Abstract: The pore structure of rocks and other materials can be determined through microscopy and subjected to digital simulation to determine the properties of fluid flows through the material. To determine a porosity-permeability over an extended range even when working from a small model, some disclosed method embodiments obtain a three-dimensional pore/matrix model of a sample; measure a distribution of porosity-related parameter variation as a function of subvolume size; measure a connectivity-related parameter as a function of subvolume size; derive a reachable porosity range as a function of subvolume size based at least in part on the distribution of porosity-related parameter variation and the connectivity-related parameter; select a subvolume size offering a maximum reachable porosity range; find permeability values associated with the maximum reachable porosity range; and display said permeability values as a function of porosity.

Abstract: A method for calculating pore pressure of a subsurface includes the steps of obtaining a resistivity value while drilling in a region wherein there is a shallow depth (reference depth) where shale is in a hydrostatic condition, or where shale is not in hydrostatic condition but where the pore pressure at such depth can be estimated and calculating, using a processor, a pore pressure at a drilling location based on the following Formula (I): PP=OvB?(OvB?Hyd)(R/R0)øn wherein PP is pore pressure, OvB is the overburden value associated with the drilling location, Hyd is hydrostatic pore pressure, R is a measured value of resistivity, R0 is the resistivity at a reference depth or is an imposed value of resistivity, and øn is a normalized value of porosity.

Abstract: A method for calculating pore pressure of a subsurface includes the steps of obtaining a resistivity value while drilling in a region wherein there is a shallow depth (reference depth) where shale is in a hydrostatic condition, or where shale is not in hydrostatic condition but where the pore pressure at such depth can be estimated and calculating, using a processor, a pore pressure at a drilling location based on the following Formula (I): PP=OvB?(OvB?Hyd)(R/R0)øn wherein PP is pore pressure, OvB is the overburden value associated with the drilling location, Hyd is hydrostatic pore pressure, R is a measured value of resistivity, R0 is the resistivity at a reference depth or is an imposed value of resistivity, and øn is a normalized value of porosity.

Abstract: A method for predicting jumps in pore pressure of a subsurface includes the steps of obtaining a porosity and a resistivity log value while drilling; dividing a cross plot of the porosity and the resistivity log values into two regions where the split of the two regions is based on the following (I): R=0.062/ø1.5; averaging the obtained porosity and resistivity log values in the subsurface within a set interval to obtain a representative value of resistivity and porosity for the subsurface within the set interval; and giving a first warning of a high overpressure region if the representative value of resistivity at the representative value of porosity is lower than 0.062/ø1.5. The method may also include giving a second warning that a jump in pore pressure is coming within 100-300 meters if the normalized values of resistivity and porosity has a turning down point in its trajectory.

Abstract: The pore structure of rocks and other materials can be determined through microscopy and subjected to digital simulation to determine the properties of multiphase fluid flows through the material. To ensure reliable results, the digital rock model is first analyzed via a series of operations that, in some embodiments, include: obtaining a three-dimensional pore/matrix model of a sample; determining a flow axis; verifying that the dimension of the model along the flow axis exceeds that of a representative elementary volume (REV); selecting a flow direction; extending model by mirroring if pore statistics at a given saturation are mismatched for different percolating phases; and increasing resolution if the smallest nonpercolating sphere dimension is below a predetermined threshold. This sequence of operations increases reliability of results when measuring relative permeability using the model and displaying relative permeability measurements to user.

Abstract: A method for computing or estimating fractional, multi-phase/multi-component flow through a porous medium employing a 3D digital representation of a porous medium and a computational fluid dynamics method to calculate flow rates, pressures, saturations, internal velocity vectors and other flow parameters is described. The method employs a unique method of introducing non-wetting and wetting fluids into the pores at the inlet face of the 3D digital representation of a porous medium and a novel process control application to achieve quasi-steady state flow at low inlet concentrations of non-wetting fluid. In addition, the method of the present invention reduces the time required to simulate to complete the fluid dynamic calculations. The resulting values of flow of non-wetting fluid, wetting fluid, saturation, and other parameters are used to generate plots of relative permeability imbibition and drainage curves. Computerized systems and programs for performing the method are also provided.

Abstract: A method for computing or estimating relative permeability for fractional multi-phase, multi-component fluid flow through a porous medium, which employs a 3D digital representation of a porous medium and a computational fluid dynamics method to calculate flow rates, pressures, saturations, velocities and other flow parameters, is described. The method employs a unique method which integrates a precursor simulation used to generate a set of variables like pressure, saturation and velocity distribution associated with a selected storage plane in the 3D digital representation of a porous medium, which variables are used as inlet condition in the workflow of a second simulation that can generate values of fractional flow rates, pressures, saturations, velocities, or other parameters of wetting and non-wetting phases, which can be used to compute or estimate relative permeability values or other fluid transport properties of the porous medium.

Abstract: The pore structure of rocks and other materials can be determined through microscopy and subject to digital simulation to determine the properties of multiphase fluid flows through the material. To conserve computational resources, the simulations are preferably performed on a representative elementary volume (REV). The determination of a multiphase REV can be determined, in some method embodiments, by deriving a porosity-related parameter from a pore-matrix model of the material; determining a multiphase distribution within the material's pores; partitioning the pore-matrix model into multiple phase-matrix models; and deriving the porosity-related parameter from each phase-matrix model. The parameter's dependence on phase and saturation can then be determined and analyzed to select an appropriate REV size.

Abstract: The pore structure of rocks and other materials can be determined through microscopy and subjected to digital simulation to determine the properties of fluid flows through the material. To determine a porosity-permeability over an extended range even when working from a small model, some disclosed method embodiments obtain a three-dimensional pore/matrix model of a sample; measure a distribution of porosity-related parameter variation as a function of subvolume size; measure a connectivity-related parameter as a function of subvolume size; derive a reachable porosity range as a function of subvolume size based at least in part on the distribution of porosity-related parameter variation and the connectivity-related parameter; select a subvolume size offering a maximum reachable porosity range; find permeability values associated with the maximum reachable porosity range; and display said permeability values as a function of porosity.

Abstract: A method for computing or estimating relative permeability for fractional multi-phase, multi-component fluid flow through a porous medium, which employs a 3D digital representation of a porous medium and a computational fluid dynamics method to calculate flow rates, pressures, saturations, velocities and other flow parameters, is described. The method employs a unique method which integrates a precursor simulation used to generate a set of variables like pressure, saturation and velocity distribution associated with a selected storage plane in the 3D digital representation of a porous medium, which variables are used as inlet condition in the workflow of a second simulation that can generate values of fractional flow rates, pressures, saturations, velocities, or other parameters of wetting and non-wetting phases, which can be used to compute or estimate relative permeability values or other fluid transport properties of the porous medium.

Abstract: The pore structure of rocks and other materials can be determined through microscopy and subjected to digital simulation to determine the properties of multiphase fluid flows through the material. To ensure reliable results, the digital rock model is first analyzed via a series of operations that, in some embodiments, include: obtaining a three-dimensional pore/matrix model of a sample; determining a flow axis; verifying that the dimension of the model along the flow axis exceeds that of a representative elementary volume (REV); selecting a flow direction; extending model by mirroring if pore statistics at a given saturation are mismatched for different percolating phases; and increasing resolution if the smallest nonpercolating sphere dimension is below a predetermined threshold. This sequence of operations increases reliability of results when measuring relative permeability using the model and displaying relative permeability measurements to user.

Abstract: The pore structure of rocks and other materials can be determined through microscopy and subject to digital simulation to determine the properties of multiphase fluid flows through the material. To conserve computational resources, the simulations are preferably performed on a representative elementary volume (REV). The determination of a multiphase REV can be determined, in some method embodiments, by deriving a porosity-related parameter from a pore-matrix model of the material; determining a multiphase distribution within the material's pores; partitioning the pore-matrix model into multiple phase-matrix models; and deriving the porosity-related parameter from each phase-matrix model. The parameter's dependence on phase and saturation can then be determined and analyzed to select an appropriate REV size.

Abstract: The present invention relates a method to estimate representative elementary volume (REV) in a sample of porous media wherein the sub-volume selected is a better approximation of the elementary volume than existing methods. REV in a sample of porous media such as rock can be defined wherein the REV is selected with respect to the expected direction of fluid flow through the porous media. The method can quantify how good is the digital representation of a rock and how accurate a description of a fluid flow through Darcy's law will be, and allows the evaluation of different length scales in different directions for the REV and an assessment of the anisotropy of the pores structures when the method is applied in different directions. The method also can determine a robust criteria to understand when a trend of porosity-permeability breaks down due to an insufficient size of the subsample.

Abstract: A method for computing or estimating fractional, multi-phase/multi-component flow through a porous medium employing a 3D digital representation of a porous medium and a computational fluid dynamics method to calculate flow rates, pressures, saturations, internal velocity vectors and other flow parameters is described. The method employs a unique method of introducing non-wetting and wetting fluids into the pores at the inlet face of the 3D digital representation of a porous medium and a novel process control application to achieve quasi-steady state flow at low inlet concentrations of non-wetting fluid. In addition, the method of the present invention reduces the time required to simulate to complete the fluid dynamic calculations. The resulting values of flow of non-wetting fluid, wetting fluid, saturation, and other parameters are used to generate plots of relative permeability imbibition and drainage curves. Computerized systems and programs for performing the method are also provided.