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PETROMAKS2-Stort program petroleum

Fishbones Post Acid Injection (FPAI) Modelling the effect of continuing acid stimulation post Fishbones jetting

Alternative title: Fishbones Post Syrestimulering Modellering av effekten av fortsatt syrestimulering etter Fishbones Jetting-operasjon

Awarded: NOK 3.7 mill.

Project Number:

328616

Project Period:

2021 - 2023

Organisation:

Location:

Partner countries:

Fishbones Jetting technology is a well stimulation technology that accelerates production of hydrocarbones from oil & gas wells, and can help increase recovery rates. The method involves generation of numerous laterals in the reservoir that drain the reservoir in an effective way. An analogue to this method is the roots of trees that have a lot of branches to maximize drainage of water from the soil. In a Fishbones Jetting operation, hydrochloric acid is pumped down the well to jet many small diameter tubes from the wellbore up to 12 meter into the reservoir. The underlying idea of the Fishbones Post Acid Injection (FPAI) project is to develop a Numerical Simulation Model to account for the rock dissolution caused by acid, while acid is jetted through to extend the needles into a hydrocarbon reservoir, and calculate consequent improvement in the well productivity, resulting from the additional flow area created by the rock dissolution by acid. This production contribution is in addition to the production created by the lateral holes themselves. As acid is distributed further in the rock, additional channels can develop leading to further increase in wells' productivity. The calculations will be based on empirical data from extensive testing in laboratory using formation rock samples.

The underlying idea is to develop a Numerical Simulation Model to account for the rock dissolution caused by acid, while acid is jetted through to extend the needles into a hydrocarbon reservoir, and calculate consequent improvement in the well productivity, often associated with a negative "skin", resulting from the additional flow area created by the rock dissolution by acid. This production contribution is in addition to the production created by the lateral holes ("needles") themselves. As the acid jets through carbonate reservoirs (e.g., chalk and dolomite), it is reasonable to assume a series of "wormholes" will be developed within the rock matrix, because of the rock dissolution by acid. The well productivity will ultimately be impacted by the length, diameter and distribution of wormholes created by the acid jetting. The wormhole geometry, path, and distribution are controlled by the heterogeneity of the pore network and the reaction kinetics between the acid and the minerals/rocks. The pore network is determined by nature. Engineers help to determine the reaction kinetics, that is, to balance the acid rock reaction rate with the acid injection rate. A dimensionless number is used to compare that, called Damkohler number (NDa = Rate of reaction / Rate of fluid flow).

Funding scheme:

PETROMAKS2-Stort program petroleum