超深气井连续油管多径组合管柱作业新工艺

A new technology for the multi-diameter combination operation of coiled tubing in ultra-deep gas wells

随着对深层超深层油气勘探开发力度的加大,“三超井”(储层温度超过177℃、储层压力超过105 MPa、井深超过6000 m)的数量越来越多,完井井身结构更为复杂,特别是生产管柱内径表现为多变径,出现生产管柱、产层段堵塞,对气井生产造成了不利的影响,严重时甚至造成关井停产。这就对连续油管在超深气井作业过程提出了新的要求。为了保证“三超井”的投产、稳产和增产,基于连续油管规格不同尺寸、设备模块化移动灵活、高自动化程度、可带压起下的优势,结合“三超井”的地质条件、井筒结构和流体介质变化等实际特点,研发了多径组合连续油管作业工艺技术,配套研发了多径连续油管对接装置,并成功应用于中国石油塔里木油田公司XX11井。研究及实践结果表明:①连续油管多径组合作业有效提高管柱载荷安全系数0.12;②有效降低管柱沿程摩阻,降阻率达到41.7%;③同等压力下提高施工排量获得更高的末端效应提高33%;④增强了返屑能力。结论认为,该工艺能够满足超深气井多变径井筒作业的要求,为超深气井连续油管作业提供了一种新的安全、高效、低成本的解决方法。

As the exploration and development of deep and ultra deep oil and gas is increased,there are more and more"three-ultra wells"(reservoir temperature,reservoir pressure and well depth exceed 177℃,105 MPa and 6000 m,respectively),the completion well structure is more complex,and especially the inner diameter of production string is variable and the production string and production interval are blocked,which brings adverse impact on gas well production and even results in well shut down.To deal with this situation,it is necessary for the operation of coiled tubing in ultra deep gas wells to meet new requirements.In order to ensure the commissioning,stable production and production increase of"three-ultra wells",this paper researches and developes a technology for the multi-diameter combination operation of coiled tubing based on the advantages of casing tubing(including different dimensions,flexible movement of modularized equipment,high automation degree and snubbing),combined with the actual characteristics of"three-ultra wells"(such as geological conditions,borehole structure and fluid medium change).In addition,a support multi-diameter coiled tubing connection device was developed.And they have been successfully applied in Well XX 11 of PetroChina Tarim Oilfield Company.And the following research and practice results were obtained.First,by virtue of the multi-diameter combination operation of coiled tubing,the safety load factor of the string is increased effectively by 0.12.Second,the friction along the string is reduced effectively,with a friction reduction rate of 41.7%.Third,under the same pressure,the end effect is increased by 33%by increasing the construction displacement.Fourth,the cuttings return capacity is enhanced.In conclusion,this technology meets the requirements of the variable-diameter wellbore operation in ultra deep gas wells and provides a new safe,efficient and low-cost solution for the operation of coiled tubing in ultra deep gas wells.