Features of gypsum deposits in the Verkhnechonsk field. Simulation of the process of scaling inhibitors squeezing into the formation

The paper discusses the features of scaling in the wells and the hole-bottom region specific to the Verkhnechonsk field. On the natural core samples filtration experiments are conducted to detect the effect of gypsum deposits in the reservoir on its permeability and to find permeability recovery techniques. For a number of scale inhibitors carried outa test of their effectiveness both static and dynamic methods. Their adsorption-desorption properties were determined. Simulation of the inhibitors injection to the hole-bottom region of VCH2 layer wells were carried out.
Materials and methods
In a plant for core research filtration experiments on VCHNG core material of various inhibitors were conducted. The adsorption-desorption properties of the inhibitors are determined, the adsorption isotherms are constructed.
Results
Based on the results of laboratory tests identified inhibitors that show high efficacy in inhibiting the gypsum deposits and good adsorption-desorption properties of the Verkhnechonsk field reservoir rock. Based on the results of laboratory testscarried out modeling of the deposit protection the Verkhnechonsk wells from gypsum deposits by squeezing scale inhibitor in horizontal wells.
Сonclusions
1. It is shown that with increasing water cut of well product increases the risk of gypsum deposits in the near-wellbore and downhole equipment.
2. A series of filtration experiments showed that injection of water into the formation with calcium ions and sulfate provokes gypsum deposits and as a consequence, decreasing permeability.
3. Testing of the effectiveness of a number of scale inhibitors was conducted by static and dynamic methods on the water model of Verkhnechonsk field.
4. It were held adsorption-desorption experiments for inhibitors which have shown the best performance-inhibiting deposits of gypsum. The purpose of thetests - to score inhibitor's ability effectively secured to the reservoir rock, and be removed from the reservoir, protecting well equipment from scaling when squeezing reagent solution into the reservoir.
5. After testing of adsorption-desorption properties of the inhibitors a test simulation of squeezing scale inhibitors for thenear-wellbore area wells of VCH2 layer ofVerkhnechonsk field was carried out.