The optimization of stimulation treatments in Mexico has required the use of novel diversion technologies to increase the productivity of wells by improving the coverage of stimulation fluids and reducing completion costs. Self-degrading particulate has become widely used in the country because of the diverter flexibility. Job experiences range from hydraulically fracturing unconventional reservoirs to the matrix acidizing of naturally fractured carbonate formations. The purpose of this paper is to verify the effectiveness of this material for achieving the selective stimulation of multiple intervals, either in horizontal or vertical wells.Because there is no confidence in a complete stimulation of all open intervals, diagnostic techniques have been implemented to determine the effectiveness of diversions. For near-wellbore (NWB) monitoring, technologies such as radioactive tracers and distributed temperature sensing (DTS) have been used to determine treatment fluid locations after the application or in real-time. Downhole microseismic monitoring has been performed for far-field indications of diversion success in hydraulic fractures of vertical wells with multiple intervals open at the same time. This paper discusses four wells from the north, central, and south regions in Mexico. All of them have completely different reservoir properties and completion types.Improved production increase was the main difference between wells where diversion with selfdegrading particulate diverters was used compared to those that were not treated with diverters; a production increase from 30 to 70% was achieved. Completion time was reduced with the implementation of the novel self-degrading particulates vs. other possible methods, allowing faster return of investment (ROI). Real-time decision making could be performed using both a diverter and monitoring techniques to assure a uniform treatment placement. Another differentiator was the simple logistics required to handle the material compared to other additives employed in the past. Because of the performance of the diverter, it has been applied in more reservoirs with extremely variable permeabilities across the country (tight gas and oil sandstones, gas and oil shales, and naturally fractured oil-bearing carbonates).Downhole temperature is the main controlling factor to accelerate or retard the degradation of the particulate, as it must take into account that in cooler formations, longer times are required to achieve complete degradation. Its independence of the wellbore geometry has increased the implementation in openhole and cased-hole completions, despite the final shape of the perforations.

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.

During the past few years, the oil industry in Mexico has taken significant steps toward improving the economic performance of hydrocarbon-producing wells in the very low-permeability, heterogeneous, compartmentalized, and hard-to-produce reservoirs of the Chicontepec paleochannel through the application of high-impact technologies used in unconventional wells for drilling, logging, perforating, zonal isolation, completions, fracturing, etc. that unquestionably helped improve well performance. However, the proper integration of these new technologies in the heavy-oil Remolino field, located in southern Chicontepec, has shown the potential to deliver better results in terms of production and recovery improvement. Some of the production problems of Remolino field include previous ineffective stimulations, low reservoir contact area, poor well productivity, and extremely low recovery factors. These problems were addressed by modifying (i) the well architecture from vertical to horizontal, (ii) the zonal isolation from conventional cemented to engineered cemented and swell-packer openhole, (iii) the wellbore-reservoir connection from perforating to hydrajetting and ball-activated sleeves, (iv) the fracturing fluids from conventional crosslinked to hybrid fluids, and (v) the fracture design and pumping schedule to achieve the required length and conductivity. The application of these completion technologies in Remolino field have evolved, based on production results and operational efficiency, from the simplest perf-and-plug method in vertical wells to more complex coiled-tubing assisted fracturing and faster ball-activated sleeves in horizontal wells. Lowering the completion time also has been a primary driving factor for choosing the proper completion option for each individual well, attempting to achieve faster fracturing and quicker production. The experience of applying new technologies in Remolino field is presented in this paper, including comparisons between openhole and cemented laterals, fracture stages with single and multiple cluster/ports, number of fractures/fracture spacing, and lateral length required to improve the production without compromising completion costs. To date, the benefit of the overall application has been a five-fold production increase and, as expected, a significant improvement in the recovery factor.

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A multistage fracturing treatment was performed in two adjacent horizontal wells (Escobal 197 and Escobal 195) in Chicontepec basin. The alternating sequential hydraulic multifrac in two parallel horizontal wells was planned and performed to create a high-density system of low-complexity planar fractures between the horizontal wells, to maximize the contact area with the reservoir and increase the stimulated reservoir volume (SRV). The wells were drilled perpendicularly to the expected fracture azimuth in Pechi-B formation and were completed as openhole using a ball-and-sleeve completion strategy. Thirty-two fracturing stages (16 stages per well) were selected based on an integral analysis of geological, petrophysical, and geomechanical disciplines. This completion technique has been the first stimulation treatment of its kind in Mexico. The fracturing entails adjacent wells in sequence, enabling one well to hold fracture pressure while the adjacent well is being fractured and it also maximizes the exposure of new reservoir rock. The fractures then avoid each other because of the stress pattern set up in the pressured well. The two adjacent horizontal wells were successfully stimulated in 108 hours of continuous work, pumping 95,000 bbl of fracturing fluid and 8.6 million lb of ceramic proppants. The stimulation technique reduced the stimulation cycle time to just four days, and the initial production of the two wells was more than 8,320 B/D, which was more than 10 times the average initial production in the area. The production later stabilized at 2,517 and 1,011 BOPD, respectively. The two horizontal wells produced 240,000 barrels in 90 days of cumulative production, which exceeds 14 times the average of cumulative production from the conventional wells in the field. The application of this completion technology was considered successful, and now it is extending to other fields located in the basin of Chicontepec.