Investigation of interference from multiple oriented hydraulic fractures while considering near-radial wellbore stress distribution

Abstract

Stratigraphic sequences are sometimes thin, rarely ideally horizontal and juxtaposed due to faulting. Wellbore trajectories targeting such strata may not be necessarily horizontal aligning with principal stress direction. Perspective from perforation orientations typically embeds understanding of fundamental fracturing issues such as high treating pressure, premature screen-outs, and tortuous and short-circuited fracture paths among others. One or more of these issues may influence other drawbacks making the overall problem more complicated. The objective of this study is to investigate the influence of stress shadow effect of multiple fracture propagation on treating pressure and fracture geometries (apertures, lengths, heights, and tortuosity) then later introduce a new concept of controlling fluid entry into multiple oriented perforations through modification of entry elements combined with radial wellbore technology. The study demonstrates that both simple bi-wing and complex multiple bi-wing fractures are associated with low treating pressure when combination of high phase/high or low orientation angles, illustrated with 1800/900 and 1800/00, is used. It has further shown that oriented perforation reduces the extent of fracture closure zone around the crack mouth. Sequential and simultaneous techniques are implemented with their comparison demonstrating that sequential fracturing is associated with elevated fluid pressure after first injection. A maximum error as low as 0.52 MPa is recorded during the bottom hole pressure analysis. Optimized results from restricted fluid entry elements, simulated within XFEM computational domain capable of accommodating fracture-turning effect, minimized fracture choke-like effect producing relatively uniform fracture development. The new elements are validated against KGD model. The model is further validated against published experiments and Daqing Oilfield data with good match of results in both cases. The study is important for field implementation of hydraulic fracturing in stratigraphically thin reservoirs with well trajectories disoriented from principal stress direction.