The Research Of Lake Facies And Low Permeability Resevoir Characteristics In Neogene System In Xiaoliangshan Oilfield Of Qaidam Basin

The Xiaoliangshan oilfield is located in the west of Qaidam Basin in Qinghai province. In2010test oil received industrial oil flow for the first time.2011-2012years,through thegeological research increased the reservoir evaluation and production test.This structureshows greater development potential. In order to provide geological support, point out themost favorable areas and give good advice for the oilfield’s scientific development.In2012,this paper studied on oil reservoir characteristics, well logging, reservoir distribution area.The paper used lots of drilling, core analysis, logging, oil testing data, and took advantageof the reservoir sedimentology, logging, logging geology theory as a guide, The paper hadstudied the oil reservoir sedimentary facies, lithology, pore throat, a system of diagenesis,oil-water relationship layer interpretation for the first time. The Xiaoliangshan oilfieldbelongs to the Shallow lake and half deep lake facies deposition. Due to the continuous farsource fine clastic substances enter into the lake, in the common role of wave transformationand chemical deposition, forming characteristics of algal limestone, lime powder sandstone,tuffaceous siltstone, shaly siltstone, silty micrite and other lithological mixed product. TheShizigou formation (N32) reservoirs is formed of siltstone lithology.The upper Youshashanformation (N22) reservoir is formed of carbonate rock mainly. Based on the study of reservoircharacteristics, the paper recognizes the reservoir is fine particles, water power weak, poorphysical property, weak diagenesis, small pore throat, high shale content. Due to the abovecharacteristics of the reservoir, it brings difficulty to the oilfield development, reservoirparameter interpretation and oil-water layer identification. The paper based on the researchprocess and make full use of core description, slice, scanning electron microscope, X raydiffraction and other data, and begins a comprehensive analysis of the key well logging data,logging four relations research and the recognition of lithology reservoir. Then this paperuses the method of core scaling logging to distinguish the lithology and establish the reservoirparameters interpretation chart and oil-water identification charts. In the end this paperestablishes the reservoir classification standard in the N32、N22formation in Xiaoliangshanoilfield. The comprehensive evaluation of reservoir put into affect by using the standard, the paper points out the distributing range of the one class quality reservoir. In N32formation,thebest quality reservoir is mainly distributed in the Xiaoliangshan faulted anticline axis and thesouth wing near the Xiaoliangshan fault zone.In N22formation, the best quality reservoir ismainly distributed in the Xiaoliangshan faulted anticline axis beam101well area. Ouecompany drilled40development wells in the best quality reservoir area in N23in2012. Thesewell’s produced very well.The single well oil production is more than2tons every day. Theproduction is1.5-2times than the adjacent oilfield’s producing wells.