The Chang 6₃ Reservoir Bed Comprehensive Evaluation In Huaqing Area Of Odors Basin

Ordos Basin, Hua Qing area is located in center of the YanChang lake, sediment is extremely complex, the reservoir heterogeneity is strong, relatively high permeability reservoir quickly to changes in vertical and horizontal segment, single well production decline rapidly, high concentration block more difficult to implement, scale capacity building development difficult. Therefore, the Chang 6 reservoir evaluation is of great significance.The Chang 6 reservoir is low permeability, low permeability reservoir of reservoir characteristics and flow compared to conventional reservoirs laws vary considerably, so the evaluation of the Chang 6 is particularly important to find out oil rich region.Chang 6₃ reservoir bed is one of the major reservoir in Huaqing area of Odors Basin. In order to achieve oilfield producing energy construction much more quickly, to select favorable producing energy construction target, it is of very necessity and importance to study on comprehensive evaluation of Chang 6₃ reservoir bed.Firstly, take sedimentary environment of Chang 6₃ reservoir bed into consideration, combine both sedimentary markers with Sequence stratigraphy, in order to established stratigraphic correlation framework for Huaqing area. From the result of geologic correlation, there comes to one conclusion, Chang 6₃ reservoir bed is more developed in the central of this lake basin , but it becomes from thin to pinching out at the lake basin margin.Secondly, analyzed sedimentary source by studying on Chang 6₃ reservoir bed's clastic constituents,heavy minerals and quartz luminescence features. Through the analysis, two large sedimentary sources are founded, they are north-east sedimentary source and south-west sedimentary source. North-east sedimentary source is more richer in feldspar,and north-east sedimentary source system mainly contain the heavy minerals of zircon and garnet, but in the south-west sedimentary source , in addition to the two kind of heavey minerals , there are also other heavy minerals such as barytophyllite, rutile and tourmaline, and the quartz luminescence in nouth-east is bluish violet but in south-west is brownish red. Based on the sedimentary source analysis ,combined other characteristics of sediments(such as lithological characteristics, sedimentary structure and well log curve characteristics), to identify the sedimentary facies finely ,through the identification, find out the favorable facies belt are sub-aqueous distributary channel facie and terminal phase of the delta sedimentary system in the north-east zone and sandy debris flow lingulate facie in the south-west zone. Based on the analysis of the sedimentary facie, re-recognized the macro-distribution of the sand body, the sand body present band distribution on north and large-scale distribution on south. the main site of underwater distributary channel,the river confluence area and the lake over deep sandy debris flow on the stacking tongue body is the main location of thick sand development,and the area is also the formation of relatively high permeability reservoir area.Finally, take such as lithological characteristics , physical property of stone and pore structure into comprehensive consideration, propose a integrative classification which take the physical property and pore structure for the key factors, the Chang 6₃ reservoir is classified into three classes using this integrative classification. Then ,take the result of reservoir classification, sedimentary facies , distribution of sand body and production testing characteristics, predict two classes of favorable producing energy construction target ,that come to five target zones.