Study On Water Discharge Mechanism And Water Control Strategy Of Multi - Layer Unconsolidated Sandstone Gas Reservoir

For water production gas reservoir, gas well water production is the main factor which is harmful to the normal development of gas field. In the development of gas reservoir, and the water production of common gas reservoir has been studied for a long time, including the mechanism and control measures of water production which have formed a set of relatively widely accepted and mature theory.However, the study condition is not that mature for multi-layer unconsolidated sandstone gas reservior. Firstly, because this type of gas field is rare crossing the world and the relevant research starts just lately, no unified cognition has been formed; secondly for the sake that unconsolidated sandstone gas reservoir has special geological features of loose rock, multi small sand layers, complex gas-water distribution, so directly using the common water gas reservoir water governance method does not have a ideal effect. These all lead to many difficulties to the water governance, therefore, it is necessary for multi-layer unconsolidated sandstone gas reservoir to do a comprehensive research of water production and a systematic analysis on the mechanism of gas reservoir water production, then find out effective water control measures.On the basis of summarizing the predecessors’ research, the following research content has been study:(1) Based on the study way and technical thinking characteristic of water invasion research of water production gas reservoir, explains the mechanism of various water source forming and production of multi-layer unconsolidated sandstone gas reservoir from view of geology, then summarized a set of comprehensive methods of identifying water.(2)Combined with the analysis of gas reservoir water invasion of knowledge and experience at home and abroad, found the reasonable evaluation method of water body, water invasion of gas reservoir in theory, and the numerical simulation technology about water production.(3)By comparing the water production gas reservoir management scheme, combining with the analysis of early water source and water invasion theory research results, summarized the methods of water controlling by classification, direct gas well water control from the geological aspect.(4) Through the research of actual field layer group (group Ⅱ-4layer of SeBei1gas field), combined theory with practice, provide support for paper theoretical research results.Thesis research thinks, there are a large number of mobile water inside and external edge-bottom water outside of multi-layer loose sandstone gas reservoir, we should make use of reserves at different levels in a phased manner, realize the whole high-speed and stable development of the gas reservoir based on the existing gas water distribution and water invasion trend, combined with the reserves producing rule, based on reservoir physical property and formation energy state, according to the natural rule of gas water movement when it comes to this complex situation.