Research On Water Invasion Dynamic Analysis In SeBei No. 2 Gas Field Ⅲ-1-2 Layer Group

SeBei No.2 gas field is the typical edge water drive, multi-layer, unconsolidated sandstone gas reservoir, with the characteristics of buried shallow, low reservoir compaction degree, and long well section. At present, the gas reservoir has been comprehensive invaded by water, which cause the gas well production greatly reduced and stable difficulty, and seriously affected the field productivity. Therefore it is need to understand the development performance of reservoir deeply, research and formulate the countermeasure to keep the reservoir’s stable production and development. This paper, on the basis of the dynamic and static gas reservoir information obtained in the course of production, using the method of gas reservoir engineering and numerical simulation technology, chooses the most serious water invasion layer—III-1-2 layer group as the main research object, to carry out the water invasion dynamic analysis, as well as formulate the water control strategies.The main work and achievements are as follows:(1) The paper carries on the study of geological characteristics, getting III-1-2 layer group’s characteristics of high porosity and medium-low permeability, three small gas layers on the vertical, strong heterogeneity, complex gas-water relationship;(2) The paper carries on the study of characteristics of the water producing in gas wells,and establishes the water recognition model. Using this model to identify the main water source of gas well, it gets the results that the edge water is main source and layer water is second source; based on production data and gas well production profile data, it is concluded that the main water invasion layer of III-1-2 layer group is 3-3-5 and 3-3-6;(3) The paper carries on the study of characteristics of water invasion in gas reservoir and evaluation of reserves producing. On the basis of gas-water production split and pressure convert, using the method of water invasion coefficient, it calculates that the accumulated water influx is 1056.1×104m3, and the edge water is more active; using the method of waterdrive characteristic curve to calaulate the dynamic reserves is 52.09 ×108m3, down 21% compared with before the water invasion, 3-3-5, 3-3-6 small layers reserve producing well, and 3-3-7 small layer reserve producing medium;(4) The paper carries on the study of water control countermeasures. According to the production dynamic and development situation of SeBei No.2 gas field, creats an overall water control strategy with strength monitoring, internal control and water drainage gasrecovery; based on the actual production situation of gas well, chooses the monitoring wells and drainage wells, and sets 4 drainage plans, using numerical simulation technology to predict 10 years production situation. Compared with the current scheme, the results show that the average decline rate of inside drainage plan reduces 2.25% than current scheme, the final recovery degree increased by 3.22%; among 30m3/d, 60m3/d, 90m3/d three outside drainage paln, the effect of 60m3/d is the best, recovery degree increased by 2.94%, decline rate reduced 1.86%, and the development effect has improved significantly.The research results of this paper has great significance in guide SeBei No.2 gas field to be developed stably and efficiently, at the same time, it has the theoretical instruction for the development of similar gas reservoir at home and abroad.