深层异常温压条件下碎屑岩成岩作用特征初探——以板桥凹陷下第三系深层碎屑岩地层为例

An approach to the diagenesis of clastic rocks under abnormal high temperature a nd pressure-Taking the Lower Tertiary deep formation in Banqiao sag as an examp le.

依据《碎屑岩成岩阶段划分规范》 ,黄骅坳陷板桥凹陷根据古地温、孢粉颜色、TAI、Ro、泥岩中黏土矿物演化等各项指标所划分的成岩阶段之间存在着明显的不吻合现象。分析认为 ,这是由于板桥凹陷普遍存在异常高压 ,而压力对有机质热演化和无机物质反应具有明显的抑制作用 ,延缓了有机质成熟 ,温度虽然较高 ,但成岩演化阶段出现相对滞后的现象。为此 ,根据自生矿物组合、黏土矿物演化及有机质热演化等 ,重新建立了异常温压背景下碎屑岩储集层成岩阶段划分方案。图 4参 2表

According to China′s Dividing Standard for Diagenetic Stage of Clastic Rocks, diagenetic stages in Banqiao sag, determined by paleo geothermal value, sporin ite colour, TAI, R o, clay mineral evaluation in mudstone, don't coincide w e ll with each other. After analysis it is believed that it is the result of overp ressure in Banqiao deep formation. Overpressure inhibited the development of org anic and inorganic matters, and slowed down the maturation of organic matters, s o diagenetic stages lagged relatively under high temperature. Finally, a new div iding standard for diagenetic stage in clastic reservoir under abnormal high tem perature and pressure is established.