川渝页岩气井油膨胀随钻防漏治漏技术及应用

川渝地区页岩气水平井使用油基钻井液过程中,井漏问题突出,急需完善现用油基钻井液堵漏技术.为此,自主研发出油膨胀堵漏剂WNPDL系列,并采用"刚性颗粒+油膨胀颗粒+薄片+纤维+沥青"的技术思路,根据不同漏速,形成了1～5#油基防漏治漏配方.室内实验结果表明:①油膨胀堵漏剂WNPDL系列可以抗150℃高温能力,抗压35 M...

A technology for oil-swelling lost-circulation prevention and control while drilling and its application to shale gas wells,Sichuan-Chongqing area

When oil-based drilling fluid is applied to some shale-gas horizontal wells in Sichuan-Chongqing area,a problem of lost circulation is obvious,so it is in urgent need to improve control technologies for the existing oil-based drilling fluid.In this study,An oil-swelling lost-circulation agent of WNPDL series was developed independently.And according to the technical idea of"rigid particle+oil-swelling particle+slice+fiber+bitumen",No.1 to No.5 formulas of oil-based lost-circulation prevention and control were developed for different loss rates.Results show that(1)the oil-swelling lost circulation agent of WNPDL series has temperature resistance of 150℃,compressive strength 35 MPa,and resilience rate of 10.0-12.2%,and its oil-absorbed swelling capacity in three kinds of base oil is good with swelling rate of 52-71%;and(2)these formulas are well compatible with oil-based drilling fluid.In which,No.1 formula has good lost-circulation prevention performance and the decrease rate of its invasion depth is 95.0%,No 2 to No,5 formulas have good lost-circulation control effect to corresponding fracture plate and the total loss under 7 MPa ranges from 28 ml to 44 ml.In addition,one technology of oil-swelling lost-circulation prevention and control while drilling was developed,and its application to Zi 201H2-5 well obtained better effect with the primary success rate of lost-circulation control up to 83%.In conclusion,the oil-swelling lost circulation agent of WNPDL series has temperature-sensitive delayed oil-absorbed swelling property.Its oil-absorbed swelling rate is low under room temperature,and may increase with increasing temperature,so it is quite suitable for preparing a kind of flowing lost-circulation slurry on the ground.And besides,its field construction and operation is convenient.After this slurry is pumped into thief zone,it absorbs oil and swells gradually with increasing geotemperature,so as to enhance certain plugging capacity to the thief zone.