Hydraulic fracturing as a means to stimulate production has become an effective way to extract oil and gas from low-porosity, low-permeability, hydrocarbon-bearing formations. The technology used in support of hydraulic fracturing is evolving at a fast rate, which has enabled operators worldwide to achieve improved recovery in increasingly complex well environments.
The well designs and completion strategies associated with hydraulic fracturing come with a unique set of challenges. During well construction, the long lateral sections of extended-reach wells may require the production (or intermediate) casing to be rotated and pushed through build sections of relatively high curvature (greater than 10° per 100 feet or 30 meters); furthermore, some operators rotate the casing during cementing to improve cement quality. This rotation can subject the casing connections in the build section to a high number of rotating-bending load cycles. This cyclic loading can result in high stresses in the thread roots of the casing connections, which may lead to localized yielding of the material and potential structural failure. The hydraulic fracturing process itself subjects the production casing to rapid increases in internal pressure to high magnitudes, which will result in cyclic pressure loading for wells with multiple stages. Given these considerations, casing connections that are used in hydraulically fractured wells can be subjected to significant cyclic loading before the well is produced, and this loading may have an impact on the overall casing connection sealing and structural capacity in subsequent well operations.