单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,中国石油川庆钻探工程有限公司工程技术研究院,CCDC,Engineering Technology Institute,王长宁 张汉林,Wang changning Zhang hanlin,中国石油川庆钻探工程 工程技术研究院,CCDC Engineering Technology Institute,二00九年十月,October,2021,天然气欠平衡钻井关键技术研究及现场应用,Research and Field Application on Key Techniques,of Natural Gas Underbalanced Drilling,概 述,General,天然气钻井,Natural,gas drilling,空气钻井,Air drilling,氮气钻井,Nitrogen,drilling,专用设备少,Fewer special,equipments,低的钻井综合本钱,Lower comprehensive drilling cost,Advantages,优 势,现场试验Field test:,苏里格气田特点,试验目的,低压,低渗,低产,保护储层,提高机械钻速,试验井位,S242井,S39-14-1井,S39-14-4井,S35-18 井,The characteristics,of Sulige gas field,Test Objective,Test Wells,Low pressure,Low permeability,Low production,Protection reservoir,Improving ROP,表1 4口天然气钻井情况,S39-14-1,S39-14-1,S39-14-4,S39-14-4,试验结果,Test Results,机械钻速大幅度提高,The ROP has been improved greatly,最大限度的保护储层,The maximum protection of reservoir,不会发生井下燃爆事故,To aviod downhole explosion,S35-18井 的 平均机械钻速18m/h,是邻井泥浆钻井的9倍,The ROP of S35-18 is 18m/h,which is 9 times of mud drilling in this region,欠平衡钻井 UBD,关键技术,Key technologies,地层出水与地层稳定性预测,Formation water production and formation stability forecast,井眼净化与最正确注气参数,Hole cleaning and the best gas injection parameters,钻头失效机理及选型,Bit failure mechanism and selection,井下复杂情况处理,Downhole complication treatment,平安钻井,Safe drilling,地层出水量评价方法,Formation water production,图1 地层出水预测分析,Formation water production forecast analysis,延安组,延长组,石盒子,地层出水Formation water production,井壁坍塌,Hole collapse,卡钻!,Sticking!,地层出水危害,Harmfulness,井眼净化恶劣,Hole cleaning worse,井壁失稳原因及井壁稳定性评价方法,Borehole stability,气体钻井井壁失稳,Instability of gas drilling,在钻井过程胶结强度低的地层出现掉块甚至坍塌,The fall-block of rock or collapse in the formation which has low bonding strength during the drilling,；,在转换泥浆过程中的井壁坍塌,The borehole collapse during the process of transferring mud.,气体钻井井壁失稳原因,Reason of gas drilling borehole instability,化学应力耦合作用 Chemistrystress coupling effect,渗流应力的耦合作用 Infiltrationstress coupling effect,微裂纹损伤区,Micro-crack-injury area,泥页岩水化,Argillutite hydration,导致严重的井壁失稳坍塌!,Cause the serious borehole instability and collapse!,图2 岩石应变软化特性,The strain softening of rock,图3 非均匀地应力与损伤区的关系,The relationship of non-uniform in-situ stress and injury area,(a),H:h=1:1(临界状态),(Critical conditions),(b),H:h=1.5:1 (c)H:h=2:1,(临界状态),(Critical conditions),井壁失稳原因及井壁稳定性评价方法,Borehole stability,Four kinds of rock in uniaxial compression test,延长组,石盒子组,山西组,石千峰组,井壁稳定性分析与实钻情况吻合!,It is identical with the real drilling situations!,图 4 井壁稳定性分析,Figure 4 Borehole stability analysis,井壁失稳原因及井壁稳定性评价方法,Borehole stability,井眼净化与注气参数设计,Hole cleaning and gas injection parameters design,携岩能力,The capability of carrying cutting,气体携带岩屑的能力比泥浆差,Gas is less than mud,气体钻井的井眼净化问题比泥浆钻井应该更加关注!,The problem of hole cleaning of gas drilling is more important than the mud drilling,图 5,岩屑团泥饼环的形成过程,Rock cuttings group,mud cake,图 6 携岩关节点,The joint point of carrying cuttings,泥饼环的形成,The formation of mud cake,当地层出水时，在井壁上或钻具上都有形成泥饼环的趋势,It will have trend of mud cake on the borehole wall or drilling tools when formation water production happened,处理措施,Treatment measures,优化注气参数,Optimization of gas injection parameters,转化钻井方式,To change the drilling mode,增加注气量,Increase the injection of gas,雾化钻井,Mist drilling,泡沫钻井,Foam drilling,泥浆钻井,Mud drilling,井眼净化与注气参数设计,Hole cleaning and gas injection parameters design,地层不出水,No formation water production,地层水或气体本身非常潮湿,Formation water production or gas is very moist,注气参数设计,Gas,injection parameters design,最小环空返速是 15m/h,The min.annular velocity is 15m/h,S242,井和,S35-18,井最小注气量是,28m,3,/min,对于,6,6,井眼,最小注气量约,21m,3,/min,For,6,6,borehole,the minimum gas injection is about,21m,3,/min,增加注气量,Increase the injection of gas,对于,6,6,井眼,在注气量大于,120m,3,/min,条件下，纯气体有效携带地层水最多,10m,3,/h,的出水量,For,6,6,bore hole,pure gas at most carries over,10m,3,/h,water yield when the injection gas is more than,120m,3,/min,井眼净化与注气参数设计,Hole cleaning and gas injection parameters design,钻头冷却与失效机理分析,Bit cooling and failure,钻头在井底工作产生的热量,The heat arising from the bit working,地层岩石温度,The rock temperature,钻头温度升高,The bit temperature rise,泥浆钻井Mud drilling,气体钻井Gas drilling,高,比热容和热传导率,High,heat absorption capacity and heat conduction,低,比热容和热传导率,Low,heat absorption capacity and heat conduction,有效地将钻头热量带走,Effectively take the heat way,钻头整体温度升高,The whole bit temperature rise,气体钻井钻头的冷却问题需要!The bit cooling problem in gas drilling!,图 7 陕242井钻头解剖分析,由图7知，密封系统油脂略发黑和变味，井底温度偏高，但对密封件及钻头牙齿、牙轮根本无影响，由此可见气体的冷却效果不可低估。,The grease of sealing system turns slightly black and a little smell,but this do not affect the seal and the bit tooth and gear wheel,from which we can see that the cooling effect of gas should not be underestimated,地层出水,Formation water production,钻头泥包,Balled bit,钻头局部温度升高Making partial temperature of drilling bit is too high,最终“烧坏钻头 Eventually“burn the drilling bit,不能有效冷却钻头,大大降低了井底气体流量Greatly reducing the gas flow in bottom hole,图8 S39-14-1井损坏的钻头,由图8可知，,S39-14-1井天然气钻井钻进1310-1388m井段地层少量出水，被水化的泥岩包裹钻头降低了气体冷却钻头效率，其后由于地层出水量逐渐增大，最终在井深1685m，钻头失效被迫起钻。,Has a small amount of formation water product