Study On Unstable Model Of Gas Well Production And Its Influencing Factors

With the increasing demand for energy, it’s hard to meet the need of energy in our domestic economic development only with petroleum resources, while as a clean energy, the proportion of natural gas in the energy structure will be greatly improved, thus it’s particularly important to realize high-efficient and rational exploitation of gas wells under the increasing development and exploration conditions. In order to achieve this goal, this paper studies gas wells rate transient analysis models and its influential factors, which further has a practical significance on well production.This paper uses related knowledge of permeation fluid mechanics, reservoir engineering, well test analysis, mathematical physics equation to study on rate transient analysis models of gas wells and varying rate interpretation methods of gas wells on the condition of variable flowing sandface pressure and flow rate. The main contents are as follows:(1) Established and solved vertical wells’flow mathematical models of different types of gas reservoirs, such as homogeneous, dual media and composite gas reservoir, drawn type curves of gas wells rate transient analysis models under different external circle boundaries, like closed, constant pressure and infinite, also analyzed flow behaviors of each flow stage and its influential parameters.(2) Established and solved fractured wells’infinite and finite conductivity flow mathematical models of different types of gas reservoirs, such as homogeneous, dual media and composite gas reservoir, drawn type curves of gas wells rate transient analysis models under different external circle boundaries, like closed, constant pressure and infinite, also analyzed flow behaviors of induced fracture and the influence of fracture capacity on rate characteristic curves of fractured wells.(3) Established and solved horizontal wells’flow mathematical models of different types of gas reservoirs, such as homogeneous, dual media and composite gas reservoir, drawn type curves of gas wells rate transient analysis models under different external circle boundaries, like closed, constant pressure and infinite, also analyzed flow behaviors of horizontal wells and the influence of net thickness and horizontal section on rate characteristic curves of horizontal wells.(4) Established and solved fractured horizontal wells’ tri-linear flow mathematical models of different types of tight gas reservoirs, such as homogeneous, dual media gas reservoir, drawn type curves of gas wells rate transient analysis models under closed external boundaries, also analyzed flow behaviors of tri-linear flow and the influence of fracture capacity and transmissibility factor ratio on rate characteristic curves of fractured horizontal wells.(5) Studied rate transient interpretation methods by use of material balance pseudo-time under the conditions of variable bottom hole pressure or flow rate, also used field data to analyze this method.Through the research of this article, it not only enriched and improved theoretical achievements of gas wells rate transient analysis, but also presented reliable theory criteria for rate transient interpretation methods under the conditions of variable bottom hole pressure or flow rate, further better serviced for development and management of gas pools.