Development Optimisation and Application in a Giant Carbonate Oilfield Under Low Remuneration Fee, Y Oilfield in Iraq

Abstract

Y is a giant carbonate oilfield with low permeability and mid-high porosity, of which the characteristic is extensive plane distribution and many series of oil-zones in the longitudinal direction. The service contract required a large scale capacity construction with nearly 30 million ton and long stable production period above 13 years, but provided a low remuneration fee with only 1.4$/bbl. Full oilfield integrated optimization is crucial to achieve high effective development and enhance economic benefit. In this paper, the procedure of research on integrated development optimization was elaborated. The paper established new productivity model with oil-water two phase to accurately evaluate oil well productivity. Depletion mode and zones combination were demonstrated and optimized through core experiments and numerical simulation. The sensitivity studies of well types, well patterns and well spacings were carried out through modelling and empirical formula method. Multifactor analysis was completed with surface engineering and external oil-gas transportation capacity as important factors, and development strategy of rapid productivity construction and rolling development is put forward. Depletion plan for each reservoir has been also optimized based on full reservoir simulation modelling. The recommended depletion plan has been implemented in the oilfield development, of which productivity coincidence rate was nearly 100%, first stage productivity capacity with 5 million ton has been set up in 2012, and IRR increased from 9% to above 13%.

Preparation and Performance Study of Microemulsion Acid for Comprehensive Plugging Removal in Carbonate Reservoir

“…Organic solvent scale remover can effectively remove organic scale but cannot remove inorganic scale [ 21 ]. The organic solvent system dissolves the crude oil in the oil sludge by physical extraction according to the mechanism of extraction and plugging removal and the principle of similar phase solubility and disperses and strips the organic heavy components such as colloid asphaltene and paraffin attached to the surface of the oil sludge to achieve the complete separation of the two phases of oil and sludge [ 22 ]. Common organic solvents are: xylene, cyclohexane and diesel [ 23 ].…”