Polymer Injectivity Test in Bhagyam Field: Planning, Execution and Data Analysis

Abstract

The Bhagyam Field development is part of the Mangala- Bhagyam -Aishwariya (MBA) development in the Barmer Basin, Rajasthan, India. The Bhagyam field is a shallow field with ~12B dip, containing good quality fluvial sand(s), medium gravity crude with a viscosity gradient (vertically) in the oil column and low water salinity (~5000 ppm). The field is currently being developed using down-dip water injection. The effectiveness of the waterflood will be limited by the adverse mobility ratio and reservoir heterogeneities. A polymer injectivity test was conducted in two wells with two main objectives: (1) to establish injectivity within the designed surface pressure, and (2) establish the ability to prepare polymer solutions of the desired viscosity using produced water for re-injection (PWRI). Operationally, the test was conducted using a skid mounted unit with regular monitoring facilities in place. Surveillance activities included frequent spinner surveys, bottom-hole pressure measurements, fall-off tests and offset production well tests. Rigorous monitoring of injection water quality, polymer solution quality was carried out. An inline viscometer was used for continuous polymer viscosity monitoring. This was supplemented by periodic sample viscosity measurements using special samplers with chemical stabilizers. The test was conducted in two wells and important lessons have been learnt which would be incorporated during full-field implementation of a polymer flood in Bhagyam. The injectivity test establishes that polymer injection is viable in Bhagyam Fatehgarh reservoirs. A history matching exercise was carried out using a sector model extracted from our full-field simulation model. The effect of production and injection in offset wells was captured in the sector model. Local grid refinement enabled us to adequately capture polymer rheology. The modelled rheology was found to be in close agreement with laboratory data. The production history of the wells in the sector and vertical injection profile of the injector well was incorporated. We obtained a good history match of the injection bottom-hole pressures. This paper presents details of the polymer injectivity tests including bottom-hole pressure measurements, fall-off tests and production logging which were conducted during the tests. As PWRI was utilized for preparing polymer solution, the effect of additives to the polymer solution viscosity was also analyzed. The test included use of not so commonly used equipment like inline viscometer, special samplers with chemical stabilizers, preparation of high concentration mother solution and injection of heated polymer solution.

Assessment of Polymer-Induced Formation Damage Using Microfluidics

“…A single-well injection/back-production implementation of polymer flooding showed important discrepancies in the polymer retention in the reservoir compared to laboratory tests using crushed material samples and coreflood samples (Juri et al, 2015). Polymer injection tests at the Bhagyam field experienced a steady increase in the injection pressure, possibly due to wellbore plugging (Kaladhar Sharma et al, 2016). Acid stimulation was used to revert the damage, though the injectivity deteriorated further with a continued polymer injection.…”

Development of novel mathematical models for laboratory studies of hydrolyzed polyacrylamide polymer injectivity in high-permeability conduits

“…If the polymer solution is too viscous, it may be extremely difficult, or sometimes impossible, to inject it into the formation (Seright et al 2018). Injectivity is therefore an extremely important factor to consider when designing any polymer flooding project since it has a direct impact on cost of the overall project and can impact safety as well if the formation is fractured during injection (Sharma et al 2016;De Simoni et al 2018).…”

Asp Injectivity Analysis as Preparation for Field Implementation

“…The injectivity of polymer during polymer fl ood have been investigated by Behr et al (2017) focusing on prediction of polymer Injectivity in damaged wellbore, Dupas et al (2013) wrote the impact of polymer mechanical degradation on shear and extensional viscosities: towards better injectivity forecasts, Glasbergen et al (2015) discussed injectivity loss in polymer fl oods: causes, preventions and mitigations. Seright et al (2008) about Injectivity Characteristics of EOR Polymers, Skauge et al (2016) presented radial and linear polymer fl ow -infl uence on injectivity, Sharma et al (2016) presented polymer injectivity test in Bhagyam fi eld, while Skauge et al (2016) investigates radial and linear polymer fl ow -infl uence on injectivity, and Yerramilli et al (2013) gave novel insight into polymer injectivity for polymer fl ooding.…”