【作者】 孙国明；

【导师】 刘永建；

【作者基本信息】 大庆石油学院 ， 油气田开发工程， 2008， 博士

【摘要】 本论文围绕徐深1区块气田开采过程中存在的问题,根据气田地质特征和不同开发阶段气井状况,深入开展了气井增产措施优选和关键技术研究,这对徐深1区块气田开发具有重要理论意义和实用价值。1确定了徐深1区块作业过程中存在的主要储层伤害问题:(1)水敏、盐敏和储层含水饱和度低于束缚水饱和度时的水锁伤害;(2)碱敏、水速敏、压力敏感性和束缚水饱和度下的水侵伤害;(3)作业液中固相对微裂缝的堵塞伤害;(4)高pH值的钙、镁等高价离子溶液引起的无机沉淀伤害。据此,提出了徐深1区块保护储层的九项实用措施,为徐深1区块增产措施优选和采用合理开发技术提供了依据。2提出了徐深1区块气井完井方式为射孔完井方式。确定了油管和套管尺寸,提出了具体的射孔参数与工艺,形成并确定了生产套管水泥返高。3提出了适用于徐深1区块气井压裂的压裂液体系配方并评价了相关性能。重点指出选择金岭集团改性胍胶和北京矿院改性胍胶作为徐深1区块气井高温压裂液增稠剂;根据深气层施工需要,提出应采用羟丙基改性胍胶;压裂液体系采用复配交联剂,采用CNN-01、CNN-02交联控制剂,使压裂液具有较好的缓速交联性能。4通过对2002~2005年火山岩储层压裂数据与实际施工效果对比分析,提出了火山岩测试压裂分析诊断特征参数,给出了诊断指标及其结论。根据工程风险评估及邻井相对应层位施工效果分析,优化并提出了火山岩储层压裂施工参数;通过分析以往大庆其他压后排液资料,提出3种压后排液求产方法。经卫深5井和肇深11井应用证明效果好;提出在压裂施工中采取追加破胶剂、压裂后强制闭合快速返排工艺,可以应用压裂-排液-试气一体化管柱和深气层分层压裂管柱。5通过徐深6井,徐深1-1井实测并结合历史拟合提出了适用于徐深1区块的地层热传导系数K为61.1923 kJ/( h.m.K)。据此,优选出了在开发配产气量条件下井口压力、温度计算方法。预测了目前至20年后井口压力与温度;研究了井口压力、温度的影响因素。6优选了气井停喷压力计算方法。对徐深1区块气井停喷压力计算和预测表明:(1)水气比增加,气井井筒压力损失增加;(2)选用大尺寸油管,井筒压力损失下降,但携载流量大幅增加;对于产能较低的气井,选用大尺寸油管反而造成气井过早停喷;(3)井口回压增大,停喷压力增大;(4)气井见水,停喷压力剧增;(5)气油管管径越大,停喷压力越高;提出了能够充分利用地层能量、降低气井停喷压力、尽量延长自喷期的技术措施;计算了气井废弃压力,认为影响废弃压力因素主要是气藏埋深、产能、含水率、最小井口回压、采气油管尺寸及排水采气技术水平等。7分析了Turner临界流速、临界产量公式适用条件,优选出了适用于大庆气田的气井持续排液计算方法;徐深1区块气井在增压开采时,水气比为0~7m3/10~4m~3,2 3/8"油管满足单井产量1.31~1.53×10~4m~3/d井筒携液要求;不增压开采时,水气比为0~7m3/10~4m~3,2 3/8"油管满足单井产量3.08~3.50×10~4m~3/d的井筒携液要求。高强度小油管满足徐深1区块气井排水采气的要求。8研究了自喷转人工排水采气举升问题,进行了排水采气技术比较分析,指出了各种技术的特点和适用性,提出优选泡沫排水采气技术及相关配套措施作为大庆徐深1区块气井采气可用技术。9研究了天然气水合物形成条件及影响因素;应用徐深1区块气田数据,经计算和分析后揭示:(1)气井储层压力高,井筒压力高,水合物形成可能性大;(2)储层温度高,井筒压力高,水合物形成的可能性小;(3)产量增大、井口压力降低、井口温度高,水合物形成的可能性小。(4)一定的产气量,存在一个最优的油管直径,此时形成水合物的可能性小;(5)井越深,温降幅度越大,井口附近形成水合物可能性越大;经计算和井口节流后温度预测,提出徐深1区块气井需要在节流前采取预防水合物形成的四条措施。10优选了井筒中防止水合物形成措施。提出了化学剂抑制法防止井筒水合物形成设计方案,提出了气井井口防止水合物形成措施。针对不同气井井况、不同化学剂种类,确定了化学剂加入量。本论文成果对其它类似气田排液采气具有借鉴和参考价值。更多还原

【Abstract】 In order to solve the problems encountered during the exploitation process in the gas field of Xushen 1 block, on the basis of the geological characteristics of gas field and the conditions of gas well in various development phase, the optimization of reservoir stimulation and the key technology study were carried out in depth, which is significant both in the theory and practice to develop the gas field of Xushen bolock-1.1 It is ascertained that the main reservoir damage problems in the operation in Xushen bolock-1 are: (1) water sensitivity, salinity-sensitivity and water-lock damage occurred when the reservoir’s water saturation is under the irreducible water saturation; (2) alkali sensitivity, velocity sensitivity, pressure sensitivity and water invasion damage under the irreducible water saturation; (3) the blockage of fracture by solid phase in the working fluid; (4) inorganic precipitate damage caused by the high pH solutions of high valence metal ions such as calcium, magnesium,etc. Hereby, nine practical measures to protect the reservoir in Xushen 1 block were brought forward, providing the basis to optimize the stimulation measures and rational development technologies.2 Perforation completion was chosen to complete the gas wells in Xushen 1 block. The sizes of tubing and casing were decided. The perforation parameters, procedure and the height of slurry back flowing in production casing were suggested.3 The formula of fracturing fluid system adequate for the fracturing operation in Xushen 1 block was given out and its properties were evaluated. It was appointed out that the modified guar gum should be used as the thichening agent for the high temperature fracturing fluid to be used in the gas well in Xushen 1 block. According to the requirements of operation in the deep gas formation, hydroxypropyl modified guar gum should be used. Compound crosslinking agent should be used in the fracturing fluid system. The crosslinking control agent of CNN-01, CNN-02 should be used, so as to endow the fracturing fluid with good performance of slow crosslinking.4 Through the contrastive analysis on the fracturing data of volcanic formation in 2002~2005 and the actual effect, the characteristic parameters to diagnose the fracturing in volcanic rock was suggested, and the operation parameters for the volcanic formation fracturing was optimized. On the basis of analyzing the data of flowing back after fracturing obtained previously in Daqing and other oilfields, three methods for flowing back and finding production volume after fracturing were introduced, which were proved to be helpful by the application in Weishen-5 well and Zhaoshen-11 well. It is suggested that during the fracturing process, the procedures of gel breaker supplement and quick back flow by compulsive closure should be applied. The integration pipe string for fracturing - fluid flowing back - gas testing and the separate layer fracturing string for deep gas formation should be used.5 Actual measurement on Xushen 6#, Xushen1-1# wells and the history matching showed the formation thermal conductivity (K) is 61.1923 kJ/( h.m.K) in Xushen 1 block. On the basis of this value, the methods to compute the pressure, temperature at wellhead under the condition of proration gas production were optimized. The wellhead pressure and temperature for 20 years from now were forecasted. The influencing factors of wellhead pressure and temperature were studied.6 The gas well flow-stop pressure computing method was optimized. The computing and forecasting on the gas well flow-stop pressure for wells in Xushen 1 block showed:(1) As the WGR increases, the borehole pressure loss in gas well increases;(2) If chose to use the big size tubing, the borehole pressure loss will decline, but the carrying capacity will increase greatly, for the low productivity gas well, choice of big tubing will cause the flow-stop of gas well prematurely;(3) As the wellhead back pressure increases, the flow-stop pressure will increase;(4)At the condition of water breakthrough, the flow-stop pressure will increase sharply;(5) The bigger the size of tubing, the higher the flow-stop pressure.The technologies were given out which could make full use of the formation energy, reduce the gas well flow-stop pressure, prolong the flowing period. The gas well abandonment pressure was computed. It is decided that the factors influencing the abandonment pressure are mainly the buried depth of gas reservoir, productivity, water cut, minimal wellhead back pressure, size of the gas production tubing and the technical level of the gas recovery by water drainage, and so on.7 The applicable conditions of Turner critical flow velocity and critical production formula were analyzed. The computing methods for continuous fluid drainage of gas well in Daqing gas field were optimized. For Xushen 1 block gas wells, when it is produced by pressurizing, the WGR is 0~7m3/10~4m~3, the tubing of 23/8" can meet the requirement of borehole fluid carrying for single well with production of 1.31~1.53×10~4m~3/d; when it is produced without pressurizing, the WGR is 0~7m3/10~4m~3, the tubing of 23/8" can meet the requirement of borehole fluid carrying for single well with production of 3.08~3.50×10~4m~3/d. the high strength small size tubing can meet the requirements of gas production by water drainage in Xushen 1 block.8 The problem of change from flowing to artificial lift water drainage to produce gas was studied. the technologies for gas production by water drainage were compared, the characteristics and applicability of various technologies were appointed out, and it is suggested that the technology of gas recovery by foam drainage and relative supporting measures can be applied in Xushen 1 block.9 The forming condition and influencing factors of natural hydrate were studied. Computation and analysis on the data from Xushen 1 block showed:(1)If the formation pressure and the borehole pressure are high, the possibility of hydrate forming is big;(2)The possibility of hydrate forming is small if the formation temperature and the borehole pressure are high;(3)If the production increases, the wellhead pressure declines, the wellhead temperature is high and the possibility of hydrate forming is small;(4)For a certain gas production, there exists a optimal tubing size, here, the hydrate forming possibility is small;(5)The deeper the well, the bigger the temperature drop scope, the bigger the possibility of hydrate forming near the wellhead.Through computing and forecasting on wellhead temperature after throttling, it is appointed out that four procedures should be carried out to prevent the forming of hydrate before throttling for Xushen-1 block.10 The procedures of preventing borehole hydrate forming were optimized. The design plan of chemical agent inhibitor preventing borehole hydrate forming was introduced. The measures of preventing wellhead hydrate forming were put forward. For different gas well conditions, various chemical species, the chemical adding amount was given out.The achievements obtained in this dissertation have reference values for the gas recovery by water drainage in the similar gas fields.更多还原