Integrated Production System Modelling for Debottleneck Solutions and Enhancing Gas Recovery
Authors: Cui Esther , Charlton Thomas , Wang Bing 
Published: May 2024

Objectives/Scope
his paper presents a tight gas production with source rock Coalbed methane in Erdos Basin, which possesses largest gas reserves and contributes highest natural gas production in China. With more significant role of natural gas in the worldwide as well as China, Operator companies have large investment to achieve higher gas reserves and production. This paper presents integrated production modelling incorporating upstream unconventional reservoir and midstream Surface Pipeline network, as well as terminal node central gas station (CGS), aiming to reproduce and digitalize entire dynamic production system, pinpoint bottleneck issues, and simulate remedial operation in surface facilities to pursue debottleneck solutions and enhance gas recovery.

Methods, Procedures, Process
Natural gas production is naturally integrated and dynamically interrelated as a unit. Therefore, integrated production modelling is applied for diagnosis of bottleneck issues in the production system. Two typical challenges are presented for low pressure gas reservoir: severe liquid holdup and pressurization. As to severe liquid loading issue caused by terrain topography, pipeline network liquid hold-up is analyzed at locations with high risk of stagnant liquid, which is mainly caused by increasing WGR and non-moving liquid column inside pipeline at "U-bend" hilly terrain topography. To further unlock surface network, booster compression station is illustrated to further lower wellhead pressure for the upstream wells with potential high deliverability. Where and how to pinpoint the bottleneck issues in the complicated production system and perform effective remedial operations to enhance gas recovery is critical for oil gas companies’ or Operators’ revenue with substantial investment in production system optimization.

Results, Observations, Conclusions
This paper reproduced and digitalize entire tight gas production system through integrated production modeling (IPM), expanded the physics, algorithms and workflow how to pinpoint bottleneck issues of high backpressure in the complicated, dynamic and interrelated production system, to pursue debottleneck solution package for oil gas companies and operators. Multiple remedial operations are simulated to unlock upstream and mid-stream production system. It is observed pressure loss along the pipeline is reduced through dewater solution performed for pipeline sections with "U-bend" hilly terrain topography, production system energy was dynamically redistributed, and upstream gas wells were unlocked with higher drawdown to achieve sustained gas production. In addition, upstream wellhead pressure was further lowered through introducing booster compression station based on the digitalized IPM model. The high backpressure issues were successfully solved.

Novel/Additive Information
The entire gas production system consists of many nodes, complicated and dynamically interrelated system as a unit. This paper present integrated production modeling for unconventional tight gas reservoir with the goal of pinpointing pain points, pursuing debottleneck solution package to optimize surface production system, enhancing gas production and further unlock tight gas reservoir production system and eventually enhance gas recovery.