Abstract:

Although widely applied in China for years,the application of water drive curve method has been ge-nerally limited to the study of sandstone reservoirs both in theory and practice.This time,however,it is used in the study of the Ordovician carbonate reservoirs in the Tahe Oilfield.The water drive performance of carbonate reservoirs is much more complicated and changeable than that of sandstone reservoirs.Three types of curves are observed in the study of these reservoirs,including regular curve with single linear portion,regular curve with two linear portions(step-like curve),and irregular curve.Among them,the second one reflects such features of these reservoirs as well-developed fracture and vugs,unstable water body energy,and complicated water-driving pattern.It also indicates that the decline of energy affects different water bodies.An analysis of water from a typical well verifies the existence of several water bodies in one fractured-vuggy unit.

Key words: water drive curve, regular pattern of water drive, carbonate rock, fractured-vuggy reservoir, Ordovician, Tahe oilfield