Casing Optimization Of Thermal Recovery Wells In Block Hong003 And Its Application In Prestressed Cementing

Steam huff and puff is the most basic production measure for heavy oil field development.Hot production Wells inject high-temperature steam in the production process,so the production environment is more severe than ordinary Wells,and the stress is more complex.Compared with thin oil condition,it performs worse in durability.Steam flow in the casing,release a lot of heat,cause a deformation of the casing,but difficult to free elongation under the bondage of cement,the resulting stress,its size and temperature rise was a positive correlation between relations,once the temperature reached a certain level,the compressive stress will be higher than the material yield limit,which led to the damage of casing.Casing loss is an important factor affecting oilfield production and economic benefit.Therefore,the optimization of casing design and pipe selection is an important guarantee for the safe production of thermal recovery Wells.Firstly,based on the statistics of field data,the effective factors of casing loss for thermal recovery of heavy oil in hong003 well area of xinjiang oilfield are analyzed from the aspects of damage form,location of casing loss,steam injection parameters,steam injection times and sand production.The results show that necking deformation and misalignment are the main forms of casing damage,and steam huff and puff cycles have great influence on casing damage.Secondly,by means of metallographic,high-temperature tensile,impact and hardness tests,the mechanical properties and composition of HSN80 Q,BG80H,TP90 H and 80 SH casing materials were analyzed and compared.270?high temperature,80 sh casing uniform elongation as high as 10.2%;80SH casing vertical impact energy is greater than 150 J,lateral is larger than 100 J,the pipe body and coupling materials within the range of 60?-20?without obvious brittle;At high temperature,the stress of 80 SH casing pipe decreases less than that of other three pipes.Then the comprehensive performance of full-size casing was evaluated by means of thermal simulation,upper and lower shackles,constant displacement,gas seal and tensile failure test.Then the comprehensive performance of full-size casing was evaluated by means of thermal simulation,upper and lower shackles,constant displacement,gas seal and tensile failure test.Results show that the internal pressure of 16 mpa and 500 mpa tensile,compression cycle load only ? under 177.8 mm × 8.05 mm 80 SH casing through the test,and can withstand 41 mpa steam injection pressure,the main reason is that 80 sh collar adopted in flat design,through the external thread ends extrusion collar shoulder,auxiliary sealing effect.Thirdly,the stress and strain of 80 SH casing are analyzed by using prestressed cementing technology.The results show that the mechanical properties of casing and cement ring should be considered comprehensively when the prestress value is actually applied.Under different constraints,the maximum stress and strain of casing generally appear at the constraint position.The field test shows that the structure size of the optimized thermal-production casing is basically normal after the test well has been in service for 3-7 rounds of steam injection and oil production,and the local well segments in the test well have slight deformation of millimeter magnitude.Compared with conventional thermal production Wells,casing deformation in local well sections of test Wells is significantly reduced,and casing wall thickness of test Wells is changed from 9.19 mm to 8.05 mm,and the casing can still be in service within the safe range.On the premise of guaranteeing casing service quality,the pipe material is saved,the production cost is reduced,and the economic benefits of heavy oil thermal production Wells are improved.