In-Situ Steam Generation A New Technology Application for Heavy Oil Production

Abstract

The recovery of unconventional oil such as heavy oil is receiving great interest as the world oil demand is increasing along with relatively high oil prices. Producing such high viscosity oil is complex and challenging, which usually require thermal techniques. Thermal recovery methods are widely used to recover the heavy oil and bitumen basically by thermally reducing oil viscosity, improving the mobility ratio and enhancing the heavy oil displacement. In response to the recent effort of leveraging heavy oil and tar plays in Saudi Arabia, Saudi Aramco has launched a new thermochemical research program to tackle challenges associated with lowering oil viscosity to improve well productivity and the overall reservoir depletion efficiency. One of the promising new technologies is enabling in-situ steam generation by chemical reaction (EXO-Clean) to mobilize the low API crude oil or tar reserves. In this paper a new steam flooding methodology will be introduced and compared with existing technologies. Steam will be generated in-situ by chemical reactions, which will have better efficiency and lower cost compared to conventional steam injection methods. Simulation study, lab experiments, and field treatment showed great promises of the technology. The developed EXO-Clean treatment relates to in-situ steam generation to maximize heat delivery efficiency of steam into the reservoir and to minimize heat losses due to under and/or over burdens and non-producing areas. The treatment consists of injecting exothermic reaction-components that react downhole and generate in-situ steam and nitrogen gas. The generated in-situ steam and gas can be applied to recover deep heavy oil, and tight oil reservoirs, which cannot be recovered with traditional steam injection methods.

Gas Production from Gas Condensate Reservoirs Using Sustainable Environmentally Friendly Chemicals

“…Solutions of ammonium chloride (NH 4 Cl) and sodium nitrite (NaNO 2 ) were used as thermochemical fluids, and the chemical reaction was triggered using an acid. The chemical reaction during thermochemical injection can be represented by Equation (1) [18,26,27]:…”

“…Injection of thermochemical fluids into gas condensate reservoirs can result in enhancing hydrocarbon production utilizing several mechanisms. The injected chemicals are able to generate a significant amount of heat and pressure at the reservoir condition; the generated heat and pressure can reach to 644.3 K and 34.5 MPa [18,26]. The induced heat and pressure change the behavior of the condensate liquid.…”

“…The chemical reaction is triggered only at the downhole conditions using the reservoir temperature or chemical activator. The thermochemical reaction can generate a significant amount of heat and pressure in situ, and the induced pressure and temperature could reach 5000 psi (34.5 MPa) and 700 • F (644.3 K), respectively [18].…”

“…Further, the thermochemical reaction can be triggered only at the reservoir conditions, which maximizes treatment efficiency and minimizes energy loss into the surrounding formations [26]. Theoretically, thermochemical reaction can generate pressures up to 5000 psi (34.5 MPa) and temperatures up to 700 • F (644.3 K) [18]. Additionally, injection of thermochemical fluids into tight formations does not induce any damage into the reservoir rocks, and no reduction in the reservoir permeability or porosity was observed [30].…”

An Experimental Study to Reduce the Fracture Pressure of High Strength Rocks Using a Novel Thermochemical Fracturing Approach

“…Through their experiments, they have found that thermochemical reduces the rock strength significantly which reduces the pumping pressure in a typical hydraulic fracturing job. Al-Nakhli et al [39] experimentally investigate the increase in production from heavy oil due to in situ generation of steam by applying new thermochemical technology. Al-Nakhli et al [40][41][42] also investigated the effect of thermochemical on different rock samples.…”