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Multilateral drilling technology has been used in many heavy-oil developmental projects to achieve maximum reservoir exposure from a single surface location. The wellbore geometry and completion strategies for multilateral wells are planned and customized to fit the known reservoir characteristics and sand distribution qualities. Typically, heavy oil reserves are found in unconsolidated sandstone reservoirs that require some form of sand exclusion strategy across the reservoir as well as at the lateral mainbore junction interface. In heavy-oil sand, effective sand-control strategies must be carefully planned since one of the difficult problems to address in heavy-oil targets is their natural tendency to suspend formation solids, often referred to as Basic Solids and Water (BS&W) solids. An effective sand control strategy should allow these solids to be produced to surface and separated by the production facility. The remainder of the solids can be controlled, based on the sand-distribution qualities. If the formation sand is uniform, liner-only completions can be used for effective sand exclusion without sacrificing rate. If the formation sand is non-uniform, gravel packing will be required. For this reason, regardless of the well scenario, the gravel pack or liner only completion should allow BS&W solids to pass through and be produced to the surface. Most heavy oil development areas use artificial lift such as PCP and ESP pumps. All multilateral completion strategies must always consider the lift strategy, the ID requirements for pump deployment as well as necessary sand exclusion requirements for the pump. The paper examines successful multilateral completion strategies used in heavy-oil development projects in Canada, Trinidad and Venezuela. It will also explore new synergistic technologies that will impact future development strategies. |
