塔河油田志留系成藏条件分析

ANALYSIS OF SILURIAN RESERVOIR- FORMATION CONDITION IN TAHE OILFIELD

塔河油田地理位置处于新疆维吾尔自治区库车县和轮台县境内,构造位置位于塔里木盆地沙雅隆起阿克库勒凸起西南部斜坡。受加里东晚期、海西早期、海西晚期和燕山早期构造运动影响,阿克库勒凸起主体部位及南部斜坡的大部分地区缺失志留系、泥盆系、上石炭统、二叠系、侏罗系中上统,另外中—上奥陶统也遭受不同程度剥蚀,以至局部地带缺失。塔河油田大部分地区缺失志留系,目前主要在其西南部钻遇该套地层,且主要保存柯坪塔格组(S1k)和塔塔埃尔塔格组(S1t)。区域烃源岩、储盖及圈闭条件分析表明,塔河油田及其邻区志留系圈闭多属于与地层削截或与超覆尖灭有关的地层—岩性、地层—构造复合型圈闭,少数为构造圈闭与岩性圈闭。综合研究认为志留系具备成藏的地质条件。

Tahe oilfield is geographically located at Kuche and Luntai county in Xinjiang Uigur Autonomous Region.It is structurally located at the southwestern slope of Akekule salient in Shaya uplift in Tarim basin. Because of the effects that are caused by late Caledonian event, early Hercynian movement, late Hercynian movement and early Yanshan movement, Silurian System, Devonian System, upper Carboniferous, Permian System and middle-upper Jurassic System are absent in the main part of Akekule salient and in a majority of south slope of Akekule salient. In addition, upper-middle Ordovician is denuded to some extent and is absent in part areas.The Silurian System is absent in most part of Tahe oil field.At present, the Silurian System is mainly met at the southwestern part of Tahe oil field and it mainly is Kepingtage group(S_1k)and Tataaiertage group(S_1t).The analyses of source rocks, reservoir bed, caprock and trap indicate that the Silurian System in Tahe oil field and its surrounding areas mostly belong to stratum-lithology and stratum-structure composite traps which are mostly connected with stratum truncation or overlap pinching out and a few of them are structural trap and lithologic trap. Researches show that the Silurian System possesses the conditions forming oil and gas accumulation.