煤层气水平井可生物降解钻井液流变性研究  

RHEOLOGICAL BEHAVIORS OF BIO-DEGRADABLE DRILLING FLUIDS IN COALBED METHANE HORIZONTAL WELL

作　　者：蔡记华[1] 乌效鸣[1] 谷穗[2] 刘浩[2] 

机构地区：[1]中国地质大学工程学院,湖北武汉430074 [2]中国地质大学江城学院,湖北武汉430200

出　　处：《西南石油大学学报（自然科学版）》2010年第5期126-130,共5页Journal of Southwest Petroleum University(Science & Technology Edition)

基　　金：国家自然科学基金项目(40802031)

摘　　要：在室内实验的基础上,对煤层气水平井钻井用可生物降解钻井液的流变模式和影响其破胶效果的影响因素(底物类型、底物浓度、生物酶类型和生物酶浓度等)进行了分析。结果表明:幂律模式可作为可生物降解钻井液的优选流变模式;相比魔芋而言,胍尔胶和羧甲基纤维素(CMC)的降解更容易被控制;CMC和生物酶SE-1反应的最佳质量分数比为3∶1;在3种生物酶中,特种酶SE-2具有较高的活性,适合在短时间内对聚合物进行破胶;生物酶浓度的增加可加快破胶过程。实验也表明,可生物降解钻井液的破胶时间在13.5～74.5h内可控、破胶率在20%～100%内可控;作为催化剂的生物酶专一性强,能使可生物降解钻井液保持井壁稳定和储层低伤害的双重优点,适于煤层气水平井钻进。The rheological model and viscosity breaking factors of the typical bio-degradable drilling fluid such as:substrate type,substrate concentration,enzyme type and enzyme concentration are investigated based on lab experiments.The results show that Power Law model is the best model to match the rheological properties of bio-degradable drilling fluids.Compared with konjak,the degradations of Na-CMC and guar gum are easier to control.In the degradation of CMC by enzyme SE-1,the optimal weight concentration of CMC to SE-1 is 3 to 1.Of the three enzymes,enzyme SE-2 has the highest activity and can be used to degrade polymer in shorter time.The increase of enzyme concentration can speed up the degradation reaction.The test results also show that viscosity breaking times fluctuating from 13.5 hours to 74.5 hours and viscosity breaking ratios varying from 20% to 100% can be controlled.Acting as a catalyst,bio-enzyme has a high specificity and provides bio-degradable drilling fluid the double function of keeping borehole stability and low damage to the reservoir.Hence,it's fit for coalbed methane horizontal well drilling.

关 键 词：煤层气水平井 可生物降解钻井液 生物酶 流型 破胶 

分 类 号：TE258[石油与天然气工程—油气井工程]