Shale shakers are components of the solids control systems. Shale shaker mainly used in the oil and gas drilling industry. Shale shaker is the first phase of a solids control system on a drilling rig, and are used to remove large solids (cuttings) from the drilling fluid (“mud”).

Solids control may be defined as the control of the quantity and quality of suspended solids in the drilling fluid so as to reduce the total well cost.

The drilling cuttings removal equipment is often called solid-control equipment because it is mostly used for removing drilling cuttings in the mud returned from the borehole. Primary solid-removal equipment should include shale shakers, a degasser, a desander, a desilter, and a decanting centrifuge. All of these parts are installed on top of the mud tanks.

Impeller sizes are determined by calculating the TOR (sometimes called the time of rollover) for each compartment. This is the time, in seconds, required to completely move the fluid in a compartment (Table 10.1) and can be calculated by knowing the tank volume and impeller displacement:

TOR = (Vt⁄D)×60

where

. Vt=tank volume, in gallons or liters . D=impeller displacement, in GPM or LPM (as displayed in Table 10.2).

For flat and canted impeller applications, TOR should range between 40 and 85 seconds. As the TOR approaches 40 seconds, the chance for vortex formation and possible air entrainment increases. At values greater than 85 seconds, the proper suspension may be jeopardized and solids will begin to settle.

Table 10.1 Typical Turnover Rate Values, in seconds

Impeller Type

Removal

Addition

Suction

Reserve

Pill

Canted/flat

50-75

50-75

65-85

50-80

40-65

Table 10.2 60-Hz Impeller Displacement D Values

Diameter Flat Canted Contour

In

Mm

Gpm

1pm

Gpm

1pm

GPM

1pm

20

508

1051

3978

909

3441

N/A

N/A

24

610

1941

7374

1645

6226

N/A

N/A

28

711

2839

10746

2468

9341

5861

22185

32

813

4635

17543

3764

14247

N/A

N/A

38

965

7342

27789

6343

24008

10604

40136

40

1016

8411

31836

7284

27570

N/A

N/A

42

1067

N/A

N/A

N/A

N/A

13940

52762

44

1118

11300

42771

9928

37577

N/A

N/A

45

1143

N/A

N/A

N/A

N/A

16812

63633

48

1219

14401

54508

12512

47358

20020

75776

52

1321

18630

70515

16100

60939

24852

94063

54

1372

N/A

N/A

N/A

N/A

27602

104475

56

1422

N/A

N/A

N/A

N/A

30353

114887

60

1524

N/A

N/A

N/A

N/A

36567

138404

64

1626

N/A

N/A

N/A

N/A

43533

164771

For contour impeller applications, values must be significantly faster (i.e., smaller numbers) to achieve the same results, but because of the impeller design, air entrainment is less probable. In symmetrical compartments, the fluid has a nearly equal distance to travel from the center of the impeller shaft or from the impeller blade tip before it contacts the vessel wall. Agitators should be placed where the shaft is centered in the tank or compartment.

When defining the area in which to mix, it is best to work with symmetrical shapes like squares or circles (as viewed in a plan drawing or overhead view of the tank layout). Rectangular tanks should be converted to nearly square compartments if possible. Maximum fluid working volumes in compartments should not be higher than 1 foot (about 3⁄10 m) from the top of the tank. This will allow for a little extra capacity in emergencies, slightly out of level installations, and/or fluid movement on floating rigs.

Working volume for square or rectangular tanks is calculated by knowing dimensional values for length (L), width (W), and height (H; in feet for gallons, in meters for liters):

For gallons:

Vt = L × W(H− 1)× 7.481

The working volume for round tanks with flat bottoms is: For gallons:

Vt = Π r²(H−1)× 7.481

For liters:

Vt = Π r²(H−0.3)× 1000

For round tanks with dish or cone bottoms, calculations for working fluid volume are based on straight wall height (i.e., this height is measured from the tank top to where the tank joins the cone or dish at the bottom). This leaves adequate free space above the maximum fluid operating level. In all cases, if H<5 feet (1.5 m), a radial flow impeller should be specified.

Nine distinct mud systems are defined here. The first seven are water-based, while the eighth is oil-based. The ninth category is a specialized one in which air or gas is the continuous fluid. The 9 categories are:

The study of History is the beginning of wisdom. – Jean Bodin

The actual money saved by using correct drilling fluids processing is difficult to document. Most operators regard the cost of drilling wells as proprietary information.