广安气田产能特征及其控制因素研究

Well production characteristics and control factor analysis of Guang'an gas field in Sichuan Basin,southwestern China

广安气田勘探开发层位为上三叠统须家河组须六段和须四段。储层砂体为三角洲分流河道、水下分流河道和河口坝沉积,为典型低孔、低渗孔隙型储层。气藏分布受构造和或岩性控制,发育了构造气藏、构造—岩性气藏和岩性气藏。为指导气田开发井位部署与合理配产,根据试采资料研究了气井产能特征,并把气井产能划分为Ⅰ、Ⅱ、Ⅲ和Ⅳ4大类7亚类,各类气井产能差异大,产水量差异也大,其中Ⅰ类、Ⅱ_1亚类和Ⅲ_1亚类气井产能较好或较稳定。通过分析控制广安气田气井产能的因素,认识到储层沉积微相、单井动储量、构造位置、产水量与工艺措施对气井产能有重要影响。在水动力强的分流河道、水下分流河道和河口坝沉积相带中,单井控制动储量越大,构造位置越高,产水量越小,压裂和储层保护措施相对合理,气井往往具有较高产能。

The exploitation and development target are the sixth and fourth Members of Upper Triassic Xujiahe Formation in Guang＇an gasfield of Sichuan Basin, southwestern China. The reservoir sandstones of these two members are deposits of deltaic distributary channels, underwater distributary channels and mouth bars and have typically low porosity（mainly 6% -12% ） and low permeability （ mostly 0. 1 ×10^-3 μm^2- 10 ×10^-3 μm^2） with rare fractures. The gas reservoir distribution is controlled by structure and/or lithology. Accordingly, the reservoir types include structural,lithological and structural-lithological ones. To offer guidance for next well location and producing capacity of this gas field, production characteristics were investigated based on well test data. The well productivities can be subdivided in four types （ I , II, Ill and IV）and seven subtypes（ II,II2, III, III2, III3, IV1 and IV2）,and change greatly among these types. Every type has different water production. Of which, type I ,subtype II1 and III1 have more enough or stable producing capacity. Factors controlling well production were explored. It can be concluded that sedimentary facies, well dynamic reserves ,elevations, water productions and technological measures have important impacts on gas well production. When the wells were drilled in the high energetic distributary channel, underwater distributary channel and mouth bar zones,they would achieve higher productivities if they have bigger well dynamic reserves, higher elevations, smaller water production and more proper fracture and protection technologies.