Study On Production Control Mode And Efficient Development Technology In Zhengzhuang Block Of Qinshui Basin

This thesis takes Zhengzhuang Block which is in the southern part of the Qinshui Basin as the study area.The main coal seams(CBM)in the study area are the Permian Shanxi Group 3# coal seams and Taiyuan Group 15# coal seams.Although the coalbed methane reserves in the study area have high resource potential and good preservation conditions,the study area has a large variability in the degree of tectonic development,complex coal body structure,and low permeability and low pressure of the reservoir,which makes development difficult.Based on the basic geological data of the study area such as structure,gas content and burial depth,as well as the actual production data such as average daily gas production and average daily water production,the paper investigates the coalbed methane production rules and the correlation of various parameters in the study area by means of data comparison and analysis and field experimental tests.The main conclusions are as follows:(1)The high-yield wells in the Zhengzhuang Block as a whole are located in relatively high parts of the structure,and from west to east,the elevation of the coal top gradually decreases and the production of single wells gradually decreases;the larger the curvature of the structure is,the worse the development effect of the well area is,and the single wells show the development characteristics of low gas and high water.The western part of the Zhengzhuang Block is rich in gas content,while the eastern part is influenced by faults,trap columns and folds,with large differences in gas content and a large impact on development.Based on this,the geological model of "two types and three types" under tectonic control is established.(2)The low production of multi-branch horizontal wells in the Zhengzhuang Block is due to the large burial depth,high ground stress and the fragmentation of the localized coal body structure,which leads to the collapse of horizontal well branches.The hole collapse problem can be effectively solved by supporting the wellbore wall with the down-screen pipe after completion.(3)As the pressure relief area of CBM determines the desorption range of CBM wells,the small desorption area is the main factor limiting the efficient development of the southern block.By optimizing the well network through technological breakthroughs and adopting a triangular well network,the overall transformation of the well group can be realized and the production can be boosted at high pressure,so as to achieve maximum capacity release.(4)The development effect of multi-branch horizontal wells is thus improved through borehole re-entry,and the application is promoted.