Abstract
Over the lifetime of a well it is possible that several squeeze operations will be performed depending on scaling severity. Downhole squeeze operations have been performed for many years and have on the whole been an effective scale management tool. However, the long term impact that successive squeezing has on treatment lifetime and well productivity has received little attention. SPE 113656 detailed the results of a unique sequence of long term corefloods that were designed to replicate five successive treatments on the kaolinite rich, Middle Tarbert core from Oseberg S⊘r. Relatively few squeeze treatments have been performed on this field, and the coreflood results were up-scaled to provide a potential prediction of the effects of long term squeezing and well productivity on Oseberg S⊘r. Furthermore, the laboratory results were cross-checked by comparing with the Heidrun field that has been squeezed for many years. Heidrun is an analog of Oseberg S⊘r with kaolinite rich producing intervals and similar productivity issues related to kaolinite mobilization.
In recent years viscosified squeeze treatments have become popular for improved inhibitor placement within horizontal wells and have been used on Heidrun and Norne. However, the long term impact that such squeezing has on treatment lifetime and well productivity has not until now been examined. The paper will give details of an identical sequence of long term corefloods as described above but in which the inhibitor was viscosified. All testing parameters have been kept identical between viscosified and non-viscosified treatments including the core material and scale inhibitor. The impact on squeeze lifetimes will be demonstrated along with potential formation damage mechanisms.
