Improving the efficiency of water shut-off treatments at late stages of oil fields development
The paper considers various approaches to improving the economics of water shut-off treatments conducted with the aim to combat the problem of channel flows behind the casing (cross-flows) both in production and injection wells. A case study of water shut-off jobs on the Vostochno-Leningradskaya area of the Romashkinskoye oil field helped classify the most common scenarios of annular seal failures and casing leaks. The study has demonstrated poor efficiency (low success rate) of currently available water shut-off technologies, particularly for remedy of behind-the-casing fluid migration problems outside the perforation interval. Selection of treatment targets is proposed based on maximum water use ratio, which does not exceed 0.7 as applied to geological and physical conditions encountered on the Vostochno-Leningradskaya area. This screening criterion is introduced due to its strong correlation with oil recovery factors intended for five blocks on this area.