Gravel packing is one of the commonly used sand control techniques in long openhole horizontal completions. Although numerous wells have been gravel packed with either one of the two placement techniques (α/β or shunt tubes), achieving a complete pack with sand control screens that have inflow control devices (ICD) can be challenging to say the least. This is because of the high pressure drops needed for the fluid to flow through the ICD into the base-pipe/wash-pipe annulus at the typical rates used for gravel packing, resulting in significant pressure rise and exceeding the fracturing pressure of the formation. Although using a screen without an ICD at the bottommost joint would certainly allow the α-wave to reach the toe, the pressure buildup will occur as soon as the β-wave proceeds upstream of that joint, which will either result in formation fracturing and bridging or significant rate reduction and α-wave height increase (near the heel first), both events resulting in a premature screenout. Ocelote field in Colombia requires sand control, and gravel packing and standalone screens (SAS) have both been used in openhole horizontal completions in various parts of the field. An additional challenge in this field has been the premature water breakthrough from the aquifer leading to very high water cuts after only a few months of production. ICDs have successfully been implemented in SAS completions to address this challenge in other parts of the world. Similarly, gravel packing has been successful in controlling sand in parts of the field where SAS was considered unsatisfactory, although water cut in most of these wells increased to 70 to 90% after only 3 months of production. In this paper, we present a novel technique for wells that require gravel packing for sand control and ICD functionality for managing water encroachment. Detailed in the paper is the first application of the proposed technique in Ocelote field, which resulted in 100% pack efficiencies using the water packing technique as well as significant reduction in water cuts, with substantial improvement in the project economics.

This paper describes the design, planning, and successful installation of a fit-for-purpose casing patch to isolate a water producing zone, the subsequent perforation of an adjacent zone, and a gravel pack completion in the same well for the first time worldwide. The proximity of the zones and the sand control requirements made the design and planning of this job a challenging task that is detailed in this manuscript. The main producing zone in the SW-21 well watered out after few years of production. A second target was identified located just four feet below the main zone. To extend the life of the well and to add reserves from the secondary target, the upper 100% water zone had to be isolated. A fit-for-purpose, thin wall casing patch solution was designed to: allow perforation of the secondary target while maintaining patch integrity, allowing for the installation of sand control screens; and resist following gravel pack completion, by keeping the minimum recommended clearance between casing and screens, inside the minimal patch-reduced diameter. The re-completions program consisted of: 1. Successful recovery of existing gravel pack from the main producing zone and thorough wellbore cleanup. 2. Casing patch installation consisting of a 23-ft long patch to isolate the water-producing zone. In this case, a specific engineering design analysis was required to ensure that, because of the very close distances between zones, the patch would still maintain integrity during perforation of the secondary target and the resulting patch overlap. 3. Successful integrity test to confirm upper interval isolation before perforating the lower interval. 4. A precise perforating operation carried out to perforate the secondary zone. Based on engineering recommendations, some length of the installed patch was perforated to guarantee a minimum unperforated distance of casing patch between zones to guarantee patch sealing features. 5. Once perforation was successfully accomplished, a gravel pack completion—inside the casing patch reduced diameter—was executed along the new zone for sand control purposes, and the well was put into production. This paper presents the different interactions between a multidisciplinary research and development team, and completions and reservoir engineers to come up with a full solution for water isolation and sand control under such challenging conditions. For the first time in the world, a casing patch was used to isolate a water zone, and at the same time, perform a gravel pack completion inside the patch reduced diameter. Well performance, without any mechanical issues, confirms the success of the provided solution.

Although the application of openhole gravel packs has been well documented, only a few cases using this type of completion in openhole intervals greater than 800 ft in length have been implemented in Latin American land wells. Recent field studies involving openhole gravel packs in long intervals were carried out in the Ocelote field in the Llanos basin of Colombia. The operating company of the field is Hocol S.A., (subsidiary of Ecopetrol) and after many trials and the use of various service providers and tools, the final customized methodology and equipment of one particular service company were selected and implemented for the openhole completion campaign of the entire field.

Hocol Colombia operates in Ocelote field at the eastern part of Colombia, a land called as Llanos Orientales (Eastern Plains). In this field Hocol produced from Carbonera formation observing problems with formation deconsolidation. Normally, gravel packs jobs are performed on vertical wells with sustained good results. However, new reservoir studies showed that horizontal wells with regular length extension (around 1000 ft) would be more profitable for this field. In order to get this objectives, Hocol design a horizontal wells Program to drill and test alternatives to get good completion of these wells. The first well was completed and gravel packed using conventional technologies and a 35% of pack efficiency was achieved. The objective for the second well was to get at least 75% of packing efficiency. In a synergetic team effort, service companies proposed operator company new technologies that are used in other places but never were applied in Colombia. After simulations and technical meetings, the Operator decided to test two new technologies to try to get their operative and technical objective. This paper presents the technical and operative fundamental used to support these changes and the results obtained with theses applications.