Experience With Chemical Sand Consolidation as a Remedial Sand-Control Option on the Heidrun Field

摘要

The Heidrun field located in the Norwegian Sea is an oil and gas producing field which has been developed with a tension leg platform (TLP) installed over a template with 56 slots.Two subsea production templates and three subsea water injection templates are also tied back to the TLP.All wells require sand control measures in the reservoir section to prevent sand production.The sand control philosophy has gradually evolved from cased hole gravel packs,through stand alone screens to todays preferred option of openhole gravel packing.Sand control in the field is challenging with high fines content in the reservoir and a potential for plugging from scaling from secondary recovery with seawater.Sand control integrity has failed in some wells and offtake rates in these wells are limited to Maximum Sand Free Rates (MSFR).In some cases intervention is required for remedial sand control or new sidetracks are planned.However,for a number of suitable wells,chemical treatments that consolidate the near wellbore area can be a viable alternative to improve well offtake rates.The chemical treatment is mixed in diesel and bullheaded in the well.The active chemical will react with the connate water in the near wellbore area and form a polymerized network which binds the sand grains together.In that way,the residual strength of the formation is increased and can withstand larger hydrodynamic forces before the grains are transported into the wellbore.To date three Heidrun wells have been treated with the sand consolidating chemical that has been developed in-house.Two of these are platform wells and the third is subsea.One of the platform wells has been retreated twice following a successful first treatment.This work describes the five different treatments;the planning,the execution and the post-job analysis.One of the treatments was not successful,another one was very successful.The reasons behind these results will be discussed.