Research On Remaining Oil Characteristics Of Hai-26 Complex Fault Block At Later Stage Of High Water Cut

With the main block of Haiwaihe Oilfield-Hai-26 Block as the research object,this paper makes fine reservoir research,establishes a comprehensive adjustment scheme,and improves the development effect at the ultra-high water cut stage.As the main fault block of Haiwaihe Oilfield,Hai-26 Block geographically lies in Bohai Sea beach,14 km from the southwest of Dawa County,Liaoning Province,and structurally in the south tip of south plunging zone of the central uplift of Liaohe Depression Basin,and is a complex petroleum accumulation zone of warped fault block.The oil-gas-bearing target stratum is Paleogene Dongying Formation.Lithologically based on siltstone and fine sandstone,sedimentary facies belong to delta front intrafacies and predelta intrafacies.The porosity is generally 27³1%;the permeability is generally 900²000×10^-3?m²,and the reservoir is the reservoir with high porosity and medium high permeability.There is an obvious directionality in the reservoir plane,and stronger plane heterogeneity;the heterogeneity coefficients among all sublayers are smaller than 2.9,and the interlayer heterogeneity is lower;the in-layer permeability contrast reaches 79 times,and relatively strong in-layer heterogeneity is shown.The oil-bearing area is 5.6km²,average effective net sand 19.4m,stock tank oil viscosity at 50? within 14.34⁴984m Pa·s,and initial oil in place 2067×10⁴t.The oil-water relation is complex,there are various oil-water combinations,and different layers and fault blocks have different oil-water interfaces.The reservoir types include lithologic-structural reservoir,lithologic reservoir and structurally controlled edge and bottom water reservoirs.After nearly 30 years of water injection development,Hai-26 Block enters the extra-high water cut development stage,and the development conflicts are prominent,and the EOR difficulty is high.It is necessary to make a comprehensive adjustment on the basis of fine reservoir research in order to further dig the resource potential.By the comprehensive use of fine stratigraphic correlation,geological structure recognition,thin layer sedimentary microfacies research,reservoir heterogeneity research,remaining oil research and other technical means,this paper conducted the fine oil reservoir description of Hai26-section,and solved the complex oil-water relations of fault-block type heavy oil water flooding development oilfield.It also researched the remaining oil pattern by applying the site production test information and dynamic analysis of oil and water well and other reservoir engineering methods.This paper provided technical supports to further improve the oil recovery rate and scientifically and effectively develop the fault-block type heavy oil water flooding development oilfield,but also provided technical reference for the oil reservoir in the same oil reservoirs in Liaohe oil region.