元坝气田深度酸压工艺技术探索及应用

Exploration and application of deep acid fracturing technology in Yuanba gas field

元坝气田为生物礁气藏,具有超深、高压、高温、高含硫、强非均质性、气水关系复杂等特征,主要以长井段裸眼完井配合笼统酸化、均匀布酸、暂堵酸化实现投产,虽取得了较好的增产效果,但也存在布酸不均、纤维承压能力弱、测试产量低于预期和产量递减快等问题。为了保持元坝气田高产稳产,通过探究超低渗岩样物性、酸岩反应机理,优化深度酸压改造和暂堵转向工艺,形成了一套超深层海相地层深度酸压改造技术。该技术改造深度大,酸压范围广,现场试验2井次,平均测试日产气量达71.52×10^(4)m^(3),平均油压31.60 MPa,增产效果显著,深度改造有效率100%,增产有效率100%,为元坝长兴组碳酸盐岩气藏深度酸压改造提供了理论依据和技术指导。

Yuanba gas field is a bio-reef gas reservoir with ultra-deep,high temperature,high sulfur content,strong heterogeneity,and complex gas-water relationship.The long-well open hole completion is combined with general acidification to achieve sufficient acid distribution and temporary plugging acidification.Although the production has achieved better results in increasing production,there are also problems such as uneven acid distribution,weak fiber bearing capacity,reformed production expectations and rapid decline,and high and stable production of gas fields are facing challenges.In order to maintain the high and stable production of Yuanba gas field,a set of deep acid fracturing technology for ultra-deep marine formation is formed by exploring the physical properties of ultra-low permeability rock samples and acid rock reaction mechanism,optimizing the deep acid fracturing transformation and temporary plugging diversion technology.The technological transformation has a large depth and a wide range of acid fracturing.It has been tested in 2 well times.The average test yield is 71.52×10^(4)m^(3)/d and the average tubing pressure is 31.60 MPa,the increase in production is significant,and the effective conversion rate of the deep transformation is 100%.The reasonable and effective acidification transformation provides theoretical basis and technical guidance for Changxing carbonate gas reservoirs in Yuanba gas field.