Abstract

This paper discusses drilling the She Murphy USA 22-7, a 23,455-foot Jurassic wildcat located in Wayne County, Mississippi. This well is extraordinary from several standpoints:

- a new state depth record was reached;

- two very severe and nearly instantaneous kicks with a flowing capacity in excess of 70 BPM were successfully brought under control;

- 3,551 feet of 4 1/8" slim hole was drilled with ultrahigh mud weights, 19.2 to 20.3 ppg, in an underbalanced condition, and

- a flow test of a high pressure (8,300 psi shut-in) salt water zone was conducted.

This report presents a chronological history of the Shell-Murphy USA 22-7 and discusses the drilling techniques that were successfully used to bring the well to total depth. In addition, the author's thoughts will be presented on the source of the ultrahigh pressures and other phenomena peculiar to this pressures and other phenomena peculiar to this well.

Introduction

In late 1969 there were two areas in Mississippi where wells deeper than 20,000 feet were being drilled, in the central part of the state around the Jackson Dome and in southeast Mississippi in a piercement salt wall province (Fig. 1). In both areas the objectives were the Smackover and Norphlet formations (Jurassic age). To date one of the most difficult wells to drill was the Shell-Murphy USA 22-7, a Wayne County, Mississippi wildcat located in the salt wall area.

Deep, high pressure sour gas wells are in themselves unique but do not individually deserve special reports. General drilling and completion practices for such wells were outlined in a previous reported However, this well is extraordinary from several standpoints:

- a new state depth record, 23,455', was reached;

- two severe and nearly instantaneous kicks (3,700 and 2,400 psi shut-in drill pipe pressure) with a flowing capacity greater than 70 pressure) with a flowing capacity greater than 70 BPM were successfully brought under control;

- 3,551' of 4 1/8" hole was drilled with ultrahigh mud weights (19.2 to 20.3 ppg) in an under-balanced condition; and

- a flow test of a high pressure zone was conducted.

This paper presents a chronological history of the USA 22-7 and outlines the drilling techniques that were successfully used to bring the well to total depth. In addition, various thoughts are presented on the possible source of the ultrahigh pressures and other phenomena peculiar to this well. peculiar to this well.

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