Perm Journal of Petroleum and Mining Engineering (Mar 2017)
Analysis and justification of selection of fluids to be used for water shut-off treatment during well completion
Abstract
The aim of the work is to increase efficiency of well completion under conditions of water inflow by use of viscoelastic gas-liquid mixtures to shut-off permeable formations. At present, there is an increase in rates of drilling of wells in abnormal conditions, such as abnormal formation pressure (both low and high), unstable rocks, rocks of high hardness, permafrost etc. The quality of well construction in such conditions influences subsequent development and operation of the field greatly. Aquifer isolation is an extremely important issue due to the fact that from them water breaks through in production wells which has a significant impact on quality of fluid produced. The main solution for water breakthrough challenge is formation isolation, which is performed by use of various plugging material. At present, there are many mixtures that limit water inflows such as fast-setting plugging materials, gel-cement mixtures, polymeric swelling nets, latexes, synthetic resins, viscoelastic mixtures, materials for selective isolation etc. Under conditions of abnormally low reservoir pressures, it is important to consider density when selecting drilling fluids and plugging materials. Therefore, it is recommended to use screens based on viscoelastic three-phase stabilized gas-liquid mixtures for temporary blockage of permeable aquifer. With use of such mixtures liquid penetration flow rate is significantly reduced compared to other viscoelastic systems, which makes it possible to increase reliability of temporary isolation of aquifers. The paper presents an analysis of domestic and foreign experience of blocking permeable formations by different mixtures. Three-phase blocking mixtures are studied and requirements for them are generalized.
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