Production Increase with Electric Heating

SPE 159219

Production Increase with Electric Heating Production Line Technology in an Extra-Heavy Oil Field in Colombia: Successful Case of Flow Assurance

J.C.M Escobar-Remolina, SPE, W. Barrios, Ecopetrol S.A, B. Silva, Insurcol Ltd.

Copyright 2012, Society of Petroleum Engineers

This paper was prepared for presentation at the SPE Annual Technical Conference and Exhibition held in San Antonio, Texas, USA, 8-10 October 2012.

This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright.

Abstract

In recent years the oil industry has focused primarily on the exploitation of heavy and extra-heavy oil reservoirs. On the other hand these crudes represent current worldwide one of the greatest potential contributions to reserves to the energy industry. The production, treatment and transportation of these crudes are a real challenge, because these crudes increase the viscosity exponential from the reservoir to the gathering collection plant. This causes a dramatic increase in the well pump pressure system, reducing the production capability of the lifting system and optimal management of fluids, resulting in lost in the flow assurance system committing millions of dollars annually in non-effective remedial techniques. This article describes a successful case of flow assurance technology application to an extra - heavy oil of 9.0 ºAPI, using electric heating of the well production line along 900 meters in a Colombian oil field. The selected well to apply this technology increases its daily oil production over 160%, well head pressure decreases 95%. Chemical dosification was optimized and BS&W values required by the control system were reached by heating technology. Additionally, lighter crude of 25 ºAPI, used as a diluent, to move this extra-heavy oil through the production line was avoided in 100%.

Introduction

Extra heavy crude oil transportation in the oil industry, presents operational problems in the well production system because the dramatic increase of the viscosity due to the temperature decrease from the reservoir to the surface (Ehlig-Economides, 2000; Trebolle, 1993).

Flow Assurance specialty has matured and currently involves a definition of activities, which include planning, development, implementation, maintenance and operation of technologies and strategies to ensure that the barrels of oil are produced, transported and processed in a clean way (without loss of life) and friendly to the environment. In the extra heavy oil production world different methods or technologies have been used to reduce the viscosity of these non conventional crude oils to give them better mobility throughout the pipes from the reservoir to the delivery points. In this way the drawbacks and associated financial losses has been reduced. The most applied technologies on viscosity reducers are: dilution, water-oil emulsions, increase and / or maintenance of temperature (Barrufet, 2003; Kokal and Al-Juraid, 1999; Abney, 2010).

This paper describes a successful application of Flow Assurance Concept (FAC) using an Electrical Heating System (EHS) to increase and maintain the temperature of a 9 ºAPI crude oil on a well gathering production line at the surface over 900 meters in an oil field in Colombia, South America. The first part of the paper is a general description of the oil field, the gathering system and fluid rheological properties. The second part of the paper an Electrical Heating System (EHS) application is presented. Technical results are presented at the end of the paper.

Tisquirama Field (Well-T1)

Tisquirama field is located in the Middle Magdalena Valley, Department of Cesar in Colombia (Figure 1). The wells of this field produce from Lisama Formation, located at 8800 feet approximately. The sands of this formation produce crude oils

2 SPE 159219

between 27 ºAPI and 9ºAPI. The oil produced by the well T1 has 9ºAPI, this crude oil is classified as extra-heavy crude, its

viscosity is around 47800 cp at temperatures of 104 ºF, this viscosity does not let this crude been pumped through the

gathering line of the well and the fluids alone never reached the treatment and collection station of the field. Since the

beginning of the production life of well T1 the produced fluids were pumped by using dilution fluids from the wells T2 and

T3 (16-27 ºAPI). Always the production of this well was a challenge for the State Oil Company Flow Assurance Group

(FAG), so this group analyzed the feasibility to install an EHS along the well gathering line. The line length of the line was

about 900 meters. Table 1 shows the characterization and properties of the fluids of the wells T1 and T3 (crude that serve as

diluent). Table 1 shows dramatic changes in the viscosity of the crude oil produced by well T1 as a function of temperature,

which greatly affects their rheological changes and high asphaltenes content by weight (9.5 Wt%), this value is not an

indication that the asphaltenes can precipitate, but can be destabilized using a diluent of lower density (de Boer, 1995).

Well Flow Line path

Tisquirama treatment station is 900 meters away from the well head T1. Well T1 delivers its production to the collection

station by a 4” diameter pipe as a flow line. Figure 2 shows the complete path of this pipe (thicker line). The arrows indicate

the points where temperature sensors were located. Additionally, Figure 2 shows four points that indicate the coordinates of

distance from the wellhead and the respective temperature. After installing the EHS technology, we observe the temperature

gets a maximum value of 198 ° F at a distance of 356 m and a minimum temperature of 137 ° F at a distance of 150 m (see

figure 6). Initially (without EHS), all temperature facilities ranged between 104ºF (at wellhead) and 94ºF (at treatment

station), according to Table 1 crude oil well T1 has a viscosity of 47800 cp, causing severe flow assurance problems (the

fluid did not flow through the well flow line even at pressures above 800 psi.).

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