新场气田须二高产气藏主控地质因素

Main controlling geological factors of Xu 2 high yield gas reservoir in Xinchang gas field

新场气田须二气藏成藏机制复杂,储层致密,裂缝分布规律不清,气水关系复杂,存在主控因素认识不清的问题。在分析新场须二气藏气井分类的基础上,结合气藏动态特征,开展了岩石相、气水关系、裂缝发育程度等方面的研究,探讨了新场须二高产气藏主控地质因素。结果表明:①千层饼状中粗砂岩相、平行层理中粗砂岩相是最有利的岩石相,是高产高效气井稳产的基础;块状层理中粗砂岩相、斜层理中粗砂岩相是较有利的岩石相,是中产有效气井稳产的基础。②构造部位控制了气水的分布,开发有效气井主要分布在构造高部位。③断层–裂缝系统控制了裂缝发育程度,距离断层小于0.5 km区域,裂缝最为发育;距离断层0.5~1.0 km区域,裂缝较为发育。裂缝发育程度是气井高产的决定因素:除流体因素影响外,裂缝最发育区是高产高效气井分布区;裂缝较发育区是中产有效气井分布区。

Xu 2 gas reservoir in Xinchang gas field has complex reservoir forming mechanism,dense reservoir,unclear fracture distribution regularity,complex gas water relationship,and unclear understanding of main control factors.Based on the analysis of the classification of gas wells in Xu 2 gas reservoir,combined with its dynamic characteristics,the study related with rock facies,gas-water relationship,fracture development degree and other aspects is carried out,and the main controlling geological factors are discussed.The results show that:①Multi-layered medium-coarse sandstone facies and parallel bedding medium-coarse sandstone facies are the most favorable rock facies,which are the basis of high producing and efficient gas wells.The medium-coarse sandstone facies of massive bedding and the medium-coarse sandstone facies of inclined bedding are the favorable rock facies,which are the basis of middle producing and effective gas wells.②The structure controls the distribution of gas and water,and the effective gas wells are mainly distributed in the high structure.③The fault fracture system controls the degree of fracture development,and the fractures are most developed in the area less than 0.5 km away from the fault,while in the area 0.5~1.0 km away from the fault,fractures are relatively developed.The degree of fracture development is the decisive factor for the high production of gas wells;the fractured area is the distribution area of middle producing and effective gas wells.