Track Fractured Well Inflow Performance Using Historic Production Logging and Surface Well Performance Data in Sultanate of Oman

PDO operates about 200 deep gas wells in the X field in the Sultanate of Oman, producing commingled from the Barik gas-condensate and Miqrat lean gas reservoir completed by multiple hydraulic fracturing. Their inflow performance relation (IPR) is tracked to diagnose condensate damage, hydraulic fracture cleanup and differential reservoir pressure depletion. The best IPR data is collected through multi-rate production logging but surface production data serves as an alternative. This paper describes the process of deriving IPR's from production logging and surface production data, and then evaluates 20 years of historic IPR data to quantify the impact of condensate damage and condensate cleanup with progressive reservoir pressure depletion, to demonstrate the massive damage and slow cleanup of hydraulic fractures placed in depleted reservoirs, to show how hydraulic fractures facilitate the vertical cross-flow between isolated reservoir intervals, and to highlight that stress-dependent permeability does not play a major role in this field.

The Fall and Rise of Oilfield Ethics

The oilfield is in many ways the backbone of the world economy. Historically economic recessions and booms were linked directly or indirectly to the oil price, itself governed by supply and demand. Since the start of this industry, it has experienced multiple scandals and major accidents that have affected its path to date. In 2001 the Enron scandal of poor accounting practices shook the entire stock market, and it contributed to the complete recession in the same year. Not too long after, a supermajor revealed in 2004 a reserves accounting error that surprised the world. In 2010 the Deepwater Horizon blow out known as the "Macondo Incident" caused serious damage to the environment and significant fines to be paid in compensation due to poor engineering practice. Incidents like these arise concurrent with times of high demand and are instructive as we study their causes and effects on the oil industry and therefore the global economy. Areas of study for this paper include reserves/production estimation as well as ethical considerations for the oil industry at large. Our study is based on the review of uncertainty in both the subsurface and surface parts of oil and gas production. We refer to the previous classifications of uncertainty for the subsurface part and focus on the uncertainty currently existing within the surface production system. Current surface production monitoring methods are discussed. We propose a more automated process to reduce the current uncertainty about hydrocarbon production. Artificial intelligence applicability in the surface production system is investigated. Additionally, in this paper we review the previously mentioned poor practices and accidents briefly and use them to guide our suggestions about preventive actions to avoid future wrongdoing and incidents. We attempt to provide an objective for oilfield ethics and advocate for a unified oilfield industry code of ethics. However due to the large diversity that exists in the wide range of oilfield disciplines, a single code of ethics may not be applicable. Accordingly, we propose a guideline that may be used by different parts of the oilfield industry to develop an application-specific code of ethics. It is hoped that this guideline will guard against the gaps that may foster errors that affect the oilfield industry and global markets.

From Basic Engineering to Ramp-Up: The New Successful Execution Approach for Commissioning in Brazil

In the last three years, COMPANY has started the production of eight Surface Production Systems (Floating, Production, Storage and Offloading Units) in the Búzios and Lula fields of the Brazilian pre-salt that have generated technical knowledge, organizational learning and many opportunities to explore in upcoming projects. The lessons learned as well as the organizational knowledge acquired in this period, resulted in a new approach for the commissioning process to apply in COMPANY's coming FPSO projects. During this period, COMPANY identified improvement opportunities and stablished structuring programs focused on adding value to these new assets. The main opportunity identified was to reduce the period required for ramping-up the oil production, considering aggressive target dates for start-up, with high up time on the gas compression systems with minimum flaring. In this manuscript, will be described some of the important actions and changes made in commissioning process that allowed COMPANY to achieve better efficiency and safety in ramp up of new FPSOs in Brazilian pre salt fields.

Evaluating Alternate Artificial Lift Methods in the Niger Delta

Gas lift is currently being utilized as the artificial lift system in OML Z, this has been so for the last thirty years. Although, the field has seen significant increase in production rates in recent times, gas lift requirement has increased with increase in production and water cut. To maximize production and value from OML Z, it is expedient to seek an alternative artificial lift method that can debottleneck and unlock the potential of fields within OML Z where production has been less than 50% since the field was brought on stream. Production from the gas lifted fields within OML Z is constrained by a combination of bottlenecked gas lift facility and surface production facility. This study explores the different artificial lift methods and selects an applicable technology for OML Z using a developed selection criterion. Electrical Submersible Pump (ESP) found suitable for OML Z is further analyzed for feasibility and application within OML Z given existing limitations. The candidate reservoir and well selection criteria are elaborated upon, taking into consideration several elements that contribute to the production process. The results of the well and network models, that shows the significant gains attributed to the conversion of selected previously gas lifted wells to ESPs, are discussed. The economic benefit of such conversion is also shown.

The Transient Dynamics of Permanent Fiber Temperature Analysis and Downhole Gauge Evaluation of an Acid Stimulation Job in a Brown Field, Offshore Malaysia

Well B-2 is a dual-string producers with Distributed Temperature Sensing (DTS) fiber installed along the long string (i.e. Well B-2L) across the reservoir sections. Each zone comprises of sub-layers. This system enabled the operator to continuously monitor the wellbore temperature across all the producing intervals including gas-lift monitoring, well integrity identification, zonal inflow profiling and stimulation job evaluation. This paper mainly discusses the post matrix acid stimulation job with interpreted DTS and zonal Permanent Downhole Gauge (PDG) data. Well B-2L has been selected for matrix acidizing treatment to improve the productivity due to potential formation damage, proven by the declining production over the years. Prior to the execution of the acidizing job, several conformance jobs such as injectivity test, tubing pickling were performed. This is followed by the main acid treatment and flow back. DTS & zonal PDG data were acquired throughout the operation. A transient simulator model was built incorporating all the reservoir properties including well trajectory and completion schematic to analyze the DTS profile and understand the zonal inflow profiling for each zone post treatment. A baseline temperature was acquired for the geothermal evaluation. The DTS data has been studied according to actual event schedules. Some significant findings are; i) completion accessories effect (feedthru packers) creates temperature anomalies, ii) leak points detected at top producing zone signifies cooling effect due to injected fluid. The main treatment was intended at zone 2 and 3 using nitrified acid. However, leak points at top zone caused bypassed injection into Zone 1 and 2 instead. Fiber optic DTS warmback profiles post main-treatment was analyzed to quantify the fluid intake from sub-layer in each zone. Qualitatively from the DTS-interpreted zonal profiling, the data clearly shows most of treatment fluid is being injected into Zone 1 and 2 with no intakes at Zone 3. Furthermore, warmback analysis confirmed the high intake zones from sub-layers within the main zone based on the permeability contrast. This paper will further discuss the zonal injectivity understanding for improvement from the zonal-inflow profiling evaluation by incorporating DTS, PDG and surface production data.

Hadal trenches are dynamic hotspots for early diagenesis in the deep sea

The deepest part of the global ocean, hadal trenches, are considered to act as depocenters for organic material. Relatively high microbial activity has been demonstrated in the deepest sections of some hadal trenches, but the deposition dynamics are thought to be spatially and temporally variable. Here, we explore sediment characteristics and in-situ benthic oxygen uptake along two trenches with contrasting surface primary productivity: the Kermadec and Atacama trenches. We find that benthic oxygen consumption varies by a factor of about 10 between hadal sites but is in all cases intensified relative to adjacent abyssal plains. The benthic oxygen uptake of the two trench regions reflects the difference in surface production, whereas variations within each trench are modulated by local deposition dynamics. Respiratory activity correlates with the sedimentary inventories of organic carbon and phytodetrital material. We argue that hadal trenches represent deep sea hotspots for early diagenesis and are more diverse and dynamic environments than previously recognized.

Research and Practice of Comprehensive Utilization Technology of Mine Water Based on Green Mining

Yannan Coal Mine in Dayan Mining Area creatively utilizes water-preserving mining technology to block abandoned roadways to build underground reservoirs and build underground sedimentation tanks. It implements a zoned utilization and zoned management optimization technical plan for mine water, so that it can meet the needs of underground working face production and surface production and domestic water use. This mine water comprehensively recycles water conservation mining technology and makes full use of mine water resources. This greatly improves the utilization rate of mine water, realizes the recycling of mine water, and accelerates the construction of green mines.