Good solids-removal equipment operation, including that of shale shakers, helps prevent these problems.
Drilling waste can be stocked in the waste pit or collected by trucks or vacuum truck, and dumped near the site work for treatment.
Smooth operations of solids-separation equipment are accomplished with proper planning and utilization of the needed equipment to efficiently and effectively remove drilled solids from a drilling fluid. This chapter provides guidelines to ensure the smooth and efficient operations of solids-removal equipment and associated drilling-fluid equipment. This chapter is primarily directed toward rig personnel as a practical guideline for better drilling practices. Many of these suggestions and guidelines are discussed in much greater detail in other chapters of this book. This chapter consists of three sections: Solids Control Equipment Guidelines and operations of the various solids-removal equipment; Equipment Guidelines and additional thoughts and considerations for smooth operations of the various drilling-fluid handling equipment and tankage; Solids Management Checklist and questions to consider for proper sizing, selection, and operation of a solids-management system.
In general, thick shale sections cause problems with UBD. They slough or cave into the hole. This is probably due to thick shale sections having some elements of laminating, geo pressuring, or sensitivity to water. As a general rule, thick shale sections should not be drilled underbalanced. In the special case of air/gas drilling, shale usually remains stable as long as it is kept dry. Even the small amount of water in mist drilling will destabilize most shale. These formations need to be put behind casing within a few days. Watch out for excessive caving and especially long, thin cuttings. Once caving starts, it cannot be controlled with under-balance operations.