Isolated Oilfield Seven West Oil Sand Bodies And Tapping The Potential

Gudong oilfield is Tertiary drape anticline structure developed on approximate south-north trend Mesonic burial hill background. This studied tract is the west seventh region in Gudong oilfield, its target zone upper Guantao Formation is fluvial facies sedimentary have such features as high porosity and permeability, strong non-uniform ,reservoir structure unsolidated formation ,easy to sanding. At present it has entered development stage of extra-high water-cut period, tapping potential is more difficult. Study on little oil sand body thin oil-bearing formation resources and development technical policy is of practical and guiding significance.The technical key of research is mainly reservoir fine description, residual oil quantitive description and development technical policy of little oil sand body thin oil-bearing formation.The basic datum bed is grey-green organism shale which is 20-30cm thick at the bottom of the fourth sand group. Upper formation fluvial facies in the west seventh region in Gudong oil field is divided into two subfacies, braided stream sedimentary facies mode and meandering river sedimentary facies mode. This fluvial facies sedimentary is more developed, is divided into 28 substratum,324 sand body, have 301 sand body oil -bearing area less than 0.5km2, average effective thickness 3.0m, petroleum geologic reserves 665×10~4t, according to different oil -bearing area rank evaluate geometric configuration, thickness, reserve, microfacies.On the basis of resources evaluation, development status analysis and residual oil potential evaluation is carried out。At present non-producing little sand bodies 218,reserves192×10~4 ,producing little sand bodies 83,reserves 473×10~4t , rate of withdrawl 12.9%,have more potential.To optimize the best production manner of little oil sand body thin oil-bearing formation ,unite numerical simulation with reservoir engineering technology, contrast vertical hole with horizontal well and optimize to different types of little sand body.This study establish three models, the former two are vertical hole with horizontal well ,the three is carrying out non-stable water injection and continuous water injection in larger sand body, vertical hole elastic production, horizontal well elastic production and single vertical hole huff and puff, inject-able little oil sand body contrast vertical hole with horizontal well and optimize, non-stable water injection. The result shows inject-able oil sand body early injection development have good effect, inject conversion at pressure drop 1-2MPa is best. Recovery efficiency of adopting huff and puff plus one injection one production or one injection two production is higher than pure elastic production.