Proppant produced during production often causes damage to downhole pumps and surface equipment. In addition to restricting production rate, frequent workovers are often required to remove proppant or sand infill, thus resulting in costly downtime. To help resolve these proppant production problems, solvent-based curable resins have often been used in remedial treatments of affected wells. These resin systems have been applied in intervals of less than 100 ft. For longer intervals, ineffective diversion of solvent-based resins and their potential interaction with water in the wellbore can prevent them from providing complete coverage over the entire perforated interval.A novel water-based consolidation system has been successfully developed to overcome safety, fluid compatibility, and placement issues, which most current solvent-based resins encounter during their field applications. This paper presents the results of laboratory testing and field applications and discusses the challenges, lessons learned, treatment procedures, and recommendations in applying this newly developed resin system.The curable consolidation component is emulsified to form a water-external emulsion so that the active material can be delivered in a brine-based solution. Extensive laboratory testing has indicated that optimum concentration of coating is necessary to maximize the bonding between proppant grains. This allows the proppant pack to withstand high production flow rates and to overcome the effects of stress cycling while minimizing any reduction in its permeability. Results from field trials showed that this aqueous-based consolidation system successfully treated both proppant and formation sand in nearwellbore regions to lock them in place without damaging production flow paths. In these field tests, intervals in excess of 300 ft were treated effectively with a bullhead squeeze using consolidation-treatment fluids that were foamed to a quality of 50 or higher to aid in diverting treatment fluids and extending treatment volume.One major advantage of this aqueous-based system is its simplicity in field treatments without the concern of fluid incompatibility between fluid stages during their placement because of its benign behavior. The new system uses small treatment volumes to impart excellent consolidation properties while, at the same time, retaining formation permeability. This makes the treatment system simple to deploy and economically viable.

Azeri-Chirag-Gunashli (ACG) is a giant field located in the Caspian Sea, Azerbaijan. The major reservoir zones are Pereriv sandstone formations with 20-25% porosity, permeability 100-1000md, and oil column up-to 1000m. These formations are weakly consolidated where Open Hole Gravel Pack (OHGP) completions have become the standard design for production wells. Development began in 1997 and to date more than 70 high rate (up to 45mbd per well) OHGPs have been installed.Wellbore stability issues require OHGP screens to be run in Oil Base Mud (OBM). Despite excellent initial success a number of sand control failures began to occur in 2008. A detailed gravel pack evaluation using multiple wash pipe gauges have revealed that earlier installations experienced screen plugging on lower section during the installation process. This leads to an incomplete pack in the toe area and subsequent screen failure as depletion increases or once water breakthrough occurs. The ultimate risk is of lost production rather than well control or loss of containment.Analysis was done to understand the root causes of screen plugging and to develop solutions for each. The work resulted in five key changes being made to the OHGP completions. o Revised TD criteria for the open hole section. o Modified OBM conditioning procedures. o Modified wellbore-clean-out procedures. o A modified screen BHA design. o The use of Ultra-Fine-Grain Barite in the OBM to reduce barite sag and the amount of large solids in the fluid system.These changes have resulted in less screen plugging, and hence increasing pack efficiency across the productive interval. This has resulted in a step change in OHGP reliability in the last 3 years with zero sand control failures over the last 24 completions. The detailed understanding of the failure mechanism also facilitated a successful intervention campaign to remediate several failed OHGP wells pre 2008. These efforts have delivered ~60mbd reduction in production losses over the past 2 years.

This paper describes a variety of Coiled Tubing perforating approaches and techniques which have been evaluated, planned and implemented during the development of the Cusiana and Cupiagua Fields. A synopsis has also been prepared which outlines the advantages/disadvantages of each of these approaches. In addition, several detailed case-histories are included which provide the actual Operating characteristics of each approach. The particular operational advantages, of Coiled Tubing Perforating, for Cusiana and Cupiagua have also been summarized. These include, the long intervals, deep wells, complex well trajectories, large gun-size, pre-frac requirements and poorly understood pore-pressures. An assessment has also been made of the additional benefits, IOR, cost savings, etc. that these techniques have potentially provided. Finally, there is some discussion as to the future direction of Coiled Tubing perforating for the Cusiana and Cupiagua Fields. Issues include a clearer definition of the Opportunities/Requirements and the additional Techniques/Systems which will be necessary to allow these to be realized. Introduction During the development of the Cusiana and Cupiagua Fields; customized charges were designed specifically for these non-homogeneous Quartz-Arenite formations. These resulted in a measurable productivity improvement, however the overall perforating efficiency remained low. As a better understanding of the mechanisms involved was acquired, it became clear that one of the primary factors affecting the perforating efficiency was the magnitude of the under-balance achieved. From the available data, it could be seen that this parameter had a considerable impact on the initial productivity or injectivity. Perforating operations utilizing electric-line are typically limited as to the absolute magnitude of under-balance at which they can safely operate. In addition tortuous, side-tracked and deep well trajectories can create excessive drag-forces, which cause operational problems and result in forces close to the operational limitations of the cable. In recent Years Coiled Tubing conveyed perforating has proven to be an excellent alternative to electric-line; in terms of achieving substantially higher values of underbalance and when attempting to access deep and highly deviated wells where dog leg severity may be a concern. Background Two major oil fields under development in the Casanare Region of Colombia are the Cusiana and Cupiagua Fields. The Cusiana and Cupiagua Fields are located in the foothills on the Eastern side of the Eastern Cordillera of the Andes mountain range. The current tectonic environment is characterized by active thrust faulting towards the South-East, the direction of maximum horizontal stress1. Reservoir bed dipping can be severe, this generally results in the wells following a natural walk, while being drilled, towards the preferred azimuth of fracture propagation.

Azeri-Chirag-Gunashli (ACG) is a giant field located in the Azerbaijan sector of the Caspian Sea. The major reservoir zones are multi layers sandstone formations with oil column up-to 1000m, and weakly consolidated where Open Hole Gravel Pack (OHGP) completions have become the standard design for production wells. Development began in 1997 and to date more than 130 high rate OHGPs have been installed. Once existing wells has been uneconomically to be produced, a Sidetrack or Up-Hole Recompletion (UHRC) will be performed. The standard 9-5/8" sidetrack technique will be done by drilling new section, installing and cemented a 7-5/8" liner, then drilling 6.5"x8" hole in pay zone followed by running 4" Shunted Screen and gravel packing. Previously C&P technique has been used for UHRC option but it was producing at limited drawdown and quickly sand up when water break through. Cased Hole Gravel Pack (CHGP) technique has been trialed as UHRC option in the past 2 years but has limitation of the number zone & length can be perforated which resulted in leaving some zones unperforated behind casing. A new concept of UHRC has been designed and successfully tested. This concept consists of sidetracking into the overburden, drilling to TD and removing 7-5/8" liner section. Shunted screen then deployed into open hole through a cased milled window followed by gravel pack operation. While standalone screens have been deployed through cased milled windows before, deploying shunted screens through a cased milled window followed by an OHGP is an industry 1st. This technique delivers the well 20 days earlier compare to standard Sidetrack OHGP well due to removal 7-5/8" production liner section. This technique is also give advantage over stacked CHGP option because can provide higher k*h access, can handle high levels of differential depletion within the completed interval and has the potential to unlock up lot more well candidates to allow and deplete the reserves from overlying reservoirs. This paper will also describe window and well design to deliver successful Shunt Tubes OHGP installation with this technique.