Study On Permian And Carboniferous Rock Mechanics Experiments And Speed-up Scheme In Mahu-Zhongguai Area

Permian and Carboniferous reservoirs in Mahu-Zhongguai area have become the key areas of oil and gas exploration and development in oilfield companies.Because of their large burial depth,complex lithological changes,high rock hardness and drillability up to 6-9 grades,the drilling cycle is longer and the speed is slow,which limits the exploration and development of reservoirs.In order to solve these problems,this paper combines field data and rock mechanics experiments to analyze and calculate the formation drilled,and puts forward the matching technology of increasing drilling speed and carries out research.The main research contents are as follows:(1)Investigate the volcanic strata in Liaohe Oilfield,Daqing Oilfield,Tarim Oilfield and Japan,the United States,India and the United Kingdom,understand the demonstrative characteristics and the corresponding methods to improve drilling speed.Chinese style(2)Aiming at the Permian Wuerhe Formation and Fengcheng Formation,62 core columns were drilled in Ma2,Madong 2-Yanbei 4,Ke80 and Guai 16 wells in the Carboniferous formation.Based on the test results,the elastic modulus,drillability and strength of the core were obtained.(3)On the basis of well test results,the in-situ stress models of Ma2 well area and Madong 2-Yanbei 4 well area are established,and the pressure plane maps of Lower Wuerhe formation in Ma2 and Madong 2-Yanbei 4 well area are drawn;the drillability plane maps of Wuerhe formation in Ma2,Madong 2-Yanbei 4 well area,Fengcheng formation in Ke80 well area and Guai 16 well area are drawn,and the drillability distribution law is determined.(4)According to the stratum and engineering characteristics of the target block,the test schemes of different special speed-up tools are demonstrated.The actual drilling situation of exploration well,evaluation well and development well in target block in 2018 is tracked,and the test schemes of different special speed-up tools are demonstrated.In view of the formation and engineering characteristics of the target block,the bit sequence and the technical scheme of the speed-up tool are recommended and get the follow-up evaluation.Through basic research on rock mechanics and pressure characteristics of target blocks and combined with the application status of volcanic rock drilling speed-raising technology at home and abroad,the speed-increasing scheme has been worked out and achieved good results in the field.Especially in Permian formation,the effect of using torsional impactor is remarkable.The drilling footage of 311.2mm well is 1190 m,the drilling speed of 3.96m/h,and the Permian directional and horizontal sections are adopted.The average penetration rate of rotary steering drilling system is 3.41m/h,which is 26.4% higher than that of conventional horizontal section in the same block.Rotary percussion drilling tools for national oil wells are used in the Permian Wuerhe formation.The maximum penetration rate is 4.8m/h.