Reservior Characteristics And Their Effects For Development In Leng43 S₃～2 Reservior Of Liaohe Oil Field

Leng 43 block is one of the major development blocks of Lengjiapu oilfield. The target interval, ES32 segment, is a heavy oil reservoir with a burial depth of about 1650-1940m and a thickness of about 80-100m..The segment, ES32 ,is a set of sedimentation deposited by gravity flow of the near-shore steep slope sublacustrine fen, is formed out of granule roundstone and also features coarse lithology and crude grading. The reservoir is middle porosity and middle-High permeability, its average porosity is 17.2%, average permeability is 454 x 10-3 um2.The lithology of reservoir is positive rhythm longitudinally, and extends in east-north direction on a plane. The intraformational heterogeneity is strong, but the interformational is weak. In addition, the principal direction of maximum horizontal stress is NE60.The crude shows the character of heavy oil, density range between 0.93 and 0.97 g/ cm3 (20 ℃), surface viscosity between 92 and 35860 MPa · s(50℃), formation crude density 0.904 g/ cm3, formation viscosity 57 MPa · s(58℃).Leng 43 block was developed in 1993 and since then conventional fracturing conduction, water flooding test, steam soaking were successively carried out, but exposing several inconsistencies such as high decline rate of output, water flooding fingering, low potential of steam soaking etc. Among them the physical properties is an important factor that affecting the result of development. Until May 2001, the pressure is only for 6.1 MPa, the recovery percent only for 9.89%, so need to seek for an economical and favorable conversion of development way in order to increase development recovery.In this paper analyzing reservoir depositional features, lithologic features, developing law of sand body , reservoir physical properties, microporosity structure and the principal direction of maximum horizontal stress of Leng 43 block, some factors affecting the effect of development and choice of development ways are studied. Based on physical simulation and numerical simulation, the conversion of hot water slug flooding with nitrogen foam is presented and some injection indices are optimized ,including foam concentration, gas-liquid ratio, injection rate, temperature of water, slug length.From reservoir research and oilfield development, studying disadvantageous factors, the paper will have guilding value for heavy oil reservoir development of leng 43 block. But because time and ability is limited, there may be some mistakes, please correct.