Automatic Shaker Control

Abstract

Traditionally, shale shakers have been manually operated machines. Key constituents such as basket angle and acceleration are featured as either fixed or manually adjustable components, which tend to yield limitations with a shaker's screen life, flow capacity, and operator safety. This work proposes an automatic shaker control to adjust the basket angle, manage acceleration, and decrease operator intervention. In order to achieve automatic shaker control, a manual-style shale shaker design was modified with electronic sensors, an actuator, an on-board computer, and software to automatically control the fluid level on the screens. The computerized shaker system measures the fluid level on the screens, detects input flow, and measures the basket angle. The shaker then adjusts the basket angle and acceleration boost in order to control the fluid level on the screens. The shaker maintains the fluid level near a constant optimum value, which is set by the user. In low flow conditions, this proper fluid pool coverage of the screens promotes screen lubrication and reduces friction, which increases screen life. In high flow conditions, the fluid level control helps prevent whole mud loss. The automated shaker does not merely rely on basket angle control to manage high flow conditions. The automated shaker's arsenal against mud loss also includes an automatic boost and anticipation of new flows. The automatic boost feature temporarily increases the shaker acceleration (g-force) applied to the basket in order to process higher flow rates. Finally, when the input flow to the shaker stops, the basket is automatically tilted to the fully uphill position to prepare for the next flow. This decreases the possibility of sudden rushes of fluid from flooding the shaker before it can automatically adjust to a more uphill position. These shaker modifications maintain screen lubrication, increase screen life, and assist in the prevention of whole mud loss, all while reducing operator HSE exposure. Tests have shown that the automated shaker increases screen life, decreases operator intervention, and helps prevent whole mud loss. Automatic shaker control can operate a shaker near optimum. The benefits of this can lead to increased shaker performance and decreased expenses. Introduction A shale shaker is designed to quickly and efficiently remove solids from mud systems in the presence of changing drilling conditions. Optimal operation typically requires manual shaker adjustments to position the fluid endpoint at ¾ of the screening area, which leaves ¼ of the screening area to dry the cuttings. Sub-optimal operation can lead to lost whole mud (in high-flow conditions) and decreased screen life (in low-flow conditions). Traditional shakers rely on the operator to manually adjust the shaker according to the mud flow conditions by tilting the basket, adjusting the gates and valves, or turning shakers on and off to operate near optimum[1]. This can lead to potential HSE issues. These manual adjustments beckon the safety and efficiency of the automated shale shaker. This work describes the automatic shaker control that is necessary to maintain near optimal operation even under changing drilling conditions. The main features include automatically controlling the fluid end point by adjusting the basket angle, increasing the basket acceleration when necessary to prevent flooding, and preparing for the next flow. Sensors are placed in the shaker to detect the level of mud on the screens. The shaker basket angle is then adjusted to maintain the desired screen mud level, which in this configuration maintains the desired fluid endpoint. This results in increased screen life due to better screen lubrication. The automated shale shaker also detects conditions leading to flooding and will temporarily increase the g-force to process the higher flow rates[2]. Bailey (1998) used manually adjustable acceleration to temporarily increase flow rates[3]. When the shaker detects that the input flow has stopped, it tilts the basket to a maximum uphill position in anticipation of the next flow. At any time, the automatic features of this shaker may be bypassed by turning a switch, and the shaker will operate like a traditional manual shaker.

Proposta de uma malha de controle de umidade do sólido retido em peneira vibratória industrial

“…Poucos trabalhos disponíveis na literatura abordam o estudo de aspectos operacionais relevantes ao controle automático na peneira vibratória, tais como a posição da interface entre a região de piscina e praia (Dorry, 2010;Scott, 2006). A principal dificuldade reside na determinação precisa, em tempo real, do teor de umidade residual presente no material sólido retido, já que é difícil manter as condições operacionais constantes em aplicações industriais, o que causa muita variabilidade nas respostas obtidas, devido às oscilações no processo.…”

“…Isto fica claro no experimento 16, que apresentou a maior umidade residual dos sólidos retidos dentre todos os ensaios, 𝑈 = 25,64%, devido ao maior nível de frequência elétrica da bomba adotado nos experimentos, que resultou na vazão 𝑄 = 300𝑘𝑔/𝑚𝑖𝑛. Por esta razão, não se recomenda operar a peneira vibratória em condições de avanço da região de piscina maiores que 3/4 de ocupação da tela (Dorry, 2010;Scott, 2006).…”

“…Além disso, a Força-G é a única variável controlada e modificada facilmente na operação, com influência quase imediata sobre a suspensão sob separação pela tela. Já a vazão de alimentação não foi incluída por não apresentar efeito significativo para a ocupação de até 75% (3/4) da tela pela região de piscina, além de ser uma variável que não é controlada durante o processo de perfuração do poço de petróleo, resultando em flutuações na operação de peneiramento vibratório (Dorry, 2010;Scott, 2006). Quanto à inclinação do cesto, em alguns modelos de peneira vibratória ela é fixa por não haver sistema de regulagem de inclinação, justificando sua não inclusão no modelo (GN Solids America, [S.D.…”