低勘探程度盆地致密油气有利区预测技术在鸡西盆地的应用

针对低勘探程度盆地资料少、致密油气有利区预测难度大等问题,通过对国内外典型致密油气盆地油气聚集机理分析,研究成藏主控因素,形成了低勘探程度盆地致密油气有利区预测理论和流程,并提出相关标准。研究表明,油气生成、储层物性和构造稳定程度直接控制致密油气形成和分布。致密油气分布有利区标准为:存在有效烃源岩,进入生烃门限,且地质历史时期生烃强度下限为7×10⁸～10×10⁸m³/km²,与烃源岩剖面紧邻的储层地表渗透率在1.00 mD以下,区域地层倾角在4 °以下且断裂不发育。鸡西盆地城子河组地层具有有效生烃能力,源储相邻,致密砂岩储层中已有油气发现,具有致密油气远景。根据生烃、储层和构造背景综合分析,致密油气有利区分布在坳陷区附近,面积约为291.3 km²。该方法符合成藏机理且有可操作性,可为类似低勘探程度盆地致密油气勘探提供参考。

Application of Prediction Technology for Favorable Tight Oil and Gas Areas in Jixi Basin with Low Exploration Degree

In view of the problems such as lack of data and high difficulty in prediction of favorable tight oil and gas areas in basins with low exploration degree, through the analysis of oil and gas accumulation mechanism of typical tight oil and gas basins at home and abroad, the main controlling factors of hydrocarbon accumulation were studied, and the prediction theory and process of favorable tight oil and gas areas in basins with low exploration degree were formed, and relevant standards were proposed. The study shows that the formation and distribution of tight oil and gas are directly controlled by hydrocarbon generation, reservoir physical properties and structural stability. The criteria of favorable distribution areas for tight oil and gas are as follows: there are effective source rocks that have entered hydrocarbon generation threshold; the minimum value of hydrocarbon generation intensity is from 7×10⁸-10×10⁸m³/km² during geological history; the surface permeability of the reservoir adjacent to the source rock profile is less than 1.00 mD; the regional stratum dip angle is below 4 °; the faults are not developed. The Chengzihe Formation in the Jixi Basin has effective hydrocarbon generation ability, it has adjacent source and reservoir, and oil and gas have been found in tight sandstone reservoir, thus it has tight oil and gas exploration prospect. According to the comprehensive analysis of hydrocarbon generation, reservoir and structural background, the favorable areas for tight oil and gas are distributed near the depression area, with an area of 291.3 km². This method accords with the reservoir forming mechanism and has operability, thus it can provide reference for tight oil and gas exploration in similar basins with low exploration degree.