Remaining Oil Distribution And Its Potential Exploitation Measures In Complex Faulted Depression Basins

In the middle and late period of oilfield development,the study of the distribution of residual oil is the key to the adjustment of oil field development and the exploitation of the potential.Bei 301 is a complex fault block conglomerate reservoir.After many years of water injection development,it has entered the mining stage at high water cut stage.The main oil reservoir water drive efficiency is low,and the single layer water flooding is serious.Since the injection of water will change the original state of the.Distribution of oil and water in the reservoir,the characteristics of fluid seepage between sand bodies will change,and the imbalance of injection and production,inter-layer interference,and intra-layer differences caused by reservoir heterogeneity obvious,petrophysics unit division deposition method to guide the development of the role of adjustment is limited.Aiming at the current contradiction of oilfield development and combining with the geological and tectonic background of complex fault block glutenite reservoirs,high-resolution sequence stratigraphy and sedimentary facies studies have been carried out.Gradually analyze the geometric shape and internal structure of the sand body,summarize the short-and mediumterm base-level cycle types and short-term base-level cycle distribution patterns.Fully considering the law of phase sequence grading,verifying closed skeleton sections through multiple well profiles,establishing an isochronal high-resolution stratigraphic framework in the entire region,drawing on previous results of stratigraphic division,the high-resolution stratigraphic division scheme of the Nantun formation in the BEI 301 area was finally established.A total of six short-term base level cycles(SSC1 to SSC6)and four medium-term base level cycles(MSC1 to MSC4)were identified.Three long-term base level cycles(LSC1 to LSC2).Based on core core data,the characteristics of the lithofacies and sedimentary microfacies of the Nantun formation are analyzed,and the well logging phase patterns established in response to log curves from different microfacies are used,the distribution rules of the plane and vertical of each deposition time unit were finely dissected.Graded sedimentary interface and structural unit features identify relatively closely related sedimentary microfacies singlegenesis sand bodies,the effects of structural types,superimposed patterns,and combinations of short-term cyclic single sand bodies on reservoir oil and water movement laws are summarized.The study of reservoir heterogeneity is carried out from the three aspects of plane,layer,and interlayer,and is the remaining oil in the oilfield in the later period of the area.Potential mining provides geological basis.The effects of structural types,superposition styles and combinations of short-term cyclic single sand bodies on reservoir oil-water movement laws are summarized,and reservoir heterogeneity studies are carried out from the three aspects of planes,layers,and layers.explore the remaining oil to provide geological basis.Comprehensive pre-geological research results,a three-dimensional geological model was constructed To determine the distribution law of reservoir porosity and permeability under phased interaction,and to study the remaining oil enrichment regularity in the reservoir's vertical and horizontal planes using reservoir numerical simulations.Combining the results of reservoir numerical simulation studies with previous geological understanding to study the main distribution of remaining oil and the main control factors,summarize fault-shielding type,plane and inter-layer interference type remaining oil,injection-production-imperfect residual oil,and well-controlled non-residual residual oil,the estuary dam and mat sand are the main adjustment targets for the next step water drive.Aiming at different types of residual oil,comprehensive technologies such as enhanced injection and production system adjustment,well network encryption and classification development,and comprehensive application of various measures were used to tap remaining oil.