SANJEL ENERGY DELIVERS GAS MIGRATION CONTROL IN SOUTHEAST ALBERTA GLAUCONITE
The Glauconite member of the Mannville formation in southern and central Alberta is a major producer of hydrocarbons. However, for operators to be profitable in this area wells need to be drilled and completed economically. Shallow gas formations, such as the Milk River and Medicine Hat formations, used to be the primary target of vertical shallow gas drilling in the 1990s and early 2000s but in recent years this has changed. Now, operators are targeting specific oil formations and drilling deeper and strategic steps must be taken to ensure that this does not result in gas migration and surface casing vent flows (SCVFs).
Cements covering the shallow, gas pressurized formations must be able to withstand the stresses of multistage fracturing treatments and not compromise vertical well isolation. These shallow formations have traditionally been problem areas on both surface and production casing jobs with low well temperatures making it difficult to achieve all desired slurry properties. This is especially true when seeking a short critical interval and early compressive strength while utilizing slurries with the lower densities desired by the industry.
Sanjel Energy’s SURFACEmix THX is an aggressive 1725 kg/m3 surface blend that contains an additive mixture not typically run in surface slurries. With the addition of fluid loss control and post set expansion minerals it effectively creates isolation in both the slurry and set cement forms. SURFACEmix THX delivers early compressive strength development and is high thixotropic with a short critical interval. Once placed, it resists gas or fluid inflow and prevents slurry fallback from surface. Reduces equivalent circulating density lowering stress on formation while pumping.
Additional blends that are ideal for this region include:
- PRODUCTIONmix 1600: A high solids blend with low fluid loss, post set expansion and short critical interval used as a lead cement to cover the shallow gas zones found between 300-700 m. It includes a mixture of supplementary cementing materials that create a cement designed to resist the cyclic stresses of the completion activities.
- iBond: Used as the liner cement or monobore tail cement in the Mannville group of formations, it is a premium production cement for low-temperature laterals. It provides superior horizontal isolation along the required producing intervals and works well with all current completion methods.
- Drastically reduces occurrences of gas flowing up surface annulus
- Delivers early compressive strength development in all casing strings to prevent the onset of problems with annular isolation
- Reduces likelihood of gas flow occurring post fracturing operations
- Achieves superior cement bond logs
- Provides long term well integrity with lower frequency of gas flows in surface vent originating from intermediate or production casing annulus
- Reduces cement costs contributing to a healthy return on investment