Interactive Analysis (IRA) Determining Focal Reservoir Parameters Dominating Estimated Ultimate Recovery (EUR)

Interactive Analysis (IRA) is a new reservoir study method which applies to both condensate oil & gas reservoir and conventional oil & gas reservoir. IRA establishes the correspondence between stage EUR equivalents and reservoir parameters. Often, reservoir parameters include but not limited to porosity, permeability, burst pressure, Poisson rate, Oil saturation or Gas content, Free gas content and adsorption gas content, pay zone thickness, resistivity, mud content, etc. In a specific compartmentalization, it is important to decide which parameter is the focal parameter dominating the productivity. If the focal parameters can be decided, operators can use this evidence to decide which zone and which sub-zone drilling must fully penetrate through. Additional, when well is designed for hydraulic fracturing, engineers can use this data to design stages and clusters. Designing of higher focal parameter quality in stage and cluster is certainly a contribution to better frac efficiency and EUR. IRA is expressed that the Normalized Correlated Coefficient (NCC) Vector is equal to the Moore-Penrose inverse of the Normalized Reservoir Parameter Quality Factors (NRPQF) matrix multiplying the Normalized EUR equivalent (NEE) vector. NCC deriving from the IRA represents the weight of productivity contribution to EUR. Analyzing IRA equation, the focal parameters dominating the well EUR can be determined. With focal parameters available, operators can optimize the drilling criteria and optimize frac design. For a specific compartmentalization, the focal parameters derived from IRA shall give consistent focal parameters which dominate the higher productivity and lower productivity. When a well is hydraulic fractured, the NEE can be tested and analyzed. To input the NEE into IRA equation, the frac efficiency is also reflected by NEE. Three shale gas wells in a compartmentalization are analyzed via IRA analysis. The positive focal parameters, irrelevant parameters and negative focal parameters in each well and overall averaging give good convergence. Two wells in condensate oil pay zone in a compartmentalization are also analyzed via IRA analysis. The positive focal parameters, irrelevant parameters and negative focal parameters in each well and overall averaging give some convergence. If a NCC is bigger, it dominates EUR. If it is small or very small, the contribution to EUR is less or measily. On the other hand, if a NCC is positive, it increases the productivity when the parameter quality is higher. If a NCC is negative, it decreases the productivity when the parameter quality is higher. No focal parameter dominating EUR can be understood until IRA is proposed. Rather than reservoir mechanics analysis, IRA gives explicit linear mathematical expression which makes engineers easier to calculate by aid of Matlab coding. IRA analysis is a breakthrough to understand the intrinsic structure between reservoir parameters and EUR.