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Use of Scale Soft Pitzer to Calculate Deposition, or Precipitation, in a Reservoir or Core Material During Long Term Flow

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Use of ScaleSoftPitzer to calculate deposition, or precipitation, in a reservoir or core material during long term flow. Approach will be presented in four steps: 1. Determine whether equilibrium, kinetics, or mass transport is controlling, 2. Relate precipitation to the physical variables in the field or laboratory core, 3. Relate the physical variables that affect scale formation or dissolution to space and time in the reservoir or core material, and 4. Combine the two into a single description explicitly and implicitly. Two physical geometries will be examined algebraically, 1st(left). linear flow as might occur in a laboratory column, and 2nd(right). radial flow as might ideally represent flow into or out from a well in …show more content…

Near well bore effects (e.g., r < 1 ft.) are not known and probably need to be tested experimentally. 2. Relationship of pressure change to flow rate using Darcy’s law. A. Linear one dimensional flow: First, the relationship will be developed in one linear dimension, x, and then the corresponding results for radial flow will be given in 2. B, below. Darcy’s Law in one dimension, x SI units of measurement are “self consistent” and will be given initially, but equations with common field and laboratory units will be presented and used. Q(m3/s) = fluid flow rate K(m/s) = hydraulic conductivity A(m2) = cross sectional area of flow dh(m) = hydraulic head in meters dx(m) = length of porous medium The hydraulic conductivity can be expressed in terms of intrinsic permeability, k(m2): k(m2) = intrinsic permeability or simply called, “permeability” (kg/m3) = fluid density; (kg/m3)water 103 kg/m3 at 25 C, 1 atm, and IS = 0 g(m/s2) = acceleration due to gravity = 9.8 m/s2 –often taken to be 10 m/s2. (kg/ms) = dynamic viscosity, (kg/ms)water 10-3 kg/ms at STP and TDS = 0 Then, by substituting k(m2) for K(m/s) Darcy’s law in SI units becomes: 1 darcy = 10-12 m2 = 1 m2 = 10-8 cm2 10-5 m/s = 10-3 cm/s, or 1 mdarcy = 10-15 m2 = 10-3 m2 = 10-11 cm2 10-8 m/s = 10-6 cm/s

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