Nitrogen Huff and Puff: Novel Method for Enhancing Liquid Production in the Brown Fields of the Mehsana

Abstract

Abstract Nitrogen cyclic stimulation is a three-stage process, which involves nitrogen injection, soaking, and production for a well. Due to low solubility and dissolution, large amount of nitrogen remains as free gas at high pressure during injection phase. In production phase, oil production rate is high due to various recovery drive mechanisms. The paper will discuss in detail about the changes taking place in the injected nitrogen and reservoir fluid. It will also bring out the challenges faced in implementing this novel technology. The breakthrough cases are discussed with the probable recovery mechanism. Nitrogen Soaking time is increased to reduce the pressure depletion at the early stage of each cycle. Oil recovery is enhanced by taking advantage of gas cap, gravity differentiation and free gas to oil production. The pressure depletion can be increased at the later stage of each cycle to take full advantage of the solution gas drive and to form a stable foamy oil flow. Nitrogen is more suitable for early application of the cyclic stimulation process. It not only has low cost and good recovery efficiency but can also keep high gas oil contact. Results are quite encouraging for heavy oil fields as compared to light oil fields. This method can be potential choice to the operators for increasing oil production with minimum water cut. Nitrogen cyclic stimulation is highly efficient techno-economic process. The Asset has realized cumulative gain of 14501 m3 in 52 production wells with reduction in average water cut from 92% to 58% and cumulative nitrogen injection of 2730 KL. The parent company is maintaining the ratio of oil produced to nitrogen injected at 5.3, indicating higher oil gain with the minimum quantity of the nitrogen injected. The Asset is planning to implement this technology at wide scale.