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.

Historically all well strings of casing and tubing have used thread compound or "dope" to enable good connectivity, lubricity and sealability of connections. During the makeup of a connection, excess running compound or dope is squeezed out into the annular space where it can gain access to wellbore fluids and cause formation damage. The innovation of surface technologies and industrial coatings allowed the development of dope-free connections. Dope-free technology can potentially eliminate the use of all dopes in well construction.Formation damage caused by excess pipe dope is not a recently developed problem but has been overlooked in the past. This, perhaps, is because the problem for production applies to higher formation permeability than the ones studied in this paper. For relatively low-permeability formations whose pore throats are smaller compared to dope particles and therefore the latter do not penetrate the rock matrix, the problem can be mitigated by the flow of reservoir fluids The problem can also be diminished by using solvent treatments (such as toluene or xylene) to help break down and dissolve the dope compounds.The key benefit of dope-free technology is the prevention of damage to the formation caused by dope entering the formation. Additional benefits include a more reliable and robust connection and a more efficient well site assembly process. Dope-free technology guarantees better downhole performance, minimization of galling and other connection damage as well as immediate savings in the operation by removing a routine and uncontrolled manual operation on the rig floor. Reduction of heavy tubular handling and lifting operations as well as the achievement of a virtual no discharge of effluents are also important benefits.In this paper, we present the laboratory test results utilizing actual core samples. Results show the creation of a harmful dope suspension that can penetrate and damage the formation. During injection operations this can result in severe damage to the well formation (greater than 99%), while in production operations the damage depends on the reservoir permeability. Within the tested permeability range (<288 md), it is observed that the harmful compounds did not penetrate the rock matrix and, instead, it formed a filter cake that can be removed by reservoir fluid flow while in injection mode. This paper will demonstrate the benefits of using dope-free pipe connections by quantifying the negative effects of the traditional way of joining connections with dope. Various "thread dopes" are tested, showing the differing potential damage from the dope product used. Production equations using a dope-induced skin effect are also presented, showing the detrimental impact on well performance.

Although invariably well tubulars have been connected with a thread compound to prevent corrosion and the galling of the metal itself, innovative technologies have allowed the introduction of dope-free connectivity by engineering the connections at the end of pipe sections. Avoiding the use of dope compounds has apparent benefits, one of which is the prevention of formation damage. Another is the efficiency and reliability of the operation itself, removing a cumbersome, albeit routine job, a major advantage in the hectic time of a drilling rig's operation.During the connection assembly a portion of the thread compound is exuded outside the connection and gets access to the well fluids through the tubing and annular space. Laboratory studies by us with core experiments, presented in this paper, show that the dope forms a suspension which penetrates and damages the formation. The damage is severe (more than 99 percent) and will be present in any well injection service. 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.The reason that this problem has not gained widespread notice is perhaps because the problem has a narrow application of formation permeability, one that we delineate in this work. Additionally, we present evidence that the dope can be washed off usually by simple flow of reservoir fluids and/or brines or it can be partially dissolved by simple solvent treatments employing toluene or xylene.We present here the clear benefits of using dope-free pipe connections by quantifying the negative effects of the alternative. Production equations using a dope-induced skin effect are presented, showing the detrimental impact on well performance.

The use of dope-free tubulars in offshore operations has been increasingly adopted by different operators since its debut in the North Sea in 2003.Dope-free tubulars replace the storage and running pipe dope historically used in casing and tubing by a dry coating applied on pipe threads in an industrial controlled environment.The elimination of dope greatly simplifies the supply chain process involved in preparing casing and tubing for offshore wells, thus increasing efficiency and safety, and lessening the environmental impact of the process.The main benefits of this technology are: improved operational efficiency -preparation, running, pulling, management of rig returns; reliability: connections are made up in a more consistent and repetitive manner as the coating is applied as part of an industrial process replacing a manual operation; improved well productivity: eliminating the damage to the formation created by the pipe dope; and reduced impact on Health, Safety & Environment.Operators' experience, after a short learning curve, showed great reductions in running time, fewer connection re-make-ups and rejects, better workers' Health & Safety conditions thanks to the elimination of unsafe tasks and the creation of cleaner work areas, and a lesser environmental impact. This paper describes the experiences and benefits of using dope-free tubulars in offshore operations in the main offshore oilfields, including the North Sea, the Barents Sea, Brazil, Indonesia, the Gulf of Mexico, and the Persian Gulf.

Environmental impact reduction is an essential component that compliments the commitment of every Oil and Gas Operator, Service provider, etc. towards the promotion of a greener environment. From the planning phase of oilfield operations, OCTG- Oil-Country Tubular Goods require the use of thread compounds (pipe dope) to protect machined surfaces from environmental corrosion, to lubricate the connections during installations and also provide sealability among other expectations. From the production, storage, preparation for operations, running and installation of OCTG, the use of thread compounds cannot be overlooked. These compounds like most Oilfield chemicals expose both personnel and environment to a harmful condition, placing all personnel involved in this value chain of material and service delivery affected one way or the other. A technologically crafted modern solution/alternative was developed in 2003 to fully eliminate the use of these thread compounds- A Dope-Free Solution replacing both storage and running compounds (Carcagno, G., Castiñeiras, T., & Dag, J., 2007). These Dope-Free connections are equipped with a dry coating applied through a controlled industrial process. It was first developed to meet the strict environmental requirements in the North Sea. In line with the "zero discharge" policy, this dry coating applied onto threads soon demonstrated other operative , health and safety advantages as compared to the traditional thread compounds. A presentation is made highlighting the benefits with the use of the Dope-Free technology, with a focus on health, safety and environment impact during storage, cleaning, inspection, running and post running operations including waste management. Two areas where tubular are used are considered; Rig site and Service yards. For example, the elimination of human application of thread compounds, the elimination of the need to clean thread protectors which could amount to other operative costs. In this study, a side by side comparison is done to realize the benefits.