The Practice of Recovering By-Passed Oil by Horizontal Wells in Guan 2 Reservoir, Linpan Oil Field

Abstract Guan 2 reservoir is located in Lin 2 block of Linpan oil field. The trip is a nose with a normal fault dipping towards North (Fig. 1). The reservoir consists of unconsolidated sandstone, which is a Tertiary fluvial deposit. The thickness of the sandstone reaches 140-150m, but only the top 15-30m reservoir is saturated by oil (Fig. 2). The depth of the initial oil water contact is 1426m from sea level. The reservoir oil viscosity is 76.5mPa.s. Since the development started in 1973, 23% OOIP had been produced, and the water cut reached 92.7% under active bottom water drive. In order to improve oil recovery, a series of studies were carried out based on the 3D seismic, drilling, logging and production data. According to the renewed understanding on the micro-structure, distribution and effect of the interbeds, advance of the oil water contact and the development of the water cones, the distribution of by-passed oil was determined. Then, 4 horizontal wells were designed and drilled. The results are inspiring. It is estimated that the ultimate oil recovery will be increased by 14.6%. This paper presents the reservoir characters, the methods and results of the studies.