Tests of ASR, DSCA, and Core Discing Analyses To Evaluate In-Situ Stresses

Abstract

The vertical distribution of the minimum horizontal in-situ stress is . the major parameter which controls the confinement height and direction of hydraulic fractures. The ininifrac technique has been extensively used to collect these data. However, its implementation in the payzone and adjacent layers is often hindered by technical and economic considerations. Consequently, the determination of the stress field on the basis of laboratory measurements in orientated core samples has been investigated. New developments and the results of three methods are described: anelastic strain recovery (ASR), differential strain curve analysis (DSCA), core discking analysis. The results obtained using these methods on cores extracted from several wells are described and discussed. A comparison is made with data available from minifracs, logs and regional tectonics. The main conclusions are that different methods give a good idea of the principal horizontal stress.

Rock Stress Measurement Methods in Rock Mechanics—A Brief Overview

“…For example, statistic of measured data (database) can be employed in hydraulic fracturing field data to improve the accuracy of determining the shut-in pressure or estimating the in situ tensile strength of hydraulic fractures [30] [31]. While core discing can provide detailed information about the stress state of a specific rock formation [32] as shown in Figure 5. The conditions for core discing are high in situ stresses and the brittle rock.…”

An Improved Differential Strain Analysis Method for Super Deep Wells

“…The magnitude and the orientation of in-situ principal stress can be predicated by Differential Strain Analysis experiments. The theory of Differential Strain Analysis (DSA) is rigorous and already proven [6,7], but more than six foil strain gages are needed in experiments, and all gages must have conformability. Due to the experimental difficulty, high workload, and low experimental efficiency, conventional Differential Strain Analysis (DSA) experiment has been restricted in application at times [8].…”