HETEROGENEITY AND IITS IMPACT ON REMAINING OIL DDISTRIBUTION OF LOW PERMEABILITY RESERVOIRS IN THE HEI46 BLOCK

Low-permeability reservoir is one of the reservoirs with the most difficult decisions during the oil and gas exploration. Hei46 block in Songliao Basin is difficult for exploitation due to poor physical property and low recovery degree, high moisture content of reservoir as well as strong heterogeneity. Reservoir heterogeneity in the first member of Qingshankou Formation including intralayer, interlayer and plane heterogeneity are studied on the basis of core observation, laboratory experiments and logging interpretation. The article links heterogeneity in different depositional facies, and determines the effects of heterogeneity on remaining oil distribution can be determined. Under the influence of reverse rhythm, the upper parts of oil-bearing layers show coarse lithology, as well as higher permeability, water injectivity index and producing degree. Combining with numerical simulation results, we hold that water flows primarily along high permeability zones causing remaining oil enrichment in low permeability regions. Results of the heterogeneity study can be correlated well with the field testing resultsand thus have significant implications for the further petroleum exploration and water-injection exploitation.