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Results
Study on Fracture Propagation Simulation with the Integration of Fully-Coupled Geomechanical and DFN Modeling
Li, Wei (Chongqing Shale Gas Exploration and Development Company Limited) | Xing, Yangyi (Gepetto Petroleum Technology Group Co., Ltd) | Zhang, Haijie (Chongqing Shale Gas Exploration and Development Company Limited) | Luo, Tongtong (CCDC Geological Exploration & Development Research Institute) | Li, Wenhong (Gepetto Petroleum Technology Group Co., Ltd) | He, Jinpeng (The Fourth Oil Production Plant of Qinghai Oilfield Company, PetroChina) | Huang, Xingning (Baker Hughes) | Singjaroen, Thanapol (Baker Hughes) | Kieduppatum, Piyanuch (Baker Hughes)
Abstract Shale gas reservoirs are characterized in low gas abundance, poor permeability, lower natural productivity than the lower limit of industrial oil flow, and rapid formation energy decline. At present, the technology of horizontal well drilling and staged hydraulic fracturing is widely used for the exploitation of such low-porosity and low-permeability reservoirs. The long well section of the horizontal well in the reservoir and the hydraulic fractures formed by fracturing act as the "underground expressway" for the deep gas in the reservoir to flow toward the wellbore. Their combination can greatly increase the production performance of the oil and gas resources in the reservoir. Staged multi-cluster fracturing in horizontal wells is the key technology to achieve the profitable shale gas production. The results of on-site downhole perforation imaging and distributed optical fiber temperature and acoustic monitoring show that there are obvious non-uniform liquid inflow and expansion phenomena in each cluster of fractures during the fracturing process. Relevant research results also show that factors such as the heterogeneity of the reservoir and the stress interference caused by the propagation of multiple fractures are the main causes of the non-uniform propagation of hydraulic fractures. Therefore, it is accessible to simulate the complex balanced expansion of each cluster of fractures in the fracturing section to improve the coverage of hydraulic fractures in the horizontal well section with numerical simulation methods based on the basic theory of elasticity and fracture mechanics, to reveal how the above engineering geological factors influence and control the fracture propagation. The results of the simulation of the fracturing treatment section of the deep shale gas horizontal well by the fracture propagation model are consistent with the micro-seismic monitoring results,which has obvious significance for accelerating the exploitation of difficult-to-exploit resources and guaranteeing the supply of gas resources.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.67)
- Asia > China > Xinjiang Uyghur Autonomous Region > Junggar Basin > Lucaogou Formation (0.99)
- Asia > China > Sichuan > Sichuan Basin (0.99)
- Asia > China > Qinghai > Qaidam Basin > Qinghai Field (0.99)
High-Resolution Remote Mapping of Thin Sand Lobes with Novel Multilayer Mapping-While-Drilling Tool: A Case Study from Nong Yao Field Offshore Thailand
Thurawat, Chaiyos (Mubadala Petroleum) | Teeratananon, Wirot (Mubadala Petroleum) | Ampaiwan, Tianpan (Mubadala Petroleum) | Carter, Raweewan (Mubadala Petroleum) | Phaophongklai, Wattanaporn (Mubadala Petroleum) | Vimolsubsin, Pojana (Mubadala Petroleum) | Watcharanantakul, Rattana (Mubadala Petroleum) | Wang, Haifeng (Schlumberger) | Foongthongcharoen, Trinant (Schlumberger) | Alang, Khairul Anuar (Schlumberger)
Abstract The recent development drilling campaign at Mubadala Petroleum's offshore Nong Yao field faced many challenges, one of which is the complexity of the reservoir which consists of mixed sand-shale sequencies with thin sand lobes of varying thicknesses. To tackle these challenges and to maximize recovery, Mubadala Petroleum planned four horizontal wells for this campaign. However, the conventional methods of geosteering have limitations. For instance, the distance-to-boundary mapping tool typically does not provide large enough depth-of-investigation for the operator to see through the interbedded shale layer to identify the multiple target sand lobes, which could pose limits on the production optimization and ultimately on the final recovery rate. Fortunately, a new technology emerged at the start of the campaign with a potential for a much larger depth of investigation and a better mapping resolution. This multilayer mapping-while-drilling tool was an extension of the previous tool with additional sensors that could read deeper into the formation. Coupled with a new advanced automatic inversion process which utilizes powerful Cloud computing, the subsurface formation resistivity profiles around the wellbore could be mapped clearly up to 25 ft away from the tool, while providing a multilayer mapping with up to 8-layer mapping capability. This new technology was evaluated and applied in two wells in this campaign to resolve the above-mentioned challenges. The result was a resounding success for the Mubadala led drilling team. In this paper, the authors explain the technology, the process of evaluating and applying it to operation, and the results from applying it. This was the first time that this technology was used in Thailand and this case study summarizes a successful outcome. The mapping results from the tool will also be used to update the reservoir model during the post-job phase and provide improvements of the overall reservoir characterization of the field.
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Seismic Processing (0.46)
- Asia > Thailand > Gulf of Thailand > Pattani Basin > G11/48 License > Nong Yao Field (0.99)
- Asia > Thailand > Gulf of Thailand > Malay Basin > G11/48 License > Nong Yao Field (0.99)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- (4 more...)
Geosteering in a Complex Deepwater Reservoir in the Niger Delta
Ndokwu, C.. (Baker Hughes a GE company.) | Foekema, N.. (Baker Hughes a GE company.) | Okowi, V.. (Baker Hughes a GE company.) | Olagundoye, O.. (Total Upstream Companies Nigeria.) | Umoren, N.. (Total Upstream Companies Nigeria.) | Delpeint, A.. (Total Upstream Companies Nigeria.) | Ndefo, O.. (Total Upstream Companies Nigeria.) | Agbejule, A.. (Total Upstream Companies Nigeria.) | Jeje, O.. (Petrobras Nigeria.)
Abstract Geological and geophysical uncertainties account for most of the challenges encountered during the placement or geosteering of high-angle and horizontal wells in deepwater environments. Structural uncertainties could result from the targeted subsurface structure that is folded, undulating and faulted. Lateral discontinuity of sand bodies, lateral variations in sand thickness, multiple beds, and formation heterogeneities are some of the more common sedimentological uncertainties. Geophysical uncertainties include the vertical depth of the seismic data and seismic reservoir characterization. These uncertainties make increasing the likelihood of success during geosteering not only dependent on the integration of geologic and seismic reservoir characterization techniques, but also on the application of a robust reservoir navigation scheme. In this paper, we present a case study of the geosteering of a horizontal producer well in a complex reservoir in the deep offshore Niger Delta. The reservoir consists of highly faulted channelized turbidites. The lateral discontinuity of sand bodies and the variations in sand thickness have been calibrated by other producer wells in the field. For efficient geosteering, geological and geophysical well planning was complemented by the availability of scenario modeling, a suitable drilling strategy, the availability of fit-for-purpose drilling and formation evaluation tools, robust software, and a multidisciplinary team with the right mix of experience for effective reservoir navigation. An extra-deep reading azimuthal propagation tool was used, and the inversion was performed with Multi-Component While Drilling (MCWD) software that utilized an algorithm to perform real-time processing of any combination of the deep and extra-deep logging-while-drilling (LWD) resistivity measurements, both coaxial and azimuthal [Sviridov et al., 2014]. The case study primarily reviews the geological and geophysical strategies employed during the geosteering, examines the role the extra-deep azimuthal resistivity inversion modeling and borehole imaging played in understanding the nature of the reservoir and checking the effect of formation anisotropy on depth of detection. The study highlights some peculiarities of the depositional environment of the area and shows the benefits of having extra-deep azimuthal propagation resistivity tools in the bottom hole assembly.
- Geology > Structural Geology > Fault (0.95)
- Geology > Geological Subdiscipline > Stratigraphy (0.95)
- Geology > Sedimentary Geology > Depositional Environment (0.70)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.50)
Abstract Channel sand reservoirs very rarely have layer cake geometries and are generally characterized by sand bodies/lenses with limited horizontal and vertical continuity. Significant lateral changes occur in reservoir thickness as well as reservoir properties and lenses are often stacked at different stratigraphic levels. The reservoir sands in the greater Burgan field show similar variations both structurally and stratigraphically. Navigating a wellbore in such complex channel sand reservoir requires precision geo-steering technology with two major requirements: Detecting reservoir boundaries with dip information for structural steering. Mapping multiple layers above and below the target layer for stratigraphic positioning. Detecting reservoir boundaries with information on layer dip and anisotropy can immensely help to forward plan trajectory as per formation changes and this require a good knowledge and study about the seismic data and offset wells information. 3D seismic data immensely help in placement of all kinds of wells, especially designing and fine-tuning a meticulous trajectory for Deviated and horizontal wells. Attributes made with seismic cube data, namely Structure and coherency volume, can image major to minor faults, which are generally viewed on slices of major formation tops. There are various other attributes like Impedance, Vp/Vs, Porosity and sand probability map, which can indicate possibility of sweeter part of reservoir. Depth of various major formation tops are predicted quite accurately within the limit of seismic resolution from Velocity model or Depth-Migrated seismic volume. These depth predictions immensely help in designing trajectory and landing the well in the actual desired zone of reservoir at the desired angle. During Geo-steering also, in spite of all the tools of drilling contractor at their disposal, the seismic data help to guide the drillers to steer in the right direction, if drilling team is out of track from the good part of reservoir. Overlaying such a well in the seismic section directly gives the predicted depth throughout the well trajectory, which helps to design the Deviation survey parameters. The paper will explain a special attribute called Ant-trak, which not only shows the major faults, but also very minor faults and sometimes, fine geological features, which cannot be seen in seismic section or slices. This attribute is taken on Burgan-Third sand top surface. All the major NW-SE faults can be seen. Over and above, some minor faults are also seen in it. PSTM seismic data and the other structural attribute which able to show together, faults very clearly. Such a blended surface gives an enhanced display of faults in the area of study including very minor ones, which help to design the survey. By using different Seismic Volume and Surface Attribute analysis, we mark the major faults trend and extracted many structural features in the study area. We try to deal with different attribute parameters and use offset wells data logs near to each planed horizontal well in the area which help us to have more control during geo-steering horizontal wells.
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (1.00)
- Geology > Geological Subdiscipline (1.00)
- Asia > Middle East > Kuwait > Ahmadi Governorate > Arabian Basin > Widyan Basin > Greater Burgan Field > Wara Formation (0.99)
- Asia > Middle East > Kuwait > Ahmadi Governorate > Arabian Basin > Widyan Basin > Greater Burgan Field > Ratawi Formation (0.99)
- Asia > Middle East > Kuwait > Ahmadi Governorate > Arabian Basin > Widyan Basin > Greater Burgan Field > Mauddud Formation (0.99)
- (13 more...)
- Well Drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
Hybrid Fracturing Treatments Unleash Tight Oil Reservoirs Consisting of Sand Shale Sequences in the Changqing Oilfield
Zongqiang, Zhou (PetroChina Changqing Oilfield Company) | Lijun, Mu (PetroChina Changqing Oilfield Company) | Xianwen, Li (PetroChina Changqing Oilfield Company) | Wen, Zhao (PetroChina Changqing Oilfield Company) | Xiaodong, Wang (PetroChina Changqing Oilfield Company) | Xiangqian, Bu (PetroChina Changqing Oilfield Company) | Wenxiong, Wang (PetroChina Changqing Oilfield Company) | Peng, Pang (PetroChina Changqing Oilfield Company)
Abstract Low reservoir permeability and pressure are the key characteristics for the tight oil reservoirs consisting of sand and shale formations in the Changqing Oilfield in the Ordos Basin. In these tight reservoirs, regular fracturing stimulation with modest treatment sizes only yields low post-treatment production that cannot meet development requirements. Recent literature is bountiful in the successful developments of tight oil and gas reservoirs, especially from North America. After conducting literature review and learning from the experience in North America, hybrid fracturing tests were carried out in vertical wells, to improve well stimulation effectiveness in the Changqing Oilfield. Hybrid fracturing treatments for these tested wells yielded very good results with production enhancement at approximately 300% folds of regular fracturing treatments in the same reservoir block. Downhole microseismic fracturing monitoring and production analysis techniques were used to evaluate hybrid fracturing performance. In this paper, the ultra-tight oil reservoirs in the Changqing Oilfield were described, and hybrid fracturing treatments applied to the Chang 7 formation were studied with the aid of minifrac analysis, microseismic monitoring and post-treatment production results.
- Asia > China > Shanxi Province (1.00)
- Asia > China > Shaanxi Province (1.00)
- Asia > China > Ningxia Hui Autonomous Region (1.00)
- (2 more...)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline (1.00)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
Abstract Frontier drilling in deepwater environments is challenging with a wide range of risks that oil operators need to evaluate carefully because of high-investment costs. The formation targets selected are typically depth transformed using a velocity function obtained from conventional 3D surface seismic data. The data are usually low resolution and may not have been processed with the best prestack depth migration (PSDM) techniques. This pitfall often leads to uncertainties in reaching drilling targets and completing the well on time. Common uncertainties faced by drillers are target confirmation ahead of an intermediate depth section and the distance to these targets. One approach to reduce this uncertainty is to use borehole seismic techniques to record a vertical seismic profile (VSP) at intermediate total depth (TD) to look ahead and estimate the target depths below the bit. Oil and Natural Gas Corporation Limited (ONGC), India’s largest oil operator, has been using this simple, effective technique in drilling deepwater wells. In one case the look-ahead prediction resulted in stopping of drilling operations because ONGC needed to ascertain if there was reservoir rock below the volcanics. The unambiguous VSP result did not show any possible reservoir below 3987 m measured depth (MD), which saved 3.5 weeks of drilling to reach the predrilling planned TD of 4415 m MD. In another example, ONGC needed to complete a vertical well that extended to basaltic basement with TD planned at 4324 m at a subsea water depth of 2135 m. Three look-ahead VSP runs were performed at various sections for guidance throughout the drilling process, setting the casing, and reaching the deeper final target. Final TD was 6205 m MD as opposed to the planned TD of 4324 m MD. While VSP techniques have been widely used by the exploration communities particularly the geologists and geophysicists, they are also a look-ahead tool applicable for drilling operations planning and ahead-of-bit drilling risk mitigation.
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Asia Government > India Government (0.96)
- Well Drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Near-well and vertical seismic profiles (1.00)
Abstract Since the beginning of Tunu field development in the late 80’s, shallow gas hazard has always been considered the major operational risk during the surface drilling operation. During the last ten years, 5 shallow gas events were reported; all have been safely controlled (no injured personnel) and the main consequences were material loss and non productive time. With the objective to reduce shallow gas reservoir crossing, a high resolution seismic survey was performed in 2005. The survey results have been used to early identify potential shallow gas hazards at planning stage by 1) checking the field history of the selected future platform area and 2) systematically reviewing the seismic data on a well by well basis. Despite of the above described mitigation measures it appears that during 2007/2008, amongst 88 wells drilled, 43 shallow gas reservoirs (thickness above 6m) have been crossed on Tunu field. This phenomenon is directly linked to the geological fluvial deposit specificities of the Mahakam delta. The shallow gas horizons (500-1200m TVD) became recently a source of interest for the geoscientists who mapped the gas in place yielding substantial reserves. After the potential has been confirmed, the drilling engineering studies started in order to design a well being able to produce shallow reservoirs. It is worth to remind that shallow gas drilling engineering is not a routine job…What kind of well architecture? Do we set a surface casing? Where do we set it? How will we manage the extremely low LOT at casing shoe? Which mud type has to be used? What will be the required mud density? How do we manage potential unconsolidated sand production....? So many questions looking for accurate technical answers in order to convert a hazard into a well. In 2010, a specific development plan has been proposed and approved for constructing 17 shallow gas wells, showing highly encouraging production results to date.
- Asia > Indonesia > East Kalimantan > Makassar Strait > Kutei Basin > Mahakam Block > Tunu Field (0.99)
- Asia > Indonesia > East Kalimantan > Kutei Basin > Mahakam Block > Handil Field (0.99)
- Asia > Indonesia > East Kalimantan > Makassar Strait > Kutei Basin > Rokan Block > Mahakam Block > Bekapai Field (0.98)
- Asia > Indonesia > East Kalimantan > Makassar Strait > Kutei Basin > Mahakam Block > Nubi Field (0.98)
Abstract To meet increasing gas demands while drawing from the shrinking reserves of a mature field, CTEP (Chevron Thailand E&P) is drilling as many wells as economically feasible. Wells have to be drilled and completed very quickly to minimize rig time and reduce the "per well" drilling cost. In 2005, the average time to drill and complete a slimhole well was 6 days; the target for 2006 is 4.5 days. During 2005, CTEP drilled and completed over 300 wells while 450 wells are planned for 2006. In addition to exceptional drilling performance in the Gulf of Thailand, value creation is enhanced by performing a high number of IFDP (in-fill drilling projects) whenever possible. This reduces cost by minimizing new platform construction, reusing slots, and reducing installation of new surface casing. The IFDP project can be categorized into two phases:slot recovery; and drilling. This paper focuses on phase 1 of the project, where CTEP uses HWO (hydraulic workover) systems along with cementing, slickline, and wireline services to perform the slot-recovery operations before rig arrival. Topics of discussion include current operational equipment, methods and procedures, logistical challenges, lessons learned, and new development plans intended to further enhance the operation. Statistically, it is estimated that for each single platform 6-well abandonment campaign, CTEP gain 7 to 8 days of drilling time by not utilizing rig time for the Phase I operation. The drilling rig focus is, therefore, maintained on, doing what it does best, drilling new wells safely and economically. Additional wells are drilled with the time saved supplying early gas to meet Thailand's expanding industrial demands. Introduction Before the acquisition of Unocal Corporation by Chevron, Unocal Thailand (UTL) had over three decades of successful energy-development history in the country. With gross natural gas production averaging more than 1.2 Bcf/D from over 100 platforms in the central Gulf of Thailand (GOT), Unocal supplied natural gas to generate over 30 % of the nation's total power demand. Unocal has continued to increase natural gas and condensate production in Thailand since 1981 to meet current and future demands while effectively replenishing reserves. This has been achieved by using advanced drilling and three-dimensional seismic technologies in conjunction with a substantial reinvestment of capital. The small, stacked reservoirs over large areal extent means that well life averages only 2 years and continual drilling and redrilling are required to maximize recovery from shrinking reserves in a mature field. This paper focuses on redrilling or IFDP, where depleted wells are abandoned and slots are reused to drill new wells. This has proved to be a very cost-effective way of gaining more wells without having to build new offshore wellhead platforms and support facilities for these new wells. In the past, the process of making slots of depleted wells available for new wells was done completely by drilling rigs with the exception of cement squeezing off the perforations, where only cement pumping equipment is used. This takes a significant amount of rig time to cut and pull tubings, casings and conductors, set kickoff cement plugs, run splitter conductors, etc. This "non-drilling" period could be better used to drill more wells. This paper discusses details of UTL's process of "well preparation for redrill" and the benefits in terms of rig-day-equivalent (RDE). Background Before 1995, most of the wells in the GOT were completed conventionally with 26-in. driven conductors, 13–3/8-in. to ±1,000 ft, 9–5/8-in. casing to ±4,500 ft total vertical depth (TVD), and 7-in. casing extended to an average depth of 12,000 ft total depth (TD). The 2–7/8-in. tubings are held in place by permanent packers, equipped with sliding side doors (SSD's) for zonal isolation. As the reserves in the ground diminish, the return on investment for new wells also diminishes. New wells have to be drilled in a more cost-saving manner resulting in the emergence of economically attractive slimhole wells. These wells are completed with 9–5/8-in. surface casing to ±1,000 ft, and 7-in. casing to ±4,500 ft TVD. The 2–7/8-in. tubing is then run inside the 6.5-in. open hole (OH) and cemented in place. After these wells are completed, the productions are commingled. Figs. 1 and 2, respectively, show diagrams of typical conventional and slimhole wells.
- Geophysics > Seismic Surveying (0.88)
- Geophysics > Borehole Geophysics (0.54)
- Well Drilling > Drilling Operations > Drilling time analysis (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (0.88)
- Well Drilling > Drilling Operations > Drilling operation management (0.69)