| Author's Name: HU Yong1,2, JIAO Chunyan1,2, ZHAO Yi3, WU Juan3, JIA Song3, YANG Dongsheng4,
GUO Changmin1,2, CHEN Can3, CHEN Luyao5 |
| Institution: PetroChina Research Institute of Petroleum Exploration & Development;The Key Laboratory of Gas Reservoir Formation and Development;The Key Laboratory of Gas Reservoir Formation and Development; |
| Abstract: |
| In order to study the effect of well pattern infilling on enhancing gas recovery of carbonate gas reservoirs,
taking the T2l11 gas reservoir of Moxi gas field in Sichuan Basin as an example, a set of large-scale 18-meter physical
simulation experimental device and method are established. The experimental model have a permeability of 0.56×10-3 μm2
and single well exploitation and well infilling (Well 1 and Well 2 are deployed at 14.1 m (78.3%) and 4.6 m (25.6%) from
the initial well, respectively) exploitation have been simulated based on the model. The experiment measure gas
production and pressure throughout the entire life cycle, revealing the reserve utilization laws under different water
saturation conditions of the gas reservoir. The study compares and analyzes the effects of batch and simultaneous infilling
methods, as well as the timing of two infilling methods at the end of stable production and under abandoned conditions, on
improving the recovery efficiency of the gas reservoir. The experimental results show that: (1) For single well exploitation,
gas recovery is significantly affected by water saturation, showing a significantly decrease with increasing water
saturation. The recovery is 14.6% to 64.7% under the condition of water saturation of 20%-50%; compared with single
well deployment, the rate of recovery can increase to 85.9%-92.7% after two wells are infilled, and the effect of infilling
is significant. (2) Infilling wells enhancing gas recovery have two functions: one is to improve the production range of
reserves in the undeveloped area, and the other is to improve the pressure drop efficiency in the developed area. The
production of gas reservoir reserves is closely related to the water saturation and the distance from the gas well. The well
pattern infilling can be deployed according to the production of reserves, and the undeveloped area and the developed
(insufficient) area of reserves are preferred. (3) The enhancement of recovery rate through the deployment of infilling
wells initially increases and then decreases as the number of well increases. Therefore, it is recommended to optimize the
number of infilling wells in developed areas based on the characteristics of the remaining reserves in the gas reservoir,
avoiding excessive infilling. Further analysis from the perspectives of enhanced gas recovery range and exploitation
efficiency shows that adopting a centralized deployment of infilling wells and simultaneous infilling at the end of stable
production period is more beneficial for extending stable production period, improving recovery, and shortening
production cycle. The research results can guide the deployment of well pattern infilling in gas reservoir to enhance gas
recovery. |
| Keywords: natural gas reservoir; carbonate rock; well pattern infilling; enhanced gas recovery; physical simulation ex⁃
periment |
|
投稿时间：
2025-05-06 |
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