Applications of Stress Field Modelling Using the Distinct Element Method for Petroleum Production

摘要

The distinct element method was first introduced in 1971rnand has been progressively developed over the past tworndecades. It is described as a finite difference distinct element,rnnumerical modelling method (DEM). The method wasrnimplemented in the computer program UDEC (2D and 3DECrn(3D) and its major application to date has been in the field ofrnrock mechanics and mining engineering. In this paper werndemonstrate the applicability of this method to the productionrnof hydrocarbons.rnThe method can be used to model 3D stress fields in arnpetroleum basin or field setting. It has been shown previouslyrnthat stress field model data is consistent with actual boreholernbreakout data and hydro-fracturing measurements. Thernmodelling methodology can be used to calculate fluid potentialrnand hence used to associate crustal stress, hydrocarbonrnmigration and accumulation. By monitoring disturbances tornthe syn-production stress field estimation of the residual oilrnpotential can be achieved.rnThe work initially presents via sensitivity analysis therngeneric effect of faults and horizon boundaries on the meanrnlocal in-situ stress field. A case study is presented whereby thernfault geometry for the Big Lake Field in the Cooper Basin ofrnSouth Australia is modelled using DEM. Predictions of thernspatial distribution of hydrocarbon accumulations and pressurerngradients using the model were found to be accurate.rnSubsequently the model is adapted to account for productionrnand the resultant pressure changes over time, which can lead tornthe prediction of residual hydrocarbon distributions.