Little Garden Oilfield Basis Of Geological Studies And Reserve Evaluation

Ordos basin is the second largest sedimentary basin on land in china which possesses abundant oil and gas resources and has bright prospects in oil and gas exploration. It has been becoming one of the important tactical area in oil and gas exploration in China. The amount of oil and gas resources and the degree which is proven will directly influence the development of China petroleum Industry. Shaoyuanzi oilfield is located in north slope of Ordos basin. It is the new area developed in the last few years. aim of exploitation is the second reservoir unit of Triassic Yanchang formation.On the basis of the geological investigations in the field and analysis indoors, combined with the theories on the sedimentary facies and petroleum geology, by means of various analytical techniques including conventional analysis of the core, analysis of capillary pressure, examination for resin-impregnated thin sections under a microscope, scanning electron microscope, analysis by x-way diffractometer,et al. the paper divide and correlate the Yangchang formation stratigraphic framework in Shaoyuanzi area. And stress to study the second reservoir unit of Yanchang formation in the sequence framework, discuss the characteristics of petrological, sedimentary facies and lithofacies palaeogeography, diagenesis and reservoir physical property in detail. The reservoir rocks are characterized with low compositionally maturity and relatively high textural maturity of fine grained arkose and the least lithic arkose; And its diagenetic mineral includes chlorite, laumonite, calcite, authigenic quartz,et al.The diagenesis mainly includes compacion,pressure solution, cementation, dissolution, et al.This paper presents an evaluation of low permeability and porous reservoir in Shaoyuanzi oilfield by means of the method adopted by PetroChina Corp. The result shows that in this type of reserves reservoir reserve is 2813. 7×10~4t, area is 41.1km~2 .