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Condensate banking has been identified as one of the most potentially damaging mechanisms affecting well productivity in Cupiagua Field. This gas-condensate giant field has reached an average recovery factor of 42%, with recovery values of approximately 60% in some layers of field. The mitigation of condensate banking phenomena, among the other important damaging mechanisms currently interacting along the entire productivity zones, has been one of the most relevant stimulation practices in the development strategy.The mitigation of condensate banking led to optimization of common stimulation practices to recover the productivity of gascondensate wells. Massive hydraulic fracturing and matrix stimulation with inhibited diesel and alcohol have been the most common practices implemented and optimized to mitigate condensate banking in Cupiagua field.Because the field is being operated by Ecopetrol (as of June 2010), the mitigation of condensate banking was recognized as one of the most important stimulation challenges to be worked by the stimulation team. The effective mitigation of condensate banking is key to reaching and even exceeding the short-and long-term production targets set by Ecopetrol.This paper describes all the engineering work carried out to implement a new stimulation technique based on the injection of inhibited dry gas. The performed laboratory job, the simulation runs, the engineering design, and the field results are clearly described in the paper, the preliminary results showing that a successful stimulation technique exists to remove and mitigate condensate banking. At the moment, this stimulation strategy has been focused on removing liquid saturation (condensate and water) and organic solids (especially asphaltenes) by incorporating alcohol and surfactants inside the gas stream. Future engineering work will address the incorporation of a chemical blend that can improve the gas-treatment life, thus reducing critical liquid saturation or/and reducing the size of no-mobile condensate rings. OverviewAmong several important sources of damage, condensate banking has become the most important factor in reducing the well potential of the majority of Cupiagua gas-condensate producer wells. The accumulated amount of condensate near the wellbore dramatically reduces the effective permeability to gas and subsequently decreases the well's productivity. When reservoir water is also produced, the problem becomes pronounced, as the combination introduces a third phase to the reservoir, inducing an additional reduction of the effective permeability to the gas phase.Currently, condensate banking is expected to be found anywhere in the reservoir because the current reservoir pressure is below the dewpoint pressure. Water is also being produced in the majority of Cupiagua's gas-condensate producer wells.The use of inhibited diesel (DI) was the first stimulation attempt carried out to mitigate the problem of condensate bank-ing. A nonionic surfactant and a mutual solvent were added to the diesel to generate the s...

This paper describes the evaluation of a fluid containing nano-materials with high adsorption capacity for Asphaltenes inhibition in a volatile oil field in Colombia. Asphaltenes precipitation has been identified as one of the most potential damaging mechanism affecting the well productivity in Cupiagua Sur Field. Before this work traditional techniques have been tested in the field for asphaltenes inhibition. The goal of the injection of nano-fluids containing nano-particles of alumina with high surface area (>120 m2/g) is to absorb the asphaltenes before being flocculated and carry them with the condensate avoiding precipitation near the well bore. In the first stage of this work, lab testing, the adsorption capacity of alumina nano-particles for the asphaltenes produced in the field was evaluated, next, the nano-fluid containing nano-particles was evaluated in the Mirador formation plug cores by performing flowing core tests at the reservoir conditions. Returns of the relative permeability curves were quite good, improving Ko from 0,09 md to 6,13 md which enabled us to recommend the application of this nano-fluid in the well CPSXL4. For the Field Application, the job was designed by forcing 220 bbl of nano-fluid within a radius of 8 ft. After the job, through monitoring with SARA analysis in produced fluids and the residual tracking of nano-particles as well. Maintenance of asphaltenes concentration in the produced fluids has been observed. Also, significant gain in the oil and gas production has been reported, with more than 100,000 bbls of cumulated gain production in only 4 months after the job was performed. Results may be promising and now it is possible to extend application of nano-fluid in other wells in this field. INTRODUCTION The Cupiagua Sur field is located 110 kilometers northeast of Bogota in the foothills of the eastern mountain chain of the Colombian Andes, close to other fields discovered in this area such as Floreña, Pauto, Volcanera, Recetor, Cupiagua and Cusiana (Fig. 1). Despite the fact that Cupiagua Sur is very close to Cupiagua, this reservoir is totally independent and separate. It is formed by a back thrust structure with several reservoir pressures, properties and contact fluids. Cupiagua Sur is a compositional volatile oil reservoir with an average API gravity of 38°; there is no free gas cap at initial conditions. The main formations are Mirador and Barco which are quite similar about petrophysical and fluid properties (average permeability is 21 md and average porosity is 6.5%). It is a prolific oil field that in fifteen years of production has recovered 88 MMstb gross out of 189 MMstb original in place from Mirador and Barco reservoirs in a developed area with four producer and two injector wells.

Condensate banking has been identified as one of the most potential damaging mechanism affecting the well productivity in Cupiagua Field. This gas-condensate giant field has reached an average recovery factor of 42% with recovery values of ~60% in some layers of field. The mitigation of condensate banking phenomena, among the other important damaging mechanism currently interacting along the entire productivity zones, has been one of the most relevant stimulation practice in the development strategy. The mitigation of condensate banking led to optimize common stimulation practices to recover the productivity of gascondensate wells, massive hydraulic fracturing and matrix stimulation with inhibited diesel and alcohol have been the most common practices implemented and optimized to mitigate condensate banking in Cupiagua field. Since the field is being operated by ECOPETROL (Jun-2010), the mitigation of condensate banking was recognized as one of the most important stimulation challenges to be worked by stimulation team. The effective mitigation of condensate banking is a key to reach and even exceed the production targets set by ECOPETROL short and long term. This paper describes all the engineering work carried out to implement a new stimulation technique based on the injection of inhibited dry gas. The performed lab job, the simulation runs, the engineering design and the field results are clearly described in the paper, the preliminary results are showing that now we have available a successful stimulation technique to remove and mitigate condensate banking. At the moment this stimulation strategy has been focused in to remove liquid saturation (condensate and water) and organic solids (especially asphaltenes) by incorporating alcohol and surfactants inside the gas stream. Future engineering job will be addressed to find a chemical blend that can improve the gas-treatment life, probably reducing critical liquid saturation or/and reducing the size of no mobile condensate rings.

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