Innovation of Tubing Conveyed Perforating Technology in the Agadem Field, Niger

Abstract

Tubing conveyed perforating technology is the main perforating method used in oil fields because of its unique advantages. For sandstone reservoirs development, the reservoirs alternate with sandstone and mudstone. There are often multiple perforated intervals with mudstone interlayers, ranging from 1–2 m to hundreds of meters, which is not required perforation. For shorter interlayer, usually use space gun to avoid the mudstone layer and transfer detonation wave.

Niger is a major oil and gas producer in West Africa. The Agadem, Bilma and Tenere blocks are being explored and developed, and the Agadem field is the largest one among them. According to the logging data, the average oil layer thickness of each well drilled in Agadem is 18–20 m, and the average single oil layer thickness is 2–3 m. It presents typical interbedded form of sand and mudstone. The perforation operations are faced with the problems of multiple layers and large span. For the mudstone interlayer with a span of 10m or more, the sealing reliability of the sealing parts of the space gun is very high, as well as the connection of the detonating cable between the guns and the reliability of the detonating tube. The large span often leads to the failure of detonating cable, and the perforating pipe string of the space gun cannot solve this problem well. It can only run perforating string many times in hole to shoot different zones in one well, which not only increases the operation cost, but also reduces the operation efficiency.

In order to solve the above problems, a new type of perforation joint was designed. The joint contained a perforating gun rack, which is used for fastening the joint of the upper perforating gun and the perforating joint. The technical effect is to reduce the tension of the string during running. There are two sealing ring grooving on the tubing transmission perforating multi-stage joint, and the sealing ring is installed before entering the well. The technical effect is to ensure that it is completely sealed with the upper perforating gun and that the well fluid cannot enter the upper perforating gun from the joint to affect the work of the detonating cord.

Based on the design and invention of multistage perforating joint, new tubing conveyed perforating technology was formed. The structure of the new tubing conveyed perforating is including tubing, initiators, upper perforating gun section, multistage perforating joint, lower perforating gun section and screwed plug, which are threaded connection from top to bottom. Through field test verification, it can replace the space gun with tubing and perforate multiple target layers in one trip, which reduces the number of single well perforating operations, reduces the operation cost and improves the overall operation efficiency. It can be regarded as a classic practice and has a strong reference value.

Copyright 2022, IFEDC Organizing Committee

This paper was prepared for presentation at the 2022 International Field Exploration and Development Conference in Xi’an, China, 16–18 November 2022.

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