Link SEMS Sensor

Estructural System 1

Estructural System 2

Estructural System 3 (as in Fig. 2)

Fig. 1

Drilling or Oil Extraction Rig

SEMS sensors

TensionLeg

SEISMOGRAPH

Blowout Preventer

SEMS and EXTRACTION of HIDROCARBONS

The following implementation of the SEMS System in the field of oil and gas extraction is the most obvious example among many utilities in this sector. This example would be based on dividing the entire operating system in three Independent Structural Systems (Fig. 1 and Fig. 2)

a) Structural System 1: The formed by the platform or ship of drill/extraction. b) Structural System 2: The formed by the outer pipe of drill/extraction. c) Structural System 3: The formed by the geological structure or soil containing the oil site, valves (BOP) and underground pipes of drilling or extraction.

Each of the three systems have their own SEMS (Structural Elasticity Measurement System), which all together would form the overall network of measures of the three structural systems by the interrelationship of all measures.

In this application the Structural System 2 would be used as sensor for the exact alignment of the three structural systems, as well as detector of malfunctions in Structural Systems 1 and 3. For greater clarity, in the Structural System 1 we take only one SEMS Sensor (Link SEMS Sensor) as in Fig. 2.

In this regard it is worth recalling the accuracy of the existing sensors on the market, where the tilt (or rotation angle) of 1º is equivalent to one hour whici is divided into 3600 seconds or parts, reaching measuring of tenths of seconds, according with Accuracy of Clinometers specifications.

In general, the pipe system is which is subjected to more fatigue by the variations of tension in the tube by internal pressure (hydraulic) due the oil extraction and due the vertical oscillations by the variation of the wave’s height. We also must consider the manipulations of the tubes, the fouling and the internal oxidation.

Moreover, the flexible pipes due to their elasticity would become ideal sensors to detect in advance any elastic variation, due to any geological or electromechanic variation which may produce a minor damage or failure, preventing said initial failure end up in a catastrophic accident.

Accuracy of Clinometers

Type of Sensors 1 and 2 SENSOR 1 SENSOR 2

Angular Range +/- 600 seg. 0 – 360º

Resolution 0,1 seg. 2 seg.

Máx. Error (Precisión)0,2 seg. +

3%10 seg.

Fig. 2 SEMS sensor over the surface of the oil well

Connection to PC

Estructural System 2

Seismograph

Estructural System 1

EstructuralSystem 3

Fig. 3 Fig. 4 Fig. 5

SEA CURRENT RESULTANT

Aº = Aº = 0º Aº = Aº Bº ≠ Cº

Aº

Aº

Aº

Aº

Cº

Bº

Fig. 6

0

Figures from 2 to 6 are based on the network formed by the Structural System 2 and Structural System 3.

The Fig. 6 on the left represents the network of measures between the Systems 2 and 3. The purpose of this network would be the record of all vibrations (elastic or micro-seismic waves) on the ocean floor produced during the drilling of the well in their advance, and the behaviour of said waves according to geologic layers or strata. Such registration would be made by sensors SEMS and with approved seismograph.

The aims is to identify the elastic (mechanical) characteristics of the geological environment where oil deposits are located, so in this way to determine accurately the influence or origin of possible earthquakes caused by the extraction of oil, gas, or use of such deposits as storage.

This network of measures is complemented with the measurements obtained by the Seismic Sensor SEMS (SSS) which is explained below according to Fig. 7 and 8.

Link SEMS Sensor

Link SEMS Sensor

Magma

Seismograph

Gas

Oil

Water

Danger Zone(Structural failure)

StructuralSystem 4(geological)

StructuralSystem 2

Vibrations

Seismic SEMS Sensor

Drill pipe

Fig. 7

Fig. 8

Seismograph

Danger Zone(Structural failure)

Vibrations

Seismic SEMS Sensor

Drill/Extraction Pipe

BOP(Blowout Preventer)

Gas

Oil

Water

Riser(Tubo de subida)

Fig. 9

Seismic SEMS Sensor

Drilling/Extraction Pipe

SEISMIC SENSOR SEMS (SSS) Said sensor (SSS) would be formed by a succession of SEMS sensors contained in a cylinder or tube of the same type used in the oil extraction (Figs. 7 and 8 in blue), which is placed as close as possible to the drilling pipe and before start drilling, to thereby capture all types of elastic waves (vibrations) produced by drilling, so that we could determine the type of seismic elasticity of the substrate or Geological Elasticity (GE) characteristic of that area. The sensor in turn would allow us to know in real time the variation of the tectonic forces and possible horizontal and vertical displacements of the geological layers.

While a Seismic Sensor (SSS) is capable of detecting any structural failures of the well, however this is not able to prevent them unless said Seismic Sensor (SSS) is integrated (attached or welded) over the well pipe (FIG. 9), which together with the BOP would be the critical structural system in preventing any uncontrolled oil spilling wich may end in a disaster, as happened with the Platform Deepwater Horizon of BP. Vibration: can also be defined as a periodic variation of the elasticity.

MIGUEL CABRAL MARTÍN