A method for developing a procedure for pretreating a section of a wellbore prior to hydraulic fracturing stimulation of the section of the wellbore includes determining an optimized notch geometry and determining an optimized chemical treatment for the section of the wellbore. The optimized notch geometry is determined by modeling a notch in the section of the wellbore using a computing system, simulating a pressure increase in the section of the wellbore and on the notch from a hydraulic fracturing stimulation, identifying breakdown pressure in the section of the wellbore, and repeating the modeling, simulating, and identifying to determine the optimized notch geometry in the wellbore as the notch having a lowest breakdown pressure. The optimized chemical treatment is determined by determining a rock type in the section of the wellbore and determining a conditioning fluid that reduces the tensile strength of the rock type.

A method, a system, and a non-transitory computer readable medium to calibrate a lithostatic stress map of a particular geological layer in a basin model are described. The lithostatic stress map is generated by simulating the basin model and calibrated based on available well data without re-simulating the basin model. In particular, the calibration is based on the mean lithostatic density, which is a constant value of density that yields a value of lithostatic stress equivalent to the lithostatic stress at the same depth produced by the existing column of rocks in the basin.

A method can include receiving data that characterizes anisotropy of a formation; receiving a model that models one or more planes of weakness in an anisotropic formation; and, based at least in part on the model and the data, outputting information germane to stability of a bore in an anisotropic formation.

A method of predicting three-dimensional fracture geometry in a subterranean region of interest is disclosed. The method includes obtaining a strain tensor for the subterranean region of interest, calculating a set of principal strain components from the strain tensor, and determining a strain cyclide from the set of principal strain components. The method further includes calculating a set of quadrimodal fault normal vectors from the strain cyclide and determining an in-plane shear strain magnitude and a shear strain orientation from the set of quadrimodal fault normal vectors.

Some systems and methods of hydraulic fracturing a formation of a borehole include receiving a length-to-radius ratio of a borehole segment of the borehole and determining when the length-to-radius ratio is less than a threshold. Responsive to determining that the length-to-radius ratio is less than the threshold, some systems and methods include predicting a breakdown pressure associated with a formation surrounding the borehole segment based on a length of the borehole segment. Responsive to determining that the length-to-radius ratio is greater than or equal to the threshold, some systems and methods include determining, a characteristic diffusion time associated with a fluid diffusing into the formation surrounding the borehole segment. Some systems and methods include pumping the fluid into the borehole segment to fracture the formation surrounding the borehole segment at the determined breakdown pressure.

Provided in some embodiments are systems and methods for preparing oriented samples of a laminated rock having different lamination orientations, for each of different stress-levels, transmitting an acoustic pulse through each oriented sample while tri-axially compressing the oriented sample at the stress-level to generate test data indicative of acoustic velocities through the laminated rock at different combinations of lamination orientations and stress levels, determining acoustic velocities through the laminated rock at the different combinations of lamination orientations and stress levels based on the test data, generating a rock model for the laminated rock based on the acoustic velocities, and determining a property of a second laminated rock (e.g., total organic carbon (TOC) content) based on the rock model for the laminated rock.

One embodiment of a wellbore to fracture connectivity apparatus comprises an opening portion representing an opening in a wellbore for receiving fluid, proppant, or any combination thereof to generate at least one fracture in a formation; a fracture portion representing the at least one fracture in the formation; and a coupling portion representing wellbore to fracture connectivity between the opening portion and the fracture portion. The coupling portion couples the opening portion and the fracture portion.

Systems and methods include a method for determining a breakdown pressure for the wellbore. Input parameters are received for computing a breakdown pressure for a wellbore. A pore pressure is determined using a Stehfest method equation using a function of a time duration, a distance from the wellbore, an injection fluid compressibility, a Biot poroelastic parameter, and a modified Bessel function. A poroelastic stress is determined using a poroelastic stress equation based on the pore pressure determined for the wellbore, a Composite Simpson's Rule for numerical integration, an empirical parameter, a pore pressure, a Biot poroelastic parameter, tensile strength of rock, and a Poisson distribution. A breakdown pressure is determined using a tested time-based formula, poroelastic stress, a minimum and a maximum horizontal stress, using a formula tested against multiple wells and a distance from the wellbore in a radial direction.

In some embodiments, an apparatus and a system, as well as a method and article, may operate to measure one or more properties associated with a fracture in a geological formation to provide a measured property. Further activities may include determining a predictive fracturing model based on the measured property, determining an objective function comprising at least one fracturing objective, generating an actuator input level that satisfies the predictive fracturing model and the fracturing objective of the objective function, and operating a controlled device according to a the actuator input level. Additional apparatus, systems, and methods are disclosed.

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for improving wellbore stability and minimizing wellbore failure issues. In one aspect, a method includes receiving, for a well site, post-drilling parameters; clustering the received post-drilling parameters into groups based on an information type of each post-drilling parameter; generating a correlation model by applying a numerical analysis or a statistical analysis to the post-drilling parameters included in each of the groups; determining a resolution to avoid wellbore failure at a new well site by processing information regarding the new well site through the correlation model; and transmitting the resolution for implementation at the well site.