Session 4

Wednesday, December 1st
8:30am – 9:30am US Central Time

Presentation 1 : 08:30 am

Discovering Bypass Reserves for a First Time With Formation Sampling Through Drill Pipe: Case Study from Onshore, Kuwait

Speaker: Irina Baca Espinoza. Weatherford

Identifying a bypassed pay is always challenging, especially for highly deviated, complex wells where well control further complicates wireline logging.  This case study examines the use a through drill pipe (TDL) conveyed of formation testing tool for a first time in the sampling history. Despite the challenging logging environment, and alone with slim open hole logging suite, the resulting data provided a conclusive formation evaluation answer for reservoir characterization of bypassed oil zones.

The logging program targeted two formations:  The primary was the Upper Burgan and the secondary target, suspected bypassed pay, was the Lower Burgan.  The well was highly deviated, using an oil-based mud system.  In addition to complex trajectory, well bore stability was marginal due to washouts.  Therefore, the logging program implemented TDL for both traditional open hole logging and formation testing.  TDL pumps the tools down the drill pipe internally, until reaching the total depth, where they were released into the well bore and pulled out to log to surface.  On the first acquisition run, a triple combo logging suite was run and a complete dataset acquired without experiencing any differential sticking. In the second run, the slim formation testing tools were run in hole in the same scenario to complete the dynamic data for pretests and sampling.

As a result, total of 22 pressure points with 2 low-contamination oil samples were conducted.  The sampling series found fluid in the secondary target.  The combination of open hole logs with porosity, saturation and dynamic pressure and fluid data helps to characterize the untapped reservoir zone.  The sampling results helps to understand the storage and flow capacity of these heterogeneous reservoirs that would be not possible without TDL conveyance.  Consequently, the well completion design was optimized by the producer.

The Sampling via TDL conveyance helped to safely log the well from total depth to casing in a complex trajectory well. Moreover, the slim sampling tool was efficient enough to identify the hydrocarbons vs. water and secure two single phase samples to the surface. The success from this job shows that there are no barriers for pressure testing and sampling, when it comes to complex wellbore and critical data acquisition.

Bio: Irina Baca Espinoza is a Formation Testing and Sampling Advisor at Weatherford with more than 13+ years of proven track record experience in field operations and in key O&G service companies and operators. She is a focal point globally, when it comes to challenging formation testing applications and recommendations. The experience in testing, production logging, and petrophysics allows her to bridge the static and dynamic data, and to provide solutions during various phases of well and reservoir development. Irina is an active committee member of the technical Oil and Gas conference (ADIPEC) for several years, with 15 technical publications on data evaluation. She is in charge of internal Formation Testing and Sampling trainings, with more than 100 specialists participated in the last 4 years.

Presentation 2 : 09:00 am

In-Situ Measurement of Asphaltene Precipitation to Determine Aspects of Flow Assurance

Speaker: Gibran Hashmi, Halliburton

Asphaltene precipitation is one of the major applications of flow assurance challenges that have been mounting in recent times due to the transition from conventional oil reserves to mature oil fields. The problem may occur in any part of the production system from the reservoir to the surface facilities; and if not properly controlled, it may lead to the point of plugging the conduit, affecting the viability of any asset in the oil production scenario. Asphaltenes can be precipitated when the oil experience changes in pressure, temperature, and composition. Of these the most common are pressure and temperature changes that are unavoidable when oil is brought up through wellbores and flowed in pipelines. Therefore, a proper understanding of asphaltene precipitation leading to deposition is crucial in completions planning and effective management of a production system. It ultimately governs the production life of the reservoir.

This understanding is traditionally achieved through the laboratory study of pressurized fluid samples that are collected during the formation testing phase. Significant developments over the years have greatly improved this process, along with the introduction of downhole fluid analysis. However, variations in different laboratory methods and surface challenges of restoration to reservoir conditions and maintenance of equilibrium have often deterred good quality results when determining an accurate and representative measurement of Asphaltene Onset Pressure (AOP). Since the post-acquisition handling of fluid samples often induces inadvertent changes to the fluid properties, the most optimum place to determine this critical parameter then becomes the sandface. In this regard, wireline formation testers can aid in providing a reliable downhole analysis.

This study presents a novel method to estimate AOP at reservoir conditions. The approach combines the two laboratory techniques of gravimetric and light scattering analyses. An isolated sample of fluid is isothermally depressurized from initial reservoir pressure. At the same time, the downhole fluid analysis monitors the fluid composition through depressurization via light scattering technique. The process does not interfere with the collected fluid samples and presents a downhole measurement of upper asphaltene onset pressure (UAOP) together with other critical onsets in the asphaltene phase envelope. The procedure also allows to study the kinetics of the precipitation process that further enhances the understanding of the asphaltenes present in the oil for future production.

The investigation includes a case study from a GOM well where the proposed workflow was implemented. The analysis obtained from this methodology has the potential to be a significant differentiator with regards to reservoir management. The study of the downhole data can serve to augment the PVT tests carried out in laboratory to facilitate a better understanding of the fluid. The knowledge also allows for effective production planning in order to avoid costly mitigation procedures.

Bio: Gibran Hashmi is a global reservoir engineering domain expert with Wireline & Perforating product line at Halliburton. His areas of interest include reservoir characterization, well testing, production analysis, reservoir simulation, fluid and heat transfer in wellbores, petrophysics and geomechanics. Dr. Hashmi holds a Bachelor’s degree in chemical engineering from University of Minnesota, and Master’s and PhD degrees in petroleum engineering from Texas A&M University. During his time in the industry, Dr. Hashmi has worked extensively on reservoirs globally, analyzing pressure transient tests in different lithologies worldwide. He has authored more than 15 industry publications and holds four patent applications. He conducts internal trainings on aspects of reservoir engineering and formation testing and sampling.

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