Thermal oil pumps
To produce enough oil in the decades ahead to meet global demand, the oil industry must find new ways of improving the recovery factor (RF) of existing ones.
The main methods, known as Primary and Secondary Recovery, include natural flow, lifting techniques such as Progressive Cavity Pumps, and water or natural gas injection to maintain reservoir pressure. The next category of methods is called Enhanced Oil Recovery (EOR) -- also known as Tertiary Recovery. Thermal Recovery is the most widely applied method EOR. Heat is introduced into the reservoir by steam injection, in order to improve the oil displacement inside the reservoir.
The existing main in-situ methods involve include thermal activation using:
- Steam (SAGD – Steam Gravity Assisted Drainage, CSS – Cyclic Steam Simulation or steam drive)
- Electrical heating (ET DSP electro thermal dynamic stripping process)
- Combustion (THAI toe to heel air injection)
- Solvent injection (VAPEX vapor extraction).
In thermal EOR, the key challenges are minimizing the steam/oil ratio (SOR), which indicates the energy spent per barrel produced, and increasing the recovery factor (leaving as little oil as possible in the reservoir when the well is abandoned). PCM Vulcain™ high temperature package is the suitable thermal oil pump to meet the different requirements of all thermal recovery methods.
Thermal EOR- SAGD challenges
Steam assisted gravity drainage (SAGD) involves the injection of steam into the reservoir to assist the heavy oil recovery by reducing the oil viscosity and improving its mobility. Two horizontal wells are drilled, one above the other. Steam is injected into the upper well to heat the oil so that it can drain down into the bottom producer well. The oil is then pumped to the surface with an artificial lift system.
SAGD process requires high capital investment and operating costs. The right artificial lift technique used is an important part of the success factor for improving thermal heavy oil recovery economics.
To overcome high temperatures, low to high operating viscosities and multiphase content, the technical challenge is to find a specific PCP technology to eliminate chemical and thermal degradation of elastomer stators. For low pressure SAGD featuring low pump inlet pressure, a reliable artificial lift offering low submergence is of the essence. The AMPCP developed by PCM answers all those needs.
Water resource and energy consumption require low steam-to-Oil ratio process. Meeting the challenges of thermal recovery also involves supporting the environment through low power consumption equipment with small profile that easily blends into the surroundings.
Thermal EOR -CSS challenges
Cyclic Steam Stimulation (CSS) or “huff and puff” technique is a three stage common thermal EOR. A single well is used to inject steam into a heavy-oil reservoir to heat the oil and reduce its viscosity. After a “soaking” period, the production phase can start and when the well productivity is too low due to the cooling of the reservoir, steam is re-injected to begin a new cycle.
Main lift difficulties are the high fluid temperatures, important viscosity changes and flow rate variations during production cycle from high to cold reservoir temperature. All elastomers used in PCP will experience accelerated deterioration with exposure to high temperature. Highly versatile artificial lift is required to handle a wide range of operations conditions of the CSS.
CSS is less capital intensive than SAGD as it can use existing wells to convert into thermal wells. However, CSS thermal heavy oil recovery involves high capital expenditures to fit with high temperatures conditions and high operating costs due to steam generation
Minimizing energy consumption and CO2 emission as well as minimizing work over on stimulated hot wells is in line with HSE requirements while meeting business savings.
Why choose PCM for the thermal EOR recovery?
Another essential aspect when it comes to artificial lift is to find solutions that can remain efficient across a wide range of temperatures. Temperature variations are greatest in CSS applications (from steam above 250°C to almost cold production), and also during the warming period of a SAGD well. PCM Vulcain™ offers this versatility.