Real-time Microseismic Fracture Monitoring

Microseismic fracturing monitoring is a new technology used in recent years in fracturing stimulation of low permeability reservoirs. In this technology, geophones deployed in offset wells are used to monitor seismic waves during fracturing operation and characterize the geometry and spatial extension of fractures in the fracturing process. It can provide fracture height, length and azimuth in real time. This information can be used to optimize fracturing design, well pattern and other field development measures so as to enhance recovery.
WLE introduced the InSite seismic processing and interpretation system from the UK company ASC and can provide accurate and comprehensive operation, processing and interpretation services for microseismic monitoring.

InSite microseismic processing and interpretation system

Drilling

Drilling is the process of drilling a hole in the ground for the extraction of a natural resource such as ground water, brine, natural gas, or petroleum, for the injection of a fluid from surface to a subsurface reservoir or for subsurface formations evaluation or monitoring.

2.2.1  Directional Drilling/MWD/LWD

WLE Directional Drilling Department provides directional and horizontal well drilling services both for land and offshore rigs in oilfields in China and overseas. The Department boasts of engineers with rich experiences and abundant operational experiences in directional drilling, MWD, LWD and gyroscope tools, which ensures our quality services. We provide specialized solutions for wells with high temperature, high pressure, large TVD, extended-reach and high mud weight. Meanwhile we also look forward to cooperation and provide customized quality services for our clients.

Directional Drilling Services

Mud Motors
We provide high quality mud motors with a wide variety of configurations and suitable for various drilling requirements.
■ New 9 5/8″ high torque low speed motor
■ Large torque and ERT power section
■ Standard motors: 1 3/4″ to 11 1/4″
■ XL motors: 2 7/8″, 4 3/4″ , 5.0″ , 6 3/4″ and 8″
■ ST: 9 5/8″
■ Plus 2 motors: 9 5/8″ and 4 3/4″
■ Low speed : 6 3/4″ , 9 5/8″ and 11 1/4″
■ Low speed plus 2 : 9 5/8″
■ Articulated motors : for high build-up rates

Rotary Equipment

Rotary Equipment
WLE has the capability of providing over 15 strings of rotary tools, including:
Stabilizers          3 1/4″ – 36″ OD
steel & non-magnetic
Collars                2 7/8″ – 9 1/2″
OD steel & non-magnetic
Roller reamers  8 1/2″ – 17 1/2″ OD
Hole openers     12 1/4″ – 24″ OD
Subs                     2 7/8″ – 9 1/2″
OD steel & non-magnetic
Flexi Collars      5″ – 5 1/2″
OD non-magnetic

Directional Drilling Tools

Standard MWD & GR Service

Measurement While Drilling (MWD) mainly measures wellbore trajectory parameters while drilling, including inclination angle, azimuth, tool face angle and auxiliary parameters such as temperature. The downhole processor activates the sensors to collect survey data for transmission to the surface via positive pressure pulses. The pressure pulses are detected by the pressure transducer on the surface. The analog signal from the transducer is decoded in the surface receiver and displayed on the remote terminal. The displayed data can then be used for guiding various drilling operations.
The MWD system is composed of several components including downhole sensors, downhole power source, downhole processor, downhole transmission assembly, surface sensors and surface computer.

Main Applications:
1. Measurement of wellbore geometry data: wellbore geometry data include inclination and azimuth. It also measures other data such as gravity, magnetic declination and magnetic field strength.
2. Measurement of formation properties: this mainly includes formation temperature and gamma ray. Sensors in the tool measure the natural radioactivity in the surrounding formation. The intensity of radioactivity is affected by the presence of radioactive elements such as potassium, thorium and uranium. This information is used to identify sandstones, shales and carbonates.
3. Measurement of tool face: tool face data are continuously transmitted in order to steer the motor along the desired path. If the wellbore angle is less than the inclination threshold (set by the operator at the rig site, commonly 5°), the tool will transmit magnetic tool face data. Below the inclination threshold, magnetic tool faces are used to kick off in the proper direction. Once the inclination angle is above the inclination threshold, the tool will transmit gravity tool face data. Gravity has a greater effect on the survey sensors once inclination angle reaches a certain height. This means a more accurate tool face measurement.

Types and Specifications of Drilling Rigs

3000 HP AC Land Drilling Rig

Specifications:

Max. Hook load	6750kN
Rated power of drawworks	3000HP
Transmission	1+1R, AC motor drive, step-less speed regulation
Main brake	Motor dynamic braking
Auxiliary brake	Hydraulic disc brake (air cooled)
Max. No. of lines for hoisting system	8×9
Diameter of drilling line	1-3/4″（Ф45mm）
Max. O.D of sheave, hoisting system	Ф1829mm（72″）
Power and Qty of mud pumps	3 Sets F-2200HL， 5 sets CAT3512B
Nominal diameter of rotary table opening	Ф1257.3mm（49-1/2″）
Transmission	1+1R (AC motor drive) , step-less speed regulation
Model and Clear Height of mast	“K” Type   52m
Model of substructure	Swing-up type
Height of drill floor	12m
Area of drill floor	13.9m × 15.7m
Height from table beam to ground	10m
Transmission mode of power	AC-DC-AC
Diesel generator set	CAT3512B DITA/SR4B
Qty × Main power of diesel engine	5×1900kVA、600V、50HZ、 0.7、1673A、
Speed	1500 r/min
Generator parameters	SR4B 600V 50Hz
Power factor
Auxiliary generating set	C18
Qty × Power	1 × 400kw
Generator parameters	400V, 50Hz, 3 phrases
AC motor set	4×1100kW (drawworks and rotary table one -to-one) 1×800kW (rotary table one to one), 6×900kW (Mud pumps one to one)
Electric transmission system
VFD unit	8 sets of cabinets (drawworks and rotary table one-to-one, mud pump one-to-one, one cabinet for spare)
Input voltage	600VAC
Output voltage	0～600V  0～120Hz
MCC system	600V/400V/230V  50Hz
Top drive	750 tons (1150HP)

2000 HP AC/DC Land Drilling Rig

Nominal range of drilling capacity

φ127mm（5＂）DP              4000～6000m

φ114mm（4 1/2＂）DP       4500～7000m

Max Hook Load                            4500kN

Rated power input

of the drawworks                         1470kW（2000HP）

Drawworks hoisting

speed                                             6+2R

Brake                                              Main brake

                                                         Hydraulic disk

                                                         type brake（air cooling）                                                                         

                                                         Auxiliary brake

                                                         DSF70 air cooling

                                                         magnetic current brake

Drilling line Diameter                   φ38mm

Hoisting line system                    6*7 parallel line reeving

Max. Fast line pulling

force                                                485kN

Rotary table opening

diameter                                        φ952.5mm（37 1/2＂）

Rotary table torque                      55000N.m

Max. input power

of rotary table                                 600kW

Steps of rotary table                     Two steps 0～240r/min,

                                                         step-less change

Centerfire Resistivity – LWD Service

The Centerfire resistivity tool has two receivers and four transmitters giving two T-R spacings (19″ and 41″) providing two different phase-derived resistivity measurements at two depths of investigation. In addition, measurements are taken at two frequencies to provide a total of four phase-derived resistivity measurements at four depths of investigation. The four depths of investigation together with the high accuracy and high vertical resolution phase difference-based measurements ensure a comprehensive and accurate evaluation of the formation resistivity. In addition to the four phase-derived resistivity, the Centerfire system also provides four attenuation based resistivity (two spacings, two frequencies). The attenuation resistivity provides deeper depth of investigation than the phase resistivity, but are limited to relatively low resistivity formations with reduced accuracy and vertical resolution.
The Centerfire tool is available in three standard sizes: 4.75″, 6.91″ and 8.25″ (120.7mm, 175.5mm, 209.6mm). The Antenna array consists of six antennae – a pair of receivers at the centre of the tool and pairs of transmitters above and below the receivers. The electronics for the receivers are located on either side of the receiver antennae, and electronics for the transmitters are located between both pairs of transmitters. Memory recorder and DSP/ power supply boards are located between the uphole transmitters. All electronic boards are located beneath sealed removable plates. The 8.25″ tool has two internal gamma sensors located at the bottom of the tool. This can replace the standard tensor gamma ray tool which is used with the smaller Centerfire tool.

Gyro – Wireline Services

Gyro advantages:
■ High accuracy north seeking
■ Small size (38mm) pressure barrel or 38mm thermal shield
■ High temperature capability
■ Multi-mode operation (survey, steering, battery, memory, drop, continuous)
■ High reliability field proven system

Specifications:

Inclination	+/- 0.1 deg
Azimuth	+/- 0.25 deg (static and continuous)
Tool size	38mm,46mm,48mm OD x 870mm long include electric board
Max. temperature	-45~175 C with thermal shield
Duration	8 hrs typical (16hr option available)
Memory capacity	3000 surveys

Workover and Sidetracking

Workover and Sidetracking
■ Cement squeeze
■ Casing replacement
■ Casing patch and reinforcement
■ Drilling and completion of CBM wells
■ Workover of H2S wells
■ Coiled-tubing workover
■ Workover of horizontal (sidetracked) wells

Formation testing and sampling services:

• Modular Dynamic Evaluation Tool (MDET)
• Repeat Formation Tester (RFT)

Perforation

•Fracture Perforation System
•Deep Penetration System
•High Shot Density System
•Big Hole System
•Other Perforators
•Pipe Cutters and Tubing Puncher
•Free Point Indicator (FPI)
•Junk Basket

Imaging Logging Services

• Nuclear Magnetic Resonance Logging
• X-Y Cross Dipole Array Acoustic Wave Well Logging Tool (XDAT)
• High Definition Array Induction Logging Tool (HDAI)
• Ultra-Sonic Borehole Imager (USBI)
• Formation Micro-resistivity Imaging Tool (FMIT)
• Hexagonal Dip Finder (HDIF)

Casedhole Logging Services

• Production logging tools
• Reservoir saturation monitoring (carbon-oxygen ratio and pulsed neutron)
• Market-leading technology for perforating both through tubing and casing guns
• Casing and tubing inspection
• Radial cement bond tools
• Bridge plugs, through tubing bridge plugs
• Pipe recovery and other auxiliary services
• Perforation service

Openhole Logging Services

• Conventional and spectral gamma ray.
• Resistivity: Measure true formation resistivity to determine saturations with laterolog or array induction techniques at different depths of investigation.
• Nuclear: Accurately measure the fundamental petrophysical properties of porosity, permeability, and lithology.
• Dipole sonic: Measure compressional and shear wave velocity with sonic logging to derive the necessary petrophysical properties of porosity,permeability, and rock mechanical properties.
• Formation imaging: Visualize the wellbore environment with micro resistivity formation imaging for both water-based and nonconductive mud.
• Formation pressures with pump through evaluation and PVT sampling capabilities: in one trip, measure pressure, temperature, and other properties in real time to conduct downhole fluid analysis.
• Rotary Sidewall Coring: Efficiently recover large-volume and standard sidewall core samples for reservoir characterization analysis.
• Pipe conveyed logging for difficult borehole environments.

Fracturing

Hydraulic fracturing is the fracturing of rock by a pressurized liquid. Some hydraulic fractures form naturally—certain veins or dikes are examples. Induced hydraulic fracturing or hydrofracturing is a technique in which typically water is mixed with sand and chemicals, and the mixture is injected at high pressure into a wellbore to create small fractures (typically less than 1mm), along which fluids such as gas, oil, uranium-bearing solution, and brine water may migrate to the well. Hydraulic pressure is removed from the well, then small grains of proppant (sand or aluminum oxide) hold these fractures open once the rock achieves equilibrium. The technique is very common in wells for shale gas, tight gas, tight oil, and coal seam gas and hard rock wells. This well stimulation is usually conducted once in the life of the well and greatly enhances fluid removal and well productivity, but there has been an increasing trend towards multiple hydraulic fracturing as production declines.

Applications:
The technique of hydraulic fracturing is used to increase the rate at which fluids, such as petroleum, water, or natural gas can be recovered from subsurface natural reservoirs. Reservoirs are typically porous sandstones, limestones or dolomite rocks, but also include “unconventional reservoirs” such as shale rock or coal beds. Hydraulic fracturing enables the production of natural gas and oil from rock formations deep below the earth’s surface (generally 5,000–20,000 feet (1,500–6,100 m)), which is typically greatly below groundwater reservoirs of basins if present. At such depth, there may not be sufficient permeability or reservoir pressure to allow natural gas and oil to flow from the rock into the wellbore at economic rates. Thus, creating conductive fractures in the rock is pivotal to extract gas from shale reservoirs because of the extremely low natural permeability of shale, which is measured in the microdarcy to nanodarcy range. Fractures provide a conductive path connecting a larger volume of the reservoir to the well. So-called “super fracking,” which creates cracks deeper in the rock formation to release more oil and gas, will increase efficiency of hydraulic fracturing. The production for a typical shale gas well generally falls off after the first year or two, although the full producing life of a well can last several decades.

Joint Operation of Perforating, Bridge Plugs & Fracturing

Horizontal well bridge plug staged perforation fracturing technology is mainly used for development and production of shale gas reservoirs. The advantage of this technology is that it can ensure excellent fracturing results for every stage.
We have introduced advanced and proven perforation technologies from overseas and combine decoding program of downhole selection switch with specialized computer system of the surface system. Joint operation of multi-stage perforating, bridge plugs and fracturing in a horizontal well is realized in a single run. It is a mature technology and a record of 23-stage operation in a single shale gas well is achieved with a success rate of 100%.

Coiled Tubing

Coiled tubing unit is a kind of hydraulic drive workover equipment and is used for both offshore and onshore oilfields. It can replace ordinary workover equipment and slickline operation equipment for intervention, completion and slickline services, and is widely used in operations including gas lift, acidizing, sand blasting, well cleaning, fishing, setting through-tubing packers and in highly deviated and horizontal wells.

Coiled tubing operation features high efficiency, and its advantages include:

■ Self-contained equipment with no need for rig support (onshore)
■ Saving operation time and cost with no need for well killing
■ Liquid can be pumped in continuously while tripping coiled tubing
■ Reducing the possibility of formation contamination, particularly used in producing wells (no kill fluid entering the formation)
■ Used as tool conveyance carrier in highly deviated and horizontal wells