The Shushufindi field is located in the Oriente basin of Ecuador. The field was discovered in 1972 and is sparsely developed with about 200 wells covering an area of approximately 400 km2. An initial lithofacies characterization based on capillary pressures, pore throat size distribution, and log derived total porosities and permeabilities has provided a coherent grouping for the reservoir types that matched in over 92% of the wells. The importance of pore throat size in the initial lithofacies characterization has spurred the use of nuclear magnetic resonance (NMR) logs. NMR laboratory measurements on core samples complement the characterization with continuously calibrated pore body size derivations. Furthermore extensive whole core studies have shown that the pore throat size has a substantial impact on the initial oil saturation. Failures to respect this later point had previously generated disappointing oil production results. The challenge for the subsurface and engineering team is to take advantage of a lithofacies-based method to determine appropriate completion intervals and generate reliable production predictions. Open hole wireline log measurements of derived pore bodies size show a good correlation to NMR laboratory measurements on plugs when grouped within the initial lithofacies characterization. These data are used to provide a calibrated continuous pore body size curve based on the NMR binned porosities, and using the inferred initial oil saturation, to estimate the flow capacities for each lithofacies. This approach provides adequate support for selecting the reservoir rock with the best flow capacity, thereby optimizing the well completion. In thin beds where the vertical resolution of standard density and NMR logs is insufficient to discriminate the best facies a modified method has been developed. Very high resolution imaging has been coupled with flushed zone (Rxo) measurements and high frequency dielectric dispersion log to identify the potential production. This paper presents a lithofacies characterization enhancement methodology using NMR derived pore body size as implemented in the Shushufindi field, the results to date, its impact on the selection of completion intervals, and the resulting improvement in production from this technique.

The Shushufindi field, located in the Oriente basin of Ecuador, has been producing since 1972. In December 2011, the field had approximately 150 wells, with a total production of 45,000 bopd. Field operations were then passed to the Consorcio Shushufindi (CSSFD) led by Schlumberger for a period of 15 years. Since then, 30 new wells and 26 workovers have been completed by Schlumberger Production Management (SPM) in the field, with a production of 60,000 bopd in May 2013.A methodology with four successive distinct phases was created, aiming for a complete reservoir characterization over 18 months prior to delivering the five-year field development plan (FDP) in October 2013. Each petrophysical phase focused on providing a reliable basis for the first two years of operations, and regular updates to the static and dynamic models.In conjunction with operations support, a comprehensive data acquisition plan was launched with advanced core analysis and special logs to support the advanced reservoir characterization. The deployment of technologies such as the Dielectric Scanner* multifrequency dielectric dispersion service, the combinable magnetic resonance tool, and the FMI* fullbore formation microimager, among others, was key in revealing the reservoir's true characteristics.Advanced petrophysics delivered a description of the main reservoir heterogeneities and properties, along with a facies characterization tied to an advanced core analysis including capillary pressure and pore throat size measurements. From this, hydraulic flow units were established in a deterministic characterization over the waterflood pilot well patterns. Additionally, a quantitative evaluation of thin beds and low resistivity pay zones provides the potential for their incorporation in the original oilin-place computation. These findings have contributed to a revision of the depositional concepts for the field.

The Auca field is located in the northern Oriente basin (Ecuador) with hydrocarbon production coming from Cretaceous fluvio-estuarine and shallow marine sandstones. The field has produced more than 547 million barrels of oil since 1972 and by the end of 2015 the field recovery factor was approximately 14%. In December 2015, the reservoir management and the field re-development activities for the Auca field were awarded to Schlumberger Production Management (SPM) under the name of Shaya project. Since then, to sustain the field re-development activities, an integrated reservoir characterization process has been implemented. In this depositional environment reservoir evaluation can be very challenging, especially when using only conventional well logs. It is proposed in this paper that the acquisition of texture dependent measurements is the solution to improve the understanding of the reservoir rocks in highly heterogeneous environments. Based on our experience in Ecuador, incorporating nuclear magnetic resonance (NMR) in the petrophysical model appears to be the best way to collect the needed texture dependent data. The Rock type characterization in the field was based on mercury injection capillary pressure data. This method enables the determination of pore throat profiles for each rock type and the dominant interconnected pore system, which corresponds to a mercury saturation of 35% in a capillary pressure curve. An empirical relationship was used to relate conventional porosity and permeability to pore throat profiles, and this was used to classify rock types. With the purpose of validating reserves and optimizing the field development plan, a model based on rock type characterization was developed using existing core, log and production data. Additionally, this model was calibrated using data from multiple fields in the basin. The propagation of the model from core to logs was accomplished through a relationship between gamma ray, density, neutron and NMR logs with core porosity and permeability in key wells. These relationships are dependent on rock type, and they were used to extrapolate core characterization to those wells without cores. Maps of rock type distribution were used to classify areas according to their petrophysical properties. These maps were also used to delineate the reservoir limits, helping to validate and identify prospective areas for future drilling and workovers. This paper presents the characterization of the reservoir into rock types by integrating geological, petrophysical and production data through Neural Network Analysis, establishing a fundamental input into and support for the development of the exploitation plan.

The Shushufindi-Aguarico field (SSFD), located in the Oriente basin of Ecuador, has been under production since1972. In December 2011, when Consorcio Shushufindi (CSSFD) joined efforts with the national oil company PetroAmazonas EP (PAM), there were about 150 wells in the field with a production of 45,000 BOPD. Since then, 109 new wells and 91workovers have been completed in the field, raising the production to 80,000 BOPD by August 2016. Reservoir characterization of the SSFD field was undertaken with sequential objectives in mind. First, to answer the project needs for primary recovery, the effort focused on the main reservoirs (Lower U and Lower T) to create the annual work plans for the initial years of the project. Thereafter, a more refined petrophysical analysis, production data re-evaluation, and individual well diagnosis for water production provided the necessary characterization results for the field development plan (FDP) with a thorough mapping of the hydraulic units (HUs). In Shushufindi-Aguarico field, stratigraphic compartmentalization occurs when flow is prevented across sealed boundaries within the reservoir. These boundaries are caused by a variety of geological and dynamic factors. The characterization of the heterogeneity in the U and T reservoirs was a key starting point in understanding how lithology controls the horizontal and vertical movement of fluids, the reservoir depletion mechanisms, and the different completion options for a specific well.