Prediction method for natural-fracture-contained tight oil and gas reservoir volume pressure fracture network

Abstract

The invention aims to provide a prediction method for a natural-fracture-contained tight oil and gas reservoir volume pressure fracture network. The method includes the steps: collecting geological information, logging data, rock core and rock debris analysis data and fracturing construction data of the target reservoir, and carrying out single well geomechanical analysis and natural fracture distribution analysis to obtain an initial geostress parameter, a rock mechanical parameter and a natural fracture description parameter of the reservoir; establishing a three-dimensional geological modelbased on the data, and performing fine ground stress field simulation by adopting a finite element method to obtain initial ground stress distribution of the reservoir; setting the distribution of aninitial damage variable field in the model according to the natural fracture distribution condition; and calculating the damage evolution of the three-dimensional stratum in the hydraulic fracturingprocess. The prediction method has the beneficial effect that the reservoir volume pressure fracture crack network form containing the natural fractures can be accurately predicted on the basis of thedamage mechanics theory.

Description

technical field [0001] The invention belongs to the technical field of geology, and relates to a method for predicting volumetric fracturing fracture networks of tight oil and gas reservoirs containing natural fractures. Background technique [0002] Tight oil and gas reservoirs generally have the characteristics of small porosity, low permeability, high content of brittle minerals, and developed natural fractures. Due to the low formation pressure, most natural fractures are closed in the natural state, and their connectivity is poor, so oil and gas usually have no natural or low productivity. At present, the development of tight oil and gas reservoirs mainly adopts horizontal well volume fracturing technology, the purpose of which is to connect the associated natural fractures in the reservoir through artificial hydraulic fracturing, and form an interlaced spatial fracture grid system together with artificial fractures, so that Increase the flow channel of reservoir fluid...

AI Technical Summary

Problems solved by technology

However, the existing hydraulic fracturing fracture prediction methods all use fracture mechanics as the basic theory and use a discretized fracture network model, which has the following disadvantages: 1. It cannot predict the initiation of fractures, and the location and shape of fractures need to be artificially set, which does not conform to 2. It can only describe the first-order secondary fractures in the fracturing fracture network system, and cannot reflect the complex existence of multi-level fractures; 3. It cannot consider the randomness of the influence of natural fractures on the expansion of the fracture network system, and cannot describe the natural fractures. The complex fracture network shape in which artificial fractures communicate with natural fractures, and the expansion of the complex fracture network cannot be predicted

Images