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The Formation And Distribution Of Residual Oil Of Putaohua Oilfield

Posted on:2010-05-17Degree:DoctorType:Dissertation
Country:ChinaCandidate:C L YuFull Text:PDF
GTID:1100360278460772Subject:Geological Resources and Geological Engineering
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To improve recovery ratio and reduce production depletion have become the key point for many old oilfields. Deeply studying on the law of residual oil formation and distribution and precisely predicting abundant residual oil are the highlights for the mature developed oilfield.Taking the narrow and thin sandstone reservoirs of PI oil group in Putaohua oilfield as a case, in view of the special geologic condition and development problems, a study on the law of formation and distribution of residual oil was carried out based on the data of geology, well logging, seismic, production test and production performance.A nine-order classification scheme was proposed to analyze the architecture elements of Putaohua reservoir, and this scheme is suitable to the scheme of stratigraphic division. Research results indicate that parts of the thick sandbodies have actually been superimposed by multiphase subaqueous distributary channels, which can be divided by erosional surface, Argillaceous or calcic constructional surfaces. Parts of thick sandbodies and the channel sandbodies thought to be flaky distribution are vertically superimposed and laterally connected by single sandbodies. Single sandbody can be identified and divided by the difference in the vertical and lateral position of sandbodies, the information of production test and integrating seismic inversion and so on.Based on the static parameters, production performances and test data, a kind of quantitative method by the integrated discrimination exponent was put forward to identify the channeling paths developed area of reservoirs by using commingled injection and production. Studies show that channeling paths would have been formed if the integrated discrimination exponent of well-group is more than 0.38 in the north of Putaohua oilfield. It has been confirmed that the rate of accuracy can reach up to 95.2% with this method, so it is a fast and effective quantitative method.On the basis of the further study on geological characters and the comprehensive research on the formation and distribution of residual oil in the narrow and thin sandstone reservoirs, a new kind of enriched residual oil model has been found. Some crotches of the subaqueous distributary channels are the areas of enriched residual oil. The enrichment rules of this model were discussed from the aspects of sandbody genesis, geological characters and water flooding. This new discovery expands the knowledge of residual oil. The synthetical evaluation of heterogeneity of PI oil group was carried out by the heterogeneous integrated index, and this index was successfully applied to optimization of residual oil. The success utilization in the narrow and thin sandstone reservoirs of delta front of heterogeneous integrated index, which was originated from the fluvial facies heterogeneity study, expanded its application field and also indicates its wider potential value and application prospect.A further knowledge of the formation and distribution of residual oil in narrow and thin sandstone reservoirs have been formed through microscopic experiment by combining with macroscopic analysis and microscopic study.The measures of tapping potentials by horizontal wells and vertical wells have been proposed referring to the formation and distribution of residual oil, and some of which were succeeded with better effects. This research is of great significance not only in the peripheral oilfields in Daqing, but also in the similar oilfields in the other areas.
Keywords/Search Tags:Narrow and thin sandstone reservoirs, Reservoir architecture, Channeling paths, Reservoir heterogeneity, Crotches of the subaqueous distributary channels, Residual oil, Putaohua oilfield
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