Brown Oil Fields Research Articles

Advanced Well Logging Interpretation for Reliable Electrotyping of Low-permeable and Low-resistivity Formation

The target formation of a brown oilfield in Western Siberia is composed of a shallowing-up succession represented by siltstones in its base gradually replaced by sandstones toward its top. Due to the absence of detailed rockand electrotyping, the siltstones, having much lower resistivity and permeability, were assigned to a water-bearing section. However, the following up well tests detected considerable oil inflow from them as well. This motivated current research aimed at developing a new methodology of rockand electrotyping of low-resistive, low-permeable clastic reservoirs. The methodology comprises detailed workflow for laboratory tests, rock typing by means of the alternative flow zone indicator (FZI), and, finally, transfer of core-derived rock types to well log electrotypes. The proposed application of the dimensionless FZI parameter, incorporating porosity and irreducible water saturation, appeared to be very effective for electrotyping of the formation, including low-resistive and low-permeable intervals.Since the intervals are characterized by a low correlation between permeability and porosity, applying the latter log for computing permeability results in unreliable calculation of the parameter and further incorrect electrotyping. In order to resolve this issue, the study suggests an effective alternative technique for calculating permeability as a multivariate parameter from other logs.Further, the research proposes a well log interpretation workflow that enables conversion of the defined rock types to electrotypes, maintaining the same classification principles for both core and well logs data. This ensures compatibility of the core and well log-derived classes.The petrophysical interpretation workflow is enhanced with machine learning algorithms for reconstructing lacking logs as well as extending the defined electrotypes to uninterpreted wells. The proposed approaches to rockand electrotyping allows detection of previously missed productive intervals and thus enables extend the lifetime of the brownfield.

Integrative approach for formation damage diagnosis in a Colombian brownfield: a comprehensive methodology

Formation damage is the reduction of a well's productivity due to the alteration of the permeability of the subsurface rock, leading to economically inefficient operations. This research established a methodology to diagnose such damage, which is divided into: 1) Identification of operational problems, 2) Field sampling and analysis of geological and engineering data, 3) Adaptation of API standards for the study of fluid-fluid and rock-fluid interactions, 4) Identification of damage mechanisms and recommendations. This methodology was applied to two depleted wells in a brown oilfield with reduced productivity to address scale deposition and casing corrosion issues. Finally, the application of control and stimulation fluids must satisfy technical and environmental requirements, with the objective of inducing destabilization of the identified formation damage mechanisms.

Hydrocarbon Wealth Management: Rejuvenation of a Brown Field through Analysis of Existing Water Injection System

A private company acquired operatorship of a brown oil field in 2020 from a National Oil Company (NOC) of India to enhance production from the field. Due to Covid-19 outbreak, operatorship was transferred in 2021. Soon as the company took over the operation, it met with surprises in terms of a smaller number of flowing oil wells due to operational reasons. However, the most disturbing was the significantly lower field water injection rate than reported by the NOC. The company undertook pressure measurement in wells to find reasons for production non-sustainability and reduced injectivity. Based on poor analysis of pressure data, the best injection well in the largest producing reservoir was interpreted to be hydrodynamically unconnected with the up-dip producers and recommended for disconnection from injection network by subsurface team to increase water injection rate from the remaining injectors. The study team reviewed the geological model and categorically ruled out discontinuity of the sand body with its up-dip producers. The Management ordered third-party review to resolve uncertainty and suggest remedial measures to improve water injection performance. The review of historical production, injection, pressure data and movement of oil water contact with time has improved the understanding of the inter and intra reservoir pressure communications in the field. The data synthesis has confirmed sand/hydrodynamic continuity between producers and injectors. Performance review of injection wells and the Water Injection Plant (WIP) have brought out bottlenecks in the system. The poor-quality injection water and the lapses in upkeeping of WIP were the primary reasons for loss of injectivity. WIP revamping and replacement of the existing oversized micron filter with smaller size have been recommended. To ensure uninterrupted water injection, conversion of one injector to pilot dump flooder has been suggested, a first of kind in India.

Sensitivity analysis for enhancing crude oil recovery with continuous flow gas lift: A study in reference to the porous media of the upper Assam basin, India

Despite minimal formation damage or water-cut, the majority of oil wells in brown oil fields cease to flow naturally. The current study looks into and analyses what caused a self-flowing well in the upper Assam basin to become non-flowing. The non-flow condition of the well was investigated in the current work as a function of water cut, reservoir pressure, reservoir rock permeability, and GOR. The effect of WHP and WHT on these functions was investigated. This work incorporates innovative methodology that uses the PROSPER simulation model for assessing the possibility of establishing flowability in a dead well based on inflow (IPR) and vertical lift performance (VLP). Subsequent analysis was carried out to examine the scope of producing this dead well under continuous flow gas lift. For this, the current work first examined the tubing diameter and reservoir temperature as standalone parameters to find out if they have any role to play in the flowability of the dead well. Following this, sensitivity analysis was done taking four parameters into account, i.e., reservoir pressure, reservoir rock permeability, water cut, and total GOR. In the current work, surface equipment correlation was established using Beggs and Brill correlation, while vertical lift performance was established using correlation from Petroleum Expert. The results of the current work highlight that a well's production rate under continuous flow gas lift can be enhanced by employing an optimised gas injection rate. The findings of this work conclude that higher reservoir pressure enables an oil well to produce with a high water cut under a continuous flow gas lift system, provided there are no formation damage issues on the well.

Optimum utilization of a depleted well in brown oil field

Optimum utilization of a depleted well in brown oil field

An integrated water injection solution for Southern oilfields of Iraq

After two bid rounds of oilfields, moo has planned a plateau oil production of 12mmbblsd in 2017. in order to reach the plateau production, most of the oilfields require water injection to maintain the reservoirs‟ pressure. there are three main challenges in water injection. firstly, where could the urgent water resource be available in the rehabilitation phase of the brown oilfields? secondly, how could the high amount of produced water be handled at the late stage of the oilfields? thirdly, what kind of sweeping efficiency could the reservoirs be developed by water flooding? Dump flood, produced water treatment and reinjection, combined with separate layers‟ water injection could be an integrated solution for southern oilfields of iraq.

Rheological properties and the micromodel investigation of nanosilica gel-reinforced preformed particle gels developed for improved oil recovery

Preformed particle gels (PPGs) in solutions have been widely used to suppress excess water production in mature oil reservoirs and, in turn, to improve the amount of oil recovery in brown oil fields. In this study, PPG solutions were meticulously formulated and synthesized in order to be utilized in harsh environments in terms of pressure, temperature, pH, and salinity from a free radical polymerization process.In this work, nanosilica gel at different weight percentages was added to improve the mechanical and thermal stability properties of the PPG at harsh condition: high pressure, temperature, and strain. Moreover, the effects of nanosilica gel at various concentrations, ranging from 0.0 to 1.0 wt%, on the PPG swelling properties in a 100,000 ppm brine along with the viscoelastic behavior of acrylamide copolymer (AM) and 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) with crosslinker of polyethylenimine (PEI) at 90 °C were studied. Having customized the formulation of the nanosilica-reinforced PPG, the solution was used to investigate the amount oil recovered in a water flooding process on a micromodel scale.The results for the recovery of oil obtained from the injection of PPG solutions were compared with those of water injection without PPG; i.e., the conventional water flooding. It should be stated that the microscopic images showed that nanosilica gel could affect the porous structure of the PPG and the X-ray Powder Diffraction (XRD) results confirmed the nanosilica particle distribution in the PPG pores with different diameters. Hence, the nanosilica-reinforced AM-AMPS/PEI with 1 wt% of the nanoparticles led in swelling of 8 g/g of the dried PPG. In addition, the strain sweep test at 90 °C suggest that increasing of nanosilica gel concentration from 0.2 to 1.0 wt% resulted in 3.34 times increase in the amount of elastic resistance of the PPG breakpoint and, thus, improvement in the complex modulus of initial PPG.In conclusion, the injection of PPG solutions, significant improvement in the oil recovery could be attained. The oil recovery factor increased from 32% under the conventional water flooding to 81% after injection of water with PPG containing only 1 wt% of nanosilica gel. Succinctly, the results confirmed that the tailored formulation had a great potential for field applications to enhance the oil recovery.

Optimizing Production in Brown Fields Using Re-Entry Horizontal Wells

Reviewing of some Niger Delta oil field reservoirs indicate that most of them are brown fields, thereby vulnerable to challenges such as; coning due to reduced size of the oil column, low oil production and lack of access to the residual oil trapped between existing wells of the brown field. Due to coning occurrences in the Niger-Delta brown oil field, most wells have been shut-in and a lot of recompletions are being made in order to combat this problem. To proffer solutions to these technical challenges of these brown oil fields, this study seeks to review the potentials of re-entry horizontal well technology and its viable application to optimizing oil production from brown oil field. Re-entry horizontal well Technology involves a method of converting an existing vertical well into an horizontal well to save cost as oppose to drilling a fresh horizontal well from the surface. The object of the re-entry well is to reduced cost, especially in areas where drilling costs are very high. The re-entry horizontal in this research was represented by a virtual horizontal well to study the potentials of producing brown fields. The simulation paradigm studied was Black oil with light oil type variation of 32 O API. This article is therefore aimed at suggesting the conversion of existing vertical wells in the Niger-Delta into re-entry horizontal wells as a measure to optimize oil productionof these brown oil fields.

PREDICTION STUDY OF NIGER-DELTA BROWN FIELDS USING SIMULATION HORIZONTAL WELLS TECHNOLOGY

Developing brown fields by horizontal drilling is one of the most valuable technologies employed nowadays since it can maximize matured field's benefits. Using re-entry horizontal wells in brown oil fields is essential for potential successful high oil recovery. The re-entry horizontal in this research was represented by a virtual horizontal well to study the potentials of producing from brown field reservoir. The simulation paradigm studied was Black oil with light oil type variation (32 ° API). This scenario was proposed to reproduce a possible real field situation, where more oil and less water was produced. This paper compared the anticipated cumulative recoveries of the existing vertical wells to that of re-entry horizontals well in brown fields and provide a simulation prediction results for the next 4 years (2018-2022). Based on the result of this study, oil recovery can be optimized using re-entry horizontal wells.

Applying an optimized proxy-based workflow for fast history matching

History matching is still one of the main challenging parts of reservoir study especially in giant brown oil fields with lots of wells. In these cases, history matching with conventional manual technique needs many runs and takes months to get a match. In this work, an innovative approach was suggested for fast history matching in a real brown field. The workflow was employed based on an optimized proxy model for history matching of a field consisting of 14 active wells with multiple responses (which are production rate and pressure data) in the south part of Iran. The main important features of the proposed algorithm were defining a proxy model which is response surface method in which 21 model parameters were incorporated based on cubic centered face method. The proxy model was then optimized by one of the most famous algorithms which is genetic algorithm. Proxy model was successfully performed using 256 samples leading into p- value of 0.531 and R 2 of 0.91 dataset. As a result, the proposed workflow and algorithm showed good and acceptable results for history matching of studied real model.