The objective of this work is the prediction of water salinity evolution trend for Mexico Area-1 development that foresees the injection of a mixture of seawater and produced water from the six different reservoirs connected to the same FPSO.
Prediction of salinity trend evolution is crucial for forecasting possible biogenic hydrogen sulphide (H2S) formation and foreseeing the relating impacts over completion and facility material selection and on health, safety and environment (HSE) management.
Traditional numerical simulations through stand-alone models do not consider the effects of the reciprocal interaction among the fields on production profiles and are not able to simulate salinity evolution of produced and injected water mixture, variable over time. To overcome this limit, a new tool was developed. It consists in a python script that, introduced into the Area-1 Integrated Asset Model, allowed to generate forecasts of the water salinity along the project lifetime. These simulations were essential for souring risk assessment, providing the following results: water salinity trend evolution at each injector well; water salinity trend evolution at each producer well; injection water breakthrough timing at the producer wells.
water salinity trend evolution at each injector well;
water salinity trend evolution at each producer well;
injection water breakthrough timing at the producer wells.
Moreover, it gave the opportunity to assess the injection strategy efficiency and to quantify the impact of changing salinity on water viscosity and on the field recovery.
In conclusion, the innovative methodology applied in the Area-1 IAM (Integrated Asset Model) permits to predict the salinity of injected water and to foresee salinity evolution of produced water generating several valuable information, providing a flexible tool that allows to investigate simultaneously several uncertainties related to the project and to evaluate promptly solutions and mitigation.
Moreover, when the reservoirs will be on production, the numerical models integrated with the developed script will reproduce the historical salinity data allowing to identify preferential flow path established by fluids virtually acting as a reservoir tracer technology.
In this paper, we present for the first time, a classification system for naturally-occurring gas hydrate deposits existing in the permafrost and marine environment. This classification is relatively simple but highlights the salient features of a gas hydrate deposit which are important for their exploration and production such as location, porosity system, gas origin and migration path. We then show how this classification can be used to describe eight well-studied gas hydrate deposits in permafrost and marine environment. Potential implications of this classification are also discussed.
Naturally occurring seafloor hydrocarbon macro-seeps are important indicators in deepwater exploration programs. They provide strong evidence for the presence of a working petroleum system and in theory should provide insight into the contents of the subsurface reservoir, its relationship with previously discovered hydrocarbons, and some of the characteristics of the source rock that generated the oil, all before any wells are drilled. However, in practice the hydrocarbons need to be relatively intact and free of any chemical interference to accomplish these tasks and this is not always the case. There are many physical, chemical, and biological processes in the marine environment that can obscure, diminish, or destroy the geochemical information carried by seeped hydrocarbons. In the light hydrocarbon fraction (C1-C4), microbial processes such as anaerobic oxidation of methane and methanogenesis can alter both the composition and isotopic signature of the seeped gases. For the high molecular weight hydrocarbons (C12+), their concentration is an important consideration. At low concentration, these hydrocarbons can be diluted by contributions from recent organic matter, reworked source rock organic matter, and transported hydrocarbon seepage. At higher concentrations, biodegradation of the high molecular weight hydrocarbon fraction may alter or completely eliminate the biomarker compounds used in deciphering the characteristics and source of the seeped oil.
This report will discuss methods used to recognize these interferences with the geochemical information contained in seafloor macro-seepage and how best to distinguish the seep's geochemical signal from the background geochemical noise. Application of these techniques should greatly enhance the ability to utilize hydrocarbon seep data for maximum benefit.