
套管和固井作業對井眼穩定性來說至關重要,糟糕的固井質量會給油氣井帶來致命的問題,正確理解扶正器的合理配置是成功的關鍵。
下套管時,需要使用節箍將兩根套管連接到一起,節箍使套管變得具有剛性,在將套管下入到裸眼段時可能引起諸如溝槽或鍵槽等問題,這些問題在任何位置都必須加以避免。在裸眼段,井壁比較尖銳、堅硬,同時比較脆弱。套管則很重、很結實,不易彎曲。井眼粗糙度通常被忽略,但在下套管時應該被考慮在內。
通常,假設水平井的特點為水平、平直、光滑。而實際上,在井眼鉆進過程中,鉆頭會轉動,施加扭矩,將巖石破壞,形成井眼,這會引發螺旋效應。井眼實際上既不平直也不光滑,套管下到裸眼段后,必須適應粗糙、剛性井眼的彎曲度。石油圈原創www.h29736.cn
重力有助于將套管下入井底,同時也需要輔助其他工具將管串下至井底。
如何將套管下至井底,并取得良好的固井質量,居中度是關鍵。居中度是套管壁和井壁之間的空隙,通常用百分比表示,表明套管在井眼的居中情況。井眼不同位置的居中度會有不同,但如果在任意位置出現居中度低于67%的情況,將帶來嚴重的后果。
在下套管的時候,扶正器配置不合理或者下的太少,會大幅增加摩阻。套管和節箍會增加摩阻,從而需要額外的下壓力將套管下到位。鍵槽會造成井壁形成溝槽,造成漏失,甚至是卡鉆。
上述問題都可以通過合理的扶正器配置、獲得最佳的居中效果來避免。在許多井中,常會出現井壁沖蝕現象,需要大量使用額外的水泥解決。但目前還沒有或者極少有針對這種情況使用的扶正器類型的討論。石油圈原創www.h29736.cn
合理的扶正器配置,是成本最低、最可靠的將套管下至井底并獲得最佳固井質量的方法,糟糕的固井作業會帶來致命的后果。
如果不使用扶正器進行固井,套管會貼在井壁。由于水泥流動性很強,會沿阻力最小的路線流動,在水平段水泥不會流到套管底部。
單純地靠旋轉無法使套管居中。套管不會懸浮在上井壁,我們無法保證套管在深達5公里的井底還保持良好的懸浮狀態。
水泥的作用是保持井眼穩定,避免氣侵和腐蝕。壓裂后,糟糕的固井作業會引起產量損失、地層污染和提前修井。這會減少產量,增加成本,而使用扶正器則可以提高而非縮短油氣井壽命。
自2001年成立以來,Centek公司打造了多款性能突出的扶正器產品,在全球各區塊均有良好的應用效果。其中,除了UROS-CT外,S2扶正器也是該公司最受好評的扶正器產品之一。S2扶正器徹底顛覆了在此之前的傳統設計,到目前為止,已多次被證實其可減少作業失敗次數,有效地為作業者減少作業時間,降低作業成本,多次幫助作業者順利將套管下入到目標位置。
更簡化更智能石油圈原創www.h29736.cn
S2扶正器采用非焊接的一體式結構設計,使其沒有薄弱點,并且具有超高強度。該扶正器最初的設計目的在于替換固體式扶正器,用于下套管作業,以及復雜井身結構,如水平井、大位移井、J-型井、S-型井和具有其他井身結構設計的井。
S2扶正器滿尺寸加工,具有極大的恢復力和彈性,S2弓形彈性扶正器具有如下特點:
- 在最具挑戰性的井況,仍具有極佳的居中能力;
- 無需啟動初始力和下放力;石油圈原創www.h29736.cn
- 低摩擦系數意味著極小的扭矩損失,降低了摩阻;
- 優化以后的扶正效果,可以提高固井過程中套管的旋轉和上提下放能力。
女皇創新獎得主石油圈原創www.h29736.cn
在過去幾年里,S2扶正器榮獲了諸多獎項,包括久負盛名的女皇創新大獎。
S2扶正器設計可應用于直井、大位移水平井、小公差井或者下部擴眼井:
- 符合API標準;石油圈原創www.h29736.cn
- 非焊接光滑整體弓形剖面;
- 一體式弓形設計,提高強度和性能;
- 無薄弱點;石油圈原創www.h29736.cn
- 無需啟動初始力和下放力,超大恢復力;
- 低摩擦系數;石油圈原創www.h29736.cn
- 極小的旋轉扭矩損失;
- 極小的制動效應;石油圈原創www.h29736.cn
- 通過優化扶正設計,提高旋轉能力。
Centek S2扶正器在美國頁巖氣區塊應用中取得了巨大成功,當地對固井質量的監管要求是全世界最嚴格的,S2扶正器可以帶來最佳的扶正效果和流體循環能力,形成穩固的水泥層,保證了一口井在整個生命周期內的完整性和產量。
應用范圍石油圈原創www.h29736.cn
- 膠結疏松的井;
- 大位移井、水平井、大斜度井;
- 高溫/高壓井,地熱井;
- 頁巖油氣井;石油圈原創www.h29736.cn
- 垂直井及簡單井;
- 裸眼完井、壓裂、膨脹封隔器完井;
- 防砂完井。石油圈原創www.h29736.cn
CENTEK UROS扶正器可以在套管和裸眼井段旋轉超過12個小時,起出后未損壞、無破損。
坐標:歐洲,挪威,Starfsh油田
技術挑戰石油圈原創www.h29736.cn
作業者需要將7”(磅級32.0#/ft)尾管下入8 1/2”裸眼至3600米,需要通過套管內徑為8.535”的井段( 套管尺寸9 5/8”,磅級53.5#/ft)。尾管在下入裸眼段期間,可以部分轉動,在出套管的時候以20rpm的轉速轉動了約12個小時。扶正器還通過了一個斜向器窗口,最終由于距井底40米管串無法下到位而起出了尾管。
解決方案石油圈原創www.h29736.cn
使用55個型號為7” x 9 ?” 的Centek UROS扶正器。
如果采用低質量、脆弱、鉸接的弓形彈性扶正器,可能造成嚴重的問題,損壞扶正器,而使用Centek扶正器不會出現這種情況。
應用結果石油圈原創www.h29736.cn
現場監督和固井人員檢查了所有的扶正器/接頭,發現出井扶正器唯一的損壞僅是少量的螺栓槽變彎了。
Centek UROS一體式扶正器,比其他同類產品更堅固,強度更大。盡管Centek不建議重復使用起出后的扶正器,但本次應用證明了經歷過極端應力條件后, 具有獨特設計的Centek扶正器狀態依然良好,仍然可以再次入井。
來自/Centek ? 譯者/白小明 ? 編輯/Leia
Simply Smarter
The non-welded, one-piece construction means the S2 has no weak points making it ultra-high-strength. It is designed specifically to replace a solid body type centralizer for casing running applications and severe well geometries when run in horizontal, long ERD, J-type, S-type and other well designs.
The S2 is manufactured to gauge and has exceptional restoring force and outstanding flexibility down hole. The S2 bow spring centralizer offers:
- Optimum standoff capability in even the most challenging well conditions;
- Zero start and running forces;
- A low friction coefficient, which means minimal torque losses and reduced drag;
- Enhanced rotation and reciprocation during cementing due to optimized centralization.
Award winning innovation
Over the years the S2 has received a number of awards including the prestigious Queens Award for innovation.
S2 Award Winning Innovation
- Designed for well applications and geometries for vertical, horizontal ERD, close tolerance, or under reamed well conditions;
- API Rated;
- Non-welded smooth bow profle overall;
- Integral bow design for increased strength and performance;
- Zero weak points;
- Zero start and running force with exceptional restoring force;
- Low friction coeffcient;
- Minimum rotational torque losses;
- Minimize stall out effect;
- Enhanced rotation due to optimized centralization;
- Shale Production.
The Centek S2 has been an integral part of the success of US Shale play production. Working within some of the world’s toughest regulatory guidelines, the S2 provides excellent centralization, and fluid circulation required to give a robust cement sheath, which in turn ensures the integrity, production and overall life of the well.
Applications
- Unconsolidated wells;
- Extended reach, horizontal and highly deviated wells;
- High temperature/High pressure and Geothermal wells;
- Shale oil & gas wells;
- Vertical and simple wells;
- OH Completions, Frac and Swellables;
- Sandscreen completions.
CENTEK UROS CENTRAlIZERS CAN BE ROTATED FOR MORE THAN 12 HOURS IN THE CASED AND OPEN HOlE AND COME OUT UNDAMAGED AND WITH NO BREAKAGES
Region: Europe Country: Norway Location: Starfsh 3-ST2 Field: Starfsh
THE CHAllENGE
The operator needed to run 7”- 32.0#/ft liner into 8 1/2” OH passing through the 8.535” restriction of the 9 5/8” – 53.5#/ft casing with a TD of 3,600m.The liner was partially rotated in the open hole on the way in, and it was rotated for approximately 12 hours at 20rpm in the cased hole on the way out.The centralizers were also run through a whipstock window.
The liner was pulled due to hole conditions 40m short of TD.
THE SOlUTION
55 x 7” x 9 ?” Centek UROS centralizers Rotating with low quality, weak, hinged bow spring centralizers could destroy them and create serious problems. This is not the case with Centek centralizers.
THE RESUlT
OWS and the cementers inspected all the centralizers/collars and the only damage that could be seen was bending of some of the set screw sockets. The Centek UROS single piece construction gives it robustness and strength which exceeds that of competitor products. Although Centek does not recommend the re-use of centralizers when pulled out of hole this case study proves that even when subjected to extreme stresses the unique design of Centek centralizers meant that they remained in good condition and could be re-run.
“[We] will run the same centralizers again”Halliburton, Norway
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