  Over the past decades, direct imaging has confirmed the existence of
substellar companions (exoplanets or brown dwarfs) on wide orbits (>10 au) from
their host stars. To understand their formation and evolution mechanisms, we
have initiated in 2015 the SPHERE infrared survey for exoplanets (SHINE), a
systematic direct imaging survey of young, nearby stars to explore their
demographics.} {We aim to detect and characterize the population of giant
planets and brown dwarfs beyond the snow line around young, nearby stars.
Combined with the survey completeness, our observations offer the opportunity
to constrain the statistical properties (occurrence, mass and orbital
distributions, dependency on the stellar mass) of these young giant planets.}
{In this study, we present the observing and data analysis strategy, the
ranking process of the detected candidates, and the survey performances for a
subsample of 150 stars, which are representative of the full SHINE sample. The
observations were conducted in an homogeneous way from February 2015 to
February 2017 with the dedicated ground-based VLT/SPHERE instrument equipped
with the IFS integral field spectrograph and the IRDIS dual-band imager
covering a spectral range between 0.9 and 2.3 $\mu$m. We used coronographic,
angular and spectral differential imaging techniques to reach the best
detection performances for this study down to the planetary mass regime.}
