Published November 2024, Pg. 9-13

Section: Well drilling

UOT: 622.245.42(075.3)

DOI: 10.37474/0365-8554/2024-11-9-13

U-tube effect in well cementing on the Absheron peninsula

E.M. Suleymanov Dr. in Tech. Sc. - Azerbaijan State University of Oil and Industry

R.S. Ibrahimov Cand. in Tech. Sc. - Azerbaijan State University of Oil and Industry

Sh.O. Bakhshaliyev PhD in Tech. Sc. - Azerbaijan State University of Oil and Industry

He article states that based on the processing of field data, it was found that when drilling wells on the Apsheron Peninsula, the average densities of drilling fluids fluctuate significantly, and when cementing a well, the density of the cement slurry is higher than the density of the drilling fluids. 
Therefore, under certain conditions, the U-tube effect or free fall occurs – this is a phenomenon during cementing, which results in a temporary loss of control over the fluid velocity and pressure in the annular space. The free fall effect occurs when the cement slurry is pumped into a casing filled with drilling fluid with a much lower density and begins to fall. 
It is not easy to control the flow rate in the annulus by using wellhead downhole adjustable fittings, and it results in additional pressure in the annulus, increasing the risk of loss of circulation. Using a downhole connection to control the flow inside the casing will cause additional obvious problems, so it is also a poorly effective solution
The main problem during the cement slurry drop is the brief but important change that occurs in the flow velocity in the annulus. At this point, it is necessary to predict the annulus flow rate and calculate the annulus pressure to ensure that it does not exceed the fracture pressure in the open cementing interval. Predicting the flow rate in the annulus will also indicate whether it will fall outside the limits required for effective mud removal. It is necessary to predict this optimum flow-pressure regime based on the size of the annular space and the selected fluid rheology and density.
Thus pore pressure, minimum hydrostatic pressure, minimum dynamic intervention pressure, maximum dynamic intervention pressure rock fracture pressure as it increases.
The appearance of this effect indicates the need to make changes to the cement slurry pumping mode. It is shown that in other areas of the Apsheron Peninsula it is necessary to use special large-volume buffer fluids with a density approximately intermediate between drilling and cement slurries.

References:

1. Halliburton cementing tables. Halliburton services. Duncan, О.К. 73536, USA, 2004, рp., 2-24, 82-86, 93-97, 114-149.

 2. Well Cementinq. Second Edition. Editors E. Nelson, D. Guillot. Schlumberger,225 Schlumberger Drive, Suqar Land, Texas 77478, 2006, pp. 539-677.

3. Cementinq Product Cataloq. Schlumberger Oilfield Services, 300, Schlumberger  Drive, Suqar Land, TX 77478, USA, 2006.

4. Schlumberger Dowell cementing Technology, Schlumberger Dowell publication, Sugar Land, USA,1997, pp. 5-23.

5. Bulatov A.I. Formirovaniye i rabota sementnoqo kamnya v skvajine. – M.: Nedra, 1990, s. 132-134.

6. Gayvoronskiy A.A. Raschet i texnoloqiya krepleniya neftyanix i qazovix skvajin. – M.: Nedra, 1969, s. 240-273.

7. Huseynov S.B., Huseynov M.A., Askerov A. Vliyaniye sementnoy obolochki na soprotivlyayemost obsadnix trub smyatiyu. RNTC “Bureniye”, 1967, № 3, s. 33-36.

8. Izmaylov L.B. Vliyaniye sementnoy obolochki na ustoychivost obsadnix trub pri smyatii RNTS “Bureniye”, 1963, № 6, s. 21-24.

9. Peslyak Yu.A. Raschet napryajeniy v kolonnax trub neftyanix skvajin. – M.: Nedra, 1973, s. 190-217.

10. Ishenko I.M. K voprosu o vzaimodeystvii obsadnıx trub s sementnim kamnem zatrubnoqo prostranstva // Neft i qaz, 1977, № 10, s. 29-34.

11. Bulatov A.I. Upravleniye fiziko-mexanicheskimi svoystvami tamponajnix sistem. – M.: Nedra, 1976, s. 210-248.

12. Suleymanov E.M. Sostavy dlya sementirovaniya neftyanix i qazovix skvajin. Palmarium academic publishing, Germany, 2012, ISBN 978-3-8473-9515-7, 124 s.

13. Suleymanov E.M. Sementirovaniye skvajyn v oslojnennyx usloviyax. Palmarium academic publishing, Germany, 2012. ISBN 978-3-8473-9200-2, 168 s.

14. Suleymanov E.M. Ustanovka sementnyx mostov v neftyanyx i qazovyx skvajynax. Palmarium academic publishing, Germany, 2012. ISBN 978-3-8473-9423-5, 160 s.