| CPC E21B 44/00 (2013.01) [E21B 47/10 (2013.01); G01V 1/46 (2013.01); G01V 2210/6246 (2013.01)] | 12 Claims |
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1. A method of drilling a well in a subsurface geological structure to a location in a subsurface hydrocarbon reservoir indicated by a natural fracture network model of the subsurface hydrocarbon reservoir, comprising the steps of:
obtaining reservoir parameters representing properties of the subsurface hydrocarbon reservoir for processing in a data processing system, the reservoir parameters comprising reservoir dynamic measurements, matrix permeability, and a porosity model of the reservoir, wherein obtaining the subsurface hydrocarbon reservoir parameters comprises:
drilling a plurality of wells in the subsurface geological structure;
using a production logging tool in one or more of the plurality of wells to determine the reservoir dynamic measurements;
performing a pressure transient analysis in one or more of the plurality of wells to determine the reservoir dynamic measurements;
determining the matrix permeability from a core test and wireline log data from one or more of the plurality of wells; and
determining the porosity model from a porosity well log from one or more of the plurality of wells;
forming the natural fracture network model by processing the obtained reservoir parameters in the data processing system to identify fracture properties comprising the location and stress conditions of natural fractures at the locations in the subsurface hydrocarbon reservoir, by performing the steps of:
performing a critical stress analysis comprising:
determining critical stresses of the natural fractures using normal stress and shear stress; and
identifying a portion of the natural fractures as hydraulically conductive based on the critical stresses;
determining fracture distribution based on the obtained reservoir parameters;
forming a measure of estimated fracture properties of the subsurface hydrocarbon reservoir based on the determined fracture distribution, the forming comprising:
obtaining measures indicative of rock brittleness properties of a formation rock;
forming a plurality of realizations of network fracture models by stochastic discrete fracture network modeling, the stochastic discrete fracture network modeling comprising:
receiving borehole image information and the rock brittleness properties of the formation rock;
forming a discrete fracture network representing parameters of fracture length and intensity; and
forming values for a fracture aperture, the values comprising area, porosity, shear stress, and effective normal stress;
obtaining based on the formed estimate of reservoir fracture properties an estimated reservoir flow capacity;
obtaining an indicated flow capacity of the subsurface hydrocarbon reservoir;
comparing the estimated reservoir flow capacity with the indicated flow capacity of the subsurface hydrocarbon reservoir; and
drilling an additional well in the subsurface geological structure to a location in the subsurface hydrocarbon reservoir based on the estimated reservoir flow capacity being within the specified acceptable limit of accuracy of the indicated flow capacity and the portion of the natural fractures being identified as hydraulically conductive from the critical stress analysis to avoid formations or layers regions not indicated to be hydraulically conductive and to avoid areas indicated to contain fractures likely to cause complications in the drilling or otherwise adversely impact the drilling.
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