Horizontal well development is an important technology for increasing production and improving development benefit. The horizontal well geosteering technology includes: the optimization of well sites which guarantees that construct of horizontal wells, reservoir beds and off-take potential are all substantive, so as to reduce the horizontal well performance risk; the optimization of horizontal well track design, to predict accurately target points and the following target points based on the K₁ construct, the stratum thickness and effective thickness of Majiagou team mbrs, the construct of K₂ and the top of the Ordovician, and stratum thickness and dip angle, so as to ensure the security of track design; the optimization of geological orientation tracking analysis, to insure targeting according to the coal bed and the top of the Ordovician drill-met, and to forecast the following target points by combining debris, drilling times, gas survey, GR along with drilling, stratum thickness and dip angle. The application in the Lp1 well achieved high production after acidification.