Petrovietnam Drilling and Well Services : PVD Well Services outstandingly applied CRTi into casing while drilling technology

PVD Well Services outstandingly applied CRTi into casing while drilling technology

02.06.2023

Over the 15-year journey of providing Oil and Gas well technical services, PVD Well Services - a Subsidiary of PV Drilling Corporation has completely focused on improving service quality and applying new technologies to service provision to bring more benefits to clients. Recently, PVD Well Services has created a new success milestone, which is the use of an advanced Casing Running Tool - internal gripping mechanisms (CRTi) into Casing While Drilling technology, bringing significant value-added to the clients.

Since 2013, PVD Well Services Co., Ltd. (PVD Well Services) has seriously researched for new technology that provides multiple capabilities to set the casing strings reaching desired TDs under greatly challenging hole conditions. CRTi was found as our top preferred tool to serve clients' expectations. It has been then continuously using for well construction operations in Vietnam as the most suitable solutions for difficult wells. CRTi helps enhance safely, optimizes operations and finally achieves cost efficiency. The CRTi tool, after a decade of launching in the market, has firmly provided its great advantages, in comparison to the traditional equipment and the tool is now considered as "mandatory" equipment in all Casing & Tubing Running Services (CTRS) contracts.
During well construction, in order to increase production capacity for an Oil & Gas field, clients often re-use the wellhead structure of a previously-plugged and abandoned well to drill an adjacent one. Therefore, a 20'' conductor string needs to be installed before drilling and running the next casing sizes. This conductor string needs to pass through guide funnels at various platform levels, create an inclined trajectory relative to the vertical and go down to the expected hole opening point next to the plugged and abandoned well. In the end, the construction and installation of this 20'' conductor string must not affect the adjacent wells.

Figure 1: Guide funnels with different centers, create an inclined trajectory relative to the vertical.

With conventional drilling method, the difficulty is that when the drill bit is run down to open the pilot hole, with small size of drill pipe (usually 5-1/2" OD) and a large deflection of the pipe, especially in harsh weather conditions/ high waves and the effect of subsea currents, the drill string and bit are often pushed away from the guide funnels and the drill bit cannot approach the desired well opening position on seabed.

Other method is to use Hydraulic Hammer, however, it is difficult to launch a massive and heavy equipment on a Jack up. Hydraulic Hammer becomes an expensive solution. The hammer operations create great vibration and thus it is risky of damaging adjacent live wells.

Noticing from the limitations of conventional drilling methods, PVD Well Services engineering team had started studying the situation and finding feasible solutions. The team focused on studying CwD projects with an inclination from the beginning. CwD in an angle at the spudding point is extremely complicated in process of making up connection, running the string into the well and rotating the string to minimize negative impact of the casing string onto platform guides and bore hole. Moreover, maintaining drilling regime and well stability to ensure that it does not affect adjacent wells during drilling is very important. It is a lot more concerning than CwD in vertical direction that PVD Well Services has done for other clients.

After a series of consideration with risk assessment set in place, PVD Well Services and clients have come in full agreement and called for 20" CwD operations with the following key elements:
- Platform guides would be modified onshore to achieve an angle of 1.21 degree from surface to seabed.
- CRTi would be the critical player for rotating, circulating and handling the 20" casing string.
- 24" XCD casing bit, specific design centralizers and float collar.
- 20" torque ring would be pre-installed on 20" API connection to increase connection rotational torque.
- And an experienced, fully-supportive operations, engineering team leading execution of the CwD operations.

Figure 2: PVDWS CRTi prepared for Casing While Drilling operation

It was highlighted that at the time of 20" CwD commencement, it was unfortunately crossing monsoon season, strong wind in combination with high sea swell pushed the 20" string in different directions increasing challenges for PVD Well Services' engineering team. However, with enthusiasm and strong experience, PVD Well Services overcame difficulties and completed the work within the time frame. After 2 days of the CwD operations, a new slot was established from desired well opening position, the 20" casing string was cemented, and accordingly, the goal of "Recovery of Wellhead Structure" was successfully implemented.

Figure 3: 24'' casing bit installed on conductor string.	Figure 4: CRTi installed directly into Top Driver	Figure 5. Real pictures for Casing While Drilling using PVDWS CRTi

Figure 6 : PVDWS CRTi Technical Team on the rig for Casing While Drilling operations	Figure 7: Casing Bit approached hole opening position

Figure 7: Casing Bit approached hole opening position

The boldness based on professional technical foundation, extensive experience of engineers and taking advantage of the availability of equipment, together with the efforts of PVD Well Services' employees, has successfully applied CRTi in CwD technology, received high appreciation from clients and contributed to reducing costs, bringing success to clients' drilling campaigns.

Since then, PVD Well Services has become more stable, confident and ready to undertake casing while drilling services, meeting the needs of clients in the field of oil and gas drilling and exploration, continuing to affirm its number one position in the market of providing well technical services in Vietnam and proceeding to offer the services to foreign drilling markets and simultaneously contributing to complete the service supply chain of PV Drilling Corporation in the direction of high technology, increasing the competitive strength of the Corporation in the regional and worldwide oil and gas drilling markets.