"Dope-Free" Tubulars in Petroleum Well Completions

Abstract

Dope", an inorganic compound, has been used routinely during well construction for both casing and tubing to lubricate, seal and protect against corrosion of segment-connecting threads. During the well tubular assembly a portion of the thread compound is exuded inside and outside the connection and gets access to the well fluids through the tubing and annular space. Studies presented here show that the dope forms a suspension which penetrates and damages the formation. The studies used standard fluid circulation velocities during typical completion operations. The formation damage is severe (more than 99 percent) and has been confirmed with a number of core-test experiments, presented in this work.If the well is put on injection service and in the case of workovers such as matrix stimulation treatments, the formation damage caused by pipe dope will almost guarantee operational failure. For production the issue is different and will depend on the reservoir permeability and the ability or lack thereof of the dope compound to penetrate the rock matrix or whether it will form a removable filter cake.

Formation Damage From Pipe Dope: How Bad Can It Get?

“…The particle size distribution of laboratory generated dope dispersion was obtained by the "Coulter Counter" method and was generated over a 10,000 ppm NaCl solution with the use of a mixer. The particle size generated in this study ( Figure 3) is slightly larger than that generated in our previous study (Funes et al, 2013, Mathis et al, 2013 where the fluid was injected in the lower permeability cores.…”

“…Inject pipe dope dispersions at a constant pressure of 1,500 psi (the same pressure used in previous tests as done in Funes et al, 2012), registering production flow rate as a function of time at reservoir temperature and confining pressure (Tres and NOBP).…”

“…The dope gets access to the well fluids through the tubing and annular space and can cause severe formation damage (Maly et al, 1976, McLeod et al, 1983, Nasr-El-Din et al, 2002, Curtis et al, 2003. Recent studies have characterized and quantified the damage (Funes et al, 2012).…”

“…In the Funes et al, 2012 study, several tests had been conducted in the laboratory to mimic and evaluate the formation damage due to pipe dope dispersions generated during well operations. In those tests, pipe dope was dispersed in water to simulate the dope in the fluid in the wells.…”

A utilização de graxas em revestimentos durante a construção de poços de petróleo: análise de Fichas de Informações de Segurança de Produtos Químicos

“…Diversos são os benefícios obtidos por meio da utilização de revestimentos "dope-free", isto é, capazes de desempenhar com qualidade e segurança o propósito de sua fabricação sem a necessidade de aplicação de graxas. Funes et al (2013) destacam que são conexões "ready to run" (prontas para uso). É fato que a disponibilidade de produtos fabricados com tecnologia que dispense o cliente da tarefa de arcar com os custos da compra, transporte e solicitação da aplicação de graxa nas conexões não absorve, atualmente, a demanda por revestimentos.…”