The SPE has split the former "Management & Information" technical discipline into two new technical discplines:
- Data Science & Engineering Analytics
The SPE has split the former "Management & Information" technical discipline into two new technical discplines:
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Guan, Xu (Exploration and Development Research Institute of PetroChina Southwest Oil & Gasfield Company, Chengdu, China) | Zhu, Deyu (Exploration and Development Research Institute of PetroChina Southwest Oil & Gasfield Company, Chengdu, China) | Tang, Qingsong (PetroChina Southwest Oil & Gasfield Company, Chengdu, China) | Wang, Xiaojuan (Exploration and Development Research Institute of PetroChina Southwest Oil & Gasfield Company, Chengdu, China) | Wang, Haixia (Exploration and Development Research Institute of PetroChina Southwest Oil & Gasfield Company, Chengdu, China) | Zhang, Shaomin (Exploration and Development Research Institute of PetroChina Southwest Oil & Gasfield Company, Chengdu, China) | Deng, Qingyuan (Exploration and Development Research Institute of PetroChina Southwest Oil & Gasfield Company, Chengdu, China) | Yu, Peng (Exploration and Development Research Institute of PetroChina Southwest Oil & Gasfield Company, Chengdu, China) | Yu, Kai (Exploration and Development Research Institute of PetroChina Southwest Oil & Gasfield Company, Chengdu, China) | Huang, Xingning (Downhole service company of Xibu Drilling Engineering Company Limited, Karamay, China) | Xu, Hanbing (CNPC, International HK LTD Abu Dhabi, Abu Dhabi, UAE)
Abstract In recent years, tight sandstone gas as one of the important types of unconventional resources, has been rapid explored and developed. There are large-scale tight sandstone gas production in Sichuan Basin, Ordos Basin, Bohai Bay Basin, Songliao Basin and other basins, and it has become a key part in the area of increasing gas reserves and production in China. Due to the influence of the reservoir characteristics, tight gas reservoirs have low porosity and permeability, and the tight gas can only be effectively developed by improving the conductivity around the wellbore. Therefore, it is required to perform hydraulic fracturing after the completion of horizontal well drilling to improve the permeability of reservoir. It can be seen that hydraulic fracturing is the core technology for efficient development of tight gas resources. The implementation of hydraulic fracturing scheme directly determines the horizontal well production and EUR. This paper describes the workflow of 3D geomechanical modeling, technical application for Well YQ 3-3-H4 reservoir stimulation treatment, and carries out hydraulic fracture propagation simulation research based on 3D geomechanical model. This paper also compares the micro-seismic data with the simulation results, and the comparison results show that the propagation model is consistent with the micro-seismic monitoring data, which verifies the accuracy of the model. This paper clarifies the distribution law of hydraulic fractures in the three-dimensional space of horizontal wells in YQ 3 block, and the research results can be used to provide guidance and suggestions for the optimization of fracturing design of horizontal wells in tight gas of Sichuan Basin.
Al-Hamad, Hamad (Kuwait Oil Company) | Sarah, AlSamhan (Kuwait Oil Company) | Al-Naqi, Meqdad (Kuwait Oil Company) | Sajer, Abdulaziz (Kuwait Oil Company) | Hussein, Assef (Schlumberger) | Ni, Qinglai (Schlumberger) | Kumar, Surej (Schlumberger)
Abstract As a field development strategy, KOC is developing highly depleted reservoir. The field has been experiencing wellbore instability issues. Some recent wells have encountered stuck pipe and mud losses in clastic and carbonate sections. To reduce geomechanical related Non-Productive Time and rig days, it is important that combined effect of in-situ stress state and well trajectory on wellbore stability should be thoroughly investigated. Rock mechanical behaviours also need to be evaluated to optimize drilling practice. The growing appreciation of the effects of regional tectonics is making it crucial to move away from simplified characterisation of rock behaviour and to turn into advanced geomechanical modelling techniques to engineer better wells and fields. The advanced 3D coupled Geomechanical-Fluid-Flow modelling method combines input data of different origin, such as seismic data, petrophysical data, fluid-flow data and well logs. With such an integrated model, spatial variations of the in-situ stresses in the field are obtained due to reservoir structure, presence of discontinuities as we as because of reservoir depletion. The whole production history spanning seventy years was simulated. The 3D coupled geomechanical model was able to reproduce the observed wellbore instability events for fifteen wells drilled at different times and various reservoir depletion stages. Drilling instability events included tight spots, cavings and stuck pipe in major clastic sections; and mud losses in carbonate sections. Two blind tests for wells not used for model calibration were carried out to examine the mechanical properties, stress profiles and caliper logs within various formations. The match between the model prediction and the data was in good agreement. In addition, a 3D description of the mud weight was computed, which allowed to obtain drilling maps across the field highlighting zones of high, medium and low drilling risks. Such drilling maps enabled optimizing placement of future planned wells and provide guidance in mud weight design. Nevertheless, drilling through faults requires careful attention due to the localized stresses concentration developing along their geometries. High resolution near wellbore stability analysis helped to optimize the drilling mud weight for wells crossing faults. The powerful combination of multidisciplinary domains into one integrated 3D geomechanical model improved the understanding of subsurface behaviour. With such an integrated model, complex technical challenges as drilling complexities in the study field can be achieved and hence decreases the Non-Production Time by avoiding problems prior to their occurrence. The calibrated model showed satisfactory predictability for the whole production period and thus is used as a mitigate problem measure to placement of new planned wells.
Abstract Sand production erodes hardware, blocks tubulars, creates downhole cavities, and must be separated and disposed of on the surface. Completion methods that allow sand-prone reservoirs to be exploited often severely reduce production efficiency. The challenge is to complete wells to keep formation sand in place without unduly restricting productivity. To avoid sands, the dependence of rock failure on drawdown must be analyzed properly using geomechanical methods. A wide range of methods has been used in the past for sand production prediction. Modeling and designing bottom hole features, mostly perforation geometry and wellbore trajectory, based on sand body mechanical properties and near wellbore stresses is the key to mitigating or eliminating sand production issues in clastic reservoirs. In this paper, we present a full-scale geomechanical analysis and modeling using a 1D mechanical earth model (elastic and strength properties and stress field) to address the main challenges and the root causes of sanding in clastic reservoirs in South of Iraq. The analysis includes the following: Critical Draw Down Pressure (CDPP) profile in different levels of reservoir depletion resulting in sand production. CDPP is the minimum borehole pressure for which no solids are produced from a sand reservoir. Well inclination sensitivity analysis and its role in sand production Sand grain size sensitivity analysis and its role in sand production Unconfined compressive strength (UCS) as rock strength indicator sensitivity analysis and its role in sand production Perforation direction sensitivity analysis relative to stress directions, and its role in sand production. We present a case study to show how the methodology and workflows have been applied to identify sand-producing intervals for different completion scenarios, determine the optimum drawdown conditions for sand-free production and adjust completion configuration to obtain sand-free production from a clastic reservoir in the South of Iraq.
The article describes a case history of geomechanical modeling for drilling wells in a zone with active geodynamics. Two vertical wells have been drilled in the site by the time of work performing. While drilling, there were complications connected with subsurface geology. The field is located in the Arabia-Eurasia continental collision zone. To evaluate the risks of potential horizontal well drilling, it was decided to perform an in-depth complex analysis of the well log using 1D geomechanical modeling. Analysis of drilling events has shown that work area is characterized by high probability of borehole wall collapse and fluid loss, especially in Upper Cretactous formations. The main difficulty in building 1D geomechanical models is a limited range of source data. Modeling is made on the base of taken from literature dependency reports for the calculation of stress-related properties with additional model ratio adjustments. Range of studied well log is about 3000 m. The well log is represented by interlayering of various carbonaceous and terrigenous sublayers significantly differing in the values of stress-related properties. Corresponding dependencies of longitudinal and transverse wave slowness and density recovery have been selected and justified for each interval. Stress-related properties have been calculated with consideration of lithological column for each well. Due to the absence of specialized studies concerning hydraulic fracturing of formation closure pressure, calibration of minimal horizontal stress has been made using FIT data. Calibration of minimum horizontal stress and ratios in dependencies for the calculation of stress-related properties is made in such a way that lets the final model to credibly describe drilling events and destruction intervals registered by data calipers simultaneously at all wells. Using modeling results, safe drilling windows for the estimated horizontal well path are calculated and recommendations for the following trouble-free drilling are formed. Obtained modeling results may be used in preparation of project documentation for the construction of horizontal well sat this field.
Abstract Reservoir development from exploration to abandonment benefits from integrated geomechanical modeling to set guidelines and long-term operational strategies. Due to increasing operational challenges, geomechanics has become an essential part of the oil and gas industry’s daily route practice. These challenges arise when dealing with deep and tight, unconventional subsalt reservoirs, especially when drilling deviated or horizontal boreholes in a depleted formation in the minimum stress direction when intended to place multistage hydraulic fractures. This study provides innovative geomechanical solutions to address exploration challenges. This integrated approach will incorporate all available data to construct 3D geomechanical static models to assess and characterize the reservoir properties. These properties include reservoir quality index, sweet spot, reservoir compartmentalization, pore pressure prediction, in-situ stress regime, and presence of faults and fractures. The study will also investigate the relationship between in-situ stress, fractures, faults distributions, and fluid flow and correlate fracture properties variations to the lithology changes. The results from this study will be used as guidelines strategies for hydrocarbon exploration. The research will address the impact of the in-situ stress variations on petroleum systems, fault seal integrity evaluation, reservoir mapping, and heterogeneity. The study also provides an understanding of vertical and lateral variations of the in-situ stresses and their impact on well placement and well spacing. The types of geomechanical modeling implemented here can be used to accurately drill a safe and cost-effective wellbore that meets completion and stimulation requirements and maximize hydrocarbon production. Implementing this innovative geomechanical workflow addresses exploration challenges and plays an essential role during reservoir development to characterize the reservoirs and optimize operations. The studies showed that implementing this workflow improves reservoir developments by saving millions of dollars and minimizing the non-productive time during the planning and exploration phase.
Abstract Geomechanics has become an essential part of the petroleum industry's daily routine due to the increase in operational challenges when dealing with deep, tight, unconventional, and subsalt reservoirs, in addition to depleted zones and multilateral drilling in the direction of minimum stress. This research aims to provide innovative integrated geomechanical solutions during the exploration phase and investigate the relationship between in-situ stress, fractures, faults distributions, and fluid flow to correlate fracture variations to lithology changes. This integrated approach will incorporate all available field data, including seismic velocities, petrophysical well logs, geological, and structural models that will be used to construct 3D geomechanical static models to assess and characterize the reservoir properties, such as reservoir quality index (RQI), sweet spot, reservoir compartmentalizations, pore pressure, in-situ stress regime, and presence of faults and fractures. The fracture properties and dynamic simulation will be conducted by studying the fracture properties from the core sample, image log interpretation, and fluid flow using Finite Element models The results from this study will be used as a guideline during the field exploration phase to set the field development strategies and answer the question such as: How stress field variations will impact petroleum systems, fault seal integrity assessment, reservoir mapping, and heterogeneity, in-situ stress vertical and lateral variations and their impact on well placement and well spacing, and what types of geomechanical modeling that can be used to accurately drill a save and cost-effective wellbore to meet completion and stimulation requirements that maximize hydrocarbon production. The studies showed that implementing this workflow has a huge business impact on reservoir developments by saving millions of dollars and minimized nonproductive time during planning and field development. This workflow is special in a way that it will be calibrated and updated when acquiring new data at the exploration stage and througout the well life to yield better results.
Cheng, Leiming (Engineering Technology Research Institute of Xinjiang Oilfield Company, PetroChina) | Wang, Yingwei (Research Institute Exploration & Development of Xinjiang Oilfield Company, PetroChina) | Zhao, Haiyan (Engineering Technology Research Institute of Xinjiang Oilfield Company, PetroChina) | Li, Jiacheng (Engineering Technology Research Institute of Xinjiang Oilfield Company, PetroChina) | Liu, Xiao (PetroChina Tarim Oilfield Company, CNPC) | Liu, Qiyao (PetroChina Tarim Oilfield Company, CNPC) | Huang, Xingning (Baker Hughes) | Singjaroen, Thanapol (Baker Hughes) | Kieduppatum, Piyanuch (Baker Hughes)
Abstract The unconventional oil and gas resources continuously discovered in China are mainly concentrated in the Junggar Basin, Ordos Basin, Sichuan Basin and Songliao Basin. However, the porosity and permeability of its shale reservoirs are extremely low, which brings relatively great difficulties and challenges to the economic development of shale oil reservoir. Long horizontal well section drilling and multi-stage hydraulic fracturing are the key technologies of unconventional resources development. The operations can increase the stimulated volume and ultimately achieve the goal of improving production. In addition, shale reservoirs natural fractures and horizontal bedding are developed, leading to shear slip and tensile failure during the fracturing propagation process. Moreover, the hydraulic fracture is no longer a single symmetrical two-wing fracture, and it is very likely to form a relatively very complex fracture network. This will bring many inconveniences to shale hydraulic fracturing design, fracture monitoring and interpretation, and post-fracturing productivity prediction. Geomechanics is the important influencing parameter that affects the design of hydraulic fracturing. This research is mainly based on the research results of 3D geomechanics to continuously optimize hydraulic fracturing design for horizontal wells. In addition, the implementation of hydraulic fracturing can significantly reduce the seepage resistance of fluids in the formation near the bottom of the well. This will be a very effective mean to increase well production for unconventional resources. Hydraulic fracturing optimization technique fully-coupling 3D geomechanical modeling was applied in the unconventional reservoir in the northeast of Junggar Basin. The shale oil reservoir of Permian Lucaogou formation is one of the main unconventional resources in China. This case study discusses the multi-stages fracturing optimization of horizontal well-A based on the fully coupled 3D Geomechanical modeling. The research result clearly characterizes the stress model variation and reduces the uncertainties in horizontal well-A1 for hydraulic fracturing operation. The uncertainty of the fracture modeling geometry was greatly reduced, and fracture geometry was verified by micro-seismic patterns. The geomechanical modeling helps to optimize the pressure pumping rate, the volume of proppant and fracturing fluids, eventually maximizes the increase of fracture flow conductivity and post-stimulation production.
Lutfullin, A. A. (Tatneft PJSC) | Usmanov, I. T. (TatNIPIneft) | Girfanov, I. I. (TatNIPIneft) | Khabibullin, R. A. (TatNIPIneft) | Sotnikov, O. S. (TatNIPIneft)
The paper presents the results of studies of the effects of geomechanical factors on development of reservoirs confined to poorly cemented Tulskian sandstones. The study aims to assess the risks of irreversible reservoir changes in the interwell space due to deformations resulting from stresses beyond the elastic limit when reservoir pressure changes, provide recommendations on optimal bottomhole pressures for injection wells to ensure maximum injectivity, and determine critical drawdowns which result in carryover of solids into the wellbore for production wells. The results are based on 1D and 3D/4D geomechanical modeling. Input data used to build a geomechanical model included laboratory core study data and well logging data. Determination of elastic and strength properties, their dependence on other reservoir parameters and well logging data for each production target is a unique challenge. The paper presents the findings of geomechanical research efforts. The results of hydraulic fracturing processes analysis, downhole equipment maintenance data, reservoir pressure history, and well log interpretations were also used as input data. Laboratory core studies yielded the dependences on the parameters of radioactive logging methods (normalized gamma-ray logging, gamma-ray neutron logging) for estimation of geomechanical properties. Changes of the minimum horizontal stress with reservoir pressure variations were determined, recommended injection well overbalance ranges were obtained, analysis of solids carryover was conducted as well as calculations of critical drawdowns for production wells. Probability of irreversible reservoir changes in the interwell space for poorly cemented rocks was analyzed. Geomechanical modeling was conducted in GMS corporate software package of Tatneft PJSC.
Cai, Wenjun (College of Petroleum Engineering, China University of Petroleum) | Deng, Jingen (College of Petroleum Engineering, China University of Petroleum) | Feng, Yongcun (College of Petroleum Engineering, China University of Petroleum) | Wang, Yangang (College of Petroleum Engineering, China University of Petroleum) | Ma, Chenyun (College of Petroleum Engineering, China University of Petroleum)
ABSTRACT: Bohai A Oilfield is a fractured oil and gas field, and the lost circulation problems in the non-reservoir and the reservoir are severe during the drilling process. The vicious lost circulation problem in the A Oilfield is characterized by the suddenness of the lost circulation event, the uncertainty of the lost circulation layer, the large amount of mud loss, and the long plugging time. This type of lost circulation problem has seriously plagued the drilling speed-up work of the A Oilfield. To clarify the loss mechanism of the non-reservoir and the reservoir, this paper consults and analyzes all relevant data (geology, logging records, drilling fluid characteristics, drill cuttings test results, and so on) of the A Oilfield. Based on the well data and seismic data, a set of analysis methods for the loss mechanism of fractured formations are established by the geomechanical modeling method. This work establishes the spatial distribution of essential parameters such as the three-dimensional elastic modulus, the three-dimensional Poisson’s ratio, and the three-dimensional pore pressure of the A Oilfield. Based on the finite element method, the three-dimensional stress field model of the A Oilfield is calculated by constructing a heterogeneous-pore-elastoplastic model. And then, the lost circulation pressure of the reservoir and non-reservoir of Bohai A Oilfield is also calculated, respectively. The main lost circulation factors in the entire oilfield area are determined by the complex working conditions and the three-dimensional lost circulation pressure calculation results. The results show that the loss mechanism of the non-reservoir is insufficient pressure bearing capacity of the fracture zone. The loss mechanism of buried-hill reservoirs is a prominent, very narrow safe drilling window in the fracture area. 1. INTRODUCTION The Bohai A Oilfield is about 55 kilometers away from Tanggu district in Tianjin, with an average water depth of 14m. According to the drilling data, the strata in this area developed from old to new in sequence: Paleozoic Formation (Pz), Shahejie Formation (E2s), Dongying Formation (E3d), Guantao Formation (N1g), Minghuazhen Formation (N1m). The reservoir of Bohai A Oilfield is the Pz Formation. The interpretation result of the geological horizon is shown in Fig. 1. There are many faults and fractures in this Oilfield. The geological conditions have brought significant challenges to drilling operations.
Xianglong, Meng (China University of Petroleum (Beijing)) | Yongcun, Feng (China University of Petroleum (Beijing)) | Wenjun, Cai (China University of Petroleum (Beijing)) | Shiqi, Wang (China University of Petroleum (Beijing)) | Wei, Yan (China University of Petroleum (Beijing)) | Qingping, Jiang (Research Institute of Exploration and Development, Xinjiang Oilfield Company, PetroChina)
ABSTRACT: Mahu oilfield in Junggar basin is rich in oil and gas resources, because the reservoir has the characteristics of low porosity and permeability, horizontal well and stimulated reservoir volume were applied here. The conventional 1D MEM (mechanical earth model) obtained from single well logging data can not reflect the changes of reservoir geomechanical parameters in long horizontal section, 3D geomechanical modeling is carried out to achieve the fine description of reservoir geomechanical characteristics. During the development of the 3D geomechanical model, a variety of field data and core experimental data were used to ensure its accuracy. The 3D structural model of the reservoir was interpreted from seismic data and a fine description of wave velocity distribution in the 3D model was obtained by a combined interpretation of the acoustic logging data and seismic data. Rock mechanical test data were used to calibrate the predicted geomechanical parameters in the model, ensuring its accuracy. Furthermore, the in-situ stresses determined from diagnostic fracture injection tests and 1D MEM were used to verify the stress calculation results of the 3D geomechanical model. The modeling results show that the direction of the maximum horizontal principal stress in the Mahu oilfield is east to west. The minimum and maximum horizontal principal stresses are in the regions of 42-55 MPa and 63-70 MPa, respectively. There are obvious stress differences between layers, in the range of 10-25 MPa. A comparison of the modeling results against the micro-seismic signals and instantaneous shut-in pressure data recorded during hydraulic fracturing operations further confirmed the reliability of the model. The 3D geomechanical model can provide important guidelines for new drilling and hydraulic fracturing designs in this oilfield. 1. INTRODUCTION Mahu Oilfield is a large conglomerate tight oil reservoir under development. It is difficult to apply conventional reservoir development methods because of the deep burial of the reservoir, the large natural in-situ stress difference, the low porosity and permeability, and the strong heterogeneity which is caused by the poor particle size sorting of the gravel in the rock mass. In order to realize the efficient development of the Baikouquan Formation conglomerate reservoir in Mahu Oilfield, Mahu Oilfield engineers applied horizontal wells and volumetric hydraulic fracturing based on the idea of multi-layer 3D development.