Geochemical characteristics of the braided river reservoir in block 19 of the sulige gas field

The sand body structure and geochemical characteristics of braided river reservoirs are the key geological factors affecting gas production development effects. Sulige field in Ordos Basin is an important large-scale gas-producing layer. Owing to control sedimentary facies, changes greatly its connectivity poor. have not yet been elucidated, this problem restricting Gas Field. To solve problem, study focuses on reservoir Shihezi Formation Block 19 Field, conducts surveys area, analyzes reservoir, obtains samples through drilling. Through a thin-section test, gas-water two-phase experiment, simulation configuration pore obtained. results show that lithology area mainly composed quartz sandstone, lithic quartzy with porosity 3%–13% permeability (0.05–0.7) × 10 −3 m 2 . has low permeability. After drilling were obtained, 32 rock selected. types block (82.9%) consisted intragranular intergranular dissolved pores. difference was reflected by size distribution throat. physical properties 6%–10%, saturation 61%, NMR effective 7.49%, 4.08 μm , relatively good. In terms average thickness single channel lower section He 8 4.7 m, width 963 composite distributed potato shape, parallel direction main flow. length 2,147 844 m. As increased, efficiency gas-driven water also there linear positive correlation between efficiency. With increase movable saturation, water-air ratio became larger greater. low-amplitude structures under low-permeability background conditions, for good local properties, remaining at bottom or controlled accumulation conditions weak structural differentiation after accumulation. produced simultaneously less than 4 3 /d large more /d; downdip part island lens-shaped permeable bodies trapped surrounding tight layers. provide theoretical data support exploration