织金区块煤层气井产能差异主控地质因素分析

Analysis of Main Controlling Geological Factors for Productivity Difference of CBM Well in Zhijin Block

从资源条件和产出条件两方面分析了织金区块珠藏、比德2个次向斜煤层气井产能差异的主控地质因素。结果表明:2个次向斜均具有较高含气量,具备煤层气高产的资源基础,产能差异主要受产出条件影响;织金区块煤岩兰氏压力较低使煤层气在低压区吸附量大、解吸效率高,比德次向斜煤层埋深大,储层压力高,降压至低压区较缓慢,造成产气上涨慢;煤层埋深大造成的地应力高,渗透率低是制约比德次向斜煤层气井产能的另一个重要因素。

Main controlling geological factors for productivity difference of CBM well were analyzed from two aspects of resource condition and production condition. Results show that Zhuzang and Bide syncline both have high gas content which guarantee the resource base. Productivity difference is mainly affected by the production condition. Langmuir pressure of Zhijin block is low, gas adsorption is low in the area of high pressure, while Bide syncline reservoir pressure is high, reservoir pressure reduction is slow at low pressure area, causing gas production increase slowly. Coal bed in Bide syncline has a higher ground stress, as a result the permeability is low, which is another important factor restricts the well productivity.