Scale inhibitor impregnated gravel (SIIG) is a new technology for combined sand and scale control that features porous ceramic proppant particles that are impregnated with scale inhibitor chemistry. The particles have been designed to be suitable for gravel pack pumping operations and can be pumped as 100% scale inhibitor impregnated particles or mixed with conventional gravel. The scale inhibitor impregnation technology has been optimised to provide a steady, controlled release of scale inhibitor chemical on contact with produced water. The technology provides for the first time in the oil industry a method of placing large quantities of solid state scale inhibitor in gravel packs. In typical gravel packed deepwater completions, particularly, sub-sea wells, the technology offers considerable cost benefits for scale control when compared to scale inhibitor squeeze treatments and negates the need for pre-emptive squeeze treatments in anticipation of seawater breakthrough.
After qualification of the product through a comprehensive laboratory development programme a field trial has been performed on a Heidrun well. The well was a sidetrack from the mother well, and it was chosen for the field trial as the initial water breakthrough was predicted to contain around 20% sea water. The field trial demonstrated that placement of the scale inhibitor impregnated particles could be successfully performed. However, the loss of scale inhibitor to the gravel pack fluid was higher than anticipated since it took three weeks between gravel packing and startup of the well. Despite the high intial loss of scale inhibitor to the gravel pack fluid the release of inhibitor during production was as planned. Unfortunately it did not protect the well from scaling since the mixing of sea water and formation water probably took place in the near well area behind the gravel pack.
This paper will provide a detailed description of the laboratory development of SIIG technology and, in addition, will also present details of the first gravel pack deployment of this technology for combined sand/scale control in a Heidrun well.