长垣南地区扶余致密油层物性下限确定及分类

DETERMINATION OF THE PHYSICAL PROPERTY CUTOFFS AND CLASSIFICATION OF FUYU TIGHT OIL RESERVOIRS IN SOUTH PLACANTICLINE

松辽盆地长垣南地区扶余致密油层紧邻上部青山口组优质烃源岩,为典型的近源致密油藏。随着近年水平井和大型体积压裂的推广,致密油层已成为较现实的勘探突破目标,其物性下限与油层分类标准也需要重新界定。考虑致密油层受源岩影响特点,采用可动孔喉半径法、含油产状法、核磁法和试油法等分别确定了高成熟源岩区和低成熟源岩区扶余致密油层物性下限。在油层分类时考虑了致密油层孔隙结构的差异性和可压性参数,优选平均孔隙半径、排驱压力和脆性指数等参数建立了扶余致密油层分类评价标准。以此为基础,分别建立了常规压裂和体积压裂直井产能预测模型。研究成果对致密油储量动用、"甜点"区段优选及有效开发具有重要意义。

Fuyu tight oil reservoirs in South Placanticline of Songliao Basin are close to the excellent source rocks of Upper Qingshankou Formation, and moreover they are the typical tight reservoirs which are near to the source rocks. With the promotions of the horizontal wells and large-volume fracturing in recent years, the tight oil reservoir has become the more realistic exploration breakthrough objective, so it is necessary to redefine the classifying stand- ards for the physical property cutoffs and reservoirs. Considering the influences of the source rocks on the tight oil reservoirs, with the help of the following methods： movable pore throat radius, oil occurrences, NMR, oil test and so on, the physical property cutoffs are determined for Fuyu tight oil reservoirs in the high and low maturity source rock areas. When classifying the oil reservoirs, the differences of the reservoir pore structures and compressibility parameters are considered, the parameters such as the average pore radius, replacing pressure, brittleness index and so on are optimized to establish the classifying and evaluating standards for Fuyu tight oil reservoirs. Based on the achievements stated above, the predicting models of the vertical-well productivity are established for the conven- tional and volume fracturings. The research results possess the very important significances for the development of the tight oil reserves, optimization and effective production of the ＂sweet spot＂ blocks and intervals.