SUCCESSFUL SAND CONTROL CAMPAIGN FOR THE DEVELOPMENT OF A HIGHLY HETEROGENEOUS AND MULTILAYERED SANDSTONE RESERVOIR IN INDONESIA: A CASE STORY OFFSHORE NATUNA SEA

摘要

The Natuna Sea in Indonesia contains highly laminated and partly consolidated sandstone, with a combination of high-and low-permeability zones, requiring different types of sand control completions (frac packs or high-rate water packs). Previous operators developing the same area have used multizone single-trip (MST) completion tools to be able to optimize completion time while tailoring the pumping treatment to each interval specific properties. In order to do so, operators have used rigs with ample deck space or vessels temporarily outfitted with pumping equipment to keep the flexibility of completion types for each zone. In this specific case story, the operator had different constraints but was able to successfully complete the campaign and to overcome the challenges operating from on board a relatively small jackup rig. The challenges were addressed using an optimized skid-based pumping spread and exclusive carrier fluid technology. In addition, pumping design optimization was done through minifrac analysis to evaluate formation mechanical properties and fluid efficiency to ensure the final treatment pumped would be placed successfully. From the completion point of view, the wells for this campaign were highly deviated, increasing the risk of early screenout due to proppant settling and high tortuosity. Rigorous onsite fluid QA/QC during operations eliminated risks of premature sand settling due to fluid quality, and prefracturing diagnostic tests and use of a low-concentration slurry stage enabled recognition of high near-wellbore friction pressures and then overcoming them when necessary. A total of 24 pumping stages comprised of 16 frac packs and 8 high-rate water packs were successfully placed in eight wells. The treatments utilized a carrier fluid whose properties were easily adjustable on the fly allowing appropriate treatments for each zone within the limitations posed by the available equipment and the constraint to optimize completion time. As a main result, production targets have been exceeded by 57% versus initial expectations.