Difficulties in Cementing Liners in Block Tambococha 43 and Corresponding Measures

The daily production rate of a single well in the Block Tambococha in Ecuador is from 300 t to 1,100 t. The casing program is special because of special production requirements; the distance between the running depth of the φ177.8 mm liner and the top of the reservoir is less than 30 m. Caliper logging data acquired from LWD are seriously distorted, making it difficult to determine the amount of cement slurry, and a high risk of cementing the φ177.8 mm liner exists. Previous practice shows that the job quality of cementing cannot be ensured if wiper trip is not performed prior to running liners, or a high displacement efficiency in narrow annulus cannot be obtained, or the oil and water in the reservoir are active. A rotating liner cementing technology for use in bottom water reservoirs in Block Tambococha was developed through designing of a compound spacer, studying on micro-expansion latex cement slurry as well as studying on the rotating liner cementing techniques for annulus of narrow clearance. This technology is helpful to run liner to the designed depth, to accurately determine the annular volume of an open hole section and to improve the casing centrality. The flushing efficiency of the spacer is 93%, and the 12 h compressive strength of the set cement slurry is 36.4 MPa. Application of the technology on 15 wells gave a rate of excellent cementing job quality of 95%, providing a technical support to the success of cementing narrowannular-clearance highly deviated wells for strong bottom water reservoirs and resolving the problem of cementing wells with special casing profile in Block Tambococha in Ecuador.