Field Experience with Chemical Sand Consolidation as a Remedial Sand Control Option

摘要

Sand production from wells is an ongoing challenge for the oil industry. In some wells intervention is required for remedial sand control or new sidetracks are required. However, for a limited number of suitable wells, chemical treatments that consolidate the near wellbore area can be a viable alternative to improve well offtake rates. Chemical sand consolidation can give a formation some additional residual strength in order to enhance the maximum sandfree rate (MSFR). Sand production in weakly consolidated reservoirs will occur when stresses in the well/perforation tunnel walls are large enough to disrupt the binding between the individual sand grains. This will generate a plasticised layer of sand in the near well bore area. The layer will erode by the produced fluid and may be transported to the surface. The rate of erosion will depend on the residual strength of the plastified material and the fluid rate. The chemical treatment developed to overcome these problems is environmentally acceptable with a low value for bioaccumulation and a high value for biodegradation.The chemical is mixed in diesel and bullheaded into the well allowing placement that can be complimentary to existing control measures. Once placed the active chemical components 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 (i.e. production rates) before the grains are transported into the wellbore. The method has been employed in eight different StatoilHydro operated wells in four different fields, with encouraging results. Moreover, there are indications that water cut could be reduced due to the treatment. Combined with a higher draw down potential, this gives support for the use of the sand consolidation method as an IOR initiative.