METHOD FOR DETERMINING HORIZONTAL STRESSES IN A ROCK MASS Russian patent published in 2023 - IPC E21C39/00 G01N3/12 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry and can be used to determine the horizontal stresses in a rock mass in the preparation of a geomechanical model for hydraulic fracturing design. In the method for determining horizontal stresses in a rock mass, including drilling wells with core sampling, assessing the nature of the destruction of rocks on the core, experimental studies are preliminary carried out in order to establish quantitative dependences of the core disking parameters on the level of tension of the rock mass. Based on the results of the experimental studies, a nomogram of the dependence of the core disking parameters on the level of tension of the rock mass is built, and the ratio of the thickness of the resulting disks to their diameter (t/D) is plotted along the abscissa axis, and the ratio of the horizontal stress to the ultimate strength of the rock by uniaxial compression (σ_hor/σ₀). Wells are drilled with core sampling, core material is examined and whole intervals and core disc intervals are identified with their simultaneous reference by depth. In the intervals with a solid core, the uniaxial compression strength of the rock is determined, in the intervals with the disking of the core, the average thickness of the disks is determined, and for evaluation, disks with a thickness of not more than half the core diameter are taken, and the thickness of the disks is measured along their axis with a caliper. The ratio of the average thickness of the disks to their diameter is calculated, the abscissa of the ratio of the average thickness of the disks to their diameter is found from the nomogram and, accordingly, the ordinate of the ratio of the horizontal stress to the ultimate strength of the rock in uniaxial compression. The value of the horizontal stress is found by multiplying the ratio of the horizontal stress to the uniaxial compressive strength of the rock by the uniaxial compressive strength of the rock.

EFFECT: simplification, as well as increasing the accuracy and efficiency of the method for determining horizontal stresses in a rock mass.

1 cl, 1 dwg