Shaker screens are components that directly contact drilling fluid and solid particles, resulting in a high failure rate that directly impacts screening efficiency, throughput, and drilling fluid recovery. Based on the actual operating conditions of oil well solids control systems (e.g., high temperature, high solids content, corrosive mud, high-frequency vibration), the following details the symptoms, causes, and solutions/preventions for these malfunctions.
What are the common malfunctions of shaker screens
Q1: Frequent clogging of the screen during use leads to a decrease in drilling fluid throughput. What are the main causes? How can this be resolved?
A1: There are four main causes of screen clogging: ① Mismatch between particle size and screen mesh size, resulting in large particle accumulation; ② High drilling fluid viscosity, causing fine particles to adhere to the screen openings; ③ Inappropriate vibration parameters, resulting in insufficient vibration force; ④ Insufficient screen cleaning, leading to residual particles clogging the openings.
Solutions: ① Replace the screen with a matching mesh to adjust particle distribution; ② Adjust the drilling fluid formula within the allowable process range to reduce viscosity; ③ Adjust the eccentric block angle or motor frequency to optimize vibration parameters and enhance the rapping effect; ④ Establish a regular cleaning system, rinsing the screen surface with high-pressure water or a special cleaning agent.
Q2: What factors are related to localized damage or tearing of the screen after short-term use? How to prevent and handle this?
A2: Factors causing localized screen damage: ① Poor screen quality, insufficient material strength, or defective weaving; ② Improper installation, resulting in loose or misaligned screens causing uneven stress; ③ Concentrated feed impact, with drilling fluid directly hitting the screen in certain areas; ④ Foreign objects such as metal shavings inside the screen frame scratching the screen.
Remedial Measures: ① Use high-quality screens from reputable manufacturers and verify their quality upon arrival; ② Install according to specifications, clean debris from the screen frame, and ensure the screen is flat and taut; ③ Add a buffer plate to the feed inlet to ensure even distribution of drilling fluid; ④ Repair small damage with special adhesive, and immediately stop the machine and replace the screen for large-area damage.
Q3: Operators can resolve the shaker screen’s misalignment, where one side of the screen surface is tight against the screen frame while the other side is raised.
A3: Screen misalignment stems from unbalanced forces, with three possible causes: ① Improper adjustment of the tensioning mechanism, resulting in uneven tension on both sides; ② Asymmetrical angle of the eccentric blocks on the vibrating shaft, leading to inconsistent vibration amplitude of the screen frame; ③ Feed offset, causing prolonged impact on one side.
Solution steps: ① Stop the machine and adjust the tensioning mechanism to ensure consistent tension on both sides. After adjustment, test the screen to confirm stability; ② Check and calibrate the angles of the eccentric blocks on both sides until they are consistent; ③ Adjust the feed guide device to ensure the drilling fluid falls onto the center of the screen surface.
Q4: After a period of use, the screening efficiency of the screen decreases significantly, but no obvious blockage or damage is found. How can the screening efficiency be improved?
A4: The decrease in screening efficiency without obvious damage or blockage may be due to: ① Screen aging, reduced wire elasticity, and poor vibration transmission; ② Vibration parameters not matching the current operating conditions; ③ Inappropriate screen inclination angle, resulting in abnormal drilling fluid residence time; ④ Large gap between the screen and the screen frame, causing a “short circuit”.
Improvement measures: ① Replace the screen if the wires are loose or deformed; ② Readjust the vibration parameters according to the drilling fluid viscosity and solids content; ③ Adjust the support feet according to the instruction manual, setting the inclination angle to 15°-25°; ④ Replace the sealing strip or adjust the screen to prevent “short circuits”.
Q5: In a shaker screen using multiple screen sets, some screens fail prematurely while others continue to function normally. How can this “localized failure” problem be solved?
A5: The core issue of localized failure in multiple screen sets is uneven load distribution. Reasons include: ① Improper screen mesh matching, with the preceding stage failing to trap large particles, leading to overload impact on subsequent stages; ② Poor screen surface connections, with steps or gaps causing concentrated pressure on accumulated liquid; ③ Inconsistent screen tension, with loose screens causing particle accumulation.
Solutions: ① Match screens according to the “coarse to fine” principle to reduce the load on subsequent stages; ② Repair joints, replace seals, and ensure a smooth screen surface; ③ Unified tension adjustment of all screen sets, establish replacement records, and shorten the inspection cycle for vulnerable parts.
Screens are key components of shale shakers, directly affecting the screening efficiency of oil equipment. Drilling operations frequently use screens in vibrating shakers and consider them wear parts. Therefore, operators should inspect them regularly and keep spare screens on hand for timely replacement.The screens provided by HL Solid Control can replace Swack screens and have API certification. The company has sold them to many countries abroad, and customers have rated them as a high-performance, cost-effective option.
