Research On Drilling Long Horizontal Wells Technology Of Honghe Oilfield

Honghe oilfield is one of the important explorations and development blocks in the south of the Ordos Basin. It has good prospects for development. Yan’an and Yanchang formations are the main oil layers of Honghe oilfield. Both layers have these features which are low pressure, low porosity and low permeability. In recent years, exploration and development of Honghe oilfield have proved that long horizontal wells technology can effectively solve the major issues that the productivity of vertical well, directional well and single well are lower. However, due to the well structures and technical measures of long horizontal wells are different from others, make it with big friction and torque, slow drilling speed, long drilling cycle in the process of drilling and completion wells. And due to the complexity geological conditions of red river oil field, more formation fracture, small pressure, poor stability, rich in mudstone and coal seam, easy swelling, make it liable to occur well complex conditions, such as hole collapse, adhesion sticking and impellers sticking during the drilling process. The existence of rock cream layer can easily lead to the drilling fluid being invaded salt paste, so that the next drilling, casing and electrical logging more difficult.To solve the problems that occur during the process of long horizontal well drilling like leaking easily, sticking, collapse, Salt paste invasion and other issues. This paper conducts an extensive investigation on the drilling state of Honghe oilfield, and the traceability statistics of 42 wells’historical data. For its complex and difficult, we analyze the borehole stability risks of long horizontal well, and adopted the mechanical drilling rate method and principal component analysis (PCA) to optimize bit type and BHA. Using computer language and iteration mathematical calculation analysis software calculated friction and torque under different working conditions. Finally, this paper proposes several methods to decrease the friction and torque.Through the research on this subject, not only to speed up the Red River oil field drilling long horizontal wells speed and reduce underground complex accidents and shorten the construction cycle, but also provide technical reference for achieving the large-scale block construction and increasing the overall economic efficiency of exploration and development.Main results and understanding are as follows:(l)Through statistical analysis the down hole troublesome condition of the Honghe oilfield, we concluded that the drilling difficulties for the block mainly are:easy to leak, fragile, easy card, easy to paste, friction and torque are too big.(2)Analysis and study the rock drill-ability of each layer, through the mechanical drilling rate method and principal component analysis, suggesting preferred PDC bit in order to improve productivity gains. In order to better control the horizontal well trajectory, raise the rate of target, we finalized for the Honghe oilfield excellent and fast drilling BHA by comparative analysis of the drilling data.(3) Adopting three-dimensional soft rod model conduct the down hole tubing string stress analysis, establish calculation model and calculated friction and torque under different working conditions. And proposed several measures to reduce friction and torque, such as mud performance optimization, using reduced friction nipple and so on.(4) Field application results show that this process effectively solved the problem of drilling long horizontal wells of Honghe oilfield. The test wells rate of penetration was greater 54.7% than the previously drilling rate. The total time of complexity was also reduced 71.76%. The construction cycle of the long horizontal well was shortened 34.9%. It provides a strong technical reference for the construction of the Honghe oilfield long horizontal wells.