Equations to Calculate the Overburden Pressure in Water Layers of Definite Dimensions Using Experimental, Macroscopic and Microscopic Data

Intergranular space (IGS), inter-fracture space (IFS) and fracture width (FW) are parameters that affect fluid conductivity and the overburden pressure Pob in hydrocarbon reservoir layers. These parameters vary in porous media and are important in well treatment operations such as acidizing, hydraulic fracturing and fluid injection during drilling and completion. These treatment processes require the computation of these parameters to determine Pob. This study presents three classification tables with new formulations for IGS, IFS and FW based on microscopic and macroscopic experimental data for different reservoir rock lithologies. Using the petrophysical and geological information and the parameters in the tables for specific reservoir conditions (temperature ≥ 176 °F and reservoir depth), Pob is calculated for a layer with definite dimensions for three ranges of porosity. Because most reservoir properties are heterogeneous, geologists and drillers constantly need to control the type of drilling mud and reservoir pressure. The equations presented here can be applied in calculations for salt water disposal into depleted layers. This formula is also used to calculate Pob at a defined point of in water wells.

► Estimation and quantitative classification of inter-granular space (IGS), inter-fracture space (IFS) and fracture width (FW) for types of reservoir layers lithology. ► Use of experimental, microscopic date and wellhead macroscopic date in calculation the quantities of (IGS),(IFS) and (FW). ► Overburden Pressure in definite dimensions Water Layers is formulated for three various ranges of rocks porosity. ► Use of the quantities of (IGS), (IFS) , (FW) and petro-physical characteristics in equations structure.