Novel Microbial Process for Mitigating Wax Deposition in Down hole Tubular and Surface Flow Lines

Abstract

Many oil fields producing waxy crude, face severe wax deposition problem in down hole tubulars and surface flow lines. Sometimes this problem is also encountered at the face of producing zone in the well bore region due to changes in temperature & pressure conditions. This problem frequently results in complete blockage of the crude passage and poses severe production problem. Conventional methods such as thermal, magnetic, mechanical scraping, solvent cleaning and chemical treatment etc. are not only cumbersome, costly and hazardous but provide only temporary respite. Two separate microbial systems, capable of mitigating the vexed problem of paraffin deposition in oil well tubulars and surface flow lines have been developed.The microbial system for down hole tubular comprises of paraffin degrading bacterial (PDB) consortium named as PDS-10, nutrient supplements and growth enhancer. Laboratory studies showed significant reduction in pour point and flow behaviour of the crude. The process is effective up to 90 0 C but maximum efficiency was observed at 55 0 C. Field trial in 100 wells of different fields of Western & Eastern sector has shown that the treatment not only checked the paraffin deposition in all the treated wells but also improved oil production by 20-80 % in many wells. Most of the treated wells flowed without any wax deposition for 6-8 months after the treatment.For flow assurance in surface flow lines bacterial consortium named as FIB-19, which shows high degree of wax degradation capability has been developed. The bacterial consortium is aerophilic, mesophilic and remains active upto 43 0 C. Field trial in surface flow lines of twelve wells of Ahmedabad Asset was quite successful resulting in elimination of requirement of line flushing for considerable time along with reduction in pressure in the flow line. The average period of effectiveness of the jobs has been found to be around 4-5 months.

Preventing and removing wax deposition inside vertical wells: a review

“…Biological wax removal methods have been thoroughly investigated in recent years by several researchers. The results attained by Rana et al showed that the developed bacterial systems of paraffin-degrading bacteria with nutrient supplements and growth enhancers could eliminate the need for repeated scrapings of wax over a period of several months (Rana et al 2010). If successfully implemented, these methods have the benefit of providing continuous control of wax deposition through constant biodegradation, instead of just providing a temporary solution.…”

Fundamental Study of Wax Deposition in Crude Oil Flows in a Pipeline via Interface-Resolved Numerical Simulations

“…The specic heat and molecular thermal conductivity of the mixture uid are evaluated based on the pseudo-components specic values as done for the molecular viscosity, see Eqs. (8) and (9); the turbulent thermal conductivity is computed as λ t = c p µ t /Pr t , where…”

Friction behavior of waxy oil deposit removal using polymeric bristled brushes

“…[8][9][10][11][12][13][14][15][16][17][18] Several traditional methods are used for removing the accumulated wax deposit from the inner wall of a pipeline, such as mechanical removal (pigging), [19][20][21][22] inductive heating, 23 biological treatment (hydrochloric acid, paraffin solvents). [24][25][26][27][28] Regular pigging is the most effective and common way for removal of the wax deposits in pipelines. [20][21][22][23] A mechanical pig driven by the differential pressure of the oil flow, usually equipped with rubber sealing discs or brushes as shown in Figure 1.…”