Research On Recoverable Reserve Evaluation And Well Pattern Optimization Of Low Permeability Carbonate Reservoir

The X reservoir is located in the middle of Y oilfield,accounting for more than25% of the geological reserves of Y oilfield.Currently,only 8 production wells are put into production,with huge development potential.However,X reservoir belongs to ultra-low permeability carbonate reservoir with strong heterogeneity,so it still faces great challenges to realize efficient development of X reservoir.Based on the research,this paper guides the well spacing scheme design of target reservoir by evaluating the recoverable reserves of existing production wells under different physical properties and engineering sweet spots combination modes and proving well spacing under different energy supplement modes,so as to guide the efficient development of target reservoir.Firstly,physical sweet spot model,geomechanical model and engineering sweet spot model were established according to the existing geological model of X reservoir.Then,blasingame modern decline analysis method was used to evaluate the productivity and recoverable reserves of 3 existing fractured wells and 5 existing unfractured wells based on their physical sweet spot and engineering sweet spot types.It provides guidance for fine evaluation of single well productivity and recoverable reserves based on integrated geological engineering technology.Then,a single well fine fracturing fitting analysis is carried out for existing wells based on the integrated geological engineering technology of Petrel platform.Through the fitting analysis,the geomechanical model of reservoir is revised and the understanding of reservoir is improved.Based on the understanding,the feasibility of stratified system development is proposed.At the same time,the limit of recoverable reserves in single well under the combination mode of main physical properties and engineering sweet spot of X reservoir is studied,and the productivity chart under the combination mode of different physical properties and engineering sweet spot is obtained.According to the reservoir characteristics of X demonstrates the two energy supplement water injection and gas injection mode stratification and regardless of formation of well pattern well spacing parameters and energy supplement,five result was designed based on the argument X reservoir of district development plan,through the comparison and analysis to determine X reservoir reasonable development plan,to guide the efficient development of X reservoir formation.