The Chicontepec basin in the northern region of Mexico has experienced an increase in the application of completion technologies using fracturing sleeves (FSs) activated by baffles in long, extended horizontals. Because of the oil’s high viscosity in that zone and the inherent decrease in initial production, the milling of such FS baffles has become a necessity. Milling jobs have proven to be difficult using conventional coiled tubing (CT) milling methods, tools, and processes. Analysis of previous variables, well constructions, CT strings, and CT equipment led to the development of an unconventional work method that has been applied with success in more than 12 wells in the region. CT milling operations rely heavily on two variables—the amount of effective weight on bit (WOB) that is applied over the obstruction and the torque generated by the tool. An intervention in a long, extended horizontal using CT implies the following constraints: Normal force of CT in the extended section. Friction caused by the previous normal force. Friction pressure loss resulting from limited CT diameters and lengths. While observing the long time intervals involved with most interventions and a few events in which the CT became stuck, a new intervention method was developed. Highlights of this method include the following: Specific bottomhole assemblies (BHAs) for milling and cleaning of debris generated. Static friction reducers. Pressure friction reducers. Staged milling/cleaning work method of the total amount of FSs. The first deployments of the combined work method were observed with caution and were not fully supported by the customer. The staged milling was supposed to increase the operating times in these interventions. However, by the time the third well was milled using this method, this perception began to change because of comparisons between the time lost during unwanted events, such as the tool becoming stuck and difficulty during milling. Previous events had reduced the occurrence of these issues in the last 12 wells and the use of associated FSs. The importance of this work method is evident by the observed reduction in overall intervention time, delivering production earlier with no quality issues for the Chicontepec area.

Injection profile enhancement has been one of the primary objectives for an operator in Kuwait. Stimulation interventions in injector wells directly affect the enhancement of oil recovery in producer wells. This paper presents the application of a verifiable stimulation intervention in a water injector well to help achieve the operator's objectives. The intervention presented several challenges. There was limited information available for the newly drilled carbonate formation under consideration in the Greater Burgan Field. Additionally, the fiberglass well tubing required significant attention before running in hole (RIH) with coiled tubing (CT). A high concentration of H2S was identified in Formation A; therefore, gas returns were also a potential issue. This paper discusses the methods used to help address these challenges. During this case study, real-time fiber-optic cable CT (RTFOCT) technology was applied in the fiberglass tubing injector well to determine initial well injection profile and adjust treatment accordingly. This technology includes a fiber-optic cable integrated into the CT pipe and a modular sensing bottomhole assembly (BHA). RTFOCT technology allows for rigless operations and performs interval diagnostics, stimulation treatment, and evaluation in a single CT run. During this case study, the well injectivity increased by more than 100%. Diagnostics and evaluation were performed by analyzing the well thermal profile using fiber-optic distributed temperature sensing (DTS). The BHA helped ensure accurate fluid placement during the treatment using real-time pressure, temperature, and depth-correlation sensors. The RTFOCT technology provided real-time downhole information that was used to analyze reservoir parameters, help ensure accurate fluid placement, and enable quick and smart decisions regarding the stimulation treatment stages based on the fluid intake in different zones. During injection, the heterogeneous fluid flow became homogeneous along the interval confirmed with the thermal-hydraulic model (THM). This helped reliably complete the intervention operations and delay possible water breakthrough in the producer wells and extended reservoir recovery.

This paper presents an alternative for operators regarding tools and methods using coiled tubing (CT) during the implementation of horizontal completions.To help address challenges faced developing horizontal completions, both cemented liners and open holes have been widely used in conventional and unconventional reservoirs. Various completion techniques have evolved from traditional tubing conveyed perforation (TCP) and plug setting, and hydrajet assisted fracturing has become the preferred pumpdown technique within the last six years in northern Mexico.The criteria used to determine the completion technique is based on three parameters-extension of horizontal length developed [well geometry, dogleg severity (DLS), deviation], fracture design (pump rate, number of intervals) and type of reservoir being exploited. For the case discussed, a pumpdown technique was selected.Pumpdown techniques are considered one of the fastest completion techniques to provide mechanical isolation between fracture stages; nevertheless, it has not been completely effective during all stages. Some of these techniques can cause premature setting of bridge plugs because of poor sand displacement or adverse well geometries, including high DLS. During the application of this technique, CT interventions are primarily considered in the event of contingencies, such as screenouts (sand cleanout) and plugs prematurely setting (plug millouts).Even though no completion operation is immune to contingencies and associated costs and nonproductive time (NPT), a constant repetition of them because of inherent well conditions or poor fluid admission by the formation increases associated completion costs and diminishes equipment efficiency in place (frac set, logging unit).As a result, CT has become an effective solution with the development of new tools and techniques to avoid such contingencies. This paper develops the concept "plugging and jetting," wherein a mechanical isolation bridge plug (BP) is placed with CT, allowing abrasive perforations to help the producing formation communicate with the wellbore in a single run, thus allowing reduction of NPT up to 30% and providing a new alternative for horizontal completions.This paper presents case histories with benefits and results. Bottomhole assembly (BHA) design considerations with improvements that provide a new alternative to operators are also presented. This method allows completion of fracturing stages in a continuous manner, thus being advantageous in terms of operational time reduction and consequently cost savings.

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