川中充西须四段气藏气井单井开采特征及开采对策研究

INDIVIDUAL-WELL PRODUCTION PERFORMANCE AND OFFTAKE STRATEGY IN XUJIAHE 4 MEMBER GAS RESERVOIR,CHONGXI OF CENTRAL SICHUAN BASIN

针对川中地区充西气田须四气藏在开发过程中产水严重的问题,应用Dupuit临界产量模型,获取了一系列保证产水气井地层岩石不发生速敏效应、井筒不积液的优化产量,由此制定出产水气井合理工作制度,以尽量延长无水采气期。同时,还利用气井排液临界流量数学模型,计算气水同产期气井不同井口压力条件下的携液临界流量,从而确保实际产气量大于携液临界流量,充分利用地层能量带出液体。研究分析结果表明:①为维持气井正常生产,初步优选出优选管柱为须四气藏产水气井的排水采气工艺技术;②随着地层能量的进一步的衰竭,气井生产后期应用复合排水技术提高气藏采收率。

In Chongxi gasfield of Central Sichuan Basin, a severe water production exists during the development of Xujiahe 4 Member. A Dupuit critical model is applied to water-producing gas wells. It ensures formation rock not occurring velocity sensitivity and keeps an optimized production without accumulation in borehole. Therefore, a reasonable working system for the wells is worked out in order to expand a gas -producing period without water as possible. Meanwhile, a gas-well discharge critical flow-rate mathematical model is applied to gas wells. It calculates the liquid-carried critical flow rate under different wellhead pressure during gas/water-producing period, ensures the actual gas production more than the liquid-carried critical flow rate, and carries liquid by formation energy. Research analysis illustrates that optimized pipe string is taken as a water-drainage and gas-recovery tool in water-producing gas wells of Xujiahe 4 Member gas reservoir in order to keep a normal production. Results also show that with a further depletion of formation energy, a compound discharge technique is applied to later-stage development in gas wells so as to enhance gas recovery.