ИСТИНА

Injection wells are widely used in the oilfields of Western Siberia to maintain reservoir pressure and increase ultimate recovery of hydrocarbons. Typically, the ratio is one production well per one-two injection wells. During injection, water adsorbs solids admixtures from wellbore walls and fine particles from the pores in the near-wellbore zone, which results in the flow of suspension in the near-wellbore zone. Suspended particles are trapped in pores, which results in permeability damage and, as a result, in the decrease in injectivity of the well. In order to maintain the injection flow rate (injectivity), one needs to either increase the pumping pressure or to introduce additional water cleaning equipment on surface. Both results in the increase of the cost of development of the reservoir. To optimize the process of water injection, it is proposed to use a combined approach based on modeling of suspension filtration in porous media with account for permeability damage and recovery. In order to do so, we present a development of the multi-fluid model of suspension filtration in a porous medium, which was first disclosed by the authors in [1]. The derivation of the governing equations from conservation laws is carried out in the multi-continua approach [2], where the three phases, namely the carrier fluid, the suspended particles, and the particles trapped in pores are treated as three different continua described by different hydrodynamic field variables. Fluid fluxes through large pores of the porous medium and through narrow pores of the packed bed of deposited particles are explicitly taken into account, via two different values of permeability. These are the key novel features, which distinguish it from the classical deep bed filtration model [3, 4]. The model predictions are compared with laboratory data sets on the contamination of a core sample. The most recent progress in the model development is mainly in taking into account particle mobilization, compressibility of the fluid, two-phase filtration (oil/water), and reservoir influx. Applications of the model are primarily in the oil and gas industry: drilling mud invasion and cleanup in the near-wellbore zone, fines migration in porous medium and suspension filtration in propped hydraulic fractures; permeability damage and recovery in the near-wellbore zone of injection wells, which are used to maintain reservoir pressure. References: 1. Boronin, S.A., Osiptsov, A.A. and Tolmacheva, K.I., 2015. Multi-fluid model of suspension filtration in a porous medium. Fluid Dynamics, 50(6), pp.759-768. 2. Nigmatulin, R.I., 1990. Dynamics of multiphase media (Vol. 2). CRC Press. 3. Gruesbeck, C. and Collins, R.E., 1982. Entrainment and deposition of fine particles in porous media. Society of Petroleum Engineers Journal, 22(06), pp.847-856. 4. Boek, E.S., Hall, C. and Tardy, P.M., 2012. Deep bed filtration modelling of formation damage due to particulate invasion from drilling fluids. Transport in porous media, 91(2), pp.479-508.