast to the 12 1/4-inch hole in surface section SLA. Primarily due to reduction in energy requirement results in a higher Rate of Penetration (ROP), thereby enabling an accelerated rate of progress in the drilling process. Drilling the 6-inch section in the shallow zone offers efficiency benefits for mud and cement usage. The smaller diameter of the 6-inch section means less drilling fluid is needed, saving costs on mud procurement and disposal. Similarly, the smaller diameter of the 7-inch casing during cementing requires less cement, reducing expenses. The smaller space between the casing and formation allows for precise cement placement and better quality of the cement bond.

SOLA well trial conducted in TN-F313 for a duration of 8.21 days, encountered various challenges related to drilling a 6-inch hole encompassed parameters such as ROP, Equivalent Circulating Density (ECD), and hole cleaning. Nonetheless, simulations indicate that the hole cleaning parameter remained within an acceptable range. An in-depth analysis of the total costs associated with the SOLA well trial revealed significant cost savings of $230,000 when compared to SLA wells. The most substantial savings were observed in fluid and cement expenditures, amounting to $143,000 and $67,000, respectively. The performance of the 6-inch hole in the shallow section (On Bottom ROP) was recorded at 45 m/h and can still be further optimized by managing the ECD value. Improving bit design can enhance performance and achieve faster ROP should ECD permits. Notably, the absence of any issues related to Bottom Hole Assembly (BHA) design, BHA tendency, and steerability affirms the well's capability for safe deliverability, ensuring operational integrity.

The forthcoming SOLA well candidate is scheduled for implementation in the near future, with a primary objective of gathering learning curve data to inform future roadmap planning. This masterpiece will further open a lot opportunity in Mahakam with slimmer, efficient and simple well which will reduce both CAPEX and OPEX thus extending life of Mahakam.