AN APPROACH TO FORMATION DAMAGE CONTROL, IN HORIZONTAL, WELLS
PED, 1997, 24(4):68-71Zhang Ningsheng (Xi'an Petroleum Institute, Shanxi, 710065)
Formation damage, during drilling and completion of horizontal wells, has been a serious problem which affects the production capacity of pay zones in horizontal wells, because of cutting's bed forming on bottom side of horizontal wells and drilling and well completion fluids invading into formation. This paper presents an analysis of the main factors of influencing formation damage in horzontal wells, introducing the particular techniques to prevent or release the damage. A mathematical model was established to calculate and compare the damage degree between horizontal and vertical wells. Analysis results show that: (1) formation damage is an important reason affecting the production capacity of horizontal wells; (2) the damage zone, caused by drilling and well completion fluids invasion, made a more serious damage in horizontal wells than in vertical wells ; (3) in general, the sensitivity to formation damage in horizontal wells are Iess than that in vertical wells, nevertheless, once the horizontal well is damaged, the production capacity of the horizontal well will decline obviously and it is hard to treat. The paper also discussed the techniques to prevent the formations in horizontal wells from damage.
【CateGory Index】： TE35