The Research On The Micro-pore Structure And Seepage Characteristics Of Chang6Reservoir In Banqiao-Heshui District

Chang6reservoir of Triassic Yanchang Formation in Banqiao-Heshui district belongs to a typical low permeability reservoir. It has a poor reservoir property, strong reformation in the later diagenesis, a complicated micro pore structure and the seepage characteristics are affected by many factors, so there has no great breakthrough in the field of exploration and development of oil and gas yet. The paper studies on the following aspects. First of all, the paper has studied on the sedimentary facies and distribution characteristics of sand on the plane and vertical; Then study of reservoir lithology, physical property, diagenesis, pore structure and seepage characteristics by scanning electron microscope, the casting thin sections, high-pressure mercury injection and oil-water relative permeability and other conventional experimental methods combining with emerging technologies of constant speed mercury penetration and nuclear magnetic resonance (NMR) testing methods; Finally, on the basic research of the static reservoir characteristics, it is analyzed the main factors on the influence of reservoir physical properties combined with dynamic production data. Main achievements is displayed detailed in following paragraph:1. Chang6reservoir in Banqiao-Heshui has a complex reservoir sedimentary type, and develop hunan delta front subfacies deposition and half deep lacustrine turbidite deposit generally. Reservoir are mainly lithic arkose, high content of interstitial material (up to14.6%), fine rock particles, poor psephicity, angular, medium degree of separation, cementation method is given priority to with increasing-pore type cementation and pore cementation, line contact is given priority to, high clay mineral content, especially in the development of illite overall maturity chang6reservoir structure is not high, destructive diagenesis is strong, and poor overall property;2. The pore types of Chang6reservoir in the research district mainly feldspar solution pores, intergranular pore, the face of a rate of about accounted for70%of the total rate of face, throat types are mainly flake-bending sheet. Main pore combination types of pores, solution pores, intergranular pore, solution pores. Overall, the pore growth is poorer, throat, small, big pore throat ratio; Commonly found in the second type (Ⅱ), the third type(Ⅲ) capillary pressure curve, high displacement pressure, low efficiency of mercury withdrawal, maximum into mercury saturation is low; Uneven distribution of throat, and the pore connectivity is poor lead to poor reservoir property, strong heterogeneity, make pore structure is more complicated; 3. The study area has a poor reservoir property, microscopic, complicated pore structure and high filler content of factors lead to complex oil-water two phase flow characteristics, high bound water saturation, two phase seepage area small, two phase flow interference is strong, overall lower reservoir movable fluid saturation;4. Reservoir property in the research area mainly in the mutual influence of sedimentation, diagenesis.