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Well-killing operations in water-sensitive hydrophilic formations are often complicated by extended well clean-up periods and, in some cases, failure to restore the well’s production potential post-kill. Typical development targets exhibiting these properties include the Neocomian and Jurassic deposits of fields in Western Siberia and Western Kazakhstan. This paper proposes a well-killing method incorporating simultaneous near-wellbore treatment. In cases where heavy oil components (asphaltenes, resins, or paraffins) are deposited in the near-wellbore zone, their removal with a solvent results in post-operation flow rates that exceed pre-restoration levels. For wells not affected by asphaltene, resin, and paraffin deposits, killing is performed using a blocking pill of invert emulsion stabilized with an emulsifier and hydrophobic nanosilica. During filtration into the formation, this emulsion does not break but rather reforms according to the pore throat sizes. Flow rates in such wells typically match pre-restoration levels. The described engineering solution proves less effective when the well fluid water cut exceeds 60%. For wells exhibiting premature water breakthrough that have not yet produced their estimated oil volume, the water source is identified, and water shutoff operations are conducted. This involves polymer-gel systems crosslinked with resorcinol and paraform, reinforced with inorganic components such as chrysotile microdispersions, micro- and nanodispersions of shungite mineral, and gas black. Oscillation testing identified the optimal additive concentration range of 0.6–0.7 wt%, resulting in a complex modulus increase of up to 25.7%. The most effective polymer-inorganic composite developed by us, incorporating gas black, demonstrates high water shutoff capability (residual resistance factor ranges from 12.5 to 65.0 units within the permeability interval of 151.7 to 10.5 mD). Furthermore, the developed composites exhibit the ability to selectively reduce water permeability disproportionately more than oil permeability. Filtration tests confirmed that the residual permeability to oil after placing the blocking composition with graphene is 6.75 times higher than that to water. Consequently, such treatments reduce the well water cut. Field trials confirmed the effectiveness of the developed polymer-inorganic composite systems.
Details
; Asadullin Rustem 2 ; Vezhnin Sergey 3 ; Voloshin, Alexander 4
; Gallyamova Rida 4
; Annaguly, Deryaev 5
; Dokichev Vladimir 4
; Eshmuratov Anvar 6
; Lenchenkova Lyubov 2
; Pavlik Artem 2
; Politov Anatoly 7 ; Ragulin Victor 3 ; Danabek, Saduakassov 8
; Safarov Farit 3
; Maksat, Tabylganov 8
; Telin Aleksey 3
; Yakubov Ravil 2
1 Department of Logistics and Economic Informatics, International Institute of Resource Saving Logistics and Technological Innovation, Dmitry Mendeleev University of Chemical Technology of Russia, 9 Miusskaya Square, 125047 Moscow, Russia, World-Class Laboratory “LaMiUr”, Saint-Petersburg State Institute of Technology, Moscow Prosp. 24-26/49, 190013 Saint-Petersburg, Russia
2 Faculty of Mining and Petroleum, Ufa State Petroleum Technological University, 1 Kosmonavtov Street, 450064 Ufa, [email protected] (A.P.);
3 Ufa Scientific and Technical Center, LLC, 99/3 Kirova Street, 450078 Ufa, Russia
4 Ufa Institute of Chemistry, Ufa Federal Research Center, Russian Academy of Sciences, 71 Oktyabrya Avenue, 450054 Ufa, Russia; [email protected] (A.V.); [email protected] (R.G.);
5 Department of Well Drilling, Scientific Research Institute of Natural Gas of the State Concern “Turkmengas”, Ashgabat 744000, Turkmenistan
6 Department of Geodesy, Cartography and Natural Resources, Karakalpak State University, Nukus 230100, Uzbekistan
7 Institute of Solid State Chemistry and Mechanochemistry of Siberian Branch RAS, 18 Kutateladze Street, 630128 Novosibirsk, Russia
8 Department of Petrochemical Engineering, S. Yessenov Caspian University of Technologies and Engineering, 1 Microdistrict 32, Aktau 130000, Kazakhstan; [email protected] (D.S.);