The Assisted Identification Of Hydrocarbon Zone By The Microbial Abnormity In Satellite Oilfield Of Daqing Area

After50year’s exploration, most of china’s petroliferous basins have been well exploration, and found a lot of oil and gas fields which are apt to discovery. But, followed with further development, the rest of petroleum resources distributed decentralized, oil/gas reservoirs is small, and most of them are non-structural oil-gas reservoirs. If we use routine method, it’s very difficult and the cost is expensive. So MPOG can forecast non-routine oil/gas reservoirs and deep oil/gas reservoirs, can ascertain petroleum resources distributed in geological structure, and can indicate location of oil drainage. It is very important to improve oil/gas exploration.The aims of MPOG are:①delineate hydrocarbon-oxidizing bacteria anomalies region which is relate with deep oil/gas reservoirs, indicate location, provide an experimental basis for exploration area valuation and the locations of wells for prospecting drilling.②study every index in MPOG on forecasting hydrocarbons accumulating.③classify the anomalies in MPOG.④made the suggestions for the future exploration.The mechanics of MPOG is:light hydrocarbons migrate predominantly vertically from deep reservoirs up to surface soil driven by "microbubble buoyancy", which provides favorable conditions for obligate bacteria, i.e. hydrocarbon-oxidizing bacteria (HCO),and results in great increase of number and activity of HCO and then anomaly zones. On the basis of these zones, the existence and characteristics of underground reservoirs can be appraisable and predictable.In this paper,the practical programs of MPOG are expounded, such as field geological survey and sample collection, microbial experimental technique, data process and assess criteria, comprehensive evaluation and potential prediction of oil and gas, etc.Field geological survey and sample collection is base on the difference of exploration aims and the degree of knowledge in geological structure, when we general investigation in the areas, sample collection distance usually deign500m or1000m. when we have some knowledge about this area, sample collection distance usually deign under250m. In study area, sample collection distance is EW250m×NS250m.Microbial experimental technique is evaluation the quantity of microbial. In order to evaluate microbial anomalies, we adopt a suit of assessment index-MU value. It contains the quantity of microbial(n), activity(a), microscope assay results(o), earths surface humidity(t), sample humidity(h), lithology(1), color(c), PH value(p)and earths surface vegetation(v).Data process and assess criteria is base on microbial analysis report, geology structural map, two or three dimensional seismic map. Study microbial anomalies area is correspondence with the location of geology structural, location of oil well and reservoir’s characters and it exploration history, microbial anomalies is correspondence with existence achievement. Last, give the well design.In the study Satellite oilfield, collect1548samples, about81.5km2. After this area microbial abnormity analysis, we finished microbial assisted identification hydrocarbon zone.After the study preliminary achievements, based on the statistical analysis of65wells which related putaohua oil layer, its hydrocarbon possibility, compared with microbial abnormity, which matches55wells,10wells doesn’t match,the consistent rate about85%.Combined with the prospecting results of geochemistry, geology and geophysics, the microbial anomalies are provided, with which the oil and gas prospecting zones are ranked, at the same time the optimal target area and the well sites are designed. It is that northwest anomalies zone is explorationable zone, middle anomalies zone is optimal target area, southeast anomalies zone is less explorationable zone.Based on the microbial abnormity zone, through the the faults, sand body distribution, productivity distribution, and compared with abnormity adjacent areas, detailed analysis of the hydrocarbon Resources prospect.In the study, We take microbial abnormity as the major premise, combined with area fault, the predicted sandstone thickness and the area integral deployment, with the exception of deploying to two completed well by the first party. The MPOG result s were verified by the hydrocarbon-bearing conditions of the drilled10wells. After drilling to confirm the practice, Its hydrocarbon-bearing is consistent of microbial abnormity results. According to the result s of MPOG, explored petroleum geological reserves75×104t were newly added.Finally, the report gives the main conclusions and recommendations for exploration. The report recommends strengthening the region’s seismic data analysis, and further strengthen the reservoir sand body of material research. We take fault block sheltered as trap-oriented,to the reservoir sand body good properties as target. On this basis, to consider the issue of evaluation of the deployment, it can greatly improve the success rate of exploration. This technology can provide a new technical support for complicated reservoirs, especially for the late development of litho-reservoirs in China.