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The purpose of this study was to develop a physical understanding of the bit damage that occurs in the Brushy Canyon and Avalon formations in the southern Delaware Basin and to develop practices to mitigate it. The operator had already implemented a programmatic initiative to move the organization toward physics-based, limiter-redesign workflows in order to achieve performance gains in a safe and efficient operation. A significant performance limiter was trips for damaged bits.
Two dominant causes of bit damage were observed. One was tangential overload of the outside cutters, which tends to occur if hard streaks are exited with high WOB and depth of cut (DOC). The second is continuous wear of the outside cutters that occurs if lower WOB is used to avoid the tangential overload. There was no operating window in which any given WOB did not enable one or the other form of damage in 12-1/4″ holes.
An explanation of how the overload may occur is presented along with the results of changes in field practices that were consistent with the concept. The progress that was made was partly due to physics-based training of operations personnel which enabled them to interpret observed behaviors and manage dysfunction more intensely. Some elements of the physics-based workflow and training are also discussed at length because they are integral to the improvements achieved in performance (
Bits from two wells drilled were pulled green after drilling from the surface casing through the Brushy Canyon. While this is encouraging the results from rig to rig was inconsistent. Bit design needs were identified that should enable higher success, and some of these features are now found in the current market. They were not available at the time of this initiative in 2018.
The nature of the interfacial severity damage varies from the southern to northern end of the Delaware basin, with laminar calcite streaks dominating in the south (the operator's acreage) and nodular chert inclusions occurring in some areas of the north. Both create high loading of a small number of cutter studs and the real time and engineering design practices that limit the interfacial severity damage discussed in this paper may be useful across the basin.
You have access to this full article to experience the outstanding content available to SPE members and JPT subscribers. To ensure continued access to JPT's content, please Sign In, JOIN SPE, or Subscribe to JPT Financial reports have long lumped shale acreage like cuts of meat, with tier 1 for the best reservoir rock, and tiers 2 and 3 ranked as lower quality. Tier 1 is rated superior to the lower tiers based on a handful of geological measures related to the oil in the ground and the ability to stimulate flow with fracturing. A recent study by the energy advisory arm of Deloitte of 35,000 wells in the Permian Basin and Eagle Ford found that production in regions outside tier 1 in those basins are not that different. In the Eagle Ford shale, the breakdown in wells based on early production showed little difference between the tiers.
Li, Baozhen (State Key Laboratory of Offshore Oil Exploitation) | Zhang, Jian (State Key Laboratory of Offshore Oil Exploitation) | Kang, Xiaodong (State Key Laboratory of Offshore Oil Exploitation) | Zhang, Fengjiu (State Key Laboratory of Offshore Oil Exploitation) | Wang, Shanshan (State Key Laboratory of Offshore Oil Exploitation) | Zhao, Wenshen (State Key Laboratory of Offshore Oil Exploitation) | Wang, Xiujun (State Key Laboratory of Offshore Oil Exploitation) | Wei, Zhijie (State Key Laboratory of Offshore Oil Exploitation)
The research and application of chemical EOR technology has been carried out worldwide for many years, and many theoretical and practical achievements have been obtained in China's onshore oil fields. At present, it has become one of the most important means to develop mature oilfields for stable & improved production in oilfield. Also, it has been successfully applied in China offshore oilfields as a major EOR technology. CNOOC has preliminarily established a chemical flooding (polymer, polymer-surfactant, polymer-weakgel, etc) technology system including high-efficiency chemical flooding agents, platform injection facilities, and produced liquid treatment technology. Since 2003, pilot tests and field applications were carried out in S, L and JW oilfields, and predicted oil increment and good economic benefits have been achieved, which proved that offshore chemical EOR technology is feasible and economical. It has explored a new road for increasing the recovery of offshore oilfields, and provided a solid technical guarantee for their economic and efficient development.
The major challenges of shale reservoir development in Weiyuan gasfield are: (1)strong geologic heterogeneity, such as geo-stress, horizontal lamination, limited complexity and propagation of hydraulic fracture; (2)casing deformation, which caused the reservoir fractured insufficiently for many engineering problems. To avoid the problem above and increase complexity and SRV of hydraulic fracture, a deeply fracturing technology (DFT) was proposed, which was validated available and had been applied in 20s wells.
Based on ununiform distribution of geo-stress, the mechanism of DFT is using temporary plugging materials to fracture the reservoir sufficiently, which can be classified in 3 major patterns, include Intrasegment/Multi-segments/Closely spaced fracturing. Firstly, according to reservoir and stimulation objectives, choosing the appropriated development pattern. Then, considering geological and engineering factors, the optimization of temporary plugging materials and pumping parameters are needed in making pumping schedule. Finally, conducting fracturing by the schedule, and combined with operation curve and micro-seismic data, choosing proper time to release temporary agents.
With the application in the field, some conclusions are as follows:(1) Intra-segment development pattern was preferred in single-segment sufficient simulation; multi-segment was favored in the development of multi-stages without bridge plug situation, especially in the stimulation of casing deformation intervals. Which also improved operational timeliness; Closely spaced perforation pattern was benefit for the segment with big geo-stress difference and the well with small well spacing.(2) DFT was validated available by fracturing curve and micro-seismic monitoring. Event response points coverage rate of segment was 100%, SRV per segment and micro-seismic events were increase by 11%-45% and 54%-429%, respectively.(3) A combination of temporary plugging ball and powder was recommended, and the optimal agents pumping rate was 3m3/min. With the treatment above, pumping pressure was increased after agents released, the peak increment is 10 MPa, plugging effect was clear.
DFT is suitable for high heterogenous horizontal interval development, and also can be combined with bridge plug to achieve segment sufficient fracturing. The most important is, it is available in casing deformation interval stimulation, which is so serious in Weiyuan gas-field.
The next time you are tempted to scold your son or daughter for spending too many hours playing videogames, think twice: they may be training to be the best workers of the 21st century and even replace your position…
Collaborative Work Environments (CWE) combined with Telepresence and Mixed Reality technologies are revolutionizing the design, engineering and building large petrochemical projects. This paper provides an overview of the technologies and describes how the design, implementation and control processes in these projects can be performed more safely and accurately at lower cost.
Over three decades ago, businesses experienced a leap in performance, code reusability and maintainability when their information technologies moved from numbered line to object-oriented programming (OOP). We are now poised at the cusp of another quantum change in efficiency as a result of technology. In this new era data travels from "cradle to grave." From design, construction or assembly, to use, service and final dismantling of refineries and industrial facilities, the physical world of discrete elements will have an accurate digital equivalent. Thanks to powerful computing and Big Data warehousing, complex structures with millions of individual parts can now be tracked and displayed like intelligent LEGO® structures.
The vision is that by adopting an open, agree-upon, and
Extending this model and common language of data communication to include various industries, such as engineering, construction, aviation and military operations provides economies of scale in the adoption of an open, global and flexible platform for use by all, but without restricting innovation or compromising security.
Ajao, Wale (OML26 AMT) | Isiba, Ezinwanneakolam (OML26 AMT) | Okoh, Eddy (OML26 AMT) | Okoruwa, Immaculate (OML26 AMT) | Omenai, Stanley (OML26 AMT) | Abu, Nicholas (OML26 AMT) | Babalola, Olusegun (OML26 AMT) | Oke, Oluwatobi (OML26 AMT)
Oil Mining Lease 26 (OML 26) is held by NNPC and First Hydrocarbon Nigeria Limited (FHN) in a Joint Venture relationship and operated by an Asset Management Team (AMT). The license consists of several oil and gas discoveries including the Ogini, Isoko, and Ozoro fields on the western part, Ovo in the central area and Aboh to the east.
Oil Production is mainly from the Ogini and Isoko fields with the Ogini field contributing the largest volume. The Ogini oil is relatively heavy, with in-situ oil viscosity ranging from 3 to 59cp, and an oil gravity ranging from 15°API to 19°API. Field development and production from the Ogini field has been very challenging with the characteristic low GOR, low rate and high watercut. Oil production peaked at 8,900 stb/d shortly after field start-up in the 80s and has been declining since then.
In 2018 however, the field witnessed breakthrough performance stemming from production optimization initiatives and strategies which unlocked resource potential of the field. A peak production of ca 17,000 bopd was recorded during Q4 of 2018 without drilling new wells. A number of production enhancement activities carefully designed, planned, and executed coupled with change in operations philosophy released more volumes transforming the production levels and production profile of the field from a mere 3,000bopd to ca 17,000 bopd peak production. This paper highlights the strategies, optimization techniques and the paradigm shift in operational culture that resulted in the significant change and ramp up of production in the field.
Hydraulic fracturing has become a common practice in the petroleum industry, and several systems have been developed to obtain a suitable crosslinked polymer for the treatment. However, each system has its strengths and weaknesses. This study aims to investigate the effect of three different ligand types attached to zirconium (Zr) on the performance of carboxymethylhydroxypropylguar (CMHPG) crosslinked with Zr-based crosslinkers with the different ligands. The shear recoverability and rapid viscosity buildup at the high pH of Zr-based crosslinkers were overcome by a new aluminum-zirconium (Al-Zr) dual crosslinker in this research.
The polymer used was CMHPG, and the tests were conducted at pH of 3.8 and 10.8. One of the factors that affects the gel performance is the type of ligand attached to the Zr. Because the Zr-based crosslinkers are shear-sensitive, ligands were introduced to delay the crosslinking until the fluid passes the high-shear environments (perforations). Therefore, in this study, lactate, propylene glycol, and triethanolamine (TEA) were studied as ligands attached to the Zr. Two Zr crosslinkers with almost the same concentration of Zr can display different performances if the ligand attached to the Zr is not the same.
The rapid viscosity buildup at high pH had always been a limitation of Zr crosslinkers; however, a new Al-Zr dual crosslinker was introduced in the present study to address this limitation. The Al-Zr crosslinker outperformed all the other crosslinkers examined in the present study. Immediate viscosity buildup at a high pH and a lack of shear recoverability of Zr-based crosslinkers was addressed through the Al-Zr crosslinker. The Al-Zr crosslinker introduced in this study is one compound that is easy to use in the field. The Al-Zr crosslinker performance was compared with the boron-zirconium (B-Zr) crosslinker: Both had lactate as a ligand attached to them. Among all the Zr-based crosslinkers in this study, the Zr crosslinker with lactate and propylene glycol as a ligand performed the best. The CMHPG crosslinked with each of the crosslinkers was tested for proppant-carrying purposes along with static leakoff rates. The results revealed gel-proppant-suspending capabilities and acceptable leakoff rates.
Extensive laboratory research is a key to a successful field treatment. These results indicate that fracturing fluids are complex, and the ligand type is one of the important factors in determining the final properties of fracturing fluids. Therefore, the results of this study will assist in developing Zr-based crosslinkers that address their current shortcomings.
The concept of distance of investigation (DOI) has been widely applied in rate- and pressure-transient analysis for estimating reservoir properties and for optimizing hydraulic fracturing. Despite its successful application in conventional reservoirs, significant errors arise when extending the concept to unconventional reservoirs. This work aims to clearly demonstrate such errors when using the traditional square-root-of-time model for DOI calculations in unconventional reservoirs, and to develop new models to improve the DOI calculations.
In this work, the following mechanisms in unconventional reservoirs are first incorporated into the calculation of DOI: (1) pressure-dependency of rock and fluid properties; (2) continuous/discontinuous spatial variation of reservoir properties. To achieve this, pseudopressure, pseudotime, and pseudodistance are introduced to linearize the diffusivity equation. Two novel methods are developed for calculating DOI: one using the concept of continuous succession of steady states, and the other using the concept of dynamic drainage area (DDA). Both models are verified using a series of fine-grid numerical simulations. A production-data-analysis workflow using the new DOI models is proposed to analytically characterize reservoir heterogeneity and fracture properties.
The new DOI models compensate for the inability of the traditional square-root-of-time model to capture spatial and temporal variations of reservoir and fluid properties. The pressure-dependency of fluids and reservoirs (i.e., fluid density, fluid viscosity, rock permeability, and rock porosity) and reservoir heterogeneities (i.e., deterioration of reservoir quality from the primary fracture to the reservoir) can significantly retard the propagation of the DOI. Another important outcome of this work is to provide a practical and analytical approach to directly estimate the spatial heterogeneity from the production history of field cases.
As active oil reservoirs mature, marginal fields development and management is becoming increasingly important. Early identification of high degree reservoir heterogeneity served as starting point for an in-depth analysis for both, geologist and reservoir engineer. This paper describes complex approach applied during evaluation and development of marginal oil field "Is" located in Serbia (Pannonian Basin). Effective transition from exploration to development took place in 3 stages. I-stage: 1 exploration well drilled, detailed analysis (seismic, sedimentology, core, PVT) and interpretation (log, well-test). Identification of vertical heterogeneity led to detailed analysis, which resulted in local depositional environment theory. Integration of seismic attribute and sedimentological analysis results was done. Due to geological uncertainties several 3D models were done for STOIIP range estimation. Recovery factor range was estimated using statistical, analytical and simulation model approach.
KS is a tight-sandstone and high-pressure-high-temperature (HPHT) gas reservoir in northwest China. It is characterized by a depth of more than 6000 m, temperature over 175°C, and pore pressure over 110 MPa. Despite the high unconfined compressive strength (UCS) of sandstone, almost half of the wells encountered sanding issues. The sanding wells exhibited low production rate, nozzle and pipeline erosion, sanding up, and even permanent closure. Investigating the sanding mechanism and developing solutions for sanding prevention are urgent needs due to the economic loss of low production.
An integrated sanding study was conducted to investigate the sanding mechanism. The entire sanding process was analyzed, including stress field alteration during production, rock failure, softening, and sand grain migration. First, wells with sanding issues were identified through production characteristics and field observation. After this, analysis of laboratory tests was performed to better understand the tight-sandstone properties, especially UCS, the softening parameter, and residual strength. Based on the tests, an elastoplastic damage model was proposed to delineate rock failure and sanding behavior. Then, a finite element model was built to simulate the damage of a perforation hole with field data, including hole diameter and length, rock stiffness and strength, drawdown, depletion, and so on. More simulation scenarios were performed to investigate the continuous sanding, transient sanding, and water hammer effect. Grain migration in perforation holes and in pipelines was also studied.
It was revealed that shear failure of perforation hole induced by drawdown and depletion was the root cause of sanding problem. Meanwhile, it was also confirmed that erosion and water hammer effect had very limited effect on sanding. Use of the elastoplastic damage model for the simulation of perforation hole failure enabled predicting the sand amount and determining the critical drawdown and depletion for sanding. In the end, an approach to identifying wells with high sanding risk and the key factors behind the sanding were provided, and sanding prevention suggestions were proposed.
The new elastoplastic damage model explains the sanding mechanism in a tight-sandstone reservoir and enables evaluating the sand volume, which has rarely been published previously. Laboratory tests, field observation, and numerical simulation were combined effectively to investigate the sanding issue. By utilizing the model, producers can find the key factors behind sanding issues, prevent sanding with a better production strategy, and avoid the economic loss, which are critical for the long-term exploration and production of this area.