| JAZMIN oilfield is a significant exploration block in Magdalena basin, but so far, as for this area, there have been few systematic studies and the rule of its reservoir has not been fundamentally acknowledged. Based on sedimentary petrology and sedimentary facies, the paper makes an integrate study on strategic framework, characteristics of sedimentary facies and reservoir distribution of JAZMIN block in terms of well data, geophysical logging and other sheet information.First, through continuous tracking of multiple sets of marker beds, overall acknowledgement of regional strata is achieved and 47 wells within the block are selected to carry out the thickness statistics on the main producing formations and other top layers as well as draw a sand distribution map. Also the sand thickness of such area is analyzed to completely show the obvious decreasing rule from east to west. At the same time, it s thought that the main factors leading to the decreasing of strata's thickness include that the west is in the upper river with low sedimentary or no sedimentary and the incision in the upper river take place in light of the rising water.Then, the sedimentary facies in the cross-section of the single well is classified and the study on sedimentary facies of the target layers is carried out in terms of four phases. Moreover, the target layers are compared in the sub-system domain to draw a plane distribution diagram. The conclusion is that JAZMIN oilfield is in an alluvial plain with the main characteristics of river development. The sedimentary facies such as several sets of channel sands, floodplain, abandoned channel and flood plain are vertically formed and presented.Then the dominating factors on the sedimentary facies are analyzed to conclude that this area is controlled by three factors including lake level variation, structure and climate. By the same token, it is the first time to point out that the area is dominantly controlled by the lake level variation. In particular, the shale's regional distribution is closely associated with seasonal Basin compact-expansion in the east of Mugrosa.The average porosity and permeability on multiple sections of a single well are extracted as data sample and studied to draw a cross figure concerning about porosity and permeability. The statistics on the types of divided reservoir is carried out to draw a conclusion on three types of reservoir that porosity of typeâ… is above 33% and permeability is above 8000 mD; porosity of typeâ…¡is from 29 to 33%, permeability from 7500 to 9000 mD; porosity of typeâ…¢from 25 to 29%, permeability from 5000 to 7500.The effective classification of approximate 20 single wells is made as well as the average porosity and permeability with total thickness of reservoir is calculated. Then the obtained three data is applied to make a contour map in the project point to carry out the correction by way of the relative contour map targeted at sedimentary in the end.Finally, the integrate analysis is made on the sand thickness, porosity, permeability and sedimentary distribution to make a graph in the plain so as to make a reservoir distribution graph on JAZMIN oilfield. From the analysis, it is believed that the development location of typeâ… in the northeast of this area is best and the A layer in exploration area is the best exploration layer. In general, the deposition performance in the whole area is good and the exploration on the unstressed area should be increased. Meanwhile, the study on oil and gas should take several factors into consideration. So through the analysis, it shows that the hydrocarbon in this area is not only associated with reservoir performance, but also with the location of source rocks, filling direction of oil and gas, and the later transformation of reservoir. |
PDF Full Text Request