吉木萨尔凹陷页岩油物性变化规律  

Variations of Physical Properties of Shale Oil in Jimsar Sag,Junggar Basin

作　　者：姚振华[1] 覃建华[1] 高阳[1] 陈超[1] 刘振平[1] 张效恭[1] YAO Zhenhua;QIN Jianhua;GAO Yang;CHEN Chao;LIU Zhenping;ZHANG Xiaogong(Research Institute of Exploration and Development,Xinjiang Oilfield Company,PetroChina,Karamay,Xinjiang 834000,China)

机构地区：[1]中国石油新疆油田分公司勘探开发研究院,新疆克拉玛依834000

出　　处：《新疆石油地质》2022年第1期72-78,共7页Xinjiang Petroleum Geology

基　　金：国家科技重大专项(2017ZX05070-002)。

摘　　要：准噶尔盆地吉木萨尔凹陷二叠系芦草沟组页岩储集层非均质性强,水平井体积压裂开采产量递减快,衰竭式开采预测采收率低,产出原油物性变化复杂。通过原油物性测试、原油赋存状态与产出液物性变化规律研究,结合储量动用模式与剩余油分布特征,从孔隙、储集层和井筒3个尺度表征了页岩油物性与分布规律。在大孔隙内油质较轻,吸附态原油占比较低;小孔隙中油质较重,重质组分易于吸附在小孔隙壁面。不同物性储集层的交替动用,导致井口产出原油黏度变化复杂,具无明显变化、微幅降低、明显降低和微幅上升4种类型。下甜点油质较重,原油普遍发生乳化,含水率大于30%时乳状液黏度激增,含水率可能是导致原油乳化的主要原因。因此,通过CO_(2)吞吐,可动用衰竭式开发不能动用的吸附态原油;在高含水期加入表面活性剂,降低乳化原油黏度和弹性,提高原油采收率。Shale reservoirs of the Permian Lucaogou formation in the Jimsar sag, Junggar basin are highly heterogeneous, so that the production of horizontal wells after volumetric fracturing stimulation declines rapidly. The oil recovery is predicted to be low by depletion development and the properties of the produced oil are very complex. After analyzing the physical properties and occurrence of the crude oil,and the physical properties of the produced fluid, and combining with the producing modes of reserves and the distribution of remaining oil,the physical properties and distribution of the shale oil are characterized in terms of pores, reservoirs and wellbore. The oil in large pores is lighter and uneasily adsorbs to the pore wall, whereas the oil in small pores is heavier and easily adsorbs to the pore wall due to more heavy components in it. The viscosity of the crude oil produced alternatively from the reservoirs with different physical properties has been changing, which can be classified into four types such as unobvious change, slight decrease, significant decrease and slight increase. The crude oil produced from the lower sweet spot interval is heavier and easy to emulsify. The viscosity of the emulsion increases sharply when the water cut is greater than 30%, so the water cut may be the primary cause for the emulsification of the crude oil. CO_(2) huff and puff may be effective to produce the adsorbed crude oil that cannot be displaced through depletion development. In high water-cut period, injecting surfactants may help reduce the viscosity and elasticity of emulsified crude oil and improve the oil recovery.

关 键 词：吉木萨尔凹陷 二叠系 芦草沟组 页岩油 原油赋存状态 物性变化规律 储集层类型 

分 类 号：TE122.3[石油与天然气工程—油气勘探]