A method to design a wellbore cement sheath in compacting or subsiding formations is provided. The method may include performing a field scale analysis on a formation surrounding a wellbore. The field scale analysis may output boundary conditions including a pore pressure of the formation and a three-dimensional movement of the formation. The method may also include performing a wellbore scale analysis based on the boundary conditions, a wellbore scale model, wellbore conditions, and cement material properties. The wellbore scale analysis may output an indication of stress applied over time to a cement sheath within the wellbore. Further, the method may include determining cement material properties of the cement sheath to withstand the stress applied over time output by the wellbore scale analysis, and the method may include installing the cement sheath within the wellbore. The cement sheath may include the cement material properties.

A penetration-type monitor includes a casing pipe and sensor penetration scissors, the sensor penetration scissors are arranged in a shear shape, and a first blade and a second blade rotate close to each other or away from each other in the vertical direction so as to define an initial position and a monitoring position of the sensor penetration scissors; when the sensor penetration scissors are located at the initial position, ends of pressed portions of the first blade and the second blade are arranged at an interval one above the other, when the sensor penetration scissors are located at the monitoring position, the pressed portions move close to each other, and shearing portions penetrate out of a mounting hole to shear a sliding mass; and a monitor arrangement system drives the sensor penetration scissors to move from the initial position to the monitoring position.

An in-situ stress measurement method is provided. The method includes measuring a length of a maximum diameter at which an amount of distortion relative to a diameter of a standard circle of a measurement cross section of a boring core is largest and a length of a minimum diameter at which the amount of distortion relative to the diameter of the standard circle is smallest based on a shape of the measurement cross section of the boring core; measuring a length of a diameter in a vertical direction and a length of a diameter in a horizontal direction of the measurement cross section of a side-wall core acquired by hollowing ground in a well in an excavation direction thereof, based on a shape of the measurement cross section of the side-wall core; and calculating a maximum horizontal stress and a minimum horizontal stress by first and second equations.

Methods, systems, and computer-readable medium to perform operations for identifying fracture barriers in a well. The operations include converting rebound hardness values of a rock specimen from the well to unconfined compressive strength (UCS) values, where each of the rebound hardness values corresponds to a respective coordinate of a measurement grid imposed on the specimen. The operations further include, for each column of the grid, plotting the UCS values versus depth. Further, the operations include mapping, based on a maximum UCS value and a minimum UCS value, a relative strength contour plot for the specimen. Yet further, the operations include mapping, based on a fixed strength range, an absolute strength contour plot for the specimen. In addition, the operations include determining, based on the relative strength contour, the absolute strength contour, and mineralogy of the rock specimen, that the rock specimen is indicative of a fracture barrier in the well.

Hydraulic fracturing a subterranean formation with frac fluid, the hydraulic fracturing including complex shear fracturing of the subterranean formation. The technique includes determining an amount of the complex shear fracturing occurring, and adjusting operating parameters of the hydraulic fracturing to increase the complex shear fracturing occurring. The amount may consider fracture surface area. The adjusting may consider resonant frequency of the subterranean formation rock being fractured. The complex shear fracturing may assist with diffusion production. The techniques may include a non-transitory, computer-readable medium having instructions executable by a processor of a computing device to facilitate the aforementioned actions.

A casing pipe extends in a vertical direction, and two adjacent casing pipes are connected by a plurality of link mechanisms; the link mechanism includes two supports, the two supports are hinged by a first pin to form a hinged portion, an upper end and a lower end of the link mechanism are hinged to two adjacent casing pipes by second pins separately, a sensor is fixed to the link mechanism, and the link mechanism has an initial state of extending in the vertical direction and an extending state in which the hinged portion extends outwards to be located on an outer side of the casing pipe; a driving mechanism drives a push portion to move towards the link mechanism; and a downward pressing apparatus is used for pressing a top end of the topmost casing pipe downwards to push the hinged portion into a side wall of the borehole.

Disclosed is a method of quantitatively evaluating structural disturbance characteristics of present in-situ geo-stress in deep shale gas reservoirs, including: measuring geomechanics key parameters of key wells in different tectonic zones within a study area; performing interpretations of single-well profile rock mechanics and continuity of the in-situ geo-stress in magnitude and direction; establishing a geological model; performing anisotropic sequential Gaussian stochastic simulation to obtain three-dimensional (3D) heterogeneous rock mechanics parameter field distribution; performing prediction of distribution of geo-stress states in the study area, and calculating a stress structural index and stress disturbance factor of the target layer and a rotation degree of a maximum horizontal principal stress; and performing quantitative evaluation on an in-situ geo-stress structural disturbance and mapping.

A method for optimizing borehole drilling by a drill string having a drill bit at a rotated and axially urged to drill formations includes measuring a parameter related to at least axial and torsional motion of a drill string propagating as elastic waves at a selected position along the drill string. An axial force exerted by the drill bit and torque applied to the drill bit are determined from the measurements related to at least axial and torsional motion. A confined compressive strength of the formations is determined from the measurements related to at least axial and torsional motion. At least one of the determined axial force and the determined torque is adjusted such that a mechanical specific energy applied to the formation is closest in value to the confined compressive strength.

A method for predicting a total minimum horizontal stress (σ.sub.h) and a total maximum horizontal stress (σ.sub.H) for an anisotropic formation may comprise: measuring Young's moduli parallel ±15° and perpendicular ±15° to a transverse isotropy plane of a horizontal core sample from the anisotropic subterranean formation; measuring Poisson's ratios parallel ±15° and perpendicular ±15° to the transverse isotropy plane of the horizontal core sample; inputting the measured Young's moduli and Poisson's ratios of the horizontal core sample into a 1-dimensional mechanical earth model (1-D MEM); and calculating, using the 1-D MEM, a predicted total minimum horizontal stress (σ.sub.h) and a predicted total maximum horizontal stress (σ.sub.H).

The present invention discloses a method for comprehensive evaluation of shale fracability under the geology-engineering “double-track” system, comprising the following steps: S1: Divide the target horizontal fracturing interval into multiple sampling sections; S2: Establish the reservoir property evaluation factor of each sampling section, and calculate the geological evaluation index of the target horizontal fracturing interval according to the reservoir property evaluation factor of each sampling section; S3: Establish the brittleness factor, natural fracture factor and natural fracture opening factor of each sampling section, and then establish the engineering evaluation index of each sampling section according to these factors; S4: Calculate the engineering evaluation index of the target horizontal fracturing interval according to the engineering evaluation factor of each sampling section; S5: Evaluate the fracability of the target horizontal fracturing interval according to the geological evaluation index and the engineering evaluation index.