珠江口盆地白云凹陷原油半开放条件下裂解成气模拟实验

Simulation of crude oil cracking and gas generation with semi-open condition, Baiyun Sag, Pearl River Mouth Basin

龙祖烈 石创 朱俊章 黄玉平 史玉玲 张小龙

LONG Zulie SHI Chuang ZHU Junzhang HUANG Yuping SHI Yuling ZHANG Xiaolong

中海石油深海开发有限公司, 广东 深圳 518054 中海石油(中国)有限公司 深圳分公司, 广东 深圳 518054

CNOOC Deepwater Development Limited, Shenzhen, Guangdong 518054, China Shenzhen Branch of CNOOC Limited, Shenzhen, Guangdong 518054, China

为深入研究珠江口盆地白云凹陷原油裂解机制及产物变化特征，选取了白云凹陷渐新统珠海组原油样品，利用高温高压模拟实验，模拟了地下压力、地下流体介质及半开放条件下、不同升温速率的原油裂解过程，分析了气产率和气体组分特征。研究表明，原油样品在365℃开始裂解，裂解产率随温度增加而增加，在20℃/h的升温速率下，最终（550℃）裂解气体产率、烃气产率和非烃气体产率分别为580.13，394.25，185.88 mg/g；而在60℃/h的升温速率下，最终（550℃）裂解气体产率、烃气产率和非烃气体产率分别为707.68，485.77，221.91 mg/g。不同升温速率下最终产率的差异和烃气的组分差异均与不同温度下原油裂解机制差异有关。从原油裂解成气模拟实验的组分特征来看，大部分原油裂解气具有较高的重烃气含量，而较高重烃含量可作为判识原油裂解气和干酪根裂解气的辅助指标。

In order to study the mechanism and product compositions of oil cracking, crude oil samples from the Zhuhai Formation of the Baiyun Sag of Pearl River Mouth Basin were carried out for the high-temperature, high-pressure pyrolysis with different heating rates with the pressure close to the conditions of underground. The underground fluid was also considered to be included with a semi-open condition for the pyrolysis, the gas yields and gas composition characteristics were then analyzed. Results showed that crude oils start to crack at 365 ℃, and the cracking yield increases with the increase of temperature. At a heating rate of 20 ℃/h, the final yields (at 550 ℃) of pyrolysis gas, hydrocarbon gas and non-hydrocarbon gas were 580.13, 394.25, and 185.88 mg/g, while at a heating rate of 60 ℃/h, these values increased to 707.68, 485.77, 221.91 mg/g, respectively. The composition of hydrocarbon gases at different heating rates also varied, and these variations were assumed to be related to the difference of cracking mechanisms of crude oils at different temperatures of pyrolysis. According to the composition characteristics of pyrolytic gas products, most of the gases from crude oil cracking has a relative higher content of high molecular weight hydrocarbon gas, thus these compounds can be used as an auxiliary index to distinguish crude oil cracked gas from kerogen cracked gas.

国家科技重大专项“珠江口盆地深水区古温压演化与油气生排聚过程” 2016ZX05026-003-006

https://doi.org/10.11781/sysydz202103507