An Improved Method for Heavy Oil Fields Production and Cost Optimization

Uzcategui, Elio Antonio (Maraven) | Vasquez, Hebert Ramon (Maraven)

OnePetro 

Abstract

Electricity, pumps and rig time are the major costs associated with beam pump artificial lifting method in heavy crude oil.

In reducing operation costs, which are mainly associated with sand production, high viscosity, high GOR and rod flotation, Ma raven has successfully tested the progressive cavity pump in Bolivar Coast progressive cavity pump in Bolivar Coast fields.

The application of the method has reduced energy consumption over 60%, increased well production an average of 12% and reduced rig production an average of 12% and reduced rig activity sore than 40% in extraheavy and heavy type crude oils. This equipment was also tested in extraheavy oil slanted wells with excellent results.

The application of this method through an in house computer program has saved 10 million dollars/year in Maraven operational costs. It is expected to extend this program to other areas.

Introduction

The Bolivar Coast fields are located in the east side of lake of Maracaibo. These fields are characterized by a variable viscosity crude (100 - 60000 cps) with gravity in the range of 9 deg. - 21 deg. API. The reservoir produces by depletion and compactation mechanism and is normally lifted by a conventional beam pumping system. Intensive activity is required to pull and run

plunger due to problems associated with the plunger due to problems associated with the high viscosity of the oil and sand content.

Numerous solutions to handle these production problems have been attempted with production problems have been attempted with various degree of success. The most prevalent remedies have been the use of heavy pony rod and gravel-pack completion, which increase the stroke of the travelling pump and reduce the influx of loose sand with adequately selected gravel held in place by screens.

Production problems attributed to high viscosity are broken rods and polish rod, pump and gear box damage by hitting, low pump and gear box damage by hitting, low production, etc. that normally cause production, etc. that normally cause premature hoist entry which considerably premature hoist entry which considerably increased production costs.

In order to reduce operating cost, alternative lifting methods were investigated. The progressive cavity pump being one of them. This equipment consist basically of a rotary type positive displacement pump driven by standard API sucker rods. A motor installed at the wellhead transmits the rotational movement to the subsurface pump.

The advantages of progresive cavity pump system are related to its capacity to move fluid continously, contrary to beam pump which produces only on up-stroke c.g. or one half the time. This results in better efficiency in handling sand and gas problems.

PROGRESSIVE CAVITY PUMP SYSTEM DESCRIPTION PROGRESSIVE CAVITY PUMP SYSTEM DESCRIPTION A diagram of the complete equipment is shown in Figure 1.