The Huamampampa formation is one of the best gas reservoirs of Devonian basin located in the North-West of Argentina. In the Aguaragüe field, this natural highly fractured reservoir has produced a large amount of gas, even after most of the producing wells became watered-out. An excellent improvement of gas recovery factor has been achieved by the implementation of an unusual dewatering methodology. The method consists of applying a gas-lift production system to extract water from each flooded well. This type of exploitation causes a delay of the wells water encroachment and an increment of matrix gas production through the wells located at the top of the structure. In this paper we show the benefits of the implementation of this gas exploitation scheme as applied to the field. There have been numerical simulation studies performed in different stages of the exploitation and by different authors. The last study takes into account a vast gas and water production history. Different exploitation cases have been analyzed. The sensitivity scenarios presented here demonstrate the need and the benefits of dewatering. Introduction The Aguaragüe field is located in the Devonian basin to the North-West of the province of Salta in Argentina. This gas tramp is an anticline (Figure 1) originated by forces pushing from the West which generated a number of thrust faults. Huamampampa formation is a gas bearing, low porosity and highly fractured quartzite sandstone. This formation is one of the best gas producers in all the basin. Gas is produced through a network of natural fractures. The formation average section I (with layers BS1, BS2 and BS3), section II (layers BL1 and BL2) and Section III (layers BL3, BL4 and BL5) (Figure 2). BS2, BL1, BL3 and BL5 are the potential producer fractured sands, while the remaining BS1, BS3 and BL4 are considered as not producers layers. Almost all Aguarag e wells completed in Huamampampa produced gas only from layers BS2 and BL1. The field gas production started in 1979, with Cu.x-2 well, which had an initial rate of 500,000 m3/d. Since the discovery, 13 productive wells have been drilled in the structure, reaching a maximum field gas production of 4,000,000 m3/d in 1985 (Figure 3). At this stage the field produced very little water, that is associated to condensed water coming from the gas stream. However, the structurally lower wells had to be abandoned because of a sudden formation water intrusion. Since 1993 the advance of water has been evident and continuous, consecutively flooding wells located in an intermediate position. During the end of 1995 wells started to be converted to water producer through the implementation of an artificial gas-lift extraction system. Currently, only three gas producers remain active, besides a new well (Ag.ap-1001) is about to be completed in Huamampampa formation. At that time, when water started watering out the wells, gas production started to go down very quickly. So, after studies and a numerical simulation, the dewatering methodology was implemented. Thanks to this exploiting methodology we have gotten to keep gas production from crestal wells, and so increase the recovery factor of the field. Present Huamampampa gas production is around 1,000,000 m3/d, with a water rate of 1,400 m3/d coming from dewatering. Lately, we have made a numerical simulation work, which was used to study the reservoir drainage mechanism, dewatering performance and optimization. This model and its results are described below.

This paper will discuss the Managed Pressure Directional Drilling fit for purpose solution deployed to meet the drilling challenges in Mexico offshore Zaap field. This innovative solution integrates a new state-of-art Rotary Steerable System (RSS) with Managed Pressure Drilling (MPD) technology. Drilling hazards such as total losses, wellbore instability and stuck pipe were mitigated, and an improved drilling performance with reduction of NPT as compared to other directional drilling systems. The solution requires the integration of two highly technical disciplines, MPD and Directional Drilling (DD). Hence, a Joint Operating & Reporting Procedure (JORP) and a defined communication plan are crucial for the effective execution. The solution is based on a rigorous Drilling Engineering process; including detailed offset wells analysis to deliver a comprehensive risk assessment & mitigation plan in collaboration with the operator to tackle drilling hazards without compromising the directional drilling requirements. The paper will also discuss the effective communication plan between the directional drilling services, MPD services and rig contractors to ensure safe operational alignment. Also, the paper includes a planning and operational blueprint to reduce NPT related to total losses, stuck pipe & wellbore instability, increase drilling performance (ROP improvement) and quality wellbore for liner run afterwards in the Middle Cretaceous formation. Drilling challenges in the Zaap field requires the utilization of both Directional Drilling technology and MPD techniques to improve drilling performance and reduce NPT respectively. Through processes, best practices and lesson learned, this paper hope to serve as the bellwether for the combined solution to achieve technical limit drilling performance in the Zaap field, offshore Mexico.

Given the increased demands on the production of hydrocarbons and cost-effectiveness for the Operator's development wells, the industry is challenged to continually explore new technology and methodology to improve drilling performance and operational efficiency. In this paper, two recent case histories showcase the technology, drilling engineering, and real-time optimization that resulted in record drilling times. The wells are located on shallow water in the Gulf of Mexico, with numerous drilling challenges, which typically resulted in significant Non-Productive Time (NPT). Through close collaboration with the Operator, early planning with a clear understanding of offset wells challenges, well plan that minimize drilling in the Upper Cretaceous "Brecha" Formation were formulated. The well plan was also designed to reduce the risk of stuck pipe while meeting the requirements to penetrate the geological targets laterally to increase the area of contact in the reservoir section. This project encapsulates the successful application of the latest Push-the-Bit Rotary Steerable System (RSS) with borehole enlargement technology through a proven drilling engineering process to optimize the drilling bottomhole assembly, bit selection, drilling parameters, and real-time monitoring & optimization The records drilling times in the two case histories can be replicated and further improved. A list of lessons learned and recommendations for the future wells are discussed. These include the well trajectory planning, directional drilling BHA optimization, directional control plan, drilling parameters to optimize hole cleaning, and downhole shocks & vibrations management during drilling and underreaming operation to increase the drilling performance ultimately. Also, it includes a proposed drilling blueprint to continually push the limit of incremental drilling performance through the use of RSS with hydraulics drilling reamers through the Jurassic-age formations in shallow waters, Gulf of Mexico.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper describes the successful experience obtained in the use of electric submersible pumps (ESP) in the production of abrasive and corrosive fluids. The study covers 114 ESP wells completed by Harvest Vinccler, in the Uracoa and Tucupita Fields, located in the state of Monagas, Venezuela. This artificial lift method was initiated in July of 1996. Most of the failures were due to electrical failure, erosion (sand) and corrosion problems. The initial mean-time-between-failure (MTBF) of 250 days, has improved over time to 1752 days. The following are actions, which have improved the ESP MTBF: 1-An exhaustive study of the root cause of failure. 2-A new ESP design. 3-Monitoring of ESP performance. 4-The use of special abrasion/corrosion resistant alloy materials in ESP components and completion equipment. 5-Down-hole injection of de-emulsifiers, corrosion and scale inhibitors through capillary tubing, coupled with a well integrity monitoring program. 6-Improved quality and reliability of the electrical power source. All of these actions combined have enabled optimization of ESP applications in these fields. This study will present the details of the actions and their results, to achieve the optimization of ESP's in Uracoa-Tucupita Fields.