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在目前的粘土矿物转化化学动力学模型中,人们仅考虑了温度、时间和流体介质的影响。然而新近的一些研究表明,超压可以抑制粘土矿物的转化,增加反应活化能。通过超压调节反应活化能,建立超压背景下粘土矿物转化的化学动力学模型,并根据渤海湾盆地板桥凹陷、歧北凹陷超压发育井和歧南凹陷超压不发育井的粘土矿物实测资料,确定了相关参数。模拟结果表明,在超压井中,伊/蒙混层中蒙皂石层含量S%的计算值与实测数据吻合较好,但与Pytter和Reynolds(1989)模型的预测结果相差甚远,在压力系数为1.2~1.7的地层中,超压对S%的抑制最大可达15%~20%。由于在蒙皂石向伊利石转化的过程中,释放出大量S i4+、Ca2+、Mg2+、Fe3+、Na+等阳离子,所以超压对粘土矿物转化的抑制,导致了泥岩中这些阳离子生成量的减少和相邻砂岩中许多胶结作用的延迟,这非常有利于深层(埋深>3 500 m)优质储层的发育和油气藏的形成。
In the current model of chemical kinetics of clay mineral conversion, one considers only temperature, time and the influence of the fluid medium. However, some recent studies show that overpressure can inhibit the conversion of clay minerals and increase the activation energy. The kinetic energy of clay mineral transformation under overpressure background was established by adjusting the activation energy of overpressure. According to the clay mineral of overpressured development wells in Banqiao sag, Qibei sag and Qixin sag in Bohai Bay basin, Measured data to determine the relevant parameters. The simulation results show that the calculated value of S% of the smectite layer in the overpressured well agrees well with the measured data, but it is far from the prediction result of Pytter and Reynolds (1989) model. Under the pressure coefficient For the strata from 1.2 to 1.7, overpressure can suppress S% up to 15% ~ 20%. Due to the release of a large amount of cations such as S i4 +, Ca2 +, Mg2 +, Fe3 +, Na + during the conversion of smectite to illite, the inhibition of clay mineral conversion by overpressure led to a decrease of these cations in the mudstone and The delay of many cementation in adjacent sandstones is very favorable to the development of deep reservoirs (depths> 3 500 m) and the formation of reservoirs.