柴达木盆地南翼山凝析气藏裂缝性储层特征

CHARACTERISTICS OF THE FRACTURED RESERVOIR OF CONDENSATE GAS POOL OF NANYISHAN OIL FIELD IN CHAIDAMU BASIN

研究发现，柴达木盆地南翼山构造Ｅ３２裂缝性储层既具有国内一些裂缝性储层的共同特点，又在裂缝性储层的成因、岩性、识别、评价和分布规律等方面独具特色。这类裂缝性储层的裂缝细而密，孔缝连通性好，有高角度裂缝、斜交裂缝和水平裂缝。该类储层在平面上从构造两翼到构造高部位分布较为均匀，岩性也较为稳定，具有内陆湖相稳定沉积的特点；储层段的排驱压力为１．３０～８．０６ＭＰａ，饱和中值压力为３．１２～１０．２２ＭＰａ，非储层段的排驱压力一般大于３０ＭＰａ，饱和中值压力为８０～１２４ＭＰａ。在储层段，钻进过程中几乎所有的井都发生了井漏或井喷；声波时差曲线有明显的周波跳跃现象，井径曲线有显著的扩径现象，同时该储层段还具有碎屑岩储层的电测特征（如自然电位的负异常）。储层岩性为碳酸盐岩、钙质泥岩和碎屑岩的混合体，结构上粗细混杂，成分上没有单一、质纯的岩石类型。

Through research,it is found that the E32 fractured reservoir in Nanyishan structure in Chaidamu Basin has some common characteristics the fractured reservoirs at home have,as well as an unique feature in the aspects of genesis,lithology,identification,evaluation and distribution law.In this kind of fractured reservoir,the fissures are fine and dense;the pores have a good connectivity and there are highangle fissures,oblique fissures and horizontal fissures.This kind of reservoir is fairly uniformily distributed on plane from structure's two limbs to high position and its lithology is also relatively stable,having a feature of stable inland lacustrine deposit.The drainage pressure at the reservoir interval is 1.308.06MPa and the saturation midvalue pressure is.3.1210.22MPa.The drainage pressure at the nonreservoir interval is more than 30 MPa generally and the saturation midvalue pressure is 80124MPa.At the reservoir interval,lost circulation and well blowout used to occurr nearly in all wells in the course of drilling.The interval travel time curves have an obvious cycle skip phenomenon and the caliper log curves have a notable diameterenlarged phenomenon,and meanwhile,the reservoir interval has an electric log feature in clastic reservoir rock (such as SP negative anomaly).The reservor lithology is a mixture of carbonate rock,calcareous mudstone and clastic rock,being a mix structure with coarse and fine particles and a nonsingle and nonpure rock type.The oil and gas reservoir space and the percolation flow passage are fissures mainly.