吐鲁番-哈密盆地吉深1区致密砂岩气藏储层“甜点”预测

Prediction of "sweet spots" of tight sandstone gas reservoirs in Jishen 1 area,Turpan-Hami Basin

提出多相带匹配分析法预测致密砂岩气藏储层"甜点",即以有利的沉积相带、构造相带、储集相带等控带因素为单因子,针对不同地区,综合考虑各单因子的影响程度,依据不同因子控带贡献大小,采用叠合匹配原则,根据匹配程度将"甜点"由好到差分成Ⅰ、Ⅱ、Ⅲ和Ⅳ类。通过分析吐鲁番-哈密盆地吉深1区中侏罗系西山窑组一段沉积、构造、储层等控带因素认为:研究区有利沉积相带主要为辫状河三角洲平原的辫状河道和河道叠置体微相;有利构造相带主要为南部斜坡带、中部凹陷局部微隆起及断裂发育储层改造区和北部长轴状大型背斜构造带;有利储集相带主要为孔隙度>3.2%、渗透率>0.1×10-3μm2的储层分布区。通过多相带匹配分析,预测研究区Ⅰ类"甜点"主要位于南部斜坡吉深1井西侧、吉1井附近、中部凹陷带的西侧狭长条带、北部构造带的吉3背斜中部、东深2井背斜西翼及之间的局部小构造。对比分析预测结果与录井及测井解释成果,符合度较高,该方法能够直观有效地预测致密砂岩气藏储层"甜点",对于指导该类油气勘探具有重要意义。

A multiphase matching analysis method to predict the ' sweet spots' of tight sandstone gas reservoirs is put forward. The controlling factors of ' sweet spot',favorable favorable reservoir belt,sedimentary facies belt,and favorable tectonic belt are used as the first controlling factor,the second controlling factor and the third controlling factor separately,and the ' sweet spots' in the studied area are divided into 4 types ofⅠ,Ⅱ,Ⅲ and Ⅳ from good to bad according to the matching degree of three single factors. Based on the analysis of the sedimentary,structural and reservoir controlling factors of the first member of Jurassic Xishanyao Formation in Jishen 1 area,Turpan-Hami Basin,it is held that the favorable sedimentary facies in this area is the braided river channel and superimposed river channel microfacies of the braided river delta plain; the favorable structures are the southern slope belt,the local uplift and the areas where faults are developed in central sag,and the northern large-scale long anticline structural belt; the favorable reservoir is the effective reservoir zones whose porosity is higher than 3. 2% and permeability is higher than 0. 1 × 10- 3μm2. According to the multiphase belt matching analysis of the studied area,Ⅰ type of ' sweet spots' is mainly located in the west of well Jishen1 and near to well Ji1 in the southern slope belt,the long and narrow strip in the west of central sag,and the middle of the Ji3 anticline,the west wing of Dongshen 2 anticline and local small structures between them in the north. The predicting result is in great correspondence with single well logging interpretation result,so this method can be used for effectively predicting ' sweet spots' of tight sandstone gas reservoirs,and it is of significant importance to guide the exploration of tight sandstone gas reservoirs.