Productivity Influencing Factors Of Multi-Layer CBM Well And Interlayer Interference Analysis In Laochang Mining Area Of Eastern Yunnan Province

The development effect was less than satisfactory,despite the prospecting and exploitation of CBM in Lao-chang mining area was earlier.The crux of the matter is that,the complex spatial configuration systems of coal reservoirs make the CBM recover to be very tough.Taking Lao-chang mining area as the research objece in this paper,the reservoir characteristics and the influencing factors of yield in CBM wells have been discussed,based on a great amount of data on coal exploration and coalbed methane development of the study area.In addition,the mechanism and mathematics models of quantitative characterization of interlayer interference for multi-seam drainage in a CBM well were proposed.Cluster well has become the effective one for the complex terrain area.For cluster well in the study area,the distance between target spot is not very far,so the technology of drainage is the major influencing factors.The volatility of luqid depth have been evaluate by using VIX index(a very important variable in finance).The significant difference between the single layer drainage and multi-layer drainage are summarized below,division for series of development strata,three phase fluidized in full bore,pressure transmission medium and artificial regulation.The complex flow pattern of the three-phase medium in the wellbore can be simulated,which may have less influence on the gas production efficiency.The division of development strata is the geological basis for achieving effective coal seam methane recovery in multiple coal seams,and reasonable manual regulation is the technical guarantee for achieving high production.This article has redefined the concept of inter-layer interference and defined it as the redistribution or rebalance of energy under various conditions,resulting the difficulty level change of CBM recovery.Pressure interfence is the main form of expression.And this is a dynamic concept,with the dynamic changes in the mining operations,its dominant factors,form of expression and mechanism are also converted accordingly.Interlayer interference influence factors include the causes of inter-layer pressure differences and the conduction conditions where pressure tends to balance.All influencing factors can be attributed to the dynamic changes in the pressure system.Therefore,the interlayer interference coefficient and its quantitative characterization method are proposed from the perspective of pressure disturbance.Base the mechanism of inter-layer interference,the countermeasures to reduce or suppress inter-layer interference in the early stage of production have been proposed.