An Economic Early Production and Testing System for the Deepwater Gulf of Mexico

Abstract

ABSTRACT This paper presents the results of a study which was conducted to show that an Early Production and Testing System is technically feasible and can be economic under certain conditions, providing the oil price, well rate, and duration of production are adequate. An Early Production and Testing System (EPTS) is a collection of conventional offshore production equipment which is used to producecrude oil from wells which are drilled for the purpose of exploration. The system consists of: a subsea completion tree, a freestanding riser, a buoyant flowline and a moored vessel. The moored vessel provides support for the oil processing equipment and processed crude oil storage. Produced crude is offloaded into shuttle tankers for sale and thus the generation of, early cash flow. Besides the early production andcash flow, vital well productivity and crude characteristics are obtained. With the extended well testing, more data can be supplied for modeling the reservoir anddetermining the economics of potential field development. This information will lead to a more accurate characterization of the reservoir, and a better design of the permanent production facilities. EPTS for various water depths, well production rates, production durations and oil prices were evaluated for the Gulf of Mexico environment. A sensitivity study on these variables was conducted and the results were analyzed to give guidance on the economic use of an EPTS. The results of the study show that the EPTS can be designed using conventional offshore components andconstructed and installed at a reasonable cost. The concept appears to be technically feasible, even to 8,000 ft water depths. The EPTS can be economic and provide a positive cash flow, provided the well rate and production duration are adequate for a given oil price. Profits of tens of millions of dollars are possible. INTRODUCTION The successful development of an offshore oil field depends on having adequate information about the reservoir production characteristics and an accurate estimate of the field development costs. From thisinformation a decision can be made on whether or not to develop the field and the type of production concept which should be used, to be the most cost effective. An Early Production and TestingSystem (EPTS) is one method which can be used to supply information to make decisions on the reservoir'sproduction characteristics and what type of field development concept would be most cost effective. These systems are designed to remain on location during the exploration and delineation phase of a field development. The initial exploration well and subsequent delineationwells are produced for an extended period of time so that the wellproduction characteristics can be defined and the generation of an early cash flow can be established. The purpose of this study is to identify under what conditions it would be economically beneficial toconduct an extended test or establish early production utilizing an EPTS.