塔河油田卡拉沙依组储层物性及评价

PETROPHYSICS AND EVALUATION OF THE KALASHAYI FORMATION, TAHE OILFIELD

魏福军 何发岐 蒲仁海

WEI Fu-jun HE Fa-qi PU Ren-hai

中国石化, 新星石油公司, 北京, 100083 2. 西北大学, 大陆动力学教育部重点实验室, 陕西, 西安, 710069

Star Petroleum Corporation, SINOPEC, Beijing 100083, China 2. Key Laboratory of Continental Dynamics, Ministry of Education, Northwest University, Xi'an, Shaanxi 710069, China

塔里木盆地塔河油田石炭系卡拉沙依砂岩储层尽管埋深达4800～5200m,但仍具中等物性条件,孔隙度一般为8%～12%,最高可达20%,渗透率一般为(10～100)×10-3μm2,最大可达1000×10-3μm2以上。压汞资料显示该储层喉道偏粗,具中孔粗喉的孔隙结构特点。铸体薄片和电镜照片显示孔隙类型主要为长石溶蚀形成的粒间孔、粒内孔和残余原生粒间孔,其次为填隙物微粉晶灰质(溶蚀)晶间孔、裂缝孔等。孔隙度和渗透率受物源和沉积相影响较明显,在距物源近、河道砂岩多而厚的地方,孔隙度和渗透率明显变高。在目前对长石溶蚀孔隙的空间发育规律尚难预测的情况下,储层预测的手段仍只是依靠沉积相和地震等对砂体的预测。

Although the Carboniferous Kalashayi sandstone reservoirs of Tahe Oilfield in Tarim Basin are buried at the depth of 4 800-5 200 m,they have fairly good petrophysical property.The porosities range generally from 8% to 12%,with the maximum of 20%;and the permeabilities vary typically from 10×10-3 to 100×10-3μm2,with the maximum of over 1 000×10-3μm2.Mercury injection data indicate that,the reservoir is characterized by medium-pore-coarse-throat structure with coarse skew in pore size distribution.Thin sections with blue epoxy impregnation and electron microscope scanning photograph show that' the main pore types are intergranular and intragranular pores from dissolved feldspar and residual original intergranular pores,while the smaller part of porosity is contributed by interstitial microcrystalline to very fine crystalline limestone intercrystalline pores and fissure pores.It is obvious that the depositional facies and distance from the source area affect porosity and permeability which increase conspicuously approaching to source area along with the enhancement in quantity and thickness of channel sandstones.The present reservoir prediction is still mainly relied on sand bodies forecast by means of analysis of seismic data and depositional facies due to the lack of method for spatially predicting the dissolution of feldspars.

https://doi.org/10.11781/sysydz200404344