致密砂岩气藏高产富集带逐级深入的预测方法

元坝西部地区须四段上亚段气藏埋藏深，储层岩石类型主要为灰白色、浅灰色钙屑砂砾岩、钙屑砂岩，整体较致密，厚度薄，为低孔、低渗裂缝孔隙型储层。多口井测试成果表明，具有一定厚度和孔隙较发育的钙屑砂砾岩、钙屑砂岩分布和裂缝发育共同控制了天然气的高产富集带。针对须四上亚段气藏特点，根据钙屑砂砾岩岩石物理响应特征，按照逐级深入的预测思路，在叠前联合反演基础上，利用叠前反演弹性属性进行岩性概率统计学预测，得到有利的岩性分布区；以有利岩性区为约束，采用基于分频数据体的物性参数预测方法，得到有效储层厚度及分布范围；在叠前地震裂缝密度预测的基础上，综合岩性和物性参数，预测了须四上亚段气藏高产富集带分布区。

Prediction about the Abundant Belts of Tight Sandstone Gas#br#Reservoirs Through Gradual Penetration

The sand gas reservoir of the upper sub-member of segment Xu4 in the western Yuanba region is characteristic of deepburial，and the reservoir rock is mainly compose of grey and light-grey calcarenaceous sandy conglomerate and calcare-naceoussandstone. Generally the reservoir is dense and thin，and of low porosity and low permeability fracture-pore. The testing resultsof many wells show that calcarenaceous sandy conglomerate and calcarenaceous sandstone distribution with certain thicknessand pore development and fracture development control the abundant belts of natural gas. Considering the characteristics ofgas reservoir in the upper sub-member of segment Xu4，the characteristics of rock physical response of calcarenaceous sandyconglomerate，and according to the gradual penetration principle，we made statistical probability prediction about the lithologicusing pre-stack elastic inversion on the basis of pre-stack simultaneous inversion，and obtained the beneficial lithologic distributionarea. By using physical parameter prediction method，we obtained effective thickness and distribution of the reservoirin the beneficial lithologic distribution area on the basis of frequency division data volume. On the basis of pre-stack seismicfracture density prediction and petrophysical parameters，made prediction about the abundant belts of natural gas of the uppersub-member of segment Xu4.